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Robotic Spacecraft (Astronomy, Planetary, Earth, Solar/Heliophysics) => Space Science Coverage => Topic started by: Chris Bergin on 03/09/2006 06:37 PM

Title: NASA - Cassini updates
Post by: Chris Bergin on 03/09/2006 06:37 PM
RELEASE: 06-088

NASA'S CASSINI DISCOVERS POTENTIAL LIQUID WATER ON ENCELADUS

NASA's Cassini spacecraft may have found evidence of liquid water
reservoirs that erupt in Yellowstone-like geysers on Saturn's moon
Enceladus. The rare occurrence of liquid water so near the surface
raises many new questions about the mysterious moon.

"We realize that this is a radical conclusion - that we may have
evidence for liquid water within a body so small and so cold," said
Carolyn Porco, Cassini imaging team leader at the Space Science
Institute, Boulder, Colo. "However, if we are right, we have
significantly broadened the diversity of solar system environments
where we might possibly have conditions suitable for living
organisms."

High-resolution Cassini images show icy jets and towering plumes
ejecting large quantities of particles at high speed. Scientists
examined several models to explain the process. They ruled out the
idea the particles are produced or blown off the moon's surface by
vapor created when warm water ice converts to a gas. Instead,
scientists have found evidence for a much more exciting possibility.
The jets might be erupting from near-surface pockets of liquid water
above 0 degrees Celsius (32 degrees Fahrenheit), like cold versions
of the Old Faithful geyser in Yellowstone.

"We previously knew of at most three places where active volcanism
exists: Jupiter's moon Io, Earth, and possibly Neptune's moon Triton.
Cassini changed all that, making Enceladus the latest member of this
very exclusive club, and one of the most exciting places in the solar
system," said John Spencer, Cassini scientist, Southwest Research
Institute, Boulder.

"Other moons in the solar system have liquid-water oceans covered by
kilometers of icy crust," said Andrew Ingersoll, imaging team member
and atmospheric scientist at the California Institute of Technology,
Pasadena, Calif. "What's different here is that pockets of liquid
water may be no more than tens of meters below the surface."

"As Cassini approached Saturn, we discovered the Saturnian system is
filled with oxygen atoms. At the time we had no idea where the oxygen
was coming from," said Candy Hansen, Cassini scientist at NASA's Jet
Propulsion Laboratory (JPL) in Pasadena. "Now we know Enceladus is
spewing out water molecules, which break down into oxygen and
hydrogen."

Scientists still have many questions. Why is Enceladus so active? Are
other sites on Enceladus active? Might this activity have been
continuous enough over the moon's history for life to have had a
chance to take hold in the moon's interior?

In the spring of 2008, scientists will get another chance to look at
Enceladus when Cassini flies within 350 kilometers (approximately 220
miles), but much work remains after the spacecraft's four-year prime
mission is over.

"There's no question, along with the moon Titan, Enceladus should be a
very high priority for us. Saturn has given us two exciting worlds to
explore," said Jonathan Lunine, Cassini interdisciplinary scientist,
University of Arizona, Tucson, Ariz.

Mission scientists report these and other Enceladus findings in this
week's issue of Science. The Cassini-Huygens mission is a cooperative
project of NASA, the European Space Agency and the Italian Space
Agency.

JPL, a division of the California Institute of Technology, manages the
Cassini-Huygens mission for NASA's Science Mission Directorate. The
Cassini orbiter was designed, developed and assembled at JPL.

For Cassini images and information about the research on the Web,
visit:

http://www.nasa.gov/cassini
Title: Re: NASA - Cassini updates
Post by: jacqmans on 08/05/2006 09:45 AM
Cassini Significant Events
for 07/27/06 - 08/02/06

Thursday, July 27 (DOY 208):

It was reported in the Cassini Significant Events last week that the
atmospheric density measured at Titan 16 was higher than expected. The
Titan Atmospheric Modeling Working Group (TAMWG) met this morning to
discuss this result and assess whether the altitudes selected for
upcoming encounters are still acceptable. At the conclusion of the
meeting, the TAMWG recommended no changes to the altitudes of upcoming
encounters. The new T16 data point has not fundamentally changed our
understanding of Titan's atmospheric profile, except to indicate a less
steep falloff in density at high latitudes. Cassini only has one future
Titan flyby at very high latitude, Titan 32. Much like T16, this
encounter is at 84 deg N latitude with a closest approach at 950 km, so
it should be safe as well.

One of the things that presents a challenge to Cassini scientists and
sequence developers is attempting to respond to new scientific
discoveries as they arise. Background sequence S24 completed Science
Operations Plan Implementation in March 2004. At that time the basic
sequence was delivered to the project file repository. Science Planning
was chartered to archive a sequence that if necessary would fly on the
spacecraft "as is." Now roll the clocks forward to July 27, 2006. S24
has been through both the Aftermarket Process and the Science Operations
Plan Update Process. It is currently in final development prior to
uplink. The first of four phases of that development process is
complete. But, due to the discovery of lakes near Titan's north pole
over the weekend, RADAR has requested re-pointing of their T19
observation to cover more of the same region. What to do?

It was decided to stick with the process and have RADAR submit their
pointing changes in the third phase. Although this decreases the number
of iterations available to get the pointing right, it allows the other
instruments and AACS time to properly assess any impacts they might
have. To support the development of this observation, an interim set of
sequence products was produced with the new RADAR pointing, to give the
Attitude and Articulation Control Subsystem (AACS) time to evaluate it
and make a c-kernel available to teams that might wish to examine it. At
this time S24 is on track for final approval in September, and it is
hoped to have lakes in its future.

Friday, July 28 (DOY 209):

Science data archive deliveries for data acquired during the period of
July through September 2005 are now complete. The next archive delivery
port is October 1.

The official port occurred today for S25 as part of the Science
Operations Plan (SOP) Update process. The merged products are currently
being run through end-to-end pointing validation by AACS. The Project
Briefing and Waiver Disposition Meeting is scheduled for August 9. The
SOP Update product is handed off to the sequence leads on August 11 for
the final development process.

Monday, July 31 (DOY 212):

The Cassini RADAR image of Titan's methane lakes is Astronomy Picture of
the Day today.

Tuesday, August 1 (DOY 213):

Orbit Trim Maneuver (OTM) #69, an apoapsis maneuver setting up for the
Titan 17 encounter on September 7, was performed today. This main engine
burn began at 2:30 PM PDT. Telemetry immediately after the maneuver
showed a burn duration of 33.8 seconds, giving a delta-V of 5.4 m/sec.
All subsystems reported nominal performance after the maneuver. A
contingency DSS-15 track that had been retained for the DOY 214 backup
OTM-69 window in case the DSS-14 antenna went red was released at the
successful completion of the burn. Cassini thanks MGS, MER and Odyssey
for their help in making this track available. The next OTM is scheduled
for September 4.

Solar Conjunction occurs when the Sun is between the spacecraft and
Earth. This year it will last from August 2 through August 12, and is a
time of reduced commanding and downlink capability. Cassini enters Solar
Conjunction tomorrow with a separation angle of 4 degrees. During
conjunction, communications with the spacecraft become degraded due to
interference from the sun. For the next ten days the Spacecraft
Operations and Mission Support and Services offices will participate in
a campaign where a command file consisting of 10 no-op commands will be
uplinked to the spacecraft ten times daily. This will allow the teams to
obtain link characterizations and accumulate statistics for uplink
reliability at decreased separation angles. With the exception of these
no-op command files, Spacecraft Operations has asked for and received a
command moratorium. Additional commands will only be sent in the event
of an emergency. On Saturday, the spacecraft will be turned so that the
High Gain Antenna is continuously pointed to Earth, and 1896 bps
telemetry continues while separation is less than 2 deg. Normal playback
downlink rates will resume on August 10.

There is a great write up on conjunction on the Cassini web site. For
more information link to: http://saturn.jpl.nasa.gov/home/index.cfm

Cassini's "For Educators" website has a hands-on activity called
"Monitoring the Sun's Corona." Scroll down the Saturn in your Kitchen
and backyard section to "Saturn System Science" to find it.
http://saturn.jpl.nasa.gov/education/edu-58-kitchen.cfm. In this
activity, students of all ages will learn how, during solar conjunction,
scientists use the relative positions of the Sun, Earth, and a
spacecraft to study the Sun's corona, or outer region.

Wednesday, August 2 (DOY 214):

An artist's rendition of the methane rain on Titan is Astronomy Picture
of the Day today

The data obtained by the six Huygens experiments is now archived in the
European Space Agency (ESA) Planetary Science Archive (PSA). A copy of
the archived data set is also available in the NASA Planetary Data
System (PDS). The data is now accessible by the scientific community and
the general public for downloads. This represents a major milestone in
the Huygens mission. Data from the Aerosol Collector and Pyrolyser
(ACP), Doppler Wind Experiment (DWE), Gas Chromatograph Mass
Spectrometer (GCMS), and Huygens Atmospheric Structure Instrument (HASI)
is accessible along with housekeeping data, calibration information, and
documentation necessary to understand and process the products, and to
carry out scientific analyses. Data from the Descent Imager Spectral
Radiometer (DISR), Surface Science Package (SSP), and the final Huygens
entry and descent trajectory data is to be released in the
September-October timeframe. To access the data, link to:
http://atmos.nmsu.edu/data_and_services/atmospheres_data/Huygens/Huygens.html

A Cassini Saturn Orbit Insertion +2 Years celebration was held in Von
Karman auditorium today for the Cassini Flight team. Talks were given by
the laboratory director Charles Elachi, and by two surprise celebrities,
Robert Picardo and Bill Nye. An additional presentation was given by
Outreach who read to the flight team some of the comments that the
public has sent to the Cassini web site letting us know how much they
appreciate what Cassini is doing, and looking forward to the next two
years of prime mission and extended mission after that. The flight team
says "THANKS" back to the public. We are looking forward to it too!

Your coffee table will never be the same. Outreach has promised the
flight team that they will let us know as books on Cassini/Saturn are
published. The first one is a beauty called Saturn: A New View in
hardcover. The pictures are phenomenal. The book has not yet been
released but may be ordered and will ship as it arrives at distributors.
See your local bookstore - either electronic or traditional.

The July 20 "Cassini Real-time Operations" presentation from the Von
Karman Lecture Series is online at the JPL public website as a
RealPlayer downloadable: http://www.jpl.nasa.gov/events

Wrap up:

The most recent spacecraft telemetry was acquired on Wednesday, August
2, from the Goldstone tracking complex. The Cassini spacecraft is in an
excellent state of health and all subsystems are operating normally.

Check out the Cassini web site at http://saturn.jpl.nasa.gov for the
latest press releases and images.
 

The Cassini-Huygens mission is a cooperative project of NASA, the European
Space Agency and the Italian Spsce Agency. The Jet Propulsion Laboratory, a
division of the California Institute of Technology in Pasadena, manages the
Cassini-Huygens mission for NASA's Science Mission Directorate, Washington,
D.C.  JPL designed, developed and assembled the Cassini orbiter.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 08/11/2006 09:04 PM
Cassini Significant Events
for 08/03/06 - 08/09/06

The most recent spacecraft telemetry was acquired Wednesday, August 9, from
the Goldstone tracking stations. The Cassini spacecraft is in an excellent
state of health and is operating normally. Information on the present
position and speed of the Cassini spacecraft may be found on the "Present
Position" web page located at
http://saturn.jpl.nasa.gov/operations/present-position.cfm .

Thursday, August 3 (DOY 215):

Due to superior conjunction and the reduction in communications quality with
the spacecraft, science this week was limited to Magnetospheric and Plasma
Science (MAPS) instruments, as they performed magnetospheric surveys. More
specifically, the Radio and Plasma Wave Science instrument (RPWS) mapped the
occurrence of plasma waves in the Saturnian magnetosphere to determine their
role in magnetospheric processes, and performed a series of observations to
establish the nature of the solar wind.

NASA Astronauts Stephanie Wilson and Piers Sellars visited the Cassini
real-time operations area this evening.

Monday, August 7 (DOY 219):

Minimum separation angle between Earth, the spacecraft, and the sun occurred
this morning. The Radio Science Solar Corona Characterization Experiment
continued with the spacecraft maintaining a high-gain antenna to Earth
attitude and 1896 bps telemetry.

A project level Operations Readiness Test began today and will run till the
end of the week.  The purpose of the test is to exercise the flight team in
the processes and procedures to be followed in the event that an Orbit Trim
Maneuver fails to execute.  The test conductor, in this case the Spacecraft
Operations Office manager, came up with the fault to use in the test.  It
was decided that at the end of S23 - remember that we are currently flying
S22 on the spacecraft - an OTM would only partially execute, the spacecraft
would be found to have entered safe mode, the next OTM will be due to
execute within three days, and the day after that a live moveable block
would need to be uplinked if we were to salvage a Radio Science Saturn
occultation. Six days after that the next background sequence would be
scheduled to start.  Remember this is only a test!

The Science Operations Plan Update kickoff meeting for S26 was held today.

Wednesday, August 9 (DOY 221):

Cassini's own Project Scientist gave a talk to the flight team today
entitled "Messages from the Icy Saturnian Satellites."

A delivery coordination meeting was held today for a patch delivery of
Mission Sequence Subsystem version D12.0.1. The delivery was driven by the
need to fix problems in SEQGEN core that impact the ability to split
sequences.  It is believed that S25 has a high potential for being larger
than the space available to store it on the spacecraft, and thus splitting
would be necessary. As a patch release, D12.0.1 will overlay D12.0 and will
be invisible to users.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 08/18/2006 10:03 PM
Cassini Significant Events
 for 08/10/06 - 08/16/06

The most recent spacecraft telemetry was acquired on Tuesday, August 15,
from the Goldstone tracking complex. The Cassini spacecraft is in an
excellent state of health and all subsystems are operating normally.
Information on the present position and speed of the Cassini spacecraft
may be found on the "Present Position" web page at
http://saturn.jpl.nasa.gov/operations/present-position.cfm .

Thursday, August 10 (DOY 222):

The Radio Science S-band equipment was powered on from DOY 219 to 221
during solar conjunction to aid in an experiment being run at Arecibo.

August 9 was the last day of the Cassini command moratorium during
conjunction. Separation angle is now at three degrees and climbing, the
command loss timer has been set to the nominal value of 85 hours, and
normal commanding has resumed. Today the spacecraft played back data
acquired during the 11 days of conjunction. Although this conjunction
was deeper than last year's, spacecraft telemetry was off lock for
shorter periods, indicating quieter solar activity. Superior conjunction
will officially end this Sunday, August 13.

Today was the final day of the 2006 Operations Readiness Test (ORT). The
training obtained by the flight team was invaluable. The test
coordinator described it as "a really hard ORT because it had serious
Navigation recovery, long term Spacecraft and Mission implications AND a
major Science objective coming in less than a week." When the test was
planned, management was looking for both strategic planning and tactical
recovery. In the final analysis, it was felt that the OTM teams really
did well - this should make the real thing - if it ever happens - look easy!

Science activities on board the spacecraft this week included an Imaging
Science Subsystem (ISS) 17-hour ansa movie of the F ring at very high
phase, the completion of several slow scans across Saturn's visible
hemisphere to form spectral images by the Ultraviolet Imaging
Spectrograph (UVIS), and the Visual and Infrared Mapping Spectrometer
(VIMS) observed Saturn to assemble a methane fluorescence mapping, and
tracked many of Saturn's atmospheric features. The Magnetospheric and
Plasma Science (MAPS) instruments simultaneously performed low-rate
outer magnetospheric surveys to observe the variability of
magnetospheric boundaries at a variety of radial distances. The AACS Z
Sigma Ratio error monitor unexpectedly exceeded the threshold on Aug.
10, 2006. The High Water Mark (HWM) value reached 13. The nominal
threshold value is 10. It remained above the threshold for 10 seconds.
This ratio compares the measured star brightness to the expected. The
last occurrence was Christmas Eve, 2005, when it reached 11 for 5
seconds, because Rhea's interference was interpreted as an unexpected
bright body.

Since this monitor triggered two of the four Cassini safing events, the
Spacecraft Team has been following a strategy of masking and unmasking
to prevent it from responding to bright bodies in the Stellar Reference
Unit field of view. This strategy prevents a call to safing, and logs
the event for future analysis. This time there was no bright body
problem so the AACS team is investigating the cause.

Friday, August 11 (DOY 223):

The DSN has examined the Goldstone 70m elevation bearings at DSS-14. The
bearings show normal wear and should have several more years of life
left in them. With this information, DSN personnel will now have a
stable environment for resource planning and track allocation. Now the
only remaining uncertainty affecting the allocation of stations to
support Cassini is related to the launch of STEREO, currently scheduled
for August 31

Monday, August 14 (DOY 226):

Today was a very busy day for sending commands and files to the
spacecraft. A Dione/Mimas/Saturn/Helene/Rhea Live Inertial Vector
Propagator (IVP) update sequence, and a RADAR Dione/Rhea instrument
expanded block (IEB) trigger update movable block sequence were
uplinked. Both files have registered and activated on-board. The IVP
update sequence will begin clocking out on DOY 227 while the RADAR
sequence will begin execution on DOY 228. Additional files uplinked
today included S23 IEBs for ISS, Composite InfraRed Spectrometer (CIRS),
VIMS, Ion and Neutral Mass Spectrometer (INMS), UVIS, Cassini Plasma
Spectrometer (CAPS), and Optical Navigation. The remaining IEBs will be
sent up tomorrow, and the background sequence will follow on Thursday.

Attitude and Articulation Control Subsystem (AACS) gyro calibration
parts A & B were executed today piggybacking on an Inertial Reference
Unit calibration.

Tuesday, August 15 (DOY 227):

Background sequence Reaction Wheel Assembly (RWA) biases were performed
on DOY 224 and today to counter the low RWA RPM rates that otherwise
would have occurred during the execution of this sequence segment. In
addition, Periodic Engineering Maintenance (PEM) was performed today.

The final development process for the S25 background sequence and
associated files kicked off today. Stripped subsequence files have been
provided to the teams to populate, and a set of integrated merged
products was produced and made available to the team. Wednesday, August
16 (DOY 228):

The final sequence approval meeting for S23 was held today. Although all
planned and required activities have been accommodated, there is concern
regarding DSN allocations. Passes are still in heavy contention between
September 2 and September 20 based on the new Stereo launch date of
August 31. Should the situation change, real-time action would be
required and may cause loss of data, and could affect the uplink of
files in mid September to support S24. The allocation schedule is being
worked on a week-by-week basis with upper project and lab management
involvement. S23 will be uplinked to the spacecraft over the Cassini DSN
pass tomorrow.

As of today, real-time commands will need to be sent to deal with DSN
station allocation changes to passes on September 2, 4 and 5. The
commands are needed to preserve the planned data playback. Changes to
the DSN allocation for these days came too late for the sequence leads
to accommodate them in the background sequence. The sequence leads for
S24 reported that an allocation file for the sequence is still not
available. Development work is proceeding on the assumption that all
requested passes will be obtained. Unfortunately, this is unlikely given
the delayed return to service of DSS-63 and the needs of the STEREO and
MRO missions.

As Cassini approached periapsis today, Cosmic Dust Analyzer (CDA) was on
a campaign to obtain Tethys orbit crossing data and E ring measurements.
In addition, the live update files mentioned on DOY 226 of this report
are intended to update this period of periapsis observations - Dione,
Mimas, Helene and Rhea observations are among the planned activities.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 08/25/2006 07:31 PM
Cassini Significant Events
for 08/17/06 - 08/23/06

The most recent spacecraft telemetry was acquired Wednesday, August 23, from
the Goldstone tracking stations. The Cassini spacecraft is in an excellent
state of health and is operating normally. Information on the present
position and speed of the Cassini spacecraft may be found on the "Present
Position" web page located at
http://saturn.jpl.nasa.gov/operations/present-position.cfm .

Thursday, August 17 (DOY 229):

Today the instrument teams had the closest view of the Saturnian satellite
Helene since the start of the mission. Cassini flew by for a non-targeted
encounter at an altitude of 48759 kilometers, traveling at a speed of around
7.7 kilometers per second. For this event the Imaging Science Subsystem
(ISS), Composite Infrared Spectrometer (CIRS), and Ultraviolet Imaging
Spectrograph (UVIS) observed Helene to obtain color, polarization, shape,
and geology measurements.

Also today the second Enceladus Plume Debris working group meeting was held.
The primary goal of this group is to characterize the Enceladus plumes so
that the orbit 61 flyby can be designed to provide excellent Enceladus
science without presenting a hazard to the spacecraft. The work of this
group is also important for creation and analysis of proposed extended
mission tours. The group needs to develop an engineering model incorporating
dust and gas that can be folded into Mission Planning and Navigation
software for planning flyby scenarios.

Friday, August 18 (DOY 230):

A non-targeted flyby of Titan occurred today.

The preliminary port of the Science Operations Plan update process occurred
today for inputs to the S26 sequence. The inputs have been merged, analyzed,
and status delivered to the teams for review. The official port is scheduled
for Thursday, August 24.

For the final week of S22, the Cassini Plasma Spectrometer (CAPS), Cosmic
Dust Analyzer (CDA), Ion and Neutral Mass Spectrometer (INMS), Magnetometer
Subsystem (MAG), Magnetospheric Imaging Instrument (MIMI), and Radio and
Plasma Wave Science (RPWS) instrument continued to perform simultaneous
magnetospheric surveys to observe the variability of magnetospheric
boundaries at a variety of radial distances. Several of these instruments
also participated in a campaign to study the interactions between icy
satellites, rings, and the magnetosphere. MIMI also imaged the dynamics of
the inner magnetosphere by sampling energetic ions with the Ion and Neutral
Camera sensor.

The Spacecraft Operations Office hosted the S28 Engineering Activities
Review. The objective of the meeting is for the Navigation and Spacecraft
teams to identify any periods where the mission is particularly vulnerable
to a missed Orbit Trim Maneuver during the sequence, and to consider
additional contingency plans, if needed. The principal participants are the
Navigation and Spacecraft teams, but other offices are also represented.

Saturday, August 19 (DOY 231):

The Traveling Wave Tube Amplifier (TWTA) B line B solid-state power switch
(SSPS) changed state from OFF to tripped at 231T09:13:20 SCET, Saturday,
August 19. This event had no effect on TWTA operation as line B is normally
unpowered, and the trip was determined to have no affect on possible System
Fault Protection (SFP) activity going forward. The most recent trip prior to
this event was on June 21 for the SSPS on the Stellar Reference Unit (SRU)
-B replacement heater. This latest trip is the 18th occurrence since launch,
the fourth this year. These trips are expected to occur at a rate of about
two per year and are attributed to Galactic Cosmic Rays. The SSPS was reset
via real time commanding on Wednesday, August 23.

The keys to the spacecraft were handed over to the sequence leads for S23
today. The background sequence began execution at 2006-231T22:06:00.000. S23
will run for 32 days from August 19 through September 20. During the
sequence there will be one targeted flyby of Titan (T17) at 1000 kilometers,
four non-targeted flybys, one each of Methone, Calypso, Atlas, and
Enceladus, orbit trim maneuvers number 70, 71, and 72, one ring plane
crossing, two possible live updates, and a Saturn solar occultation on DOY
258.

At the top of the S23 sequence, three images were taken of Saturn's
satellites that will be used by the Optical Navigation team to accurately
calibrate Cassini's reference trajectory. The Ultraviolet Imaging
Spectrograph (UVIS), Imaging Science Subsystem (ISS), and the Visible and
Infrared Mapping Spectrometer (VIMS) jointly observed Mimas for 7 hours.
UVIS is searching for a possible atmosphere on this icy satellite.

Monday, August 21 (DOY 233):

Recently Cassini Outreach launched an RSS feed. There is now an orange "RSS"
button on the home page on the left. Next to it is a link to a help page
that will help you get started. RSS in this case stands for "Really Simple
Syndication." It is a mechanism that delivers the latest content from a web
site directly to you rather than you having to check the website every day
for what's new. RSS delivers a headline, a short summary and a link to the
full text on the website, making it easy to keep up-to-date on your favorite
websites. On the Cassini website, RSS is used to deliver the latest
information about images, videos, and news coming from the Cassini
spacecraft. Go to http://www.saturn.jpl.nasa.gov and look for the orange
rectangular button on the left labeled RSS.

UVIS performed several slow scans across Saturn's visible hemisphere.
Following this 10.5-hour activity, ISS used the Narrow Angle Camera to
photograph Titan at 140 degrees phase.

Tuesday, August 22 (DOY 234):

A Mission Planning Forum was held today to review and discuss the results of
a study of all Titan Orbiter Science Team requested double playbacks, the
potential effects on other segments, a process for the playbacks, and
recommendations.

The RADAR team obtained 2.5 hours of science and calibration by collecting
radiometer data of distant Titan. This activity was one of a set that
provides coverage of Titan's northern latitudinal variation. RADAR also
performed a nine-hour calibration activity by scanning the Sun, Saturn, and
other microwave sources while collecting radiometry data. In addition, the
spacecraft performed a 6.5-hour roll about its X-axis during a periodic
calibration for MAG.

Wednesday, August 23 (DOY 235):

The Command and Data Subsystem (CDS) turned off the Cosmic Dust Analyzer
(CDA) instrument on Sunday 20, August 20, during an instrument flight
software test. CDA was powered "on" today, and is now running on version
10.0 of CDA flight software.
 
A Delivery Coordination Meeting was held today for the version 3.3.1 patch
for the Cassini Information Management System (CIMS). The patch contains a
fix to the Science Planning Attitude Spread Sheet / Spacecraft Activity
Sequence File comparison process, a performance enhancement for the
"delivery" feature, and some usability updates. There are no updates to the
CIMS Toolkit. The software was installed today and is now being used in
operations.

The Magnetospheric and Plasma Science (MAPS) instruments performed a
6.25-hour low latitude observation of the structure and dynamics of Saturn's
magnetotail, and ISS began a series of periodic, one-hour observations of
Saturn's northern hemisphere in a search for lightning.
Title: Re: NASA - Cassini updates
Post by: eeergo on 08/26/2006 02:02 PM
Thanks for the extensive info! I'd been looking for these kind of summaries for quite a long time, it's nice to have them together like this. Keep on with it! :)
Title: Re: NASA - Cassini updates
Post by: jacqmans on 09/01/2006 09:40 PM
Cassini Significant Events
for 08/24/06 - 08/30/06

The most recent spacecraft telemetry was acquired Wednesday, August 30, from
the Goldstone tracking stations. The Cassini spacecraft is in an excellent
state of health and is operating normally. Information on the present
position and speed of the Cassini spacecraft may be found on the "Present
Position" web page located at
http://saturn.jpl.nasa.gov/operations/present-position.cfm .

Thursday, August 24 (DOY 236):

A delivery coordination meeting was held today for the Spacecraft Operations
Office (SCO) Downlink Uplink Coherency Tool (DUCT) version 1.1. This is the
tool that automates the insertion of a downlink pause in the sequence at the
point of the transition from one-way to two-way where otherwise a brief
telemetry loss would occur.

The Encounter Strategy Meeting for Titan 17 and Titan 18 was held today.
The time frame addressed was from September 7 through September 23 and
included Orbit Trim Maneuvers (OTM) 71 through 73.  Presentations included a
mission overview covering special mission activities, first time events,
consumables, live updates potentially needed for this period, a sequence
overview and contingency planning for S23, and presentations by SCO,
Navigation, and Uplink Operations.

The deputy Project Scientist gave a presentation on Saturn's rings in Von
Karman Auditorium today.  The presentation included how the rings are made
up of millions of icy particles ranging in size from dust to large boulders,
and how these particles undergo an intricate dance as they orbit Saturn.
Also covered was how gravity from the nearby moons causes the ring particles
to bump into each other and create interesting patterns in the rings such as
waves and wakes. The talk was given as part of the Science Division's
monthly "Science 101" lecture series.

The S26 official port occurred today as part of the Science Operations Plan
Update process.  The input products have been sent to AACS for analysis with
the results to be delivered this week.  The S26 project briefing is
scheduled for September 6.

Friday, August 25 (DOY 237):

The Optical Remote Sensing Instruments were quite busy this week.
Observations included the occultation of the star 8 Nu Cap by Tethys by the
Ultraviolet Imaging Spectrograph (UVIS), along with calibrations performed
by observing the ring occultations of Zeta Opiuchus, Delta Sco, and Lambda
Sco. The Cassini Infrared Spectrometer (CIRS) ran a scattered light test to
quantify the effect of ring particle impacts on the performance of its
mirrors. The Imaging Science Subsystem (ISS) took a standard star image to
monitor instrument sensitivity, three pictures of Saturn's satellites were
taken for the Optical Navigation team to assist with orbit determination,
and a 13.5 hour lightning search of Saturn's northern hemisphere was
performed.  Finally, the Visual and Infrared Mapping Spectrometer (VIMS)
performed a mosaic of the entire ring system near apoapsis, Cassini's
farthest point from Saturn during the 27th orbit. The suite of
Magnetospheric and Plasma Science (MAPS) instruments continued its
magnetotail campaign by observing the structure and dynamics of Saturn's
magnetotail at low latitudes.

Saturday, August 26 (DOY 238):

An AACS Reaction Wheel Assembly (RWA) friction test was performed today on
wheels 1, 2, and 4.  In this test, performed every three months, the RWAs
are spun to +/-900 rpm and allowed to run down to zero.  The longer the
run-down time, the better.  RWA-1 exhibited no change in the counter
clockwise direction since the last test on May 29, 2006, but was poorer in
the clockwise direction.  The rundown time was 20 minutes, equaling the
previous low point in the fall of 2004.  This lower result was caused by the
presence of drag torque spikes throughout the clockwise part of the friction
test.  RWA-2 exhibited no change in either direction, with both directions
having rundown times of greater than 40 minutes.  RWA-4 showed no change in
the counter clockwise direction, but was slightly worse in the clockwise
direction, with a run-down time of 38 minutes.

Monday, August 28 (DOY 240):

The Aftermarket Process for the S28 sequence began today.  This 5-week
process addresses proposed changes that require re-integration of the
segments contained in the S28 sequence.  All proposed science and
engineering changes were submitted via the Cassini Information Management
System by last Friday, August 24, 2006.  A final decision meeting is
scheduled for September 11.

The Cassini-Huygens Analysis and Results of the Mission (CHARM)
teleconference for August was held today. The topic:  Exploring Saturn's
Moon Titan, An Earth-like Alien.  The presentation covered what is known and
what the possibilities are for Titan's atmosphere and geology, what is known
from the Huygens Probe, and specific data acquired from some of the Cassini
instruments,

Wednesday, August 30 (DOY 242):

The Navigation Team announced that OTM-070 could not be cancelled and would
execute as planned on Monday, September 4.  Currently OTM-070 has a
predicted value of 0.227 m/s. Cancellation would increase the mission
delta-V by about 15 m/s.  The preliminary and final cancellation reviews
scheduled for Thursday and Friday have been, well, cancelled.  OTM 70
removes the pointing errors at Titan, but the Enceladus post-Titan pointing
errors remain large.  Final trajectories will be provided Friday for science
evaluation.

The Radio Science Subsystem (RSS) performed a High Gain Antenna boresight
calibration near the middle of today's downlink to the Goldstone 70M
antenna.  An hour of this activity required a cross-hair maneuver that took
Cassini slightly off Earth-point.  As a result, a brief, planned
interruption to the downlink occurred.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 09/09/2006 11:30 AM
Cassini Significant Events
for 08/31/06 - 09/06/06

The most recent spacecraft telemetry was acquired Wednesday, September 6,
from the Goldstone tracking stations. The Cassini spacecraft is in an
excellent state of health and is operating normally. Information on the
present position and speed of the Cassini spacecraft may be found on the
"Present Position" web page located at
http://saturn.jpl.nasa.gov/operations/present-position.cfm .

Thursday, August 31 (DOY 243):

The Titan 17 flyby, scheduled for September 7, is set for an altitude of
1,000 km. This flyby is at the relatively low latitude of 23 degrees, in the
region where the Titan atmosphere model predicts a greater atmospheric
density. If the results from this flyby indicate that is true, as measured
by the ACS thruster duty cycle and INMS instrument data, trajectory changes
will be considered for Titan 20, which is at 1030 km altitude, but almost
equatorial at 7.5 degrees. A new candidate reference trajectory has been
developed with an increase in the altitude of the Titan 20 flyby from 1030
to 1055 km. The final decision to raise the T20 altitude, or not, will occur
at the Titan Atmosphere Model Working Group meeting on September 11. If the
decision is to raise the altitude, the new trajectory will go into effect on
September 12.

Spacecraft Operations Office personnel held an Exciter RF Loss tabletop
exercise today. This is the first in a periodic sequence of such exercises
for SCO training.

The Radio Science Subsystem (RSS) performed the first of three Operational
Readiness Tests (ORT) today using the Deep Space Network antennas at
Goldstone. Tests two and three will be performed Saturday and Sunday. These
ORTs are used to prepare for the RSS Saturn gravity observation on September
9.

Friday, September 1 (DOY 244):

The S23 sequence leads made the decision to give up the last hour of the
Cassini DSN track over Goldstone today to accommodate station maintenance
work. A glitch with the transmitter was preventing successful uplink of
command files. Maintenance will go toward ensuring the station is available
for the maneuver uplink on Monday. According to Science Planning, only
real-time data was lost. The recorded data will be played back from the SSRs
with no loss.

Monday, September 4 (DOY 247):

Orbit Trim Maneuver (OTM) #70 was performed today. This is the minus 3-day
maneuver setting up for the Titan 17 encounter on September 7. The reaction
control subsystem burn began at 12:45 PM. Telemetry immediately after the
maneuver showed the burn duration was 164.1 seconds, giving a delta-V of
approximately 227.6 mm/s. All subsystems reported nominal performance after
the maneuver.

The Imaging Science Subsystem (ISS) began a 12.5 hour observation of
Saturn's Ring System today. Images of the unlit face of the Cassini Division
at high phase were taken once every 8 minutes. This observation will be used
to search for dust, clumps and variations in the structure of the outer B
Ring.

Tuesday, September 5 (DOY 248):

The kickoff meeting was held today for the S23 Enceladus/Tethys Live
Inertial Vector Propagator (IVP) update for DOY 252-253. The final orbit
determination solution became available last Thursday, and analysis is
scheduled to begin later today. Navigation has recommended that teams look
at the size of the uncertainties as part of the decision process to perform
or not perform the update.

A beautiful image of the white cliffs of Dione was Astronomy Picture of the
Day today.

Wednesday, September 6 (DOY 249):

The Spacecraft Operations Office has requested the S25 sequence lead to
schedule a test of the Titan 20 flyby in the Integrated Test Laboratory.

The Project Briefing, the final meeting held as part of the Science
Operations Plan Update process, was held today for  S26. Input products for
the sequence will be handed off to the sequence leads at the end of this
week, and the final development process will kick-off on September 12.

Today concluded with the spacecraft on approach to Titan for the T17
encounter, an inbound flyby. The Composite Infrared Spectrometer (CIRS)
began a 7+ hour activity to obtain information on the thermal structure of
Titan's stratosphere, with ISS and the Visual and Infrared Mapping
Spectrometer (VIMS) taking advantage of the spacecraft pointing to gather
data on Titan.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 09/16/2006 09:55 AM
Cassini Significant Events
for 09/07/06 - 09/13/06

The most recent spacecraft telemetry was acquired Wednesday, September 13,
from the Goldstone tracking stations. The Cassini spacecraft is in an
excellent state of health and is operating normally. Information on the
present position and speed of the Cassini spacecraft may be found on the
"Present Position" web page located at
http://saturn.jpl.nasa.gov/operations/present-position.cfm .

Thursday, September 7 (DOY 250):

The Titan 17 flyby (T17), at 1000 km altitude, occurred September 7, 2006.
This flyby was at a latitude of 23 degrees, in a region where the Titan
atmospheric model predicted the atmospheric density to be greater than at
higher latitudes. The project anticipated thruster duty cycling between 40
and 65%, and developed an on-the-shelf reference trajectory to increase the
altitude of the T20 flyby should it be necessary. The duty cycle calculated
by AACS after the flyby was considerably lower than expected, around 20%.

Prior to closest approach, the Imaging Science Subsystem (ISS) searched for
and monitored lightning and aurora, and the Visible and Infrared Mapping
Spectrometer (VIMS) worked on Titan mapping, monitoring, and photometry, and
observed a stellar occultation through Titan's atmosphere.

Titan closest approach was designed with a spacecraft attitude suitable for
both Ion and Neutral Mass Spectrometer (INMS) data acquisition and a short
Synthetic Aperture RADAR (SAR) swath of Titan's surface. INMS data will be
used to help determine atmospheric and ionospheric thermal structure. The
Optical Remote Sensing (ORS) instruments used the time just after closest
approach to continue Titan global mapping and atmospheric analysis.

The Cassini Plasma Spectrometer (CAPS), Cosmic Dust Analyzer (CDA), Ion and
Neutral Mass Spectrometer (INMS), Magnetometer Subsystem (MAG),
Magnetospheric Imaging Instrument (MIMI), and Radio and Plasma Wave Science
(RPWS) instrument performed under the Magnetospheric and Plasma Science
campaign to make inbound approach observations, provide context for the
interaction between Titan and Saturn's magnetosphere, and determine
atmospheric and ionospheric thermal structures.

Friday, September 8 (DOY 251):

The S23 Saturn solar occultation Live Movable Block (LMB) kickoff meeting
was held today. A typical schedule for an LMB process runs from five to
seven days and looks something like this:

LMB kickoff meeting Friday (DOY 251)

Orbit Determination file available Saturday (DOY 252) at 2300 PDT

Epoch update and science analysis Sunday (DOY 253)

Go-No/Go meeting Monday (DOY 254)

Command Approval Meeting Tuesday (DOY 255) at 1600 PDT

Uplink Wednesday (DOY 256)

Execution beginning on Friday (DOY 258)

The S23 leads uplinked files for an Enceladus Live Inertial Vector
Propagator Update to execute tomorrow, September 9, and a RADAR Enceladus
trigger. Both files have been verified onboard and should execute as
planned.

Today concluded the T17 encounter activities. The Imaging Science Subsystem
(ISS) used the Narrow Angle Camera to monitor surface and atmosphere changes
and attempt to see surface color variations on Titan. The spacecraft
performed a 9-hour downlink to the Goldstone 70-meter DSN antenna to play
back the Titan flyby data.

After playback, the spacecraft turned its attention to Saturn's rings and
Iapetus. The ISS instrument made a series of zero-phase Iapetus observations
and captured five Optical Navigation images. CIRS gathered temperature data
on the rings, while UVIS used the opportunity for spectral mapping of the
rings.

Saturday, September 9 (DOY 252):

Non-targeted flybys of Atlas, Methone, Calypso, and Enceladus occurred
today. The Enceladus flyby was at an altitude of 39,932 km.

The first Cassini Radio Science Subsystem (RSS) Saturn gravity observation
in Orbit 28 concluded successfully today. The observation consisted of one
segment slightly over 6 hours in duration, and almost centered on periapsis.
This was the first of two RSS Saturn gravity observations during the Cassini
Tour that were selected as a pair. These two observations are specifically
optimized for measurement of the gravity field of Saturn. The second occurs
during Orbit 68 in May of 2008.

Sunday, September 10 (DOY 253):

Orbit trim maneuver #71 was performed today. This was the T17 post flyby
cleanup maneuver. The main engine burn began at 12:23 PM. Telemetry
immediately after the maneuver showed a burn duration of 41.0 seconds,
giving a delta-V of 6.55 m/s. All subsystems reported nominal performance
after the maneuver. The next maneuver, OTM-072, is scheduled for Thursday,
September 14.

Monday, September 11 (DOY 254):

It turns out that S25 is in conflict with the Messenger Project on October
24, DOY 297, for Deep Space Station 14. Messenger has a critical event, the
Venus-1 flyby, on that day. DSS-14 is required by Messenger to downlink the
flyby data. The current proposal is for Cassini to keep the first 3 hours
over DSS-14 and then hand over to DSS-15 for the remaining 6 hours of the
pass. Messenger will then have the remaining 6 hours over DSS-14 for
downlink.

The Titan Atmosphere Model Working Group (TAMWG) met today to review the T17
Titan flyby results and to recommend whether the T20 closest approach
altitude should be raised. T17 is significant because it is, at closest
approach, the lowest latitude flown to date at 23=B0. The results from AACS,
INMS, and Navigation showed the atmospheric density significantly lower than
predicted. As a result, the previous model, which assumed an increase in
density near the equator, is under serious question.The flybys for T18 on
September 23 and T19 on October 9 will be watched closely since these
altitudes were adopted assuming lower density at higher latitudes. However,
they are considered safe to fly based on the new information from T17. The
T20 altitude is not planned to be changed. The next two TAMWG meetings are
scheduled for September 27 and October 16 after the T18 and T19 flybys.

The Science Operations Plan Update process for S27 kicked off today.

Tuesday, September 12 (DOY 255):

A change board meeting was held today for AACS flight software version
A8.7.5. The four parameter changes approved were: secondary safing vector
pair update, A and B-branch thruster magnitude updates, Inertial Reference
Unit-A scale factor updates, and response script tier count change for a
potential fault protection case following an unexpected reaction wheel to
thruster transition.

The final approval meeting was held today for the S24 background sequence.
The instrument expanded block files will be uplinked beginning today with
the background sequence going up on September 18.

The S23 Saturn solar occultation Live Movable Block was successfully
uplinked today and has been verified as registered onboard. The file should
execute as expected beginning on DOY-258.

The final development process began today for S26. The process will run for
ten weeks with uplink of sequence files occurring during the 11th week. S26
begins execution on Friday, November 24.

A beautiful image of Saturn at night is Astronomy Picture of the Day today.

Wednesday, September 13 (DOY 256):

At the time S24 was going through the final development process, Uplink
Operations was unable to confirm the DSN allocations requested for the
sequence. The uncertainty was part of the STEREO launch and MRO aerobraking
conflict that the flight projects have been working with the DSN. Since the
allocations were uncertain, SSR data margin that is usually released for
instrument use during the development process was withheld, pending possible
station losses and the concomitant data cuts that would be required.

Now that the STEREO launch has been shifted to not earlier than October 25,
allocations are confirmed for most of S24, but not in time for the
instruments to take advantage of the now-available SSR data margin. The S24
leads are handling this by building a mini-sequence to be stored in the
movable block region of memory. It will run for most of the sequence from
DOY 269 through DOY 291. This file will contain the new data policing table
commands, all instrument commands required to take advantage of the sponge
bits, and any new instrument expanded block files required which go straight
to the instrument, and are not stored on the SSR. The mini-sequence will be
uplinked the day after S24 begins execution with a primary window of DOY
264/13:05-18:54, and a backup window of DOY 265/12:50-18:39.

The Magnetospheric and Plasma Science (MAPS) instruments continued the
magnetotail campaign to observe plasma flows and the dynamics of the
magnetotail from large distances downstream. The spacecraft is entering an
important phase of the mission that covers unique geometry optimal for MAPS
coverage of the magnetotail and plasma wake.

First viewed at the Saturn Orbit Insertion anniversary event held at JPL for
the flight team, the SOI +2 years highlights video chronicles some of
Cassini's discoveries in the last two years. Link to:

http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=128

Outreach has posted some of the images from the Titan 17 flyby on September
7. To view these images go to:

http://saturn.jpl.nasa.gov/news/events/titan20060907/index.cfm

Wrap up:

Check out the Cassini web site at http://saturn.jpl.nasa.gov for the latest
press releases and images.
Title: Re: NASA - Cassini updates
Post by: eeergo on 10/13/2006 10:18 AM

10-11-2006

NASA Finds Saturn's Moons May be Creating New Rings

Cassini scientists are on the trail of the missing moons of Saturn. A recent observation by the spacecraft leads them to believe that they will find the moons near newly discovered rings around the planet. During an unprecedented opportunity, with the sun poised behind Saturn, Cassini scientists discovered two new rings and confirmed the presence of two others. The new rings are associated with one or more small mooCassini scientists are on the trail of the missing moons of Saturn. A recent observation by the spacecraft leads them to believe that they will find the moons near newly discovered rings around the planet.

During an unprecedented opportunity, with the sun poised behind Saturn, Cassini scientists discovered two new rings and confirmed the presence of two others. The new rings are associated with one or more small moons and share their orbits with the moons, while scientists suspect a moon is lurking near a third ring.

http://www.nasa.gov/mission_pages/cassini/media/cassini-20061011c.html

Title: Re: NASA - Cassini updates
Post by: jacqmans on 07/19/2007 04:10 PM
Feature   JPL news release                                                                
July 19, 2007                          

Saturn Turns 60

Scientists have recently discovered that the planet Saturn is turning 60 –not years, but moons.

"We detected the 60th moon orbiting Saturn using the Cassini spacecraft's powerful wide-angle camera," said Carl Murray, a Cassini imaging team scientist from Queen Mary, University of London. "I was looking at images of the region near the Saturnian moons Methone and Pallene and something caught my eye."

The newly discovered moon first appeared as a very faint dot in a series of images Cassini took of the Saturnian ring system on May 30 of this year. After the initial detection, Murray and fellow Cassini imaging scientists played interplanetary detective, searching for clues of the new moon in the voluminous library of Cassini images to date.

The Cassini imaging team's legwork paid off. They were able to locate numerous additional detections, spanning from June 2004 to June 2007. "With these new data sets we were able to establish a good orbit for the new moon,” said Murray. "Knowing where the moons are at all times is important to the Cassini mission for several reasons."

One of the most important reasons for Cassini to chronicle these previously unknown space rocks is so the spacecraft itself does not run into them. Another reason is each discovery helps provide a better understanding about how Saturn's ring system and all its billions upon billions of parts work and interact together. Finally, a discovery of a moon is important because with this new knowledge, the Cassini mission planners and science team can plan to perform science experiments during future observations if and when the opportunity presents itself.

What of this new, 60th discovered moon of Saturn? Cassini scientists believe "Frank" (the working name for the moon until another, perhaps, more appropriate one is found)  is about 1.2 miles (2 kilometers) wide and, like so many of its neighbors, is made mostly of ice and rock. The moon's location in the Saturnian sky is between the orbits of Methone and Pallene. It is the fifth moon discovered by the Cassini imaging team.

"When the Cassini mission launched back in 1997, we knew of only 18 moons orbiting Saturn," said Murray. "Now, between Earth-based telescopes and Cassini we have more than tripled that number – and each and every new discovery adds another piece to the puzzle and becomes another new world to explore."

Murray and his colleagues may get the chance to explore Saturn's 60th moon. The Cassini spacecraft's trajectory will put it within 7,300 miles (11,700 kilometers) in December of 2009.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL.  The imaging team is based at the Space Science Institute, Boulder, Colo.

 

Related news releases:

+Link to Science and Technology Facilities Council:

http://www.scitech.ac.uk

+Link to Cassini Imaging Team:

http://ciclops.org


Written by: DC Agle
Media Contact: Carolina Martinez 818-354-9382

-end-

Title: Re: NASA - Cassini updates
Post by: jacqmans on 08/02/2007 08:26 PM
RELEASE: 07-168

CASSINI FINDS POSSIBLE ORIGIN OF ONE OF SATURN'S RINGS

WASHINGTON - Cassini scientists may have identified the source of one
of Saturn's more mysterious rings. Saturn's G ring likely is produced
by relatively large, icy particles that reside within a bright arc on
the ring's inner edge.

The particles are confined within the arc by gravitational effects
from Saturn's moon Mimas. Micrometeoroids collide with the particles,
releasing smaller, dust-sized particles that brighten the arc. The
plasma in the giant planet's magnetic field sweeps through this arc
continually, dragging out the fine particles, which create the G
ring.

The finding is evidence of the complex interaction between Saturn's
moons, rings and magnetosphere. Studying this interaction is one of
Cassini's objectives. The study is in the Aug. 2 issue of the journal
Science and was based on observations made by multiple Cassini
instruments in 2004 and 2005.

"Distant pictures from the cameras tell us where the arc is and how it
moves, while plasma and dust measurements taken near the G ring tell
us how much material is there," said Matthew Hedman, a Cassini
imaging team associate at Cornell University in Ithaca, N.Y., and
lead author on the Science paper.

Saturn's rings are an enormous, complex structure, and their origin is
a mystery. The rings are labeled in the order they were discovered.
From the planet outward, they are D, C, B, A, F, G and E. The main
rings -- A, B and C-from edge-to-edge, would fit neatly in the
distance between Earth and the moon. The most transparent rings are D
-- interior to C -- and F, E and G, outside the main rings.

Unlike Saturn's other dusty rings, such as the E and F rings, the G
ring is not associated closely with moons that either could supply
material directly to it -- as Enceladus does for the E ring -- or
sculpt and perturb its ring particles -- as Prometheus and Pandora do
for the F ring. The location of the G ring continued to defy
explanation, until now.

Cassini images show that the bright arc within the G ring extends
one-sixth of the way around Saturn and is about 155 miles wide, much
narrower than the full 3,700-mile width of the G ring. The arc has
been observed several times since Cassini's 2004 arrival at the
ringed planet and thus appears to be a long-lived feature. A
gravitational disturbance caused by the moon Mimas exists near the
arc.

As part of their study, Hedman and colleagues conducted computer
simulations that showed the gravitational disturbance of Mimas could
indeed produce such a structure in Saturn's G ring. The only other
places in the solar system where such disturbances are known to exist
are in the ring arcs of Neptune.

Cassini's magnetospheric imaging instrument detected depletions in
charged particles near the arc in 2005. According to the scientists,
unseen mass in the arc must be absorbing the particles. "The small
dust grains that the Cassini camera sees are not enough to absorb
energetic electrons," said Elias Roussos of the Max-Planck-Institute
for Solar System Research, Germany, and member of the magnetospheric
imaging team. "This tells us that a lot more mass is distributed
within the arc."

The researchers concluded that there is a population of larger,
as-yet-unseen bodies hiding in the arc, ranging in size from that of
peas to small boulders. The total mass of all these bodies is
equivalent to that of a 328-foot-wide, ice-rich small moon.

Joe Burns, a co-author of the paper from Cornell University and a
member of the imaging team, said, "We'll have a super opportunity to
spot the G ring's source bodies when Cassini flies about 600 miles
from the arc 18 months from now."

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The Jet
Propulsion Laboratory, Pasadena, Calif., manages the Cassini-Huygens
mission for NASA's Science Mission Directorate, Washington. The
Cassini orbiter and its two onboard cameras were designed, developed
and assembled at the laboratory. The imaging team is based at the
Space Science Institute, Boulder, Colo. The magnetospheric imaging
instrument team is based at Johns Hopkins University, Laurel, Md.

G ring movies and images are available on the Internet at:

http://www.nasa.gov/cassini
Title: Re: NASA - Cassini updates
Post by: jacqmans on 08/04/2007 08:16 AM
With data from the Cassini spacecraft, an international team of scientists may have identified the source of one of Saturn's more mysterious rings. The enigmatic G ring is likely produced by relatively large, icy particles that reside within a bright arc on the ring's inner edge.

Full story at:

http://www.esa.int/SPECIALS/Cassini-Huygens/SEMXOENEW4F_0.html
Title: Re: NASA - Cassini updates
Post by: jacqmans on 08/25/2007 07:33 AM
Cassini Significant Events
for 08/15/07 - 08/21/07

The most recent spacecraft telemetry was acquired on Tuesday, August 21,
from the Goldstone tracking complex. The Cassini spacecraft is in an
excellent state of health and all subsystems are operating normally.
Information on the present position and speed of the Cassini spacecraft may
be found on the "Present Position" web page located at
http://saturn.jpl.nasa.gov/operations/present-position.cfm.

Wednesday, August 15 (DOY 227):

Cassini entered solar conjunction today when the Sun-Earth-Probe (SEP) angle
reached 5 degrees.  This angle reached a minimum of 1.24 degrees on August
21, and will reach 5 degrees again when conjunction completes on August 27.

Thursday, August 16 (DOY 228.):

The Command Loss Timer (CLT) value was set from the nominal 85 hours to 10
days in the background sequence on August 16, 2007, and was reinforced with
a real-time command August 17 in preparation for conjunction and the period
of time when Cassini is out of communication with Earth.  The CLT decrements
down during conjunction, and will be set to the nominal value of 85 hours on
August 24, when the SEP angle has increased to about 3 degrees.

An Instrument Operations working group (IOWG) meeting was held to discuss
the extended mission processes and schedule.  With just one exception, all
instrument teams concurred that they could support the schedule.

Friday, August 17 (DOY 222):

The S35 science operations plan update (SOPU) completed today.

Saturday, August 18 (DOY 230):

A command moratorium centered around solar conjunction has started today. A
command moratorium is put into place when the SEP angle is 2 degrees or
less.  

A series of commands, which are exempted from the command moratorium because
their receipt on-board is not required, is being sent up daily (August 18 -
August 25, 2007) as part of the Radio Frequency Subsystem (RFS)
characterization of the solar corona.  The RFS team will assess which
commands "got through" the interference from the sun.

Monday, August 20 (DOY 232):

Cassini outreach and visualization activities and products were presented at
the European Planetary Science Congress 2007 in Potsdam, Germany, 20 - 24
August.

The S36 science operations plan update kicked off today.  This process
completes on September 28, 2007.  The preliminary port is scheduled for
September 4, 2007.

AACS presented six papers at the 2007 AIAA Guidance, Navigation, and Control
Conference August 20-23, 2007, in Hilton Head, South Carolina.

CDS V10 flight software preliminary end-to-end Integrated Test Laboratory
(ITL) testing began today and will run through August 24.   The final
end-to-end ITL testing will begin September 4 and run through September 11,
2007.  Uplink is set for the end of September.

Tuesday, August 21 (DOY 233)

In the last week, 1637 Imaging Science Subsystem (ISS) images were acquired,
including nine for Optical Navigation.  Since approach science began in
January, 2004, 128568 ISS images have been acquired.
   
Wrap up:

Check out the Cassini web site at http://saturn.jpl.nasa.gov for the latest
press releases and images.

The Cassini-Huygens mission is a cooperative project of NASA, the European
Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a
division of the California Institute of Technology in Pasadena, manages the
Cassini-Huygens mission for NASA's Science Mission Directorate, Washington,
D.C.  JPL designed, developed and assembled the Cassini orbiter.
Title: Re: NASA - Cassini updates
Post by: eeergo on 09/12/2007 03:25 PM
Cassini Mission Status: Cassini Flies by Walnut-Shaped Moon Iapetus

09.11.07

Cassini completed its closest flyby of the odd moon Iapetus on Sept. 10, 2007. The spacecraft flew about 1,640 kilometers (1,000 miles) from Iapetus' surface and is returning amazing views of the bizarre moon.

All the data were successfully recorded on the spacecraft. Twenty-one minutes into the first post-flyby data downlink, the spacecraft went into a precautionary condition called safe mode. The cause has been determined to be a solid state power switch that was tripped due to a galactic cosmic ray hit.
[...]

Raw images of the flyby: http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-list.cfm?browseLatest=0&cacheQ=0&storedQ=0

Title: Re: NASA - Cassini updates
Post by: jacqmans on 09/13/2007 08:01 PM
Cassini scientists are poring through hundreds of images returned from the 10 September fly-by of Saturn's two-toned moon Iapetus.

More at:
http://www.esa.int/esaCP/SEM5E613J6F_index_0.html
Title: Re: NASA - Cassini updates
Post by: jacqmans on 10/09/2007 04:34 AM
Scientists are on the trail of Iapetus' mysterious dark side, which seems to be home to a bizarre 'runaway' process that is transporting vaporised water ice from the dark areas to the white areas of the Saturnian moon.

More at:
http://www.esa.int/SPECIALS/Cassini-Huygens/SEMQE3V7D7F_0.html
Title: Re: NASA - Cassini updates
Post by: eeergo on 10/10/2007 07:33 PM

First direct proof that the jets (formed by water ice in large quantities) indeed come from the moon's surface "tiger stripes"' hot spots.

http://www.nasa.gov/mission_pages/cassini/media/cassini20071010.html

Title: Re: NASA - Cassini updates
Post by: jacqmans on 10/11/2007 06:00 PM
IMAGE ADVISORY: 2007-117                                                                     Oct. 11, 2007

 

Cassini Provides New Views of Titan's Land of Lakes and Seas

 

Newly assembled radar images from the Cassini spacecraft provide the best view of the hydrocarbon lakes and seas on the north pole of Saturn's moon Titan, while a new radar image reveals that Titan's south polar region also has lakes.

 

The southern region images were beamed back after an Oct. 2 flyby in which a prime goal was the hunt for lakes at the south pole.

 

A new mosaic image, created by stitching together radar images from seven Titan flybys over the last year and a half,   shows a north pole pitted with giant lakes and seas, at least one of them larger than Lake Superior.

 

Approximately 60 percent of Titan's north polar region above 60 degrees latitude has been mapped by Cassini's radar instrument. About 14 percent of the mapped region is covered by what scientists interpret as liquid hydrocarbon lakes.

 

"This is our version of mapping Alaska, the northern parts of Canada, Greenland, Scandinavia and Northern Russia," said Rosaly Lopes, Cassini radar scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif.  "It's like mapping these regions of Earth for the first time."

 

Lakes and seas are very common at the high northern latitudes of Titan, which is in winter now.  Scientists say it rains methane and ethane there, filling the lakes and seas.  These liquids also carve meandering rivers and channels on the moon's surface.  Now Cassini is moving into unknown territory, the south pole of Titan.  "We wanted to see if there are more lakes present there and, sure enough, there they are, three little lakes smiling back at us.  Titan is indeed the land of lakes and seas," said Lopes.  "It will be interesting to see the differences between the north and south polar regions."

 

It is now summer at Titan's south pole.   A season on Titan lasts nearly 7.5 years, one quarter of a Saturn year, which is 29.5 years long.  Monitoring seasonal change helps scientists understand the processes at work there.

 

Scientists are making progress in understanding how the lakes may have formed. On Earth, lakes fill low spots or are created when the local topography intersects a groundwater table. Lopes and her colleagues think that the depressions containing the lakes on Titan may have formed by volcanism or by a type of erosion (called karstic) of the surface, leaving a depression where liquids can accumulate. Karstic lakes are common on Earth.  For example in parts of Minnesota and central Florida there are hundreds of such lakes.  

 

"The lakes we are observing on Titan appear to be in varying states of fullness, suggesting their involvement in a complex hydrologic system akin to Earth's water cycle. This makes Titan unique among the extra-terrestrial bodies in our solar system," said Alex Hayes, a graduate student who studies Cassini radar data at the California Institute of Technology in Pasadena.

 

"The lakes we have seen so far vary in size from the smallest observable, approximately 1 square kilometer (0.4 square miles), to greater than 100,000 square kilometers (40,000 square miles), which is slightly larger than the Great Lakes in the Midwestern U.S.," Hayes said.  "Of the roughly 400 observed lakes, 70 percent of their area is taken up by large "seas" greater than 26,000 square kilometers (10,000 square miles)."


Future radar flybys will image closer to the southern pole and are expected to show more lakes.


For images and more information visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Title: Re: NASA - Cassini updates
Post by: jacqmans on 12/12/2007 10:01 PM
Somewhere deep below Saturn's cloud tops, the planet rotates at a constant speed. Determining this interior period of rotation has proven extremely complicated. Now, with new Cassini results, a team of European scientists have taken an important step forward.

More at:
http://www.esa.int/esaCP/SEMP7SJV3AF_index_0.html
Title: Re: NASA - Cassini updates
Post by: jacqmans on 02/01/2008 04:34 AM
Cassini Finds Rhythm in Saturn's Rings

Order can be found in the most unexpected places, as demonstrated by our neighbor three planets down. Two of Saturn's rings have been found by NASA's Cassini spacecraft to contain orderly lines of densely grouped, boulder-size icy particles that extend outward across the rings like ripples from a rock dropped in a calm pond.

"Imagine going to a town that stretches from San Francisco to Los Angeles and seeing buildings spaced the same distance apart on every block," said Cassini radio science team member Essam Marouf of San Jose State University, San Jose, Calif. "All of these groups of particles within the rings are very close together, and the space between them is extremely small, only 100 to 250 meters (320 feet to 820 feet) wide, depending on where they are in the ring."

Normally, the distances between particles change with their velocity. In the case of Saturn's rings, the distances between these ring particles stay relatively equal even though their velocities may change. This type of pattern is completely new, according to Marouf.

"This particular feature is the smallest and most detailed of anything seen in Saturn's rings so far," Marouf said. "In the chaotic environment of the rings, to find such regularity in the most cramped areas is nothing short of amazing." The regular structure can only be found in locations where particles are densely packed together, such as the B ring and the innermost part of the A ring.  

The unexpected pattern within Saturn's rings may give scientists some new ideas of what to expect from other similar planets and solar systems.

The pattern was detected when the radio on board the Cassini spacecraft sent out three signals toward Earth. The signals crossed the Saturn's rings, and their frequencies were separated by scattering from the ring particles. Once the signals were captured by Earth-based antennas of NASA's Deep Space Network, Cassini scientists saw a regular pattern in the received signal frequencies.

"The signals showed that the particle groups were arranged in an unexpectedly regular formation that had 'rhythm within the rings of Saturn,'" said Marouf. "Each particle is in its own orbit, and sometimes they collide and move apart as their velocities change. As a result, you have particles bunched together into dense groups that extend across the ring in harmony with each other."

The pattern of particles is described as an enormously extended natural diffraction grating. A diffraction grating has parallel lines like a picket fence; when light hits this fence, it separates according to wavelength, from ultraviolet to infrared light.

The same thing happened when Cassini's radio signals hit the fencelike pattern of ring particles. The signals, sent out in 2005, were meant to capture a complete view of the rings.

This research appears as a cover story in the Dec. 28 issue of Geophysical Research Letters.

Written by: Diya Chacko

Media Relations Contact: Carolina Martinez
Title: Re: NASA - Cassini updates
Post by: jacqmans on 02/13/2008 05:13 PM
Saturn's orange moon Titan has hundreds of times more liquid hydrocarbons than all the known oil and natural gas reserves on Earth, according to new Cassini data. The hydrocarbons rain from the sky, collecting in vast deposits that form lakes and dunes.

More at:
http://www.esa.int/SPECIALS/Cassini-Huygens/SEMCSUUHJCF_0.html
Title: Re: NASA - Cassini updates
Post by: jacqmans on 02/19/2008 05:51 PM
Cassini finds mingling moons may share a dark past  Saturn's moons
 
19 February 2008

Despite the incredible diversity of Saturn’s icy moons, theirs is a story of great interaction. Some are pock-marked, some seemingly dirty, others pristine, one spongy, one two-faced, some still spewing with activity and some seeming to be captured from the far reaches of the solar system. Yet many of them have a common thread - black ‘stuff’ coating their surfaces.


http://www.esa.int/esaCP/SEMMNOVHJCF_index_0.html

Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/06/2008 07:34 PM
NEWS RELEASE: 2008-039                                                             March 6, 2008

Saturn's Moon Rhea Also May Have Rings

PASADENA, Calif. -- NASA's Cassini spacecraft has found evidence of material orbiting Rhea, Saturn's second largest moon. This is the first time rings may have been found around a moon.

A broad debris disk and at least one ring appear to have been detected by a suite of six instruments on Cassini specifically designed to study the atmospheres and particles around Saturn and its moons.

"Until now, only planets were known to have rings, but now Rhea seems to have some family ties to its ringed parent Saturn," said Geraint Jones, a Cassini scientist and lead author on a paper that appears in the March 7 issue of the journal Science. Jones began this work while at the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, and is now at the Mullard Space Science Laboratory, University College, London.

Rhea is roughly 1,500 kilometers (950 miles) in diameter. The apparent debris disk measures several thousand miles from end to end. The particles that make up the disk and any embedded rings probably range from the size of small pebbles to boulders. An additional dust cloud may extend up to 5,900 kilometers (3,000 miles) from the moon's center, almost eight times the radius of Rhea.

"Like finding planets around other stars, and moons around asteroids, these findings are opening a new field of rings around moons," said Norbert Krupp, a scientist with Cassini's Magnetospheric Imaging Instrument from the Max Planck Institute for Solar System Research.

Since the discovery, Cassini scientists have carried out numerical simulations to determine if Rhea can maintain rings. The models show that Rhea's gravity field, in combination with its orbit around Saturn, could allow rings that form to remain in place for a very long time.

The discovery was a result of a Cassini close flyby of Rhea in November 2005, when instruments on the spacecraft observed the environment around the moon. Three instruments sampled dust directly. The existence of some debris was expected because a rain of dust constantly hits Saturn's moons, including Rhea, knocking particles into space around them. Other instruments' observations showed how the moon was interacting with Saturn's magnetosphere, and ruled out the possibility of an atmosphere.

Evidence for a debris disk in addition to this tenuous dust cloud came from a gradual drop on either side of Rhea in the number of electrons detected by two of Cassini's instruments. Material near Rhea appeared to be shielding Cassini from the usual rain of electrons. Cassini's Magnetospheric Imaging Instrument detected sharp, brief drops in electrons on both sides of the moon, suggesting the presence of rings within the disk of debris. The rings of Uranus were found in a similar fashion, by NASA's Kuiper Airborne Observatory in 1977, when light from a star blinked on and off as it passed behind Uranus' rings.

"Seeing almost the same signatures on either side of Rhea was the clincher," added Jones. "After ruling out many other possibilities, we said these are most likely rings. No one was expecting rings around a moon."

One possible explanation for these rings is that they are remnants from an asteroid or comet collision in Rhea's distant past. Such a collision may have pitched large quantities of gas and solid particles around Rhea. Once the gas dissipated, all that remained were the ring particles. Other moons of Saturn, such as Mimas, show evidence of a catastrophic collision that almost tore the moon apart.

"The diversity in our solar system never fails to amaze us," said Candy Hansen, co-author and Cassini scientist on the Ultraviolet Imaging Spectrograph at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Many years ago we thought Saturn was the only planet with rings. Now we may have a moon of Saturn that is a miniature version of its even more elaborately decorated parent."

These ring findings make Rhea a prime candidate for further study. Initial observations by the imaging team when Rhea was near the sun in the sky did not detect dust near the moon remotely. Additional observations are planned to look for the larger particles.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL. The Magnetospheric Imaging Instrument was designed, built and is operated by an international team led by the Applied Physics Laboratory of the Johns Hopkins University, Laurel, Md.

For information on the Cassini mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/07/2008 09:57 AM
Saturn's moon Rhea may also have rings

7 March 2008
The Cassini spacecraft has found evidence of material orbiting Rhea, Saturn's second largest moon. This is the first time rings may have been found around a moon.

http://www.esa.int/esaCP/SEMY6NK26DF_index_0.html
Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/10/2008 06:31 PM
RELEASE: 08-078

CASSINI SPACECRAFT TO DIVE INTO WATER PLUME OF SATURN MOON

PASADENA, Calif. - NASA's Cassini spacecraft will make an
unprecedented "in your face" flyby of Saturn's moon Enceladus on
Wed., March 12.

The spacecraft, orchestrating its closest approach to date, will skirt
along the edges of huge Old-Faithful-like geysers erupting from giant
fractures on the south pole of Enceladus. Cassini will sample
scientifically valuable water-ice, dust and gas in the plume.

The source of the geysers is of great interest to scientists who think
liquid water, perhaps even an ocean, may exist in the area. While
flying through the edge of the plumes, Cassini will be approximately
120 miles from the surface. At closest approach to Enceladus, Cassini
will be only 30 miles from the moon.

"This daring flyby requires exquisite technical finesse, but it has
the potential to revolutionize our knowledge of the geysers of
Enceladus. The Cassini mission team is eager to see the scientific
results, and so am I," said Alan Stern, associate administrator of
NASA's Science Mission Directorate, Washington.

Scientists and mission personnel studying the anatomy of the plumes
have found that flying at these close distances poses little threat
to Cassini because, despite the high speed of Cassini, the plume
particles are small. The spacecraft routinely crosses regions made up
of dust-size particles in its orbit around Saturn.

Cassini's cameras will take a back seat on this flyby as the main
focus turns to the spacecraft's particle analyzers that will study
the composition of the plumes. The cameras will image Enceladus on
the way in and out, between the observations of the particle
analyzers.

Images will reveal northern regions of the moon previously not
captured by Cassini. The analyzers will "sniff and taste" the plume.
Information on the density, size, composition and speed of the gas
and the particles will be collected.

"There are two types of particles coming from Enceladus, one pure
water-ice, the other water-ice mixed with other stuff," said Sascha
Kempf, deputy principal investigator for Cassini's Cosmic Dust
Analyzer at the Max Planck Institute for Nuclear Physics in
Heidelberg, Germany. "We think the clean water-ice particles are
being bounced off the surface and the dirty water-ice particles are
coming from inside the moon. This flyby will show us whether this
concept is right or wrong."

In 2005, Cassini's multiple instruments discovered that this icy
outpost is gushing water vapor geysers out to a distance of three
times the radius of Enceladus. The moon is only 310 miles in
diameter, but despite its petite size, its one of the most
scientifically compelling bodies in our solar system. The icy water
particles are roughly one ten-thousandth of an inch, or about the
width of a human hair. The particles and gas escape the surface at
jet speed at approximately 800 miles per hour. The eruptions appear
to be continuous, refreshing the surface and generating an enormous
halo of fine ice dust around Enceladus, which supplies material to
one of Saturn's rings, the E-ring.

Several gases, including water vapor, carbon dioxide, methane, perhaps
a little ammonia and either carbon monoxide or nitrogen gas make up
the gaseous envelope of the plume.

"We want to know if there is a difference in composition of gases
coming from the plume versus the material surrounding the moon. This
may help answer the question of how the plume formed," said Hunter
Waite, principal investigator for Cassini's Ion and Neutral Mass
Spectrometer at the Southwest Research Institute, San Antonio.

This is the first of four Cassini flybys of Enceladus this year. In
June, Cassini completes its prime mission, a four-year tour of
Saturn. Cassini's next flyby of Enceladus is planned for August, well
into Cassini's proposed extended mission. Cassini will perform seven
Enceladus flybys in its extended mission. If this encounter proves
safe, future passes may bring the spacecraft even closer than this
one. How close Cassini will be allowed to approach will be determined
based on data from this flyby.

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. JPL manages the
Cassini-Huygens mission for NASA's Science Mission Directorate. The
Cassini orbiter was designed, developed and assembled at JPL.

For images and more information about the Cassini mission and the
Enceladus flyby, visit:

http://www.nasa.gov/cassini

Title: Re: NASA - Cassini updates
Post by: eeergo on 03/12/2008 09:09 PM
The flyby has been performed! What mysteries are just on the verge of being thrown into the light? Wow, this week there's too many news!

Great video of the flyby's observations in the blog: http://blogs.nasa.gov/cm/blog/Enceladus%20Flyby
http://blogs.nasa.gov/cm/blog/Enceladus%20Flyby/1000811main_61En_movie_h264.mov
Title: Re: NASA - Cassini updates
Post by: eeergo on 03/14/2008 11:29 AM

News about the flyby: http://www.nasa.gov/mission_pages/cassini/media/cassini-20080313.html

Apparently, while the CDA (Cosmic Dust Analyzer, see the thread in the general section) wasn't able to record any data during closest approach because of a software glitch, it did before and after, so the instrument wasn't rendered useless after all.

"During Cassini's closest approach, two instruments were collecting data--the Cosmic Dust Analyzer and the Ion and Neutral Mass Spectrometer. An unexplained software hiccup with Cassini's Cosmic Dust Analyzer instrument prevented it from collecting any data during closest approach, although the instrument did get data before and after the approach. During the flyby, the instrument was switching between two versions of software programs. The new version was designed to increase the ability to count particle hits by several hundred hits per second. The other four fields and particles instruments on the spacecraft, in addition to the ion and neutral mass spectrometer, did capture all of their data, which will complement the overall composition studies and elucidate the unique plume environment of Enceladus. "

Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/20/2008 09:20 PM
MEDIA ADVISORY: M08-061

NASA TO RELEASE NEW DETAILS FROM CLOSE FLYBY OF SATURN MOON

WASHINGTON - NASA will hold a news conference at 2 p.m. EDT,
Wednesday, March 26, to present new clues on the composition of the
icy plumes jetting off the surface of Saturn's moon Enceladus. The
findings were obtained March 12 during the closest flyby of the moon
by the Cassini spacecraft. The briefing will take place in the NASA
Headquarters television studio, 300 E St., S.W., Washington, and will
be carried live on NASA Television.

Participants in the press conference will be:
- Hunter Waite, Southwest Research Institute, San Antonio, principal
investigator, Ion and Neutral Mass Spectrometer
- John Spencer, Southwest Research Institute, Boulder, Colo.,
co-investigator, Composite Infrared Spectrometer
- Larry Esposito, University of Colorado, Boulder, principal
investigator, Ultraviolet Imaging Spectrograph
- Carolyn Porco, Space Science Institute, Boulder, team leader,
Imaging Science Subsystem

Participating NASA centers will provide question-and-answer capability
for reporters.

For NASA TV streaming video, scheduling and downlink information,
visit:

http://www.nasa.gov/ntv
Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/20/2008 09:20 PM
RELEASE: 08-085

CASSINI SPACECRAFT FINDS OCEAN MAY EXIST BENEATH TITAN'S CRUST

PASADENA, Calif. - NASA's Cassini spacecraft has discovered evidence
that points to the existence of an underground ocean of water and
ammonia on Saturn's moon Titan. The findings made using radar
measurements of Titan's rotation will appear in the March 21 issue of
the journal Science.

"With its organic dunes, lakes, channels and mountains, Titan has one
of the most varied, active and Earth-like surfaces in the solar
system," said Ralph Lorenz, lead author of the paper and Cassini
radar scientist at the Johns Hopkins Applied Physics Laboratory in
Laurel, Md., "Now we see changes in the way Titan rotates, giving us
a window into Titan's interior beneath the surface."

Members of the mission's science team used Cassini's Synthetic
Aperture Radar to collect imaging data during 19 separate passes over
Titan between October 2005 and May 2007. The radar can see through
Titan's dense, methane-rich atmospheric haze, detailing
never-before-seen surface features and establishing their locations
on the moon's surface.

Using data from the radar's early observations, the scientists and
radar engineers established the locations of 50 unique landmarks on
Titan's surface. They then searched for these same lakes, canyons and
mountains in the reams of data returned by Cassini in its later
flybys of Titan. They found prominent surface features had shifted
from their expected positions by up to 19 miles. A systematic
displacement of surface features would be difficult to explain unless
the moon's icy crust was decoupled from its core by an internal
ocean, making it easier for the crust to move.

"We believe that about 62 miles beneath the ice and organic-rich
surface is an internal ocean of liquid water mixed with ammonia,"
said Bryan Stiles of NASA's Jet Propulsion Laboratory (JPL) in,
Pasadena, Calif. Stiles also is a contributing author to the paper.

The study of Titan is a major goal of the Cassini-Huygens mission
because it may preserve, in deep-freeze, many of the chemical
compounds that preceded life on Earth. Titan is the only moon in the
solar system that possesses a dense atmosphere. The moon's atmosphere
is 1.5 times denser than Earth's. Titan is the largest of Saturn's
moons, bigger than the planet Mercury.

"The combination of an organic-rich environment and liquid water is
very appealing to astrobiologists," Lorenz said. "Further study of
Titan's rotation will let us understand the watery interior better,
and because the spin of the crust and the winds in the atmosphere are
linked, we might see seasonal variation in the spin in the next few
years."

Cassini scientists will not have long to wait before another go at
Titan. On March 25, just prior to its closest approach at an altitude
of 620 miles, Cassini will employ its Ion and Neutral Mass
Spectrometer to examine Titan's upper atmosphere. Immediately after
closest approach, the spacecraft's Visual and Infrared Mapping
Spectrometer will capture high-resolution images of Titan's southeast
quadrant.

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The mission is
managed by JPL, a division of the California Institute of Technology
in Pasadena. The Cassini orbiter also was designed, developed and
assembled at JPL.

For information about Cassini visit:

http://www.nasa.gov/cassini/
Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/25/2008 12:51 PM
Cassini has discovered evidence that points to the existence of an underground ocean of water and ammonia on Saturn's moon Titan. The findings were made using radar measurements of Titan's rotation.


Read more at:

http://www.esa.int/SPECIALS/Cassini-Huygens/SEM52QQ03EF_0.html
Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/26/2008 06:26 PM
RELEASE: 08-089

CASSINI TASTES ORGANIC MATERIAL AT SATURN'S GEYSER MOON

PASADENA, Calif. -- NASA's Cassini spacecraft tasted and sampled a
surprising organic brew erupting in geyser-like fashion from Saturn's
moon Enceladus during a close flyby on March 12. Scientists are
amazed that this tiny moon is so active, "hot" and brimming with
water vapor and organic chemicals.

New heat maps of the surface show higher temperatures than previously
known in the south polar region, with hot tracks running the length
of giant fissures. Additionally, scientists say the organics "taste
and smell" like some of those found in a comet. The jets themselves
harmlessly peppered Cassini, exerting measurable torque on the
spacecraft, and providing an indirect measure of the plume density.

"A completely unexpected surprise is that the chemistry of Enceladus,
what's coming out from inside, resembles that of a comet," said
Hunter Waite, principal investigator for the Cassini Ion and Neutral
Mass Spectrometer at the Southwest Research Institute in San Antonio.
"To have primordial material coming out from inside a Saturn moon
raises many questions on the formation of the Saturn system."

"Enceladus is by no means a comet. Comets have tails and orbit the
sun, and Enceladus' activity is powered by internal heat while comet
activity is powered by sunlight. Enceladus' brew is like carbonated
water with an essence of natural gas," said Waite.

The Ion and Neutral Mass Spectrometer saw a much higher density of
volatile gases, water vapor, carbon dioxide and carbon monoxide, as
well as organic materials, some 20 times denser than expected. This
dramatic increase in density was evident as the spacecraft flew over
the area of the plumes.

New high-resolution heat maps of the south pole by Cassini's Composite
Infrared Spectrometer show that the so-called tiger stripes, giant
fissures that are the source of the geysers, are warm along almost
their entire lengths, and reveal other warm fissures nearby. These
more precise new measurements reveal temperatures of at least minus
135 degrees Fahrenheit. That is 63 degrees Fahrenheit warmer than
previously seen and 200 degrees Fahrenheit warmer than other regions
of the moon. The warmest regions along the tiger stripes correspond
to two of the jet locations seen in Cassini images.

"These spectacular new data will really help us understand what powers
the geysers. The surprisingly high temperatures make it more likely
that there's liquid water not far below the surface," said John
Spencer, Cassini scientist on the Composite Infrared Spectrometer
team at the Southwest Research Institute in Boulder, Colo.

Previous ultraviolet observations showed four jet sources, matching
the locations of the plumes seen in previous images. This indicates
that gas in the plume blasts off the surface into space, blending to
form the larger plume.

Images from previous observations show individual jets and mark places
from which they emanate. New images show how hot spot fractures are
related to other surface features. In future imaging observations,
scientists hope to see individual plume sources and investigate
differences among fractures.

"Enceladus has got warmth, water and organic chemicals, some of the
essential building blocks needed for life," said Dennis Matson,
Cassini project scientist at NASA's Jet Propulsion Laboratory in
Pasadena, Calif. "We have quite a recipe for life on our hands, but
we have yet to find the final ingredient, liquid water, but Enceladus
is only whetting our appetites for more."

At closest approach, Cassini was only 30 miles from Enceladus. When it
flew through the plumes it was 120 miles from the moon's surface.
Cassini's next flyby of Enceladus is in August.

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The mission is
managed by JPL for NASA's Science Mission Directorate, Washington.

For images and more information, visit:

http://www.nasa.gov/cassini
Title: Re: NASA - Cassini updates
Post by: eeergo on 03/26/2008 07:10 PM
This is huge... another moon to look really seriously at, to add to the Titan and Europa list (my list would run too long if we counted geologically interesting moons, I'm just referring to the best candidates for liquid water ;) )Still shuffling through the information, Cassini is simply wonderful.
Title: Re: NASA - Cassini updates
Post by: Eerie on 03/26/2008 07:27 PM
Quote
eeergo - 26/3/2008  3:10 PM

This is huge... another moon to look really seriously at, to add to the Titan and Europa list (my list would run too long if we counted geologically interesting moons, I'm just referring to the best candidates for liquid water ;) )Still shuffling through the information, Cassini is simply wonderful.

Meh, luquid water underground is boring. Give me liquid water on the surface any day...
Title: Re: NASA - Cassini updates
Post by: on 03/26/2008 10:55 PM
The impressive result here is the beginnings of a rational understanding of how Saturn's moons "geology" functions.

Didn't think we'd learn this to much later missions. Cassini/Huygens is turning out to be a legendary mission in many ways.

It also has humorous notes - we're looking at the end of hydrocarbon fuels on Earth, at a time when a planetary-scale refinery has been discovered within our solar system. How ironic. We are even understanding how it works.
Title: Re: NASA - Cassini updates
Post by: eeergo on 03/27/2008 07:54 PM

Quote
nobodyofconsequence - 27/3/2008  12:55 AMThe impressive result here is the beginnings of a rational understanding of how Saturn's moons "geology" functions.Didn't think we'd learn this to much later missions. Cassini/Huygens is turning out to be a legendary mission in many ways.It also has humorous notes - we're looking at the end of hydrocarbon fuels on Earth, at a time when a planetary-scale refinery has been discovered within our solar system. How ironic. We are even understanding how it works.

Agreed on those. :) There has been a media briefing update (kindly recorded by John44, now in Space-Multimedia) and here  it can be replayed.

Title: Re: NASA - Cassini updates
Post by: eeergo on 04/06/2008 09:32 PM
Interesting article by Planetary Society blogger Emily Lakdawalla about topographic features in Titan:

http://www.planetary.org/blog/article/00001385/
Title: Re: NASA - Cassini updates
Post by: meiza on 04/06/2008 10:11 PM
Thanks eeergo, good stuff.
Title: Re: NASA - Cassini updates
Post by: Crispy on 04/06/2008 10:35 PM
This is some fascinating science right here and no mistake :)
Title: Re: NASA - Cassini updates
Post by: jacqmans on 04/15/2008 03:06 PM
RELEASE: 08-098

NASA EXTENDS CASSINI'S GRAND TOUR OF SATURN

PASADENA, Calif. -- NASA is extending the international
Cassini-Huygens mission by two years. The historic spacecraft's
stunning discoveries and images have revolutionized our knowledge of
Saturn and its moons.

Cassini's mission originally had been scheduled to end in July 2008.
The newly-announced two-year extension will include 60 additional
orbits of Saturn and more flybys of its exotic moons. These will
include 26 flybys of Titan, seven of Enceladus, and one each of
Dione, Rhea and Helene. The extension also includes studies of
Saturn's rings, its complex magnetosphere, and the planet itself.

"This extension is not only exciting for the science community, but
for the world to continue to share in unlocking Saturn's secrets,"
said Jim Green, director, Planetary Science Division, NASA
Headquarters, Washington. "New discoveries are the hallmarks of its
success, along with the breathtaking images beamed back to Earth that
are simply mesmerizing."

"The spacecraft is performing exceptionally well and the team is
highly motivated, so we're excited at the prospect of another two
years," said Bob Mitchell, Cassini program manager at NASA's Jet
Propulsion Laboratory in Pasadena, Calif.

Based on findings from Cassini, scientists think liquid water may be
just beneath the surface of Saturn's moon, Enceladus. That's why the
small moon, only one-tenth the size of Titan and one-seventh the size
of Earth's moon, is one of the highest-priority targets for the
extended mission.

Cassini discovered geysers of water-ice jetting from the Enceladus'
surface. The geysers, which shoot out at a distance three times the
diameter of Enceladus, feed particles into Saturn's most expansive
ring. In the extended mission, the spacecraft may come as close as 15
miles from the moon's surface.

Cassini's observations of Saturn's largest moon, Titan, have given
scientists a glimpse of what Earth might have been like before life
evolved. They now believe Titan possesses many parallels to Earth,
including lakes, rivers, channels, dunes, rain, snow, clouds,
mountains and possibly volcanoes.

"When we designed the original tour, we really did not know what we
would find, especially at Enceladus and Titan," said Dennis Matson,
the JPL Cassini project scientist. "This extended tour is responding
to these new discoveries and giving us a chance to look for more."

Unlike Earth, Titan's lakes, rivers and rain are composed of methane
and ethane, and temperatures reach a chilly minus 290 degrees
Fahrenheit. Although Titan's dense atmosphere limits viewing the
surface, Cassini's high-resolution radar coverage and imaging by the
infrared spectrometer have given scientists a better look.

Other activities for Cassini scientists will include monitoring
seasons on Titan and Saturn, observing unique ring events, such as
the 2009 equinox when the sun will be in the plane of the rings, and
exploring new places within Saturn's magnetosphere.

Cassini has returned a daily stream of data from Saturn's system for
almost four years. Its travel scrapbook includes nearly 140,000
images and information gathered during 62 revolutions around Saturn,
43 flybys of Titan and 12 close flybys of the icy moons.

More than 10 years after launch and almost four years after entering
into orbit around Saturn, Cassini is a healthy and robust spacecraft.
Three of its science instruments have minor ailments, but the impact
on science-gathering is minimal. The spacecraft will have enough
propellant left after the extended mission to potentially allow a
third phase of operations. Data from the extended mission could lay
the groundwork for possible new missions to Titan and Enceladus.

Cassini launched Oct. 15, 1997, from Cape Canaveral, Fla., on a
seven-year journey to Saturn, traversing 2.2 billion miles. It is one
of the most scientifically capable spacecraft ever launched, with a
record 12 instruments on the orbiter and six more instruments on the
European Space Agency's Huygens probe, which piggybacked a ride to
Titan on Cassini. Cassini receives electrical power from three
radioisotope thermoelectric generators, which generate electricity
from heat produced by the natural decay of plutonium. The spacecraft
was captured into Saturn orbit in June 2004 and immediately began
returning data to Earth.

The Cassini-Huygens mission is a cooperative project between NASA, the
European Space Agency and the Italian Space Agency.

For more information on the Cassini-Huygens mission, visit:

http://www.nasa.gov/cassini
Title: Re: NASA - Cassini updates
Post by: marsavian on 04/15/2008 05:29 PM
Excellent news.
Title: Re: NASA - Cassini updates
Post by: iamlucky13 on 04/15/2008 06:52 PM
Awesome. I've been waiting to hear this for a while.

I noticed that the original mission completed 62 revolutions in 4 years. The extension will do 60 revs in 2 years. I guess they've over time through gravity assists off the moons and perhaps thruster burns reduced the apoapsis?

Does anyone know how much fuel is left? Is there just enough for RCS needs, or will they be able tailor the flyby's as they've been doing? Has NASA determined if they will need to (or even can) ultimately terminate Cassini's mission a la Galileo for planetary protection purposes?
Title: Re: NASA - Cassini updates
Post by: Lampyridae on 04/16/2008 04:32 AM
I guess this must be how people felt when the first radar maps of Venus started coming in. This is really fascinating, really wonderful science being done by the Cassini crowd. I'm already itching for a second probe to Titan!
Title: Re: NASA - Cassini updates
Post by: jacqmans on 04/17/2008 07:20 PM
NEWS RELEASE: 2008-065                                                                        April 17, 2008

Saturn Images Showcased in New York City

A selection of the best images from Saturn, its rings and moons will appear in an exhibition opening on April 26 at the American Museum of Natural History in New York City.

The show, called "Saturn: Images from the Cassini-Huygens Mission," will run through March 29, 2009. It features dramatic, up-close-and-personal images in small individual views and super-large mosaics. Roughly 50 images taken by the Cassini-Huygens mission in visible light, infrared and radar have been hand-picked by a team of Cassini scientists.

"The images show the Saturn system as we had never seen it before. They perfectly blend exploration, science and beauty," said Joe Burns, the exhibit's guest co-curator and a Cassini imaging scientist at Cornell University, Ithaca, N.Y. "We are excited to have the opportunity to show these breathtaking photographs to the broader public in one of the world's greatest science museums." Burns, along with colleagues at Cornell University and on the Cassini project, has been collaborating with museum curators for the past year on the image selection, scientific captions and exhibit design.

The Cassini spacecraft has been in orbit around Saturn for nearly four years. It is the first orbiter to study Saturn in detail. The piggybacked Huygens probe, provided by the European Space Agency, plunged through the atmosphere of Saturn's largest moon, Titan, in 2005. Huygens was the first probe to land on the surface of a moon other than our own. The orbiter and probe have shown birdseye and ground-level views of Titan, an Earth-like world featuring river valley networks and lakes filled with hydrocarbons. Cassini has discovered water-ice geysers spewing from Enceladus, a smaller moon of Saturn, and has detected five new moons and observed a very dynamic ring system.

For exhibition information see: http://www.amnh.org/exhibitions/photo/saturn/ .   More information about the Cassini-Huygens mission is available at: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL.

-end-

Title: Re: NASA - Cassini updates
Post by: jacqmans on 04/29/2008 08:50 PM
Image Advisory: 2008-069                            April 29, 2008

NASA Spacecraft Tracks Raging Saturn Storm

PASADENA, Calif. -- As a powerful electrical storm rages on Saturn with lightning bolts 10,000 times more powerful than those found on Earth, the Cassini spacecraft continues its five-month watch over the dramatic events.

Scientists with NASA's Cassini-Huygens mission have been tracking the visibly bright, lightning-generating storm--the longest continually observed electrical storm ever monitored by Cassini.

Saturn's electrical storms resemble terrestrial thunderstorms, but on a much larger scale. Storms on Saturn have diameters of several thousand kilometers (thousands of miles), and radio signals produced by their lightning are thousands of times more powerful than those produced by terrestrial thunderstorms.

Color images of the storm are available at: http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini and http://ciclops.org .

Lightning flashes within the persistent storm produce radio waves called Saturn electrostatic discharges, which the radio and plasma wave science instrument first detected on Nov. 27, 2007. Cassini's imaging cameras monitored the position and appearance of the storm, first spotting it about a week later, on Dec. 6.

"The electrostatic radio outbursts have waxed and waned in intensity for five months now," said Georg Fischer, an associate with the radio and plasma wave science team at the University of Iowa, Iowa City. "We saw similar storms in 2004 and 2006 that each lasted for nearly a month, but this storm is longer-lived by far. And it appeared after nearly two years during which we did not detect any electrical storm activity from Saturn."



The new storm is located in Saturn's southern hemisphere--in a region nicknamed "Storm Alley" by mission scientists--where the previous lightning storms were observed by Cassini.

"In order to see the storm, the imaging cameras have to be looking at the right place at the right time, and whenever our cameras see the storm, the radio outbursts are there," said Ulyana Dyudina, an associate of the Cassini imaging team at the California Institute of Technology in Pasadena, Calif.

Cassini's radio plasma wave instrument detects the storm every time it rotates into view, which happens every 10 hours and 40 minutes, the approximate length of a Saturn day. Every few seconds the storm gives off a radio pulse lasting for about a tenth of a second, which is typical of lightning bolts and other electrical discharges. These radio waves are detected even when the storm is over the horizon as viewed from Cassini, a result of the bending of radio waves by the planet's atmosphere.

Amateur astronomers have kept track of the storm over its five-month lifetime. "Since Cassini's camera cannot track the storm every day, the amateur data are invaluable," said Fischer. "I am in continuous contact with astronomers from around the world."

The long-lived storm will likely provide information on the processes powering Saturn's intense lightning activity. Cassini scientists will continue to monitor Storm Alley as the seasons change, bringing the onset of autumn to the planet's southern hemisphere.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of Caltech, manages the Cassini mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. The radio and plasma wave science team is based at the University of Iowa, Iowa City.

-end-

Title: Re: NASA - Cassini updates
Post by: jacqmans on 05/08/2008 03:14 AM
Feature                                                         May 7, 2008

 

Saturn Does the Wave in Upper Atmosphere

 

 Two decades of scrutinizing Saturn are finally paying off, as scientists have discovered a wave pattern, or oscillation, in Saturn's atmosphere only visible from Earth every 15 years.

The discovery of the wave pattern is the result of a 22-year campaign observing Saturn from Earth (the longest study of temperature outside Earth ever recorded), and the Cassini spacecraft's observations of temperature changes in the giant planet's atmosphere over time.

The Cassini infrared results, which appear in the same issue of Nature as the data from the 22-year ground-based observing campaign, indicate that Saturn's wave pattern is similar to a pattern found in Earth's upper atmosphere. The earthly oscillation takes about two years. A similar pattern on Jupiter takes more than four Earth years. The new Saturn findings add a common link to the three planets.

Just as scientists have been studying climate changes in Earth's atmosphere for long periods of time, NASA scientists have been studying changes in Saturn's atmosphere. Glenn Orton of NASA's Jet Propulsion Laboratory in Pasadena, Calif., says patience is the key to studying changes over the course of a Saturnian year, the equivalent of about 30 Earth years.

"You could only make this discovery by observing Saturn over a long period of time," said Orton, lead author of the ground-based study. "It's like putting together 22 years worth of puzzle pieces, collected by a hugely rewarding collaboration of students and scientists from around the world on various telescopes."

The wave pattern is called an atmospheric oscillation. It ripples back and forth within Saturn's upper atmosphere. In this region, temperatures switch from one altitude to the next in a candy cane-like, striped, hot-cold pattern. These varying temperatures force the wind in the region to keep changing direction from east to west, jumping back and forth. As a result, the entire region oscillates like a wave.

A "snapshot" of the hot-cold temperature patterns in Saturn's atmosphere was captured by the Cassini Composite Infrared Spectrometer. Along with Earth-based data, the "snapshot" also uncovered other interesting phenomena. Among them: the temperature at Saturn's equator switches from hot to cold, and temperatures on either side of the equator switch from cold to hot every Saturn half-year.

Mike Flasar, co-author of the Cassini paper, and principal investigator for Cassini's Composite Infrared Spectrometer at NASA's Goddard Space Flight Center, Greenbelt, Md., said that Cassini helped define this oscillation in combination with the ground observation campaign.

"It's this great synergy of using ground-based data over time, and then getting up close and personal with the oscillation in Saturn's atmosphere through Cassini," said Flasar. "Without Cassini, we might never have seen the structure of the oscillation in detail."

Cassini scientists hope to find out why this phenomenon on Saturn changes with the seasons, and why the temperature switchover happens when the sun is directly over Saturn's equator.

More information on the Cassini-Huygens mission can be found at: http://saturn.jpl.nasa.gov, and http://www.nasa.gov/cassini.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The Composite Infrared Spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md.

-- Written by Diya Chacko

Media Contact:

Diya Chacko/ Carolina Martinez    818-393-5464/354-9382

Title: Re: NASA - Cassini updates
Post by: eeergo on 05/08/2008 12:03 PM
Interesting pdf about Cassini's next flyby of Titan (T48), with a detailed timeline at the end:

http://saturn.jpl.nasa.gov/multimedia/products/pdfs/20080512_titan_mission_description.pdf

Coming up this Monday!
Title: Re: NASA - Cassini updates
Post by: jacqmans on 06/27/2008 07:16 PM
NEWS RELEASE: 2008-122                                                                          June 27, 2008

Cassini to Earth: 'Mission Accomplished, But New Questions Await!'

PASADENA, Calif.—NASA's Cassini mission is closing one chapter of its journey at Saturn and embarking on a new one with a two-year mission that will address new questions and bring it closer to two of its most intriguing targets—Titan and Enceladus.

On June 30, Cassini completes its four-year prime mission and begins its extended mission, which was approved in April of this year.

Among other things, Cassini revealed the Earth-like world of Saturn's moon Titan and showed the potential habitability of another moon, Enceladus. These two worlds are primary targets in the two-year extended mission, dubbed the Cassini Equinox Mission. This time period also will allow for monitoring seasonal effects on Titan and Saturn, exploring new places within Saturn's magnetosphere, and observing the unique ring geometry of the Saturn equinox in August of 2009 when sunlight will pass directly through the plane of the rings.

"We've had a wonderful mission and a very eventful one in terms of the scientific discoveries we've made, and yet an uneventful one when it comes to the spacecraft behaving so well," said Bob Mitchell, Cassini program manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We are incredibly proud to have completed all of the objectives we set out to accomplish when we launched.  We answered old questions and raised quite a few new ones and so our journey continues."

A new addition to the Cassini science team is Bob Pappalardo who will step into the role of Cassini Project Scientist in July, taking over for Dennis Matson, a multi-year veteran on the project who will be working on future flagship mission studies to the outer solar system. "I am honored and humbled to be able to work with such a scientifically rich mission, and with the outstanding scientists and engineers who are the backbone of Cassini," said Pappalardo.

Pappalardo is a geologist whose research focuses on processes that have shaped the icy moons of the outer solar system, including processes that power the geysers of Saturn's moon Enceladus.

He received his bachelor's degree from Cornell University, Ithaca, N.Y., and his Ph.D. in geology from Arizona State University, Tempe. He worked with the Galileo imaging team while a Postdoctoral Researcher at Brown University, Providence, RI. Prior to joining JPL in 2006, he was an assistant professor of planetary sciences at the University of Colorado at Boulder. Currently he resides in Venice, Calif.  More information on Pappalardo is at http://science.jpl.nasa.gov/people/Pappalardo .

Cassini launched Oct. 15, 1997, from Cape Canaveral, Fla., on a seven-year journey to Saturn, traversing 3.5 billion kilometers (2.2 billion miles).  The mission entered Saturn's orbit on June 30, 2004, and began returning stunning data of Saturn's rings almost immediately. The spacecraft is extremely healthy and carries 12 instruments powered by three radioisotope thermoelectric generators. Data from Cassini's nominal and extended missions could lay the groundwork for possible future missions to Saturn, Titan or Enceladus.

Information about the Cassini Equinox Mission is at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

The Cassini Equinox Mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL.

Title: Re: NASA - Cassini updates
Post by: jacqmans on 07/31/2008 04:28 AM
RELEASE: 08-193

NASA CONFIRMS LIQUID LAKE ON SATURN MOON

PASADENA, Calif. -- NASA scientists have concluded that at least one
of the large lakes observed on Saturn's moon Titan contains liquid
hydrocarbons, and have positively identified the presence of ethane.
This makes Titan the only body in our solar system beyond Earth known
to have liquid on its surface.

Scientists made the discovery using data from an instrument aboard the
Cassini spacecraft. The instrument identified chemically different
materials based on the way they absorb and reflect infrared light.
Before Cassini, scientists thought Titan would have global oceans of
methane, ethane and other light hydrocarbons. More than 40 close
flybys of Titan by Cassini show no such global oceans exist, but
hundreds of dark lake-like features are present. Until now, it was
not known whether these features were liquid or simply dark, solid
material.

"This is the first observation that really pins down that Titan has a
surface lake filled with liquid," said Bob Brown of the University of
Arizona, Tucson. Brown is the team leader of Cassini's visual and
mapping instrument. The results will be published in the July 31
issue of the journal Nature.

Ethane and several other simple hydrocarbons have been identified in
Titan's atmosphere, which consists of 95 percent nitrogen, with
methane making up the other 5 percent. Ethane and other hydrocarbons
are products from atmospheric chemistry caused by the breakdown of
methane by sunlight.

Some of the hydrocarbons react further and form fine aerosol
particles. All of these things in Titan's atmosphere make detecting
and identifying materials on the surface difficult, because these
particles form a ubiquitous hydrocarbon haze that hinders the view.
Liquid ethane was identified using a technique that removed the
interference from the atmospheric hydrocarbons.

The visual and mapping instrument observed a lake, Ontario Lacus, in
Titan's south polar region during a close Cassini flyby in December
2007. The lake is roughly 7,800 square miles in area, slightly larger
than North America's Lake Ontario.

"Detection of liquid ethane confirms a long-held idea that lakes and
seas filled with methane and ethane exist on Titan," said Larry
Soderblom, a Cassini interdisciplinary scientist with the U.S.
Geological Survey in Flagstaff, Ariz. "The fact we could detect the
ethane spectral signatures of the lake even when it was so dimly
illuminated, and at a slanted viewing path through Titan's
atmosphere, raises expectations for exciting future lake discoveries
by our instrument."

The ethane is in a liquid solution with methane, other hydrocarbons
and nitrogen. At Titan's surface temperatures, approximately 300
degrees Fahrenheit below zero, these substances can exist as both
liquid and gas. Titan shows overwhelming evidence of evaporation,
rain, and fluid-carved channels draining into what, in this case, is
a liquid hydrocarbon lake.

Earth has a hydrological cycle based on water and Titan has a cycle
based on methane. Scientists ruled out the presence of water ice,
ammonia, ammonia hydrate and carbon dioxide in Ontario Lacus. The
observations also suggest the lake is evaporating. It is ringed by a
dark beach, where the black lake merges with the bright shoreline.
Cassini also observed a shelf and beach being exposed as the lake
evaporates.

"During the next few years, the vast array of lakes and seas on
Titan's north pole mapped with Cassini's radar instrument will emerge
from polar darkness into sunlight, giving the infrared instrument
rich opportunities to watch for seasonal changes of Titan's lakes,"
Soderblom said.

Launched in Oct. 1997, Cassini's 12 instruments have returned a daily
stream of data from Saturn's system. The mission is a cooperative
project of NASA, the European Space Agency and the Italian Space
Agency.
Title: Re: NASA - Cassini updates
Post by: Orbiter on 07/31/2008 04:44 AM
Thanks for your info!
Title: Re: NASA - Cassini updates
Post by: jacqmans on 08/07/2008 06:46 PM
NEWS RELEASE: 2008-156                                                             Aug. 7, 2008

Cassini Prepares to Swoop by Saturn's Geyser-Spewing Moon

Fractures, or "tiger stripes," where icy jets erupt on Saturn's moon Enceladus will be the target of a close flyby by the Cassini spacecraft on Monday, Aug. 11.

Cassini will zoom past the tiny moon a mere 50 kilometers (30 miles) from the surface. Just after closest approach, all of the spacecraft's cameras -- covering infrared wavelengths, where temperatures are mapped, as well as visible light and ultraviolet -- will focus on the fissures running along the moon's south pole. That is where the jets of icy water vapor emanate and erupt hundreds of miles into space. Those jets have fascinated scientists since their discovery in 2005.

"Our main goal is to get the most detailed images and remote sensing data ever of the geologically active features on Enceladus," said Paul Helfenstein, a Cassini imaging team associate at Cornell University in Ithaca, NY. "From this data we may learn more about how eruptions, tectonics, and seismic activity alter the moon's surface. We will get an unprecedented high-resolution view of the active area immediately following the closest approach."

Seeing inside one of the fissures in high resolution may provide more information on the terrain and depth of the fissures, as well as the size and composition of the ice grains inside.  Refined temperature data could help scientists determine if water, in vapor or liquid form, lies close to the surface and better refine their theories on what powers the jets.

Imaging sequences will capture stereo views of the north polar terrain, and high resolution images of the south polar region will begin shortly after closest approach to Enceladus. The image resolution will be as fine as 7 meters per pixel (23 feet) and will cover known active spots on three of the prominent "tiger stripe" fractures.

In addition to mapping the moon's surface in visible light as well as infrared and ultraviolet light, Cassini will help determine the size of the ice grains and distinguish other elements mixed in with the ice, such as oxygen, hydrogen, or organics.

"Knowing the sizes of the particles, their rates and what else is mixed in these jets can tell us a lot about what's happening inside the little moon," said Amanda Hendrix, Cassini ultraviolet imaging spectrograph team member at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Other instruments will measure the temperatures along the fractures, which happen to be some of the hottest spots on the moon's surface.

"We'd like to refine our numbers and see which fracture or stripe is hotter than the rest because these results can offer evidence, one way or the other, for the existence of liquid water as the engine that powers the plumes," said Bonnie Buratti of JPL, team member on Cassini's visual and infrared mapping spectrometer.

Cassini discovered evidence for the geyser-like jets on Enceladus in 2005, finding that the continuous eruptions of ice water create a gigantic halo of ice and gas around Enceladus, which helps supply material to Saturn's E-ring. This marks Cassini's second flyby of Enceladus this year. During Cassini's last flyby of Enceladus in March, the spacecraft snatched up precious samples and tasted comet-like organics inside the little moon. Two more Enceladus flybys are coming up in October, and they may bring the spacecraft even closer to the moon. The Oct. 9 encounter is complimentary to the March one, which was optimized for sampling the plume. The Oct. 31 flyby is similar to this August one, and is again optimized for the optical remote sensing instruments.

For images, videos and a mission blog on the flyby, visit:   

http://www.nasa.gov/cassini . More information on the Cassini mission is also available at http://saturn.jpl.nasa.gov .

Title: Re: NASA - Cassini updates
Post by: jacqmans on 08/12/2008 08:51 AM
Mission Status Report: 2008-157                                                         Aug. 11, 2008

Cassini Begins Transmitting Data From Enceladus Flyby

Shorty after 9:03 p.m. Pacific Time, the Cassini spacecraft began sending data to Earth following a close flyby of Saturn's moon Enceladus. During closest approach, Cassini successfully passed only 50 kilometers (30 miles) from the surface of the tiny moon. 

Cassini's signal was picked up by the Deep Space Network station in Canberra, Australia, and relayed to the Cassini mission control at NASA's Jet Propulsion Laboratory in Pasadena, Calif.


"We are happy to report that Cassini's begun sending data home," said Julie Webster, Cassini team chief at JPL. "The downlink will continue through the night and into tomorrow morning.”

Closest approach occurred at approximately 3:21 p.m. PDT, while Cassini was traveling at a swift 17.7 kilometers per second (40,000 miles per hour) relative to Enceladus. 

During the flyby, Cassini focused its cameras and other remote sensing instruments on Enceladus with an emphasis on the moon’s south pole where parallel stripes or fissures dubbed "tiger stripes" line the region. That area is of particular interest because geysers of water-ice and vapor jet out of the fissures and supply material to Saturn's E-ring. Scientists hope to learn more about the fissures and whether liquid water is indeed the engine powering the geysers.


"There is a lot of anticipation and excitement about what today’s flyby might reveal" said Bob Pappalardo, Cassini project scientist, also of JPL. “Over the next few days and weeks, the Cassini teams will be analyzing the photos and other data to tease out new clues about this tiny, active world". 

Two more Enceladus flybys are planned for October. The first of those will cut Monday’s flyby distance in half and bring the spacecraft to a remarkable 25 kilometers (16 miles) from the surface. Enceladus measures about 500 kilometers (310 miles) in diameter--just one-seventh the diameter of Earth’s moon.


The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate. The Cassini orbiter was designed, developed and assembled at JPL.

For images, videos and a mission blog on the flyby, visit: http://www.nasa.gov/cassini . Raw (unprocessed) images are available at: http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-list1.html .

-end-
Title: Re: NASA - Cassini updates
Post by: eeergo on 08/13/2008 02:29 PM
First images are starting to appear, mesmerizing details can be seen!

Apparently, in the blog they say the surface is covered in ice blocks released from the Tiger Stripes.

Blog: http://blogs.nasa.gov/cm/blog/cassini-aug08/
Raw images: http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-list1.html

(http://www.nasa.gov/images/content/266310main_PIA11109-512.jpg)
Title: Re: NASA - Cassini updates
Post by: iamlucky13 on 08/14/2008 09:57 PM
One more image from even closer. The caption says this was taken at 545 km, which for an 0.35 degree field of view, works out to about 3 m/pix. Check out the boulders (of ice?) scattered around. I don't know if they're actually certain they're blocks ejected from the tiger stripes, or if they could be material of different consistency or composition exposed by erosion, etc.

(http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGBrowseS43/N00118361.jpg) (http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=165897)
Title: Re: NASA - Cassini updates
Post by: robertross on 08/15/2008 12:06 AM
quote:
{snip}
Two more Enceladus flybys are planned for October. The first of those will cut Monday’s flyby distance in half and bring the spacecraft to a remarkable 25 kilometers (16 miles) from the surface. Enceladus measures about 500 kilometers (310 miles) in diameter--just one-seventh the diameter of Earth’s moon.

Wow!! 25 km from the surface. And here I thought these images were stunning! They are doing some fantastic work with Cassini.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 08/15/2008 09:57 AM
News Release: 2008-160                                                                Aug. 14, 2008

Cassini Pinpoints Source of Jets on Saturn's Moon Enceladus

PASADENA, Calif. -- In a feat of interplanetary sharpshooting, NASA's Cassini spacecraft has pinpointed precisely where the icy jets erupt from the surface of Saturn's geologically active moon Enceladus.

New carefully targeted pictures reveal exquisite details in the prominent south polar "tiger stripe" fractures from which the jets emanate. The images show the fractures are about 300 meters (980 feet) deep, with V-shaped inner walls. The outer flanks of some of the fractures show extensive deposits of fine material. Finely fractured terrain littered with blocks of ice tens of meters in size and larger (the size of small houses) surround the fractures.

"This is the mother lode for us," said Carolyn Porco, Cassini imaging team leader at the Space Science Institute, Boulder, Colo. “A place that may ultimately reveal just exactly what kind of environment -- habitable or not -- we have within this tortured little moon.”

One highly anticipated result of this flyby was finding the location within the fractures from which the jets blast icy particles, water vapor and trace organics into space. Scientists are now studying the nature and intensity of this process on Enceladus, and its effects on surrounding terrain. This information, coupled with observations by Cassini's other instruments, may answer the question of whether reservoirs of liquid water exist beneath the surface. 

The high-resolution images were acquired during an Aug. 11, 2008, flyby of Enceladus, as Cassini sped past the icy moon at 64,000 kilometers per hour (40,000 miles per hour). A special technique, dubbed "skeet shooting" by the imaging team, was developed to cancel out the high speed of the moon relative to Cassini and obtain the ultra-sharp views.

"Knowing exactly where to point, at just the right time, was critical to this event," said Paul Helfenstein, Cassini imaging team associate at Cornell University, Ithaca, NY., who developed and used the skeet-shoot technique to design the image sequence. "The challenge is equivalent to trying to capture a sharp, unsmeared picture of a distant roadside billboard with a telephoto lens out the window of a speeding car."

Helfenstein said that from Cassini's point of view, "Enceladus was streaking across the sky so quickly that the spacecraft had no hope of tracking any feature on its surface. Our best option was to point the spacecraft far ahead of Enceladus, spin the spacecraft and camera as fast as possible in the direction of Enceladus' predicted path, and let Enceladus overtake us at a time when we could match its motion across the sky, snapping images along the way." 

For scientists, having the combination of high-resolution snapshots and broader images showing the whole region is critical for understanding what may be powering the activity on Enceladus.

"There appears to have been extensive fallout of icy particles to the ground, along some of the fractures, even in areas that lie between two jet source locations, though any immediate effects of presently active jets are subtle," Imaging scientists suggest that once warm vapor rises from underground to the cold surface through narrow channels, the icy particles may condense and seal off an active vent. New jets may then appear elsewhere along the same fracture.

"For the first time, we are beginning to understand how freshly erupted surface deposits differ from older deposits," said Helfenstein, an icy moons expert. "Over geologic time, the eruptions have clearly moved up and down the lengths of the tiger stripes."

The new images, with jet source locations labeled, are available at: http://www.nasa.gov/cassini, http://saturn.jpl.nasa.gov and http://ciclops.org .


 
Title: Re: NASA - Cassini updates
Post by: iamlucky13 on 08/15/2008 09:36 PM
quote:
{snip}
Two more Enceladus flybys are planned for October. The first of those will cut Monday’s flyby distance in half and bring the spacecraft to a remarkable 25 kilometers (16 miles) from the surface. Enceladus measures about 500 kilometers (310 miles) in diameter--just one-seventh the diameter of Earth’s moon.

Wow!! 25 km from the surface. And here I thought these images were stunning! They are doing some fantastic work with Cassini.

Unfortunately, I don't think we'll be seeing much higher resolution. At 40,000 mph and with the relatively dim sun, the blur that close to the ground is hard to deal with. My understanding is for this pass they set Cassini rotating ahead of time at a rate that would allow it to pan (their so-called skeet shoot) and minimize the blur. Despite this, the closest image I've been able to find in the database was the one I posted above, taken at 545 kilometer.

But it will be really useful to the mission team to get their spectrometers up closer.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 09/05/2008 07:17 PM
News release: 2008-172                                    Sept. 5, 2008

Cassini Images Ring Arcs Among Saturn's Moons

PASADENA, Calif. -- NASA's Cassini spacecraft has detected a faint, partial ring orbiting with one small moon of Saturn, and has confirmed the presence of another partial ring orbiting with a second moon.  This is further evidence that most of the planet's small, inner moons orbit within partial or complete rings.

Recent Cassini images show material, called ring arcs, extending ahead of and behind the small moons Anthe and Methone in their orbits. The new findings indicate that the gravitational influence of nearby moons on ring particles might be the deciding factor in whether an arc or complete ring is formed.

Both Anthe and Methone orbit Saturn in locations, called resonances, where the gravity of the nearby larger moon Mimas disturbs their orbits. Gravitational resonances are also responsible for many of the structures in Saturn's magnificent rings. Mimas provides a regular gravitational tug on each moon, which causes the moons to skip forward and backward within an arc-shaped region along their orbital paths, according to Nick Cooper, a Cassini imaging team associate from Queen Mary, University of London. "When we realized that the Anthe and Methone ring arcs were very similar in appearance to the region in which the moons swing back and forth in their orbits due to their resonance with Mimas, we knew we had a possible cause-and-effect relationship," Cooper said.

Scientists believe the faint ring arcs from Anthe and Methone likely consist of material knocked off these small moons by micrometeoroid impacts. This material does not spread all the way around Saturn to form a complete ring, because of the gravitational resonance with Mimas.  That interaction confines the material to a narrow region along the orbits of the moons.

This is the first detection of an arc of material near Anthe. The Methone arc was previously detected by Cassini's Magnetospheric Imaging Instrument, and the new images confirm its presence. Previous Cassini images show faint rings connected with other small moons either embedded within or near the outskirts of Saturn's main ring system, such as Pan, Janus, Epimetheus and Pallene. Cassini had also previously observed an arc in the G ring, one of Saturn's faint, major rings.

"This is probably the same mechanism responsible for producing the arc in the G ring," said Matthew Hedman, a Cassini imaging team associate at Cornell University in Ithaca, N.Y. Hedman and his Cassini imaging team colleagues previously determined that the G-ring arc is maintained by a gravitational resonance with Mimas, much like the new, small moon arcs. "Indeed, the Anthe arc may be similar to the debris we see in the G-ring arc, where the largest particles are clearly visible. One might even speculate that if Anthe were shattered, its debris might form a structure much like the G ring," Hedman said.

Additional analysis by scientists indicates that, while the gravitational influence of Mimas keeps the Anthe, Methone and G-ring arcs in place, the material that orbits with the moons Pallene, Janus and Epimetheus is not subject to such powerful resonant forces and is free to spread out around the planet, forming complete rings without arcs.

The intricate relationships between these ring arcs and the moons are just one of many such mechanisms that exist in the Saturn system.  Cassini Imaging Team Member and Professor Carl Murray, also from Queen Mary, University of London, said, "There are many examples in the 

Saturn system of moons creating structures in the rings and disturbing the orbits of other moons. Understanding these interactions and learning about their origins can help us to make sense of what we are seeing in the Cassini images."

Images of Anthe and Methone with their ring arcs are available at: http://www.nasa.gov/cassini, http://saturn.jpl.nasa.gov and http://ciclops.org.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

-end-
 

Title: Re: NASA - Cassini updates
Post by: jacqmans on 10/07/2008 01:41 PM
NEWS RELEASE: 2008-185                                                             Oct. 6, 2008

Cassini Plans Doubleheader Flybys of Saturn's Geyser Moon

PASADENA, Calif. -- As major league baseball readies for the World Series, NASA's Cassini team will come to bat twice this month when the spacecraft flies by Saturn's geyser moon, Enceladus.

The Oct. 9 flyby is an inside pitch—the closest flyby yet of any moon of Saturn, at only 25 kilometers (16 miles) from the surface. The Oct. 31 flyby is farther out, at 196 kilometers (122 miles).

Scientists are intrigued by the possibility that liquid water, perhaps even an ocean, may exist beneath the surface of Enceladus. Trace amounts of organics have also been detected, raising tantalizing possibilities about the moon's habitability.



While Cassini's cameras and other optical instruments were the focus of an Aug. 11 flyby, during Cassini's Oct. 9 flyby, the spacecraft's fields and particles instruments will venture deeper into the plume than ever before, directly sampling the particles and gases. The emphasis here is on the composition of the plume rather than imaging the surface.

"We know that Enceladus produces a few hundred kilograms per second of gas and dust and that this material is mainly water vapor and water ice," said Tamas Gambosi, Cassini scientist at the University of Michigan, Ann Arbor. "The water vapor and the evaporation from the ice grains contribute most of the mass found in Saturn's magnetosphere.

"One of the overarching scientific puzzles we are trying to understand is what happens to the gas and dust released from Enceladus, including how some of the gas is transformed to ionized plasma and is disseminated throughout the magnetosphere," said Gambosi.

On Oct. 31, the cameras and other optical remote sensing instruments will be front and center, imaging the fractures that slash across the moon's south polar region like stripes on a tiger.

These two flybys might augment findings from the most recent Enceladus flyby, which hint at possible changes associated with the icy moon. Cassini's Aug. 11 encounter with Enceladus showed temperatures over one of the tiger-stripe fractures were lower than those measured in earlier flybys. The fracture, called Damascus Sulcus, was about 160 to 167 Kelvin (minus 171 to minus 159 degrees Fahrenheit), below the 180 Kelvin (minus 136 degrees Fahrenheit) reported from a flyby in March of this year.

"We don't know yet if this is due to a real cooling of this tiger stripe, or to the fact that we were looking much closer, at a relatively small area, and might have missed the warmest spot," said John Spencer, Cassini scientist on the composite infrared spectrometer, at the Southwest Research Institute, Boulder, Colo.

Results from Cassini's magnetometer instrument during the August flyby suggest a difference in the intensity of the plume compared to earlier encounters. Information from the next two flybys will help scientists understand these observations.

Four more Enceladus flybys are planned in the next two years, bringing the total number to seven during Cassini's extended mission, called the Cassini Equinox Mission. The next Enceladus doubleheader will be November 2 and 21, 2009.   

The Enceladus geysers were discovered by Cassini in 2005. Since then, scientists have been intrigued about what powers them, because the moon is so tiny, roughly the width of Arizona at only 500 kilometers (310 miles) in diameter.

"The October doubleheader gives Cassini two more opportunities to hit the ball out of the park," said Bob Pappalardo, Cassini project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "With high scores in geology, surface heat, watery plumes and magnetospheric effects, Enceladus could win the 'world championship' title this year!"

Scientists anticipate reporting results from the two flybys in November and early December.

Cassini has been orbiting Saturn since 2004. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate. The Cassini orbiter was designed, developed and assembled at JPL.

For images, videos and a mission blog on the flyby, visit: http://www.nasa.gov/cassini .

More information on the Cassini mission is also available at http://saturn.jpl.nasa.gov .

 
Title: Re: NASA - Cassini updates
Post by: jacqmans on 10/13/2008 05:24 PM
IMAGE ADVISORY: 2008-192                                                                     Oct. 13, 2008

Giant Cyclones at Saturn's Poles Create a Swirl of Mystery

New images from NASA's Cassini spacecraft reveal a giant cyclone at Saturn's north pole, and show that a similarly monstrous cyclone churning at Saturn's south pole is powered by Earth-like storm patterns.

The new-found cyclone at Saturn's north pole is only visible in the near-infrared wavelengths because the north pole is in winter, thus in darkness to visible-light cameras. At these wavelengths, about seven times greater than light seen by the human eye, the clouds deep inside Saturn's atmosphere are seen in silhouette against the background glow of Saturn's internal heat.

The entire north pole of Saturn is now mapped in detail in infrared, with features as small as 120 kilometers (75 miles) visible in the images. Time-lapse movies of the clouds circling the north pole show the whirlpool-like cyclone there is rotating at 530 kilometers per hour (325 miles per hour), more than twice as fast as the highest winds measured in cyclonic features on Earth. This cyclone is surrounded by an odd, honeycombed-shaped hexagon, which itself does not seem to move while the clouds within it whip around at high speeds, also greater than 500 kilometers per hour (300 miles per hour). Oddly, neither the fast-moving clouds inside the hexagon nor this new cyclone seem to disrupt the six-sided hexagon.

New Cassini imagery of Saturn's south pole shows complementary aspects of the region through the eyes of two different instruments. Near-infrared images from the visual and infrared mapping spectrometer instrument show the whole region is pockmarked with storms, while the imaging cameras show close-up details.

The new views are available online at: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

Unlike Earth-bound hurricanes, powered by the ocean's heat and water, Saturn's cyclones have no body of water at their bases, yet the eye-walls of Saturn's and Earth's storms look strikingly similar. Saturn's hurricanes are locked to the planet's poles, whereas terrestrial hurricanes drift across the ocean.

"These are truly massive cyclones, hundreds of times stronger than the most giant hurricanes on Earth," said Kevin Baines, Cassini scientist on the visual and infrared mapping spectrometer at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Dozens of puffy, convectively formed cumulus clouds swirl around both poles, betraying the presence of giant thunderstorms lurking beneath. Thunderstorms are the likely engine for these giant weather systems," said Baines.

Just as condensing water in clouds on Earth powers hurricane vortices, the heat released from the condensing water in Saturnian thunderstorms deep down in the atmosphere may be the primary power source energizing the vortex.

In the south, the new infrared images of the pole, under the daylight conditions of southern summer, show the entire region is marked by hundreds of dark cloud spots. The clouds, like those at the north pole, are likely a manifestation of convective, thunderstorm-like processes extending some 100 kilometers (62 miles) below the clouds. They are likely composed of ammonium hydrosulfide with possibly a mixture of materials dredged up from the depths. By contrast, most of the hazes and clouds seen on Saturn are thought to be composed of ammonia, which condenses at high, visible altitudes.

Complementary images of the south pole from Cassini's imaging cameras, obtained in mid-July, are 10 times more detailed than any seen before. "What looked like puffy clouds in lower resolution images are turning out to be deep convective structures seen through the atmospheric haze," said Cassini imaging team member Tony DelGenio of NASA's Goddard Institute for Space Studies in New York. "One of them has punched through to a higher altitude and created its own little vortex."

The "eye" of the vortex is surrounded by an outer ring of high clouds. The new images also hint at an inner ring of clouds about half the diameter of the main ring, and so the actual clear "eye" region is smaller than it appears in earlier low-resolution images.

"It's like seeing into the eye of a hurricane," said Andrew Ingersoll, a member of Cassini's imaging team at the California Institute of Technology, Pasadena. "It's surprising.  Convection is an important part of the planet's energy budget because the warm upwelling air carries heat from the interior. In a terrestrial hurricane, the convection occurs in the eyewall; the eye is a region of downwelling. Here convection seems to occur in the eye as well."

Further observations are planned to see how the features at both poles evolve as the seasons change from southern summer to fall in August 2009.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The visual and infrared mapping spectrometer team is based at the University of Arizona. The imaging team is based at the Space Science Institute, Boulder, Colo.

 
Title: Re: NASA - Cassini updates
Post by: eeergo on 10/13/2008 06:38 PM
Thanks for the link, Jacques!

The images available are really mesmerizing:

(http://www.nasa.gov/images/content/282838main_pia11104-516.jpg)

(http://www.nasa.gov/images/content/282846main_pia11216-516.jpg)

Now if someone could figure out why on Earth (on Saturn, more appropriately) that stable, huge hexagon is there...
Title: Re: NASA - Cassini updates
Post by: Eerie on 10/13/2008 08:43 PM
I think it is figured out already. It`s not a hexagon, but six stable waves on a circle.
Title: Re: NASA - Cassini updates
Post by: eeergo on 10/13/2008 09:19 PM
I wasn't aware of the explanation, but your post made me find some interesting references. Indeed, although not completely understood, it seems the phenomenon is not so bizarre as it may appear at first sight.

Some enlightening sources I've found. The most graphical explanation, a team that managed to create polygonal vortices, rotating at different speeds from the surrounding medium:
Article: http://www.physorg.com/news66924222.html
Main site: http://dcwww.fys.dtu.dk/~tbohr/RotatingPolygon/
Some similar phenomena appears to take place on Earth too:
http://www.math.nyu.edu/caos_teaching/hurricanes/BAMS_KosSch.pdf
Interesting discussion about this effect:
http://www.freelists.org/archives/sac-forum/04-2007/msg00001.html
Title: Re: NASA - Cassini updates
Post by: mike robel on 10/14/2008 12:37 AM
As I think I read in a Jerry Pournelle Book, <yawn> "just another spectacular view and puzzle of Saturn."  :)
Title: Re: NASA - Cassini updates
Post by: jacqmans on 12/16/2008 01:58 PM
RELEASE: 08-325

SATURN'S DYNAMIC MOON ENCELADUS SHOWS MORE SIGNS OF ACTIVITY

SAN FRANCISCO -- The closer scientists look at Saturn's small moon
Enceladus, the more they find evidence of an active world. The most
recent flybys of Enceladus made by NASA's Cassini spacecraft have
provided new signs of ongoing changes on and around the moon. The
latest high-resolution images of Enceladus show signs that the south
polar surface changes over time.

Close views of the southern polar region, where jets of water vapor
and icy particles spew from vents within the moon's distinctive
"tiger stripe" fractures, provide surprising evidence of Earth-like
tectonics. They yield new insight into what may be happening within
the fractures. The latest data on the plume -- the huge cloud of
vapor and particles fed by the jets that extend into space -- show it
varies over time and has a far-reaching effect on Saturn's
magnetosphere.

"Of all the geologic provinces in the Saturn system that Cassini has
explored, none has been more thrilling or carries greater
implications than the region at the southernmost portion of
Enceladus," said panel member Carolyn Porco, Cassini imaging team
leader at the Space Science Institute in Boulder, Colo.

A panel of Cassini scientists presented these new findings Monday in a
news briefing at the American Geophysical Union's Fall Meeting in San
Francisco.

"Enceladus has Earth-like spreading of the icy crust, but with an
exotic difference -- the spreading is almost all in one direction,
like a conveyor belt," said panelist Paul Helfenstein, Cassini
imaging associate at Cornell University in Ithaca, N.Y. "Asymmetric
spreading like this is unusual on Earth and not well understood."

"Enceladus has asymmetric spreading on steroids," Helfenstein added.
"We are not certain about the geological mechanisms that control the
spreading, but we see patterns of divergence and mountain-building
similar to what we see on Earth, which suggests that subsurface heat
and convection are involved."

The tiger stripes are analogous to the mid-ocean ridges on Earth's
seafloor where volcanic material wells up and creates new crust.
Using Cassini-based digital maps of the moon's south polar region,
Helfenstein reconstructed a possible history of the tiger stripes by
working backward in time and progressively snipping away older and
older sections of the map, each time finding that the remaining
sections fit together like puzzle pieces.

Images from recent close flybys also have bolstered an idea the
Cassini imaging team has that condensation from the jets erupting
from the surface may create ice plugs that close off old vents and
force new vents to open. The opening and clogging of vents also
corresponds with measurements indicating the plume varies from month
to month and year to year.

"We see no obvious distinguishing markings on the surface in the
immediate vicinity of each jet source, which suggests that the vents
may open and close and thus migrate up and down the fractures over
time," Porco said. "Over time, the particles that rain down onto the
surface from the jets may form a continuous blanket of snow along a
fracture."

Enceladus' output of ice and vapor dramatically impacts the entire
Saturnian system by supplying the ring system with fresh material and
loading ionized gas from water vapor into Saturn's magnetosphere.

"The ions added to the magnetosphere are spun up from Enceladus'
orbital speed to the rotational speed of Saturn," said Cassini
magnetometer science team member Christopher Russell of the
University of California, Los Angeles. "The more material is added by
the plume, the harder this is for Saturn to do, and the longer it
takes to accelerate the new material."

With water vapor, organic compounds and excess heat emerging from
Enceladus' south polar terrain, scientists are intrigued by the
possibility of a liquid-water-rich habitable zone beneath the moon's
south pole.

Cassini's flybys on Aug. 11 and Oct. 31 targeted Enceladus' fractured
southern region. An Oct. 9 flyby took the spacecraft deep into the
plume of water vapor and ice shooting out of the moon's vents.
Cassini's next flyby of Enceladus will be in November 2009. The
Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency.

For more information about the Cassini-Huygens mission, visit:

http://www.nasa.gov/cassini
Title: Re: NASA - Cassini updates
Post by: jacqmans on 12/16/2008 01:59 PM
News release: 2008-237                                Dec. 15, 2008

Titan's Volcanoes Give NASA Spacecraft Chilly Reception

PASADENA, Calif. -- Data collected during several recent flybys of Titan by NASA's Cassini spacecraft have put another arrow in the quiver of scientists who think the Saturnian moon contains active cryovolcanoes spewing a super-chilled liquid into its atmosphere. The information was released today during a meeting of the American Geophysical Union in San Francisco, Calif.

"Cryovolcanoes are some of the most intriguing features in the solar system," said Rosaly Lopes, a Cassini radar team investigation scientist from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "To put them in perspective -- if Mount Vesuvius had been a cryovolcano, its lava would have frozen the residents of Pompeii."

Rather than erupting molten rock, it is theorized that the cryovolcanoes of Titan would erupt volatiles such as water, ammonia and methane. Scientists have suspected cryovolcanoes might inhabit Titan, and the Cassini mission has collected data on several previous passes of the moon that suggest their existence. Imagery of the moon has included a suspect haze hovering over flow-like surface formations. Scientists point to these as signs of cryovolcanism there.

"Cassini data have raised the possibility that Titan's surface is active," said Jonathan Lunine, a Cassini interdisciplinary scientist from the Lunar and Planetary Laboratory, University of Arizona, Tucson. "This is based on evidence that changes have occurred on the surface of Titan, between flybys of Cassini, in regions where radar images suggest a kind of volcanism has taken place."

What led some Cassini scientists to believe that things are happening now were changes in brightness and reflectance detected at two separate and distinct regions of Titan. Reflectance is the ratio of light that radiates onto a surface to the amount reflected back. These changes were documented by Visible and Infrared Mapping Spectrometer data collected on Titan flybys from July 2004 to March 2006. In one of the two regions, the reflectance of the surface surged upward and remained higher than expected. In the other region, the reflectance shot up but then trended downward. There is also evidence that ammonia frost is present at one of the two changing sites. The ammonia was evident only at times when the region was inferred to be active.

"Ammonia is widely believed to be present only beneath the surface of Titan," said Robert M. Nelson of JPL, a scientist for Cassini's Visual and Infrared Mapping Spectrometer team. "The fact that we found it appearing at times when the surface brightened strongly suggests that material was being transported from Titan's interior to its surface."

Some Cassini scientists indicate that such volcanism could release methane from Titan's interior, which explains Titan's seemingly continuous supply of fresh methane. Without replenishment, scientists say, Titan's original atmospheric methane should have been exhausted long ago.

But other scientists familiar with the spectrometer data argue that the ammonia identification is not certain, and that the purported brightness changes might not be associated with changes on Titan's surface. Instead they might result from the transient appearances of ground "fogs" of ethane droplets very near Titan's surface, driven by atmospheric rather than geophysical processes. Nelson has considered the ground fog option, stating, "There remains the possibility that the effect is caused by a local fog, but if so, we would expect it to change in size over time due to wind activity, which is not what we see."

The chilly volcanoes of Titan are not a fait accompli. An alternative hypothesis to an active Titan suggests the Saturnian moon could be taking its landform evolution cues from a moon of Jupiter.

"Like Callisto, Titan may have formed as a relatively cold body, and may have never undergone enough tidal heating for volcanism to occur," said Jeffrey Moore, a planetary geologist at the NASA Ames Research Center, Moffett Field, Calif. "The flow-like features we see on the surface may just be icy debris that has been lubricated by methane rain and transported downslope into sinuous piles like mudflows."     

More revelations may be forthcoming. Scientists are still analyzing the data from Cassini's most recent flyby on Dec. 5. Cassini's next Titan flyby is scheduled in 11 days, when the spacecraft will come within 970 kilometers (603 miles) of its cloud-shrouded surface.

For more information about the Cassini-Huygens mission, visit: http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini .

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington, D.C.

The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries. The Visual and Infrared Mapping Spectrometer team is based at the University of Arizona.

Title: Re: NASA - Cassini updates
Post by: toddbronco2 on 02/23/2009 02:48 AM
I haven't seen much interest from NSF toward Cassini, but the spacecraft is preparing for one of the more significant mechanical changes of the last several years with a switch to the backup B-branch thrusters, a move needed with the possibly imminent failure of one or two of the Reaction Control thrusters. Hopefully all will go well
Title: Re: NASA - Cassini updates
Post by: iamlucky13 on 02/23/2009 05:07 AM
Yeah, the unmanned mission definitely don't get nearly as much attention, especially when all is running smoothly. It doesn't sound like there's any expectations of problems, fortunately.
Title: Re: NASA - Cassini updates
Post by: rdale on 02/23/2009 07:33 AM
Thanks for the update - the unmanned stuff is covered much more thoroughly at http://www.unmannedspaceflight.com/
Title: Re: NASA - Cassini updates
Post by: madscientist197 on 02/25/2009 07:57 AM
Yeah, that's a really incredible forum -- it's so highly moderated though, I'm always a bit afraid to post!
Title: Re: NASA - Cassini updates
Post by: Analyst on 02/26/2009 05:58 PM
Yeah, that's a really incredible forum -- it's so highly moderated though, I'm always a bit afraid to post!

You can always leave after posting there, as I did.

Back to topic: The now proposed second mission extension will give us a total of 11 years in Saturnian orbit, hundreds of orbits, more than 100 Titan encounters, dozens of icy satellite encounters ... Talk about bang for the buck, or ROI, here it is.

Analyst
Title: Re: NASA - Cassini updates
Post by: jacqmans on 02/27/2009 04:36 PM
Image advisory: 2009-032                                                     Feb. 26, 2009


Cassini Maps Global Pattern of Titan's Dunes

Titan's vast dune fields, which may act like weather vanes to determine general wind direction on Saturn's biggest moon, have been mapped by scientists who compiled four years of radar data collected by the Cassini spacecraft. 

Titan's rippled dunes are generally oriented east-west. Surprisingly, their orientation and characteristics indicate that near the surface, Titan's winds blow toward the east instead of toward the west. This means that Titan's surface winds blow opposite the direction suggested by previous global circulation models of Titan. 

"At Titan there are very few clouds, so determining which way the wind blows is not an easy thing, but by tracking the direction in which Titan's sand dunes form, we get some insight into the global wind pattern," says Ralph Lorenz, Cassini radar scientist at Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "Think of the dunes sort of like a weather vane, pointing us to the direction the winds are blowing." A paper based on these findings appeared in the Feb. 11 issue of Geophysical Research Letters. 

"Titan's dunes are young, dynamic features that interact with topographic obstacles and give us clues about the wind regimes," said Jani Radebaugh, Brigham Young University, Provo,

Utah. "Winds come at these dunes from at least a couple of different directions, but then combine to create the overall dune orientation."

The new map, based on all the high-resolution radar data collected during a four-year period, is now available at: http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini .

The wind pattern is important for planning future Titan explorations that might involve balloon-borne experiments.

Some 16,000 dune segments were mapped out from about 20 radar images, digitized and combined to produce the new map.

Titan's dunes are believed to be made up of hydrocarbon sand grains likely derived from organic chemicals in Titan's smoggy skies. The dunes wrap around high terrain, which provides some idea of their height. They accumulate near the equator, and may pile up there because drier conditions allow for easy transport of the particles by the wind. Titan's higher latitudes contain lakes and may be "wetter" with more liquid hydrocarbons, not ideal conditions for creating dunes. 

Cassini, which launched in 1997 and is now in extended mission operations, continues to blaze its trail around the Saturn system and will visit Titan again on March 27. Seventeen Titan flybys are planned this year. 

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

                                                                    -end-
Title: Re: NASA - Cassini updates
Post by: MBK004 on 03/04/2009 07:26 AM
http://www.nasa.gov/mission_pages/cassini/media/cassini-20090303.html (http://www.nasa.gov/mission_pages/cassini/media/cassini-20090303.html)
Image advisory: 2009-035
March 3, 2009

Newfound Moon May Be Source of Outer Saturn Ring
 
Cassini imaging scientists analyzing images acquired over the course of about 600 days found the tiny moonlet, half a kilometer (about a third of a mile) across, embedded within a partial ring, or ring arc, previously found by Cassini in Saturn's tenuous G ring.

The finding is being announced today in an International Astronomical Union circular. Images can be found at http://www.nasa.gov/cassini, http://saturn.jpl.nasa.gov and http://ciclops.org .

"Before Cassini, the G ring was the only dusty ring that was not clearly associated with a known moon, which made it odd," said Matthew Hedman, a Cassini imaging team associate at Cornell University in Ithaca, N.Y. "The discovery of this moonlet, together with other Cassini data, should help us make sense of this previously mysterious ring."

Saturn's rings were named in the order they were discovered. Working outward they are: D, C, B, A, F, G and E. The G ring is one of the outer diffuse rings. Within the faint G ring there is a relatively bright and narrow, 250-kilometer-wide (150-miles) arc of ring material, which extends 150,000 kilometers (90,000 miles), or one-sixth of the way around the ring's circumference. The moonlet moves within this ring arc. Previous Cassini plasma and dust measurements indicated that this partial ring may be produced from relatively large, icy particles embedded within the arc, such as this moonlet.

Scientists imaged the moonlet on Aug. 15, 2008, and then they confirmed its presence by finding it in two earlier images. They have since seen the moonlet on multiple occasions, most recently on Feb. 20, 2009. The moonlet is too small to be resolved by Cassini's cameras, so its size cannot be measured directly. However, Cassini scientists estimated the moonlet's size by comparing its brightness to another small Saturnian moon, Pallene.

Hedman and his collaborators also have found that the moonlet's orbit is being disturbed by the larger, nearby moon Mimas, which is responsible for keeping the ring arc together.

This brings the number of Saturnian ring arcs with embedded moonlets found by Cassini to three. The new moonlet may not be alone in the G ring arc. Previous measurements with other Cassini instruments implied the existence of a population of particles, possibly ranging in size from 1 to 100 meters (about three to several hundred feet) across. "Meteoroid impacts into, and collisions among, these bodies and the moonlet could liberate dust to form the arc," said Hedman.

Carl Murray, a Cassini imaging team member and professor at Queen Mary, University of London, said, "The moon's discovery and the disturbance of its trajectory by the neighboring moon Mimas highlight the close association between moons and rings that we see throughout the Saturn system. Hopefully, we will learn in the future more about how such arcs form and interact with their parent bodies."

Early next year, Cassini's camera will take a closer look at the arc and the moonlet. The Cassini Equinox mission, an extension of the original four-year mission, is expected to continue until fall of 2010.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.
Title: Re: NASA - Cassini updates
Post by: jimvela on 03/04/2009 08:25 PM
I have to wonder if the moonlet is the source of the ring, or if we're seeing a ring coalesce into a moon...  The ring systems are very interesting places indeed.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/12/2009 03:26 PM
STATUS REPORT: 2009-047                                                                       March 12, 2009

Cassini-Huygens Mission Status Report       

Cassini Swaps Thrusters

PASADENA, Calif. – Early this morning the Cassini spacecraft relayed information that it had successfully swapped to a backup set of propulsion thrusters late Wednesday.

The swap was performed because of degradation in the performance of the primary thrusters, which had been in use since Cassini's launch in 1997. This is only the second time in Cassini's 11 years of flight that the engineering teams have gone to a backup system.

The thrusters are used for making small corrections to the spacecraft's course, for some attitude control functions, and for making angular momentum adjustments in the reaction wheels, which also are used for attitude control. The redundant set is an identical set of eight thrusters. Almost all Cassini engineering subsystems have redundant backup capability.

Cassini has successfully completed its original four-year planned tour of Saturn and is now in extended mission operations.

More information on the mission is available at: http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini .

Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/24/2009 05:30 PM
IMAGE ADVISORY: 2009-058                                         March 24, 2009                                   

Cassini Provides Virtual Flyover of Saturn's Moon Titan

PASADENA, Calif. – "Fly me to the moon"--to Saturn's moon Titan, that is. New Titan movies and images are providing a bird's-eye view of the moon's Earth-like landscapes.

The new flyover maps show, for the first time, the 3-D topography and height of the 1,200-meter (4,000-foot) mountain tops, the north polar lake country, the vast dunes more than 100 meters (300 feet) high that crisscross the moon, and the thick flows that may have oozed from possible ice volcanoes.

The topographic maps were made from stereo pairs of radar images. They are available at: http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini .

Cassini radar team member Randy Kirk with the Astrogeology Science Center at the U.S. Geological Survey in Flagstaff, Ariz., created the maps. He used some of the 20 or so areas where two or more overlapping radar measurements were obtained during 19 Titan flybys. These stereo overlaps cover close to two percent of Titan's surface. The process of making topographic maps from them is just beginning, but the results already reveal some of the diversity of Titan's geologic features.

"These flyovers let you take in the bird's-eye sweeping views of Titan, the next best thing to being there," said Kirk. "We've mapped many kinds of features, and some of them remind me of Earth. Big seas, small lakes, rivers, dry river channels, mountains and sand dunes with hills poking out of them, lava flows."

Kirk will present these results today at the Lunar and Planetary Science Conference in The Woodlands, Texas.

High and low features are shown in unprecedented detail at about 2.4-kilometer (1.5-mile) resolution.  The maps show some features that may be volcanic flows.  These flows meander across a shallow basin in the mountains.  One area suspected to be an ice volcano, Ganesa Macula, does not appear to be a volcanic dome.  It may still have originated as a volcano, but it's too soon to know for sure.  "It could be a volcanic feature, a crater, or something else that has just been heavily eroded," added Kirk.

The stereo coverage includes a large portion of Titan's north polar lakes of liquid ethane and methane. Based on these topographical models, scientists are better able to determine the depth of lakes. The highest areas surrounding the lakes are some 1,200 meters (about 4,000 feet) above the shoreline. By comparing terrain around Earth to the Titan lakes, scientists estimate their depth is likely about 100 meters (300 feet) or less.

More 3-D mapping of these lakes will help refine these depth estimates and determine the volume of liquid hydrocarbons that exist on Titan. This information is important because these liquids evaporate and create Titan's atmosphere. Understanding this methane cycle can provide clues to Titan's weather and climate.

Launched in 1997, Cassini completed its primary four-year mission in 2008 and is now in extended mission operations, which run through September 2010. Over the course of the mission, Cassini plans to map more than three percent of Titan's surface in 3-D. About 38 percent of Titan's surface has been mapped with radar so far. On March 27, Cassini will complete its 52nd targeted flyby of Titan.   

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

Title: Re: NASA - Cassini updates
Post by: jacqmans on 06/03/2009 07:51 PM
IMAGE ADVISORY: 2009-093                                                         June 3, 2009             

Cassini Finds Titan's Clouds Hang on to Summer

Cloud chasers studying Saturn's moon Titan say its clouds form and move much like those on Earth, but in a much slower, more lingering fashion.

Their forecast for Titan's early autumn -- warm and wetter.

Scientists with NASA's Cassini mission have monitored Titan's atmosphere for three-and-a-half years, between July 2004 and December 2007, and observed more than 200 clouds. They found that the way these clouds are distributed around Titan matches scientists' global circulation models. The only exception is timing -- clouds are still noticeable in the southern hemisphere while fall is approaching.

"Titan's clouds don't move with the seasons exactly as we expected," said Sebastien Rodriguez of the University of Paris Diderot, in collaboration with Cassini visual and infrared mapping spectrometer team members at the University of Nantes, France. "We see lots of clouds during the summer in the southern hemisphere, and this summer weather seems to last into the early fall. It looks like Indian summer on Earth, even if the mechanisms are radically different on Titan from those on Earth. Titan may then experience a warmer and wetter early autumn than forecasted by the models."

On Earth, abnormally warm, dry weather periods in late autumn occur when low-pressure systems are blocked in the winter hemisphere. By contrast, scientists think the sluggishness of temperature changes at the surface and low atmosphere on Titan may be responsible for its unexpected warm and wet, hence cloudy, late summer.

The new infrared images showing the global cloud pattern are now available at: http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini .

As summer changes to fall at the equinox in August 2009, Titan's clouds are expected to disappear altogether. But, circulation models of Titan's weather and climate predict that clouds at the southern latitudes don't wait for the equinox and should have already faded out since 2005. However, Cassini was still able to see clouds at these places late in 2007, and some of them are particularly active at mid-latitudes and the equator.

Titan is the only moon in our solar system with a substantial atmosphere, and its climate shares Earth-like characteristics. Titan's dense, nitrogen-methane atmosphere responds much more slowly than Earth's atmosphere, as it receives about 100 times less sunlight because it is 10 times farther from the sun. Seasons on Titan last more than seven Earth years.

Scientists will continue to observe the long-term changes during Cassini's extended mission, which runs until the fall of 2010. Cassini is set to fly by Titan on May 5.

Title: Re: NASA - Cassini updates
Post by: jacqmans on 06/24/2009 06:10 PM
European scientists on the joint NASA/ESA Cassini mission have detected, for the first time, sodium salts in ice grains of Saturn's E-ring, which is primarily replenished by material from the plumes of water vapour and ice grains emitted by Saturn’s moon Enceladus. The detection of salty ice indicates that the little moon harbours a reservoir of liquid water, perhaps even an ocean, beneath its surface.

More at:
http://www.esa.int/SPECIALS/Cassini-Huygens/SEMH0X0P0WF_0.html
Title: Re: NASA - Cassini updates
Post by: jacqmans on 06/24/2009 08:59 PM
RELEASE: 09-147

SALT FINDING FROM NASA'S CASSINI HINTS AT OCEAN WITHIN SATURN MOON

PASADENA, Calif. -- For the first time, scientists working on NASA's
Cassini mission have detected sodium salts in ice grains of Saturn's
outermost ring. Detecting salty ice indicates that Saturn's moon
Enceladus, which primarily replenishes the ring with material from
discharging jets, could harbor a reservoir of liquid water -- perhaps
an ocean -- beneath its surface.

Cassini discovered the water-ice jets in 2005 on Enceladus. These jets
expel tiny ice grains and vapor, some of which escape the moon's
gravity and form Saturn's outermost ring. Cassini's cosmic dust
analyzer has examined the composition of those grains and found salt
within them.

"We believe that the salty minerals deep inside Enceladus washed out
from rock at the bottom of a liquid layer," said Frank Postberg,
Cassini scientist for the cosmic dust analyzer at the Max Planck
Institute for Nuclear Physics in Heidelberg, Germany. Postberg is
lead author of a study that appears in the June 25 issue of the
journal Nature.

Scientists on Cassini's cosmic dust detector team conclude that liquid
water must be present because it is the only way to dissolve the
significant amounts of minerals that would account for the levels of
salt detected. The process of sublimation, the mechanism by which
vapor is released directly from solid ice in the crust, cannot
account for the presence of salt.

"Potential plume sources on Enceladus are an active area of research
with evidence continuing to converge on a possible salt water ocean,"
said Linda Spilker, Cassini deputy project scientist at NASA's Jet
Propulsion Laboratory in Pasadena, Calif. "Our next opportunity to
gather data on Enceladus will come during two flybys in November."

The makeup of the outermost ring grains, determined when thousands of
high-speed particle hits were registered by Cassini, provides
indirect information about the composition of the plume material and
what is inside Enceladus. The outermost ring particles are almost
pure water ice, but nearly every time the dust analyzer has checked
for the composition, it has found at least some sodium within the
particles.

"Our measurements imply that besides table salt, the grains also
contain carbonates like soda. Both components are in concentrations
that match the predicted composition of an Enceladus ocean," Postberg
said. "The carbonates also provide a slightly alkaline pH value. If
the liquid source is an ocean, it could provide a suitable
environment on Enceladus for the formation of life precursors when
coupled with the heat measured near the moon's south pole and the
organic compounds found within the plumes."

However, in another study published in Nature, researchers doing
ground-based observations did not see sodium, an important salt
component. That team notes that the amount of sodium being expelled
from Enceladus is actually less than observed around many other
planetary bodies. These scientists were looking for sodium in the
plume vapor and could not see it in the expelled ice grains. They
argue that if the plume vapor does come from ocean water the
evaporation must happen slowly deep underground rather than as a
violent geyser erupting into space.

"Finding salt in the plume gives evidence for liquid water below the
surface," said Sascha Kempf, also a Cassini scientist for the cosmic
dust analyzer from the Max Planck Institute for Nuclear Physics. "The
lack of detection of sodium vapor in the plume gives hints about what
the water reservoir might look like."

Determining the nature and origin of the plume material is a top
priority for Cassini during its extended tour, called the Cassini
Equinox Mission.

"The original picture of the plumes as violently erupting
Yellowstone-like geysers is changing," said Postberg."They seem more
like steady jets of vapor and ice fed by a large water reservoir.
However, we cannot decide yet if the water is currently 'trapped'
within huge pockets in Enceladus' thick ice crust or still connected
to a large ocean in contact with the rocky core."

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The Cassini
cosmic dust analyzer was provided by the German Aerospace Center. The
Cassini orbiter was designed, developed and assembled at JPL. JPL
manages the mission for the Science Mission Directorate at NASA
Headquarters in Washington.

More information about the Cassini mission is available at:



http://www.nasa.gov/cassini

Title: Re: NASA - Cassini updates
Post by: ChrisGebhardt on 06/29/2009 11:57 PM
And just the other day....

http://www.time.com/time/health/article/0,8599,1907238,00.html?cnn=yes
Title: Re: NASA - Cassini updates
Post by: Ben the Space Brit on 06/30/2009 09:44 AM
First Europa, now Enceladus! Some findings also suggest that Ganemeyde and Titan may have sub-crust liquid water too.  Combined with geothermal energy sources, it is beginning to seem that the outer solar system might be more potentially habitable than we thought. 

It is strange to think how long Mars has held the top spot as the extraterrestrial potential abode for life.  However, IMHO anyway, it seems to be dropping down the league table compared to some OSS moons.

[edited for clarity]
Title: Re: NASA - Cassini updates
Post by: jacqmans on 07/23/2009 04:21 AM
Feature                                                               July 22, 2009 


Saturnian Moon Shows Evidence of Ammonia

Data collected during two close flybys of Saturn's moon Enceladus by NASA's Cassini spacecraft add more fuel to the fire about the Saturnian ice world containing sub-surface liquid water. The data collected by Cassini's Ion and Neutral Mass Spectrometer during Enceladus flybys in July and Oct. 2008, were released in the July 23 issue of the journal Nature.

"When Cassini flew through the plume erupting from Enceladus on October 8 of last year, our spectrometer was able to sniff out many complex chemicals, including organic ones, in the vapor and icy particles," said Hunter Waite, the Cassini Ion and Neutral Mass Spectrometer Lead Scientist from the Southwest Research Institute in San Antonio, Texas. "One of the chemicals definitively identified was ammonia."

On Earth, the presence of ammonia means the potential for sparkling clean floors and counter tops. In space, the presence of ammonia provides strong evidence for the existence of at least some liquid water.

How could ammonia equate to liquid water inside an ice-covered moon in one of the chillier neighborhoods of our solar system? As many a homeowner interested in keeping their abodes spick and span know, ammonia promptly dissolves in water. But what many people do not realize is that ammonia acts as antifreeze, keeping water liquid at lower temperatures than would otherwise be possible. With the presence of ammonia, water can exist in a liquid state to temperatures as low as 176 degrees Kelvin (-143 degrees Fahrenheit).

"Given that temperatures in excess of 180 Kelvin (-136 degrees Fahrenheit) have been measured near the fractures on Enceladus where the jets emanate, we think we have an excellent argument for a liquid water interior," said Waite.

Cassini discovered water vapor and particles spewing from Enceladus in 2005. Since then, scientists have been trying to determine if the plume originates from a liquid source inside the moon or is due to other causes.

"Ammonia is sort of a holy grail for icy volcanism," said William McKinnon,
a scientist from Washington University in Saint Louis, Missouri. "This is the first time we've found it for sure on an icy satellite of a giant planet. It is probably everywhere in the Saturn system."

Just how much water is contained within Enceladus' icy interior is still up for debate. So far, Cassini has made five flybys of Enceladus, one of the chief targets for Cassini's extended mission. Two close flybys are scheduled for November of this year, and two more close flybys are scheduled for April and May or 2010. Data collected during these future flybys may help settle the debate.

"Where liquid water and organics exist, is there life?" asked Jonathan Lunine a Cassini scientist from the University of Arizona, Tucson. "Such is the case for Earth; what was found on Enceladus bolsters this moon's promise for containing potential habitable environments."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Cassini orbiter was designed, developed and assembled at JPL. JPL manages the mission for the Science Mission Directorate at NASA Headquarters in Washington.

More information about the Cassini mission is available at http://www.nasa.gov/cassini or http://saturn.jpl.nasa.gov .

Title: Re: NASA - Cassini updates
Post by: jacqmans on 08/08/2009 07:41 AM
 August 7, 2009

Saturn to Pull Celestial Houdini on August 11

In 1918, magician extraordinaire Harry Houdini created a sensation when he made a 10,000 pound elephant disappear before a mystified audience of over 5,200 at New York's famed Hippodrome theatre. But a vanishing pachyderm is nothing compared to the magnificent illusion to be performed by our solar system's own sixth rock from the sun on Aug. 11. On that day, ladies and gentlemen, boys and girls, children of all ages, the planet Saturn, with no help from either Jupiter or Uranus, will make its 170,000-mile-wide ring system disappear.

How does a mere gas giant planet, without the benefit of a magic wand, smoke and mirrors, or even sleeves for that matter, manage to hide an estimated 35 trillion-trillion tons of ice, dust and rock fragments? Saturn itself, perhaps adhering to the magician's code never to reveal how a trick is performed, is not talking. But fortunately for us, dear friends, Linda Spilker, deputy project scientist for the Cassini Saturn mission at NASA's Jet Propulsion Laboratory in Pasadena, Calif., is not in the magician's guild.



"Saturn has been performing the "ring plane crossing" illusion about every 15 years since the rings formed, perhaps as long as 4.5 billion years ago, so by now it is pretty good at it," said Spilker. "The magician's tools required to perform this trick are pure sunlight, a planet that wobbles, and a main ring system that may be almost 200-thousand miles wide, but only 30 feet thick."   

All planets in our solar system wobble on their axes to some extent. This change of attitude eventually places a planet's equator directly in line with the photons of light streaming in from the sun. This is called "equinox," and on Earth it occurs every year about March 21 (spring equinox) and September 22 (autumnal equinox). On Saturn, it occurs twice during each 29 Earth-year-long orbit around the sun (about every 15 years).

"Whenever equinox occurs on Saturn, sunlight will hit Saturn's thin rings, the ring plane, edge-on," said Spilker."The light reflecting off this extremely narrow band is so small that for all intents and purposes the rings simply vanish."

While the second largest planet in our solar system has been conjuring its ring plane phenomenon for millennia, the audience for it only began showing up about 400 years ago. By December 1612, Galileo Galilei had been studying Saturn and its "two large moons" (through his primitive telescope he mistook the ring system for moons on either side of the planet) for over two years. He had been noticing these "two moons" getting thinner and thinner. After the rings disappeared from his eyepiece entirely, Galileo shared his surprise in a letter in which he wrote, "I do not know what to say in a case so surprising, so unlooked for and so novel."

"Galileo had every right to be mystified by the rings," said Spilker. "While we know how Saturn pulls off its ring-plane crossing illusion, we are still fascinated and mystified by Saturn's rings, and equinox is a great time for us to learn more."

Far from being a loss, a ring plane crossing provides a unique opportunity for scientists. The sunlight hitting the rings at 90-degree angles can illuminate, or throw shadows, revealing ring structures and oddities previously unseen.

But fair warning for those miserly types armed with their own telescopes and determined to get a free celestial magic show. This particular conjuring of the ring-plane crossing illusion will have an audience of one.

"Saturn's orbit has brought it so close to the sun that it is extremely difficult to see even with the best of telescopes," said Spilker. "Fortunately, we have Cassini in the front row."

The Cassini spacecraft has been observing Saturn, its moons and its rings from orbit around the planet for the past five years. The spacecraft’s instruments have discovered new rings, moons, as well as changed the way we look at Saturn’s ring system. Around equinox, Cassini's thermal instrument is tasked with measuring the temperature of both sides of the rings as the sun sets to look at how the rings cool as they go through this seasonal change. The spacecraft's cameras are looking for topographic features in the rings, like tiny moons and possible ring warps, which are only visible at equinox, while the near-infrared and ultraviolet instruments will be on the hunt for signs of seasonal change on the planet.

"The great thing is we are not sure what we will find," said Spilker. "Like any great magician, Saturn never fails to impress."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Cassini orbiter was designed, developed and assembled at JPL. JPL manages the mission for the Science Mission Directorate at NASA Headquarters in Washington.

More information about the Cassini mission is available at http://www.nasa.gov/cassini or http://saturn.jpl.nasa.gov .

                                           
Title: Re: NASA - Cassini updates
Post by: jacqmans on 09/05/2009 05:27 AM
September 04, 2009

Saturn Moon Could Power 150 Billion Labor Day Barbecues

Since its discovery by Dutch astronomer Christiaan Huygens in 1655, Saturn's most massive moon, Titan, has been known as a place of mystery and intrigue. The large, cloud-enshrouded moon is such a scientific enigma that for the past five years, it has been targeted by NASAs Cassini spacecraft with more than 60 probing flybys. One of its latest findings could be a valuable asset to future generations of space explorers hunting for materials to whip up a Labor Day barbecue.

“Titan’s atmosphere is extremely rich in an assortment of hydrocarbon chemicals, including propane, which we use to fill our barbecue tanks,” said Cassini scientist Conor Nixon of the University of Maryland, College Park. "Titan’s atmospheric inventory would fuel about 150 billion barbecue cookouts, enough for several thousand years of Labor Days.”

For those who are burger, barbecue or Titan challenged, propane is a three-carbon alkane (a chemical compound consisting of carbon and hydrogen), that is non-toxic and heavier than air. With its low boiling point of minus 43.6 degrees Fahrenheit (minus 42 degrees Centigrade), propane vaporizes as soon as it is released from its pressurized container. Here on Earth, propane is commonly used as a fuel for forklifts, flamethrowers, residential central heating, portable stoves, hot air balloons, and – of course – barbecues. On other worlds propane is an untapped resource.

This gas of many terrestrial uses was first discovered in Titan's atmosphere back in 1980 when NASA's Voyager 1 spacecraft flew past the Saturnian system. Over the years, both ground and space-based instruments have added to the research, but accurately quantifying the amount of propane on Titan has proved elusive. Then, in 2004, the Cassini spacecraft entered orbit around Saturn.

Measuring the amount of propane on Titan is important to scientists because the gas is a very complex molecule, and its signature in the infrared spectrum is close to those of several molecules scientists are hoping to discover in Titan's atmosphere.

"It was not so much that measuring propane was our endgame, but it helps enormously in our hunt for other complex molecules," said Nixon. "These include pyrimidines that are potential building blocks for biological molecules, such as the nuceleobases of our DNA.” If we can detect them on Titan, that would be very significant."

Propane on Titan was measured using data from Cassini's Composite Infrared Spectrometer instrument. During multiple flybys of the moon between June 2004 and June 2008, the instrument measured infrared light from the edge of Titan's atmosphere. After a detailed analysis of the gas's characteristic ‘emission bands’ or signature, using computer predictions backed by the latest laboratory research into its infrared spectrum, the Composite Infrared Spectrometer team came up with an estimate of the amount of propane in Titan’s atmosphere So exactly how much propane does it take to fire 150 billion cookouts?

"We estimate there are nearly 700 million barrels of propane on Titan, said Nixon. "That is enough to fill six-billion 20-pound tanks of liquefied propane gas. It sounds like a huge amount, but that would satisfy total U.S. consumption of propane for only 18 months."

Which still leaves, with regards to Saturn's biggest moon, one Labor Day staple still to be determined. How many hamburgers could future generations of outer-planet explorers grill using Titan’s atmospheric propane?

"A dozen at a time, that’s two trillion hamburgers," said Cassini’s Nixon, "assuming you stop at medium-well."

Nixon is the lead author on a paper about propane on Titan to be published in an upcoming issue of Planetary and Space Science.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Cassini orbiter was designed, developed and assembled at JPL. JPL manages the mission for the Science Mission Directorate at NASA Headquarters in Washington. Cassini's Composite Infrared Spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md.

More information about the Cassini mission is available at http://www.nasa.gov/cassini or http://saturn.jpl.nasa.gov .

Doing the math: How do we get from “150 billion barbeque cookouts” to “two trillion” burgers?

You can fit 700 million barrels of propane into about six billion 20-pound tanks of liquefied propane gas (LPG). As most Labor Day cookouts will probably occur on this planet, we will use Earth as our barbecue laboratory. On Earth, a full tank of LPG burns for about nine hours – enough time to turn out 25 to 30 meals. That brings us to about 150 to 180 billion meals. If you average 12 medium-well patties per meal, then we’re talking about 2 trillion burgers. When it comes to figuring out how many hot dogs could be cooked, you’re on your own.


- end -
Title: Re: NASA - Cassini updates
Post by: jacqmans on 09/21/2009 06:55 PM
RELEASE: 09-217

CASSINI REVEALS NEW RING QUIRKS, SHADOWS DURING SATURN EQUINOX

PASADENA, Calif. -- NASA scientists are marveling over the extent of
ruffles and dust clouds revealed in the rings of Saturn during the
planet's equinox last month. Scientists once thought the rings were
almost completely flat, but new images reveal the heights of some
newly discovered bumps in the rings are as high as the Rocky
Mountains. NASA released the images Monday.

"It's like putting on 3-D glasses and seeing the third dimension for
the first time," said Bob Pappalardo, Cassini project scientist at
NASA's Jet Propulsion Laboratory in Pasadena, Calif. "This is among
the most important events Cassini has shown us."

On Aug. 11, sunlight hit Saturn's rings exactly edge-on, performing a
celestial magic trick that made them all but disappear. The spectacle
occurs twice during each orbit Saturn makes around the sun, which
takes approximately 10,759 Earth days, or about 29.7 Earth years.
Earth experiences a similar equinox phenomenon twice a year; the
autumnal equinox will occur Sept. 22, when the sun will shine
directly over Earth's equator.

For about a week, scientists used the Cassini orbiter to look at puffy
parts of Saturn's rings caught in white glare from the low-angle
lighting. Scientists have known about vertical clumps sticking out of
the rings in a handful of places, but they could not directly measure
the height and breadth of the undulations and ridges until Saturn's
equinox revealed their shadows.

"The biggest surprise was to see so many places of vertical relief
above and below the otherwise paper-thin rings," said Linda Spilker,
deputy project scientist at JPL. "To understand what we are seeing
will take more time, but the images and data will help develop a more
complete understanding of how old the rings might be and how they are
evolving."

The chunks of ice that make up the main rings spread out 85,000 miles
from the center of Saturn, but they had been thought to be only
around 30 feet thick in the main rings, known as A, B, C, and D.

In the new images, particles seemed to pile up in vertical formations
in each of the rings. Rippling corrugations -- previously seen by
Cassini to extend approximately 500 miles in the innermost D ring --
appear to undulate out to a total of 11,000 miles through the
neighboring C ring to the B ring.

The heights of some of the newly discovered bumps are comparable to
the elevations of the Rocky Mountains. One ridge of icy ring
particles, whipped up by the gravitational pull of Saturn's moon
Daphnis as it travels through the plane of the rings, looms as high
as 2.5 miles. It is the tallest vertical wall seen within the rings.

"We thought the plane of the rings was no taller than two stories of a
modern-day building and instead we've come across walls more than two
miles high," said Carolyn Porco, Cassini imaging team leader at the
Space Science Institute in Boulder, Colo. "Isn't that the most
outrageous thing you could imagine? It truly is like something out of
science fiction."

Scientists also were intrigued by bright streaks in two different
rings that appear to be clouds of dust kicked up in collisions
between small space debris and ring particles. Understanding the rate
and locations of impacts will help build better models of
contamination and erosion in the rings and refine estimates of their
age. The collision clouds were easier to see under the low-lighting
conditions of equinox than under normal lighting conditions.

At the same time Cassini was snapping visible-light photographs of
Saturn's rings, the Composite Infrared Spectrometer instrument was
taking the rings' temperatures. During equinox, the rings cooled to
the lowest temperature ever recorded. The A ring dropped down to a
frosty 382 degrees below zero Fahrenheit. Studying ring temperatures
at equinox will help scientists better understand the sizes and other
characteristics of the ring particles.

The Cassini spacecraft has been observing Saturn, its moons and rings
since it entered the planet's orbit in 2004. The spacecraft's
instruments have discovered new rings and moons and have improved our
understanding of Saturn's ring system.

The Cassini-Huygens mission is a cooperative project of NASA and the
European and Italian Space Agencies. JPL manages the mission for the
Science Mission Directorate at NASA Headquarters in Washington. JPL
also designed, developed and assembled the Cassini orbiter and its
two onboard cameras. The imaging team is based at the Space Science
Institute. The Composite Infrared Spectrometer team is based at
NASA's Goddard Space Flight Center in Greenbelt, Md.

To view Cassini images of the equinox and for more information about
the mission, visit:



http://www.nasa.gov/cassini
Title: Re: NASA - Cassini updates
Post by: jacqmans on 10/16/2009 10:25 AM
Cassini Data Help Redraw Shape of Solar System

The full version of this story with accompanying images is at: http://www.jpl.nasa.gov/news/features.cfm?feature=2337



Images from the Ion and Neutral Camera on NASA's Cassini spacecraft suggest that the heliosphere, the region of the sun's influence, may not have the comet-like shape predicted by existing models. In a paper published Oct. 15 in Science Express, researchers from the Johns Hopkins Applied Physics Laboratory present a new view of the heliosphere, and the forces that shape it.

"These images have revolutionized what we thought we knew for the past 50 years; the sun travels through the galaxy not like a comet but more like a big, round bubble," said Stamatios Krimigis of the Applied Physics Lab, in Laurel, Md., principal investigator for Cassini's Magnetospheric Imaging Instrument which carries the Ion and Neutral Camera. "It's amazing how a single new observation can change an entire concept that most scientists had taken as true for nearly fifty years."

As the solar wind flows from the sun, it carves out a bubble in the interstellar medium. Models of the boundary region between the heliosphere and interstellar medium have been based on the assumption that the relative flow of the interstellar medium and its collision with the solar wind dominate the interaction. This would create a foreshortened "nose" in the direction of the solar system's motion, and an elongated "tail" in the opposite direction.

The Ion and Neutral Camera images suggest that the solar wind's interaction with the interstellar medium is instead more significantly controlled by particle pressure and magnetic field energy density.

"The map we've created from the images suggests that pressure from a hot population of charged particles and interaction with the interstellar medium's magnetic field strongly influence the shape of the heliosphere," says Don Mitchell, Magnetospheric Imaging Instrument/Ion and Neutral Camera co-investigator at the Applied Physics Lab.

Since entering into orbit around Saturn in July of 2004, the Ion and Neutral Camera has been mapping energetic neutral atoms near the planet, as well as their dispersal across the entire sky. The energetic neutral atoms are produced by energetic protons, which are responsible for the outward pressure of the heliosphere beyond the interface where the solar wind collides with the interstellar medium, and which interact with the magnetic field of the interstellar medium.

"Energetic neutral atom imaging has demonstrated its power to reveal the distribution of energetic ions, first in Earth's own magnetosphere, next in the giant magnetosphere of Saturn and now throughout vast structures in space-out to the very edge of our sun's interaction with the interstellar medium," says Edmond C. Roelof, Magnetospheric Imaging Instrument co-investigator at the Applied Physics Lab.

The results from Cassini complement and extend findings from NASA's Interstellar Boundary Explorer, or IBEX, spacecraft. Data from IBEX and Cassini have made it possible for scientists to construct the first comprehensive sky map of our solar system and its location in the Milky Way galaxy.

Researchers from University of Arizona, Tucson; Southwest Research Institute, San Antonio; and University of Texas at San Antonio contributed to the article. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL. The Magnetospheric Imaging Instrument was developed by the Applied Physics Laboratory.

More information on the Cassini mission is available at: http://www.nasa.gov/cassini, http://saturn.jpl.nasa.gov and on the Magnetospheric Imaging Instrument Web site at http://sd-www.jhuapl.edu/CASSINI/ .

Title: Re: NASA - Cassini updates
Post by: jacqmans on 11/20/2009 02:44 PM
Cassini's Big Sky - The View from the Center of Our Solar System

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/features.cfm?feature=2370

When NASA's Cassini spacecraft began orbiting Saturn five years ago, a dozen highly-tuned science instruments set to work surveying, sniffing, analyzing and scrutinizing the Saturnian system.

But Cassini recently revealed new data that appeared to overturn the decades-old belief that our solar system resembled a comet in shape as it moves through the interstellar medium (the matter between stars in our corner of the Milky Way galaxy).

Instead, the new results suggest our heliosphere more closely resembles a bubble – or a rat – being eaten by a boa constrictor: as the solar system passes through the "belly" of the snake, the ribs, which mimic the local interstellar magnetic field, expand and contract as the rat passes. An animation is available here http://photojournal.jpl.nasa.gov/catalog/PIA12310.

"At first I was incredulous," said Tom Krimigis, principal investigator of the Magnetospheric Imaging Instrument (MIMI) at Johns Hopkins University's Applied Physics Laboratory in Laurel, Md. "The first thing I thought was, 'What's wrong with our data?'"

Krimigis and his colleagues on the instrument team published the Cassini findings in the Nov. 13 issue of the journal Science, which featured complementary results from NASA's Interstellar Boundary Explorer (IBEX). Together, the results create the first map of the heliosphere and its thick outer layer known as the heliosheath, where solar wind streaming out from the sun gets heated and slowed as it interacts with the interstellar medium.

The Cassini data also provide a much more direct indication of the thickness of the heliosheath, whereas scientists previously had to rely on calculations from models. The new results from Cassini show that the heliosheath is about 40 to 50 astronomical units (3.7 billion to 4.7 billion miles) thick and that NASA's twin Voyager spacecraft, which are traveling through the heliosheath now, will cross into true interstellar space well before the year 2020. Estimates as far out as 2030 had been suggested.

"These new data from Cassini really redefine our sense of our home in the galaxy, and we can now do better studies of whether our solar system resembles those elsewhere," Krimigis said.

The Voyagers have sent back rich data on the heliosphere and heliosheath, but just at two locations. Scientists want more context. One way to learn about the region is to track energetic neutral atoms streaming back toward the sun from the heliosheath.

Energetic neutral atoms form when cold, neutral gas collides with electrically-charged particles in a cloud of plasma, which is a gas-like state of matter so hot that the atoms split into an ion and an electron. The positively-charged ions in plasma can't reclaim their own electrons, which are moving too fast, but they can steal an electron from the cold gas atoms. Since the resulting particles are neutrally charged, they are able to escape magnetic fields and zoom off into space. The emission of these particles often occurs in the magnetic fields surrounding planets, but also happens when the solar wind mingles with the interstellar medium.

How did Cassini, with 22,000 wire connections and 14 kilometers (8.7 miles) of cabling specifically tweaked to get the most out of its investigation of the solar system's second largest gas bag, recently end up helping to redefine how we look at our entire solar system?

Krimigis and his Cassini colleagues working with MIMI weren't sure their instrument could pick up emissions from far-out, exotic locations, such as from the boundary of our heliosphere, the region of our sun's influence.

Last year, after spending four years focused on the energetic electrons and ions trapped in the magnetic field that surrounds Saturn, as well as the offspring of these particles known as energetic neutral atoms, the team started combing through the data from the instrument's Ion and Neutral Camera, looking for particles arriving from far beyond Saturn.

"We thought we could get some hits from energetic neutral atoms from the heliosheath because Cassini has really been in an excellent position to detect these particles," said Don Mitchell, MIMI instrument scientist and a researcher at the Applied Physics Laboratory.

Cassini was farther away from the sun than previous spacecraft trying to image the heliosphere and even swung very far away from Saturn on some of its orbits, Mitchell said. The data would likely be free of much of the interference that hampered other efforts.

Mitchell, Krimigis and their team were able to stitch together data from late 2003 to the summer of 2009. They created a color-coded map of the intensity of the energetic neutral atoms and discovered a belt of hot, high-pressure particles where the interstellar wind flowed by our heliosheath bubble.

The data matched up nicely with the IBEX images of lower-energy particles and connected that data set to the Voyager data on higher-energy particles.

"I was initially skeptical because the instrument was designed for Saturn's magnetosphere," Mitchell said, "But our camera had long exposures of months to years, so we could accumulate and map each particle that streamed through the tiny aperture from the far reaches of the heliosphere. It was luck, but also a lot of hard work."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif. manages the mission for NASA's Science Mission Directorate, Washington, D.C.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini.

Title: Re: NASA - Cassini updates
Post by: eeergo on 12/17/2009 09:16 PM
Jaw-dropping picture from Cassini, released at the AGU Fall Meeting in San Francisco: we can behold the reflection of (infrared) light on a northern hydrocarbon sea in Titan. Personally, I find this achievement mind-boggling, just for its artistic beauty, never mind the scientific significance.

Full story in http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20091217.html.

The picture:
Title: Re: NASA - Cassini updates
Post by: EE Scott on 12/17/2009 09:44 PM
Wow - that is amazing.  Three cheers for flagships missions!  Shouldn't we just about be expecting another one like this launchin soon?  Yea, right....    :(
Title: Re: NASA - Cassini updates
Post by: robertross on 12/18/2009 12:52 AM
Wow - that is amazing.  Three cheers for flagships missions!  Shouldn't we just about be expecting another one like this launchin soon?  Yea, right....    :(

I'll second both statements.
Title: Re: NASA - Cassini updates
Post by: madscientist197 on 12/19/2009 08:32 AM
They've been looking for specular reflections off the oceans on Titan for a long time now... Nice to see that they've finally succeeded!
Title: Re: NASA - Cassini updates
Post by: Hungry4info3 on 12/19/2009 03:51 PM
Part of the reason they've been less successful before is because the northern hemisphere of the Saturn system's bodies have been in the darkness of northern winter. The equinox wasn't too long ago, and sunlight has now returned to the north polar areas where Titan's major liquid bodies are.
Title: Re: NASA - Cassini updates
Post by: DiggyCoxwell on 12/21/2009 08:11 PM
  There's a practical spin to this too,
but I need to explain it in SF speculative fictional
form.

"It's the year 2069, the 100th aniversary of Apollo 11. You're a member of a 4 person international crew, two of which remain in orbit around
Titan onboard the nuclear-powered mothership with its VASIMR
propulsion system. You, a former US Navy carrier pilot, now astronaut,
accompanied by a female Russian glaciologist, have been on the surface of Titan for over 5 days. And having flown your refuelable hybrid helicopter-propped & rocket-motor equipped lander over 1200 miles from your original landing site
to the south polar region of Titan and landed near one of the large
 methane-ethane lakes, you use that opportunity and locale to replenish your fuel tanks with the available liquid methane-ethane nearby.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 12/24/2009 01:41 PM
Video advisory: 2009-204                                                          December 23, 2009

Cassini Holiday Movies Showcase Dance of Saturn's Moons

The full version of this story with accompanying images is at: http://www.jpl.nasa.gov/news/news.cfm?release=2009-204&cid=advisory_2009-204

Like sugar plum fairies in "The Nutcracker," the moons of Saturn performed a celestial ballet before the eyes of NASA's Cassini spacecraft. New movies frame the moons' silent dance against the majestic sweep of the planet's rings and show as many as four moons gliding around one another.

The new video can be found at http://www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://ciclops.org .

To celebrate the holidays, the Cassini imaging team has created a video collection of "mutual events," which occur when one moon passes in front of another, as seen from the spacecraft. Imaging scientists use mutual event observations to refine their understanding of the dynamics of Saturn's moons. Digital image processing has enabled scientists to turn these routine observations into breathtaking displays of celestial motion. The original images were captured between Aug. 27 and Nov. 8, 2009.

In one scene that synthesizes 12 images taken over the span of 19 minutes, Rhea skates in front of Janus, as Mimas and Pandora slide across the screen in the opposite direction. While the dance appears leisurely on screen, Rhea actually orbits Saturn at a speed of about 8 kilometers per second (18,000 mph). The other moons are hurtling around the planet even faster. Mimas averages about 14 kilometers per second (31,000 mph), and Janus and Pandora travel at about 16 kilometers per second (36,000 mph).

"As yet another year in Saturn orbit draws to a close, these wondrous movies of an alien place clear across the solar system remind us how fortunate we are to be engaged in this magnificent exploratory expedition," said Carolyn Porco, Cassini imaging team leader at the Space Science Institute in Boulder, Colo.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.



- end -
Title: Re: NASA - Cassini updates
Post by: jacqmans on 01/11/2010 08:54 PM
Feature: 2010-006                                                          January 11, 2010

As The Crust Turns: Cassini Data Show Enceladus in Motion

The full version of this story with accompanying images is at: http://www.jpl.nasa.gov/news/news.cfm?release=2010-006&cid=advisory_2010-006

Blobs of warm ice that periodically rise to the surface and churn the icy crust on Saturn's moon Enceladus explain the quirky heat behavior and intriguing surface of the moon's south polar region, according to a new paper using data from NASA's Cassini spacecraft.

"Cassini appears to have caught Enceladus in the middle of a burp," said Francis Nimmo, a planetary scientist at the University of California Santa Cruz and a co-author of the new paper in Nature Geoscience. "These tumultuous periods are rare and Cassini happens to have been watching the moon during one of these special epochs."

The south polar region captivates scientists because it hosts the fissures known as "tiger stripes" that spray water vapor and other particles out from the moon. While the latest paper, released on Jan. 10, doesn't link the churning and resurfacing directly to the formation of fissures and jets, it does fill in some of the blanks in the region's history.

"This episodic model helps to solve one of the most perplexing mysteries of Enceladus," said Bob Pappalardo, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., of the research done by his colleagues. "Why is the south polar surface so young? How could this amount of heat be pumped out at the moon's south pole? This idea assembles the pieces of the puzzle."

About four years ago, Cassini's composite infrared spectrometer instrument detected a heat flow in the south polar region of at least 6 gigawatts, the equivalent of at least a dozen electric power plants. This is at least three times as much heat as an average region of Earth of similar area would produce, despite Enceladus' small size. The region was also later found by Cassini's ion and neutral mass spectrometer instrument to be swiftly expelling argon, which comes from rocks decaying radioactively and has a well-known rate of decay.

Calculations told scientists it would be impossible for Enceladus to have continually produced heat and gas at this rate. Tidal movement – the pull and push from Saturn as Enceladus moves around the planet – cannot explain the release of so much energy.

The surface ages of different regions of Enceladus also show great diversity. Heavily cratered plains in the northern part of the moon appear to be as old as 4.2 billion years, while a region near the equator known as Sarandib Planitia is between 170 million and 3.7 billion years old. The south polar area, however, appears to be less than 100 million years old, possibly as young as 500,000 years.

Craig O'Neill of Macquarie University in Sydney, Australia, and Nimmo, who was partially funded by the NASA Outer Planets Research program, adapted a model that O'Neill had developed for the convection of Earth's crust. For Enceladus, which has a surface completely covered in cold ice that is fractured by the tug of Saturn's gravitational pull, the scientists stiffened up the crust. They picked a strength somewhere between that of the malleable tectonic plates on Earth and the rigid plates of Venus, which are so strong, it appears they never get sucked down into the interior.

Their model showed that heat building up from the interior of Enceladus could be released in episodic bubbles of warm, light ice rising to the surface, akin to the rising blobs of heated wax in a lava lamp. The rise of the warm bubbles would send cold, heavier ice down into the interior. (Warm is, of course, relative. Nimmo said the bubbles are probably just below freezing, which is 273 degrees Kelvin or 32 degrees Farenheit, whereas the surface is a frigid 80 degrees Kelvin or -316 degrees Farenheit.)

The model fits the activity on Enceladus when the churning and resurfacing periods are assumed to last about 10 million years, and the quiet periods, when the surface ice is undisturbed, last about 100 million to two billion years. Their model suggests the active periods have occurred only 1 to 10 percent of the time that Enceladus has existed and have recycled 10 to 40 percent of the surface. The active area around Enceladus's south pole is about 10 percent of its surface.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL.

- end -
Title: Re: NASA - Cassini updates
Post by: jacqmans on 02/03/2010 07:22 PM
RELEASE: 10-030

NASA EXTENDS CASSINI'S TOUR OF SATURN, CONTINUING INTERNATIONAL COOPERATION FOR WORLD CLASS SCIENCE

WASHINGTON -- NASA will extend the international Cassini-Huygens
mission to explore Saturn and its planets to 2017. The agency's
fiscal year 2011 budget provides a $60 million per year extension for
continued study of the ringed planet.

"This is a mission that never stops providing us surprising scientific
results and showing us eye popping new vistas," said Jim Green,
director of NASA's planetary science division at NASA Headquarters in
Washington. "The historic traveler's stunning discoveries and images
have revolutionized our knowledge of Saturn and its moons."

Cassini launched in October 1997 with the European Space Agency's
Huygens probe. The spacecraft arrived at Saturn in 2004. The probe
was equipped with six instruments to study Titan, Saturn's largest
moon. Cassini's 12 instruments have returned a daily stream of data
from Saturn's system for nearly six years. The project was scheduled
to end in 2008, but the mission received a 27-month extension to
Sept. 2010.

"The extension presents a unique opportunity to follow seasonal
changes of an outer planet system all the way from its winter to its
summer," said Bob Pappalardo, Cassini project scientist at NASA's Jet
Propulsion Laboratory in Pasadena, Calif. "Some of Cassini's most
exciting discoveries still lie ahead."

This second extension, called the Cassini Solstice Mission, enables
scientists to study seasonal and other long-term weather changes on
the planet and its moons. Cassini arrived just after Saturn's
northern winter solstice, and this extension continues until a few
months past northern summer solstice in May 2017. The northern summer
solstice marks the beginning of summer in the northern hemisphere and
winter in the southern hemisphere.

A complete seasonal period on Saturn has never been studied at this
level of detail. The Solstice mission schedule calls for an
additional 155 orbits around the planet, 54 flybys of Titan and 11
flybys of the icy moon Enceladus.

The mission extension also will allow scientists to continue
observations of Saturn's rings and the magnetic bubble around the
planet known as the magnetosphere. The spacecraft will make repeated
dives between Saturn and its rings to obtain in depth knowledge of
the gas giant. During these dives, the spacecraft will study the
internal structure of Saturn, its magnetic fluctuations and ring
mass.

The mission will be evaluated periodically to ensure the spacecraft
has the ability to achieve new science objectives for the entire
extension.

"The spacecraft is doing remarkably well, even as we endure the
expected effects of age after logging 2.6 billion miles on its
odometer," said Bob Mitchell, Cassini program manager at JPL. "This
extension is important because there is so much still to be learned
at Saturn. The planet is full of secrets, and it doesn't give them up
easily."

Cassini's travel scrapbook includes more than 210,000 images;
information gathered during more than 125 revolutions around Saturn;
67 flybys of Titan and eight close flybys of Enceladus. Cassini has
revealed unexpected details in the planet's signature rings, and
observations of Titan have given scientists a glimpse of what Earth
might have been like before life evolved.

Scientists hope to learn answers to many questions that have developed
during the course of the mission, including why Saturn seems to have
an inconsistent rotation rate and how a probable subsurface ocean
feeds the Enceladus' jets.

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. JPL manages the
project for NASA's Science Mission Directorate in Washington. The
Cassini orbiter was designed, developed and assembled at JPL.

More Cassini information is available at:



http://www.nasa.gov/cassini
Title: Re: NASA - Cassini updates
Post by: Analyst on 02/03/2010 08:14 PM
Great. Exploration at its best. With humans, on earth, and robots more than a lighthour away. The final orbits in 2017 will be spectacular.

Analyst

PS: Just one thing to add: While people are lamenting about HSF and the need for exploration, and the budget and bad Obama nada nada nada, here true exploration is going on, before your very eyes, and you ignore it.
Title: Re: NASA - Cassini updates
Post by: MikeMi. on 02/05/2010 12:56 AM
PS: Just one thing to add: While people are lamenting about HSF and the need for exploration, and the budget and bad Obama nada nada nada, here true exploration is going on, before your very eyes, and you ignore it.

Indeed. Sometimes Im rly piss off while readin all this lamentin cause of frozen HSF program and ppl are forgettin real exploration at far places in our US.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 02/23/2010 08:04 PM
Image advisory: 2010-061                                                                     February 23, 2010

Cassini Finds Plethora of Plumes, Hotspots at Enceladus

The full version of this story with accompanying images is at: http://www.jpl.nasa.gov/news/news.cfm?release=2010-061&cid=release_2010-061

Newly released images from last November's swoop over Saturn's icy moon Enceladus by NASA's Cassini spacecraft reveal a forest of new jets spraying from prominent fractures crossing the south polar region and yield the most detailed temperature map to date of one fracture.

The new images from the imaging science subsystem and the composite infrared spectrometer teams also include the best 3-D image ever obtained of a "tiger stripe," a fissure that sprays icy particles, water vapor and organic compounds. There are also views of regions not well-mapped previously on Enceladus, including a southern area with crudely circular tectonic patterns.

The images and additional information are online at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

"Enceladus continues to astound," said Bob Pappalardo, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "With each Cassini flyby, we learn more about its extreme activity and what makes this strange moon tick."

For Cassini's visible-light cameras, the Nov. 21, 2009 flyby provided the last look at Enceladus' south polar surface before that region of the moon goes into 15 years of darkness, and includes the most detailed look yet at the jets.

Scientists planned to use this flyby to look for new or smaller jets not visible in previous images. In one mosaic, scientists count more than 30 individual geysers, including more than 20 that had not been seen before. At least one jet spouting prominently in previous images now appears less powerful.

"This last flyby confirms what we suspected," said Carolyn Porco, imaging team lead based at the Space Science Institute in Boulder, Colo. "The vigor of individual jets can vary with time, and many jets, large and small, erupt all along the tiger stripes."

A new map that combines heat data with visible-light images shows a 40-kilometer (25-mile) segment of the longest tiger stripe, known as Baghdad Sulcus. The map illustrates the correlation, at the highest resolution yet seen, between the geologically youthful surface fractures and the anomalously warm temperatures that have been recorded in the south polar region. The broad swaths of heat previously detected by the infrared spectrometer appear to be confined to a narrow, intense region no more than a kilometer (half a mile) wide along the fracture.

In these measurements, peak temperatures along Baghdad Sulcus exceed 180 Kelvin (minus 135 degrees Fahrenheit), and may be higher than 200 Kelvin (minus 100 degrees Fahrenheit). These warm temperatures probably result from heating of the fracture flanks by the warm, upwelling water vapor that propels the ice-particle jets seen by Cassini's cameras. Cassini scientists will be testing this idea by investigating how well the hot spots correspond with the jet sources.

"The fractures are chilly by Earth standards, but they're a cozy oasis compared to the numbing 50 Kelvin (-370 Fahrenheit) of their surroundings," said John Spencer, a composite infrared spectrometer team member based at Southwest Research Institute in Boulder, Colo. "The huge amount of heat pouring out of the tiger stripe fractures may be enough to melt the ice underground. Results like this make Enceladus one of the most exciting places we've found in the solar system."

Some of Cassini's scientists infer that the warmer the temperatures are at the surface, the greater the likelihood that jets erupt from liquid. "And if true, this makes Enceladus' organic-rich, liquid sub-surface environment the most accessible extraterrestrial watery zone known in the solar system," Porco said.

The Nov. 21 flyby was the eighth targeted encounter with Enceladus. It took the spacecraft to within about 1,600 kilometers (1,000 miles) of the moon's surface, at around 82 degrees south latitude.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md., where the instrument was built.

More details are also available at the imaging team's website http://ciclops.org and the composite infrared spectrometer team's website http://cirs.gsfc.nasa.gov.



-end-
Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/11/2010 07:11 PM
News release: 2010-084                                                                     March 11, 2010

Cassini Data Show Ice and Rock Mixture Inside Titan

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-084&cid=release_2010-084

PASADENA, Calif. -- By precisely tracking NASA's Cassini spacecraft on its low swoops over Saturn's moon Titan, scientists have determined the distribution of materials in the moon's interior. The subtle gravitational tugs they measured suggest the interior has been too cold and sluggish to split completely into separate layers of ice and rock.

The finding, to be published in the March 12 issue of the journal Science, shows how Titan evolved in a different fashion from inner planets such as Earth, or icy moons such as Jupiter's Ganymede, whose interiors have split into distinctive layers.

"These results are fundamental to understanding the history of moons of the outer solar system," said Cassini Project Scientist Bob Pappalardo, commenting on his colleagues' research. Pappalardo is with NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We can now better understand Titan's place among the range of icy satellites in our solar system."

Scientists have known that Titan, Saturn's largest moon, is about half ice and half rock, but they needed the gravity data to figure out how the materials were distributed. It turns out Titan's interior is a sorbet of ice studded with rocks that probably never heated up beyond a relatively lukewarm temperature. Only in the outermost 500 kilometers (300 miles) is Titan's ice devoid of any rock, while ice and rock are mixed to various extents at greater depth.

"To avoid separating the ice and the rock, you must avoid heating the ice too much," said David J. Stevenson, one of the paper's co-authors and a professor of planetary science at the California Institute of Technology in Pasadena. "This means that Titan was built rather slowly for a moon, in perhaps around a million years or so, back soon after the formation of the solar system."

This incomplete separation of ice and rock makes Titan less like Jupiter's moon Ganymede, where ice and rock have fully separated, and perhaps more like another Jovian moon, Callisto, which is believed to have a mixed ice and rock interior. Though the moons are all about the same size, they clearly have diverse histories.

The Cassini measurements help construct a gravity map, which may help explain why Titan has a stunted topography, since interior ice must be warm enough to flow slowly in response to the weight of heavy geologic structures, such as mountains.

Creating the gravity map required tracking minute changes in Cassini's speed along a line of sight from Earth to the spacecraft as it flew four close flybys of Titan between February 2006 and July 2008. The spacecraft took paths between about 1,300 to 1,900 kilometers (800 to 1,200 miles) above Titan.

"The ripples of Titan's gravity gently push and pull Cassini along its orbit as it passes by the moon and all these changes were accurately recorded by the ground antennas of the Deep Space Network within 5 thousandths of a millimeter per second [0.2 thousandths of an inch per second] even as the spacecraft was over a billion kilometers [more than 600 million miles] away," said Luciano Iess, a Cassini radio science team member at Sapienza University of Rome in Italy, and the paper's lead author. "It was a tricky experiment."

The results don't speak to whether Titan has an ocean beneath the surface, but scientists say this hypothesis is very plausible and they intend to keep investigating. Detecting tides induced by Saturn, a goal of the radio science team, would provide the clearest evidence for such a hidden water layer.

A Cassini interdisciplinary investigator, Jonathan Lunine, said of his colleagues' findings, "Additional flybys may tell us whether the crust is thick or thin today." Lunine is with the University of Rome, Tor Vergata, Italy, and the University of Arizona, Tucson. "With that information we may have a better understanding of how methane, the ephemeral working fluid of Titan's rivers, lakes and clouds, has been resupplied over geologic time. Like the history of water on Earth, this is fundamental to a deep picture of the nature of Titan through time."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of Caltech, manages the project for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL. Cassini's radio science subsystem has been jointly developed by NASA and the Italian Space Agency (ASI).

More Cassini information is available, at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .



- end -
Title: Re: NASA - Cassini updates
Post by: stockman on 03/18/2010 09:08 AM
NasaTV just ran about a 7 or 8 minute montage of Cassini images to music - just now (about 6 AM Eastern time) ... It was fantastic and the first time I have seen it... Not sure if John44 maybe has already posted this or CAN maybe post it ( :) ) ... it was a great visual...

Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/18/2010 06:55 PM
Cassini Shows Saturnian Roller Derby, Strange Weather

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-090&cid=release_2010-090

From our vantage point on Earth, Saturn may look like a peaceful orb with rings worthy of a carefully raked Zen garden, but NASA's Cassini spacecraft has been shadowing the gas giant long enough to see that the rings are a rough and tumble roller derby. It has also revealed that the planet itself roils with strange weather and shifting patterns of charged particles. Two review papers to be published in the March 19 issue of the journal Science synthesize Cassini's findings since arriving at Saturn in 2004.

"This rambunctious system gives us a new feel for how an early solar system might have behaved," said Linda Spilker, a planetary scientist and the new Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "This kind of deep, rich data can only be collected by an orbiting spacecraft, and we look forward to the next seven years around Saturn bringing even more surprises."

In the paper describing the elegant mess of activity in the rings, lead author Jeff Cuzzi, Cassini's interdisciplinary scientist for rings and dust who is based at NASA Ames Research Center, Moffett Field, Calif., describes how Cassini has shown us that collisions are routine and chunks of ice leave trails of debris in their wakes. Spacecraft data have also revealed how small moons play tug-of-war with ring material and how bits of rubble that would otherwise join together to become moons are ultimately ripped apart by the gravitational pull that Saturn exerts.

During equinox, the period when sunlight hits the rings exactly edge-on, Cassini witnessed rings that are normally flat - about tens of meters (yards) thick - being flipped up as high as the Rocky Mountains.

The spacecraft has also shown that the rings are composed mostly of water ice, with a mysterious reddish contaminant that could be rust or small organic molecules similar to those found in red vegetables on Earth.

"It has been amazing to see the rings come to life before our very eyes, changing even as we watch, being colorful and taking on a tangible, 3-D nature," Cuzzi said. "The rings were still a nearly unstructured object in even the best telescopes when I was a grad student, but Cassini has brought us an intimate familiarity with them."

Cuzzi said Cassini scientists were surprised to find such fine-scale structure nearly everywhere in the rings, forcing them to be very careful about generalizing their findings across the entire ring disk. The discovery that the rings are clumpy has also called into question some of the previous estimates for the mass of the rings because there might be clusters of material hidden inside of the clumps that have not yet been measured.

In the review paper on Saturn's atmosphere, ionosphere and magnetosphere, lead author Tamas Gombosi, Cassini's interdisciplinary scientist for magnetosphere and plasma science who is based at the University of Michigan in Ann Arbor, describes how Cassini helped scientists understand a south polar vortex that has a diameter 20 to 40 times that of a terrestrial hurricane, and the bizarrely stable hexagon-shaped jet stream at the planet's north pole. Cassini scientists have also calculated a variation in Saturn's wind speeds at different altitudes and latitudes that is 10 times greater than the wind speed variation on Earth.

According to Gombosi's paper, Cassini has also shown us that the small moon Enceladus, not the sun or Saturn's largest moon Titan, is the biggest contributor of charged particles to Saturn's magnetic environment. The charged particles from Enceladus, a moon that features a plume of water vapor and other gases spraying from its south polar region, also contribute to the auroras around the poles of the planet.

"We learned from Cassini that the Saturnian magnetosphere is swimming in water," Gombosi said. "This is unique in the solar system and makes Saturn's plasma environment particularly fascinating."

Of course, Cassini's intense investigation has opened up a host of new mysteries. For example, Cassini has shown us images of occasional cannon-ball-like objects that rocket across one of the outer rings known as the F ring, without many clues about where they came from or why they quickly disappear.

Learning more about a kind of radio emission known as "kilometric radiation" at Saturn has unsettled debates about the planet's rotation rate rather than settled them. While the regular periods of kilometric radiation have given scientists a sense of the rotation rate at Jupiter, Saturn has clocked different periods for the radiation during NASA's Voyager flybys in 1980 and 1981 and the nearly six years of Cassini's investigations. The modulations vary by about 30 seconds to a minute, but they shouldn't be varying at all. The inconsistency may be related to a source in the magnetic bubble around the planet rather than the core of the gas giant, but scientists are still debating.

"Cassini has answered questions we were not even smart enough to ask when the mission was planned and raised a lot of new ones," Cuzzi said. "We are hot on the trail, though."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the project for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL.

More Cassini information is available, at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 04/02/2010 08:18 PM
Cassini Doubleheader: Flying By Titan and Dione

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-110&cid=release_2010-110

In a special double flyby early next week, NASA's Cassini spacecraft will visit Saturn's moons Titan and Dione within a period of about a day and a half, with no maneuvers in between. A fortuitous cosmic alignment allows Cassini to attempt this doubleheader, and the interest in swinging by Dione influenced the design of its extended mission.

The Titan flyby, planned for Monday, April 5, will take Cassini to within about 7,500 kilometers (4,700 miles) of the moon's surface. The distance is relatively long as far as encounters go, but it works to the advantage of Cassini's imaging science subsystem. Cassini's cameras will be able to stare at Titan's haze-shrouded surface for a longer time and capture high-resolution pictures of the Belet and Senkyo areas, dark regions around the equator that ripple with sand dunes.

In the early morning of Wednesday, April 7 in UTC time zones, which is around 9 p.m. on Tuesday, April 6 in California, Cassini will make its closest approach to the medium-sized icy moon Dione. Cassini will plunge to within about 500 kilometers (300 miles) of Dione's surface.

This is only Cassini's second close encounter with Dione. The first flyby in October 2005, and findings from the Voyager spacecraft in the 1990s, hinted that the moon could be sending out a wisp of charged particles into the magnetic field around Saturn and potentially exhaling a diffuse plume that contributes material to one of the planet's rings. Like Enceladus, Saturn's more famous moon with a plume, Dione features bright, fresh fractures. But if there were a plume on Dione, it would certainly be subtler and produce less material.

Cassini plans to use its magnetometer and fields and particles instruments to see if it can find evidence of activity at Dione. Thermal mapping by the composite infrared spectrometer will also help in that search. In addition, the visual and infrared mapping spectrometer will examine dark material found on Dione. Scientists would like to understand the source of this dark material.

Cassini has made three previous double flybys and another two are planned in the years ahead. The mission is nearing the end of its first extension, known as the Equinox mission. It will begin its second mission extension, known as the Solstice Mission, in October 2010.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL.

More information about the Titan flyby, dubbed "T67," is available at:
http://saturn.jpl.nasa.gov/mission/flybys/titan20100405/ .

More information about the Dione flyby, dubbed "D2," is available at:
http://saturn.jpl.nasa.gov/mission/flybys/dione20100407/
Title: Re: NASA - Cassini updates
Post by: jacqmans on 04/14/2010 09:41 PM
RELEASE: 10-085

FLASH: NASA'S CASSINI SPACECRAFT SEES LIGHTNING ON SATURN

WASHINGTON -- NASA's Cassini spacecraft has captured images of
lightning on Saturn. The images have allowed scientists to create the
first movie showing lightning flashing on another planet.

After waiting years for Saturn to dim enough for the spacecraft's
cameras to detect bursts of light, scientists were able to create the
movie, complete with a soundtrack that features the crackle of radio
waves emitted when lightning bolts struck.

"This is the first time we have the visible lightning flash together
with the radio data," said Georg Fischer, a radio and plasma wave
science team associate based at the Space Research Institute in Graz,
Austria. "Now that the radio and visible light data line up, we know
for sure we are seeing powerful lightning storms."

The movie and radio data suggest extremely powerful storms with
lightning that flashes as brightly as the brightest super-bolts on
Earth, according to Andrew Ingersoll, a Cassini imaging science
subsystem team member at the California Institute of Technology in
Pasadena. "What's interesting is that the storms are as powerful --
or even more powerful -- at Saturn as on Earth," said Ingersoll. "But
they occur much less frequently, with usually only one happening on
the planet at any given time, though it can last for months."

The first images of the lightning were captured in August 2009, during
a storm that churned from January to October 2009 and lasted longer
than any other observed lightning storm in the solar system. Results
are described in an article accepted for publication in the journal
Geophysical Research Letters.

To make a video, scientists needed more pictures with brighter
lightning and strong radio signals. Data were collected during a
shorter subsequent storm, which occurred from November through
mid-December 2009. The frames in the video were obtained over 16
minutes on Nov. 30, 2009. The flashes lasted less than one second.
The images show a cloud as long as 1,900 miles across and regions
illuminated by lightning flashes about 190 miles in diameter.
Scientists use the width of the flashes to gauge the depth of the
lightning below the cloud tops.

When lightning strikes on Earth and on Saturn, it emits radio waves at
a frequency that can cause static on an AM radio. The sounds in the
video approximate that static sound, based on Saturn electrostatic
discharge signals detected by Cassini's radio and plasma wave science
instrument.


Cassini, launched in 1997, and NASA's Voyager mission, launched in
1977, previously had captured radio emissions from storms on Saturn.
A belt around the planet where Cassini has detected radio emissions
and bright, convective clouds earned the nickname "storm alley."
Cassini's cameras, however, had been unable to get pictures of
lightning flashing.

Since Cassini's arrival at Saturn in 2004, it has been difficult to
see the lightning because the planet is very bright and reflective.
Sunlight shining off Saturn's enormous rings made even the night side
of Saturn brighter than a full-moon night on Earth. Equinox, the
period around August 2009 when the sun shone directly over the
planet's equator, finally brought the needed darkness. During
equinox, the sun lit the rings edge-on only and left the bulk of the
rings in shadow.

Seeing lightning was another highlight of the equinox period, which
already enabled scientists to see clumps in the rings as high as the
Rocky Mountains.

"The visible-light images tell us a lot about the lightning," said
Ulyana Dyudina, a Cassini imaging team associate based at Caltech,
who was the first to see the flashes. "Now we can begin to measure
how powerful these storms are, where they form in the cloud layer and
how the optical intensity relates to the total energy of the
thunderstorms."

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. NASA's Jet
Propulsion Laboratory in Pasadena manages the mission for NASA's
Science Mission Directorate in Washington. The Cassini orbiter and
its two onboard cameras were designed, developed and assembled at
JPL.

For more information about the Cassini-Huygens mission visit



http://www.nasa.gov/cassini
Title: Re: NASA - Cassini updates
Post by: agman25 on 04/21/2010 01:34 PM

A Saturn Spectacular, With Gravity’s Help

http://www.nytimes.com/2010/04/20/science/space/20cassini.html?pagewanted=all
Title: Re: NASA - Cassini updates
Post by: jacqmans on 04/30/2010 08:13 AM
Feature                                                                           April 29, 2010

Cassini and Amateurs Chase Storm on Saturn


The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-143&cid=release_2010-143


With the help of amateur astronomers, the composite infrared spectrometer instrument aboard NASA's Cassini spacecraft has taken its first look at a massive blizzard in Saturn's atmosphere. The instrument collected the most detailed data to date of temperatures and gas distribution in that planet's storms.

The data showed a large, turbulent storm, dredging up loads of material from the deep atmosphere and covering an area at least five times larger than the biggest blizzard in this year's Washington, D.C.-area storm front nicknamed "Snowmageddon."

"We were so excited to get a heads-up from the amateurs," said Gordon Bjoraker, a composite infrared spectrometer team member based at NASA's Goddard Space Flight Center in Greenbelt, Md. Normally, he said, "Data from the storm cell would have been averaged out."

Cassini's radio and plasma wave instrument and imaging cameras have been tracking thunder and lightning storms on Saturn for years in a band around Saturn's mid-latitudes nicknamed "storm alley." But storms can come and go on a time scale of weeks, while Cassini's imaging and spectrometer observations have to be locked in place months in advance.

The radio and plasma wave instrument regularly picks up electrostatic discharges associated with the storms, so team members have been sending periodic tips to amateur astronomers, who can quickly go to their backyard telescopes and try to see the bright convective storm clouds. Amateur astronomers including Anthony Wesley, Trevor Barry and Christopher Go got one of those notices in February and were able to take dozens of pictures over the next several weeks.

In late March, Wesley, an amateur astronomer from Australia who was actually the first person to detect the new dark spot caused by an impact on Jupiter last summer, sent Cassini scientists an e-mail with a picture of the storm.

"I wanted to be sure that images like these were being seen by the Cassini team just in case this was something of interest to be imaged directly by Cassini or the Hubble Space Telescope," Wesley wrote.

Cassini scientists eagerly pored through the images, including a picture of the storm at its peak on March 13 by Go, who lives in the Philippines.

By a stroke of luck, the composite infrared spectrometer happened to be targeting the latitude of the storms. The instrument's scientists knew there could be storms there, but didn't know when they might be active.

Data obtained by the spectrometer on March 25 and 26 showed larger than expected amounts of phosphine, a gas typically found in Saturn's deep atmosphere and an indicator that powerful currents were dredging material upward into the upper troposphere. The spectrometer data also showed another signature of the storm: the tropopause, the dividing line between the serene stratosphere and the lower, churning troposphere, was about 0.5 Kelvin (1 degree Fahrenheit) colder in the storm cell than in neighboring areas.

"A balloonist floating about 100 kilometers down from the bottom of Saturn's calm stratosphere would experience an ammonia-ice blizzard with the intensity of Snowmageddon," said Brigette Hesman, a composite infrared spectrometer team member who is an assistant research scientist at the University of Maryland. "These blizzards appear to be powered by violent storms deeper down - perhaps another 100 to 200 kilometers down - where lightning has been observed and the clouds are made of water and ammonia."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md., where the instrument was built.

- end -
Title: Re: NASA - Cassini updates
Post by: jacqmans on 05/11/2010 08:53 PM
Rock and Roll: Titan's Gem Tumbler

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-156&cid=release_2010-156

It appears flash flooding has paved streambeds in the Xanadu region of Saturn's moon Titan with thousands of sparkling crystal balls of ice, according to scientists with NASA's Cassini spacecraft. By analyzing the way the terrain has scattered radar beams, scientists deduce the spheres measure at least a few centimeters (inches) and maybe up to a couple of meters (yards) in diameter. The spheres likely originated as part of water-ice bedrock in higher terrain in Xanadu.

"What we believe happened in this area is a lot like what creates polished river rocks on Earth," said Alice Le Gall, a postdoctoral fellow at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the lead author of the study, which used the Cassini radar instrument. "Bouncing downstream smoothes out the edges of rocks."

As foothill residents know in southern California and other areas, sudden rains can trigger mudslides and flooding at the mountainous fringes of desert areas. Those flows can pick up boulders and debris and tumble them downstream. On Titan, the flows appear to have occurred periodically for eons, on a catastrophic scale. The process on Titan, however, involves rain made of liquid methane and ethane, rather than Earth's water rain. Titan's rocks are believed to be made primarily of water ice frozen into a hard mass about minus 180 degrees Celsius (minus 290 degrees Fahrenheit), rather than Earth's mineral rocks.

Earth-like river rocks have already been observed on Titan at the landing site of the European Space Agency's Huygens probe, near the equator in the borderland between the Adiri and Shangri-la regions. The landing site also showed signs of flash flooding that deposited cobblestones about 2 to 20 centimeters (1 to 8 inches) in diameter.

But the spidery channels in this southern lowland part of Xanadu looked brighter to Cassini's radar instrument than the Huygens landing area. In fact, the channels, which were scanned by Cassini in May 2008, are among the brightest features ever seen on Titan by the radar instrument.

In a paper now available online in the journal Icarus, Le Gall and colleagues concluded that the most plausible explanation for the extreme brightness of the Xanadu channels was a collection of transparent spherical sediments, packed more tightly together than the cobblestones at the Huygens landing site. The effect would be similar to bejeweling an area with light-catching rhinestones.

The spheres appear to be made of water ice - possibly doped with ammonia - that would look bright to the microwaves used by Cassini's radar. Spheres are good at sending light back in the direction it came from. This property has actually led manufacturers to use plastic spheres in reflective paints and tape, Le Gall said.

Xanadu may be an especially good gem grinder because of its broad expanse and gentle southward slope. Flows could have traveled long distances there and tumbled the chunks for hundreds of kilometers (miles). The subtle work to shape them into spheres could have come from fine grit rubbing against the rocks in the flowing methane. Or, ice may be malleable in Titan's cold temperatures, deforming plastically during the collisions rather than fracturing. The flows that transported these icy spheres probably traveled around 1 meter per second (2 mph).

"It's been really hard for a long time for people to understand why Xanadu is so bright," said Steve Wall, a radar team member at JPL. "You might not expect these kinds of geometries in a natural setting, but we believe this can explain the enigma."

The radar team plans to continue looking for other instances of small, smooth spheres in nature to increase their confidence about the explanation. They also said more study is needed on the mechanical properties of water ice at such cold temperatures.

"Here is yet another example of Titan as a world with Earth-like processes," said Linda Spilker, Cassini project scientist at JPL. "As the seasons change on Titan, maybe we'll get a chance to see methane flow through some of the river channels."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

For more information about the Cassini-Huygens mission visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

#2010-156

- end -

Title: Re: NASA - Cassini updates
Post by: jacqmans on 05/18/2010 03:13 AM
May 17, 2010

Cassini Double Play: Enceladus and Titan


The full version of this story with accompanying images is at: http://www.jpl.nasa.gov/news/news.cfm?release=2010-164&cid=release_2010-164
About a month and a half after its last double flyby, NASA's Cassini spacecraft will be turning another double play this week, visiting the geyser moon Enceladus and the hazy moon Titan. The alignment of the moons means that Cassini can catch glimpses of these two contrasting worlds within less than 48 hours, with no maneuver in between.

Cassini will make its closest approach to Enceladus late at night on May 17 Pacific time, which is in the early hours of May 18 UTC. The spacecraft will pass within about 435 kilometers (270 miles) of the moon's surface.

The main scientific goal at Enceladus will be to watch the sun play peekaboo behind the water-rich plume emanating from the moon's south polar region. Scientists using the ultraviolet imaging spectrograph will be able to use the flickering light to measure whether there is molecular nitrogen in the plume. Ammonia has already been detected in the plume and scientists know heat can decompose ammonia into nitrogen molecules. Determining the amount of molecular nitrogen in the plume will give scientists clues about thermal processing in the moon's interior.

The second of Cassini's two flybys is an encounter with Titan. The closest approach will take place in the late evening May 19 Pacific time, which is in the early hours of May 20 UTC. The spacecraft will fly to within 1,400 kilometers (750 miles) of the surface.

Cassini will primarily be doing radio science during this pass to detect the subtle variations in the gravitational tug on the spacecraft by Titan, which is 25 percent larger in volume than the planet Mercury. Analyzing the data will help scientists learn whether Titan has a liquid ocean under its surface and get a better picture of its internal structure. The composite infrared spectrometer will also get its southernmost pass for thermal data to fill out its temperature map of the smoggy moon.

Cassini has made four previous double flybys and one more is planned in the years ahead.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL.

More information on the Enceladus flyby, dubbed "E10," is available at: http://saturn.jpl.nasa.gov/mission/flybys/enceladus20100518/

More information on the Titan flyby, dubbed "T68," is available at: http://saturn.jpl.nasa.gov/mission/flybys/titan20100520/

Title: Re: NASA - Cassini updates
Post by: marsavian on 06/05/2010 12:23 PM
It's life Jim, but not as we know it ;).

http://www.nasa.gov/topics/solarsystem/features/titan20100603.html

What is Consuming Hydrogen and Acetylene on Titan?   06.03.10

PASADENA, Calif. - Two new papers based on data from NASA's Cassini spacecraft scrutinize the complex chemical activity on the surface of Saturn's moon Titan. While non-biological chemistry offers one possible explanation, some scientists believe these chemical signatures bolster the argument for a primitive, exotic form of life or precursor to life on Titan's surface. According to one theory put forth by astrobiologists, the signatures fulfill two important conditions necessary for a hypothesized "methane-based life."

One key finding comes from a paper online now in the journal Icarus that shows hydrogen molecules flowing down through Titan's atmosphere and disappearing at the surface. Another paper online now in the Journal of Geophysical Research maps hydrocarbons on the Titan surface and finds a lack of acetylene.

This lack of acetylene is important because that chemical would likely be the best energy source for a methane-based life on Titan, said Chris McKay, an astrobiologist at NASA Ames Research Center, Moffett Field, Calif., who proposed a set of conditions necessary for this kind of methane-based life on Titan in 2005. One interpretation of the acetylene data is that the hydrocarbon is being consumed as food. But McKay said the flow of hydrogen is even more critical because all of their proposed mechanisms involved the consumption of hydrogen.

"We suggested hydrogen consumption because it's the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth," McKay said. "If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth."

To date, methane-based life forms are only hypothetical. Scientists have not yet detected this form of life anywhere, though there are liquid-water-based microbes on Earth that thrive on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin (minus 290 degrees Fahrenheit), a methane-based organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan's surface and much too cold to support life as we know it.

The list of liquid candidates is very short: liquid methane and related molecules like ethane. While liquid water is widely regarded as necessary for life, there has been extensive speculation published in the scientific literature that this is not a strict requirement.

The new hydrogen findings are consistent with conditions that could produce an exotic, methane-based life form, but do not definitively prove its existence, said Darrell Strobel, a Cassini interdisciplinary scientist based at Johns Hopkins University in Baltimore, Md., who authored the paper on hydrogen.

Strobel, who studies the upper atmospheres of Saturn and Titan, analyzed data from Cassini's composite infrared spectrometer and ion and neutral mass spectrometer in his new paper. The paper describes densities of hydrogen in different parts of the atmosphere and the surface. Previous models had predicted that hydrogen molecules, a byproduct of ultraviolet sunlight breaking apart acetylene and methane molecules in the upper atmosphere, should be distributed fairly evenly throughout the atmospheric layers.

Strobel found a disparity in the hydrogen densities that lead to a flow down to the surface at a rate of about 10,000 trillion trillion hydrogen molecules per second. This is about the same rate at which the molecules escape out of the upper atmosphere.

"It's as if you have a hose and you're squirting hydrogen onto the ground, but it's disappearing," Strobel said. "I didn't expect this result, because molecular hydrogen is extremely chemically inert in the atmosphere, very light and buoyant. It should 'float' to the top of the atmosphere and escape."

Strobel said it is not likely that hydrogen is being stored in a cave or underground space on Titan. The Titan surface is also so cold that a chemical process that involved a catalyst would be needed to convert hydrogen molecules and acetylene back to methane, even though overall there would be a net release of energy. The energy barrier could be overcome if there were an unknown mineral acting as the catalyst on Titan's surface.

The hydrocarbon mapping research, led by Roger Clark, a Cassini team scientist based at the U.S. Geological Survey in Denver, examines data from Cassini's visual and infrared mapping spectrometer. Scientists had expected the sun's interactions with chemicals in the atmosphere to produce acetylene that falls down to coat the Titan surface. But Cassini detected no acetylene on the surface.

In addition Cassini's spectrometer detected an absence of water ice on the Titan surface, but loads of benzene and another material, which appears to be an organic compound that scientists have not yet been able to identify. The findings lead scientists to believe that the organic compounds are shellacking over the water ice that makes up Titan's bedrock with a film of hydrocarbons at least a few millimeters to centimeters thick, but possibly much deeper in some places. The ice remains covered up even as liquid methane and ethane flow all over Titan's surface and fill up lakes and seas much as liquid water does on Earth.

"Titan's atmospheric chemistry is cranking out organic compounds that rain down on the surface so fast that even as streams of liquid methane and ethane at the surface wash the organics off, the ice gets quickly covered again," Clark said. "All that implies Titan is a dynamic place where organic chemistry is happening now."

The absence of detectable acetylene on the Titan surface can very well have a non-biological explanation, said Mark Allen, principal investigator with the NASA Astrobiology Institute Titan team. Allen is based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. Allen said one possibility is that sunlight or cosmic rays are transforming the acetylene in icy aerosols in the atmosphere into more complex molecules that would fall to the ground with no acetylene signature.

"Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed," Allen said. "We have a lot of work to do to rule out possible non-biological explanations. It is more likely that a chemical process, without biology, can explain these results - for example, reactions involving mineral catalysts."

"These new results are surprising and exciting," said Linda Spilker, Cassini project scientist at JPL. "Cassini has many more flybys of Titan that might help us sort out just what is happening at the surface."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL.

For more information about the Cassini-Huygens mission visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.
 
Title: Re: NASA - Cassini updates
Post by: jacqmans on 07/08/2010 08:19 PM
News release: 2010-227                                                                      July 08, 2010

Saturn Propellers Reflect Solar System Origins

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-227&cid=release_2010-227

PASADENA, Calif. - Scientists using NASA's Cassini spacecraft at Saturn have stalked a new class of moons in the rings of Saturn that create distinctive propeller-shaped gaps in ring material. It marks the first time scientists have been able to track the orbits of individual objects in a debris disk. The research gives scientists an opportunity to time-travel back into the history of our solar system to reveal clues about disks around other stars in our universe that are too far away to observe directly.

"Observing the motions of these disk-embedded objects provides a rare opportunity to gauge how the planets grew from, and interacted with, the disk of material surrounding the early sun," said Carolyn Porco, Cassini imaging team lead based at the Space Science Institute in Boulder, Colo., and a co-author on the paper. "It allows us a glimpse into how the solar system ended up looking the way it does."

The results are published in a new study in the July 8, 2010, issue of the journal Astrophysical Journal Letters.

Cassini scientists first discovered double-armed propeller features in 2006 in an area now known as the "propeller belts" in the middle of Saturn's outermost dense ring, known as the A ring. The spaces were created by a new class of moonlets - smaller than known moons, but larger than the particles in the rings - that could clear the space immediately around them. Those moonlets, which were estimated to number in the millions, were not large enough to clear out their entire path around Saturn, as do the moons Pan and Daphnis.

The new paper, led by Matthew Tiscareno, a Cassini imaging team associate based at Cornell University, Ithaca, N.Y., reports on a new cohort of larger and rarer moons in another part of the A ring farther out from Saturn. With propellers as much as hundreds of times as large as those previously described, these new objects have been tracked for as long as four years.

The propeller features are up to several thousand kilometers (miles) long and several kilometers (miles) wide. The moons embedded in the ring appear to kick up ring material as high as 0.5 kilometers (1,600 feet) above and below the ring plane, which is well beyond the typical ring thickness of about 10 meters (30 feet). Cassini is too far away to see the moons amid the swirling ring material around them, but scientists estimate that they are about a kilometer (half a mile) in diameter because of the size of the propellers.

Tiscareno and colleagues estimate that there are dozens of these giant propellers, and 11 of them were imaged multiple times between 2005 to 2009. One of them, nicknamed Bleriot after the famous aviator Louis Bleriot, has been a veritable Forrest Gump, showing up in more than 100 separate Cassini images and one ultraviolet imaging spectrograph observation over this time.

"Scientists have never tracked disk-embedded objects anywhere in the universe before now," Tiscareno said. "All the moons and planets we knew about before orbit in empty space. In the propeller belts, we saw a swarm in one image and then had no idea later on if we were seeing the same individual objects. With this new discovery, we can now track disk-embedded moons individually over many years."

Over the four years, the giant propellers have shifted their orbits, but scientists are not yet sure what is causing the disturbances in their travels around Saturn. Their path may be upset by bumping into other smaller ring particles, or responding to their gravity, but the gravitational attraction of large moons outside the rings may also be a factor. Scientists will continue monitoring the moons to see if the disk itself is driving the changes, similar to the interactions that occur in young solar systems. If it is, Tiscareno said, this would be the first time such a measurement has been made directly.

"Propellers give us unexpected insight into the larger objects in the rings," said Linda Spilker, Cassini project scientist based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Over the next seven years, Cassini will have the opportunity to watch the evolution of these objects and to figure out why their orbits are changing."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For newly released images and more information about the Cassini-Huygens mission visit: http://www.nasa.gov/cassini, http://saturn.jpl.nasa.gov or http://ciclops.org.



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Title: Re: NASA - Cassini updates
Post by: jacqmans on 07/16/2010 01:46 PM
See Beautiful Ontario Lacus: Cassini's Guided Tour


The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-237&cid=release_2010-237

Ontario Lacus, the largest lake in the southern hemisphere of Saturn's moon Titan, turns out to be a perfect exotic vacation spot, provided you can handle the frosty, subzero temperatures and enjoy soaking in liquid hydrocarbon.
Several recent papers by scientists working with NASA's Cassini spacecraft describe evidence of beaches for sunbathing in Titan's low light, sheltered bays for mooring boats, and pretty deltas for wading out in the shallows. They also describe seasonal changes in the lake's size and depth, giving vacationers an opportunity to visit over and over without seeing the same lake twice. (Travel agents, of course, will have to help you figure out how to breathe in an atmosphere devoid of oxygen.)

Using data that give us the most detailed picture yet of a lake on another world, scientists and animators have collaborated on a new video tour of Ontario Lacus based on radar data from Cassini's Titan flybys on June 22, 2009, July 8, 2009, and Jan. 12, 2010. A Web video explaining how scientists look to Earth's Death Valley are to understand places like Titan's Ontario Lacus is available at: http://www.jpl.nasa.gov/video/index.cfm?id=913

"With such frigid temperatures and meager sunlight, you wouldn't think Titan has a lot in common with our own Earth," said Steve Wall, deputy team lead for the Cassini radar team, based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "But Titan continues to surprise us with activity and seasonal processes that look marvelously, eerily familiar."

Cassini arrived at Saturn in 2004 when the southern hemisphere of the planet and its moons were experiencing summer. The seasons have started to change toward autumn, with winter solstice darkening the southern hemisphere of Titan in 2017. A year on Titan is the equivalent of about 29 Earth years.

Titan is the only other world in our solar system known to have standing bodies of liquid on its surface. Because surface temperatures at the poles average a chilly 90 Kelvin (about minus 300 degrees Fahrenheit), the liquid is a combination of methane, ethane and propane, rather than water. Ontario Lacus has a surface area of about 15,000 square kilometers (6,000 square miles), slightly smaller than its terrestrial namesake Lake Ontario.

Cassini first obtained an image of Ontario Lacus with its imaging camera in 2004. A paper submitted to the journal Icarus by Alex Hayes, a Cassini radar team associate at the California Institute of Technology in Pasadena, and colleagues finds that the lake's shoreline has receded by about 10 kilometers (6 miles). This has resulted in a liquid level reduction of about 1 meter (3 feet) per year over a four–year period.

The shoreline appears to be receding because of liquid methane evaporating from the lake, with a total amount of evaporation that would significantly exceed the yearly methane gas output of all the cows on Earth, Hayes said. Some of the liquid could also seep into porous ground material. Hayes said the changes in the lake are likely occurring as part of Titan's seasonal methane cycle, and would be expected to reverse during southern winter.

This seasonal filling and receding is similar to what occurs at the shallow lakebed known as Racetrack Playa in Death Valley National Park, Hayes said. In fact, from the air, the topography and shape of Racetrack Playa and Ontario Lacus are quite similar, although Ontario Lacus is about 60 times larger.

"We are very excited about these results, because we did not expect Cassini to be able to detect changes of this magnitude in Titan's lakes," Hayes said. "It is only through the continued monitoring of seasonal variation during Cassini's extended mission that these discoveries have been made possible."

Other parts of the Ontario Lacus' shoreline, as described in the paper published in Geophysical Research Letters in March 2010 by Wall, Hayes and other colleagues, show flooded valleys and coasts, further proof that the lake level has changed.

The delta revealed by Cassini radar data on the western shore of Ontario Lacus is also the first well-developed delta observed on Titan, Wall said. He explained that the shape of the land there shows liquid flowing down from a higher plain switching channels on its way into the lake, forming at least two lobes.

Examples of this kind of channel switching and wave-modified deltas can be found on Earth at the southern end of Lake Albert between Uganda and the Democratic Republic of Congo in Africa, and the remains of an ancient lake known as Megachad in the African country Chad, Wall said.

The radar data also show a smooth beach on the northwestern shore of Ontario Lacus. Smooth lines parallel to the current shoreline could be formed by low waves over time, which were likely driven by winds sweeping in from the west or southwest. The pattern at Ontario Lacus resembles what might be seen on the southeastern side of Lake Michigan, where waves sculpt the shoreline in a similar fashion.

"Cassini continues to take our breath away as it fills in the details on the surfaces of these far-off moons," said Linda Spilker, Cassini project scientist based at JPL. "It's exhilarating to ride along as it takes us on the ultimate cold-weather adventure."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

More Cassini information is available, at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.



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Title: Re: NASA - Cassini updates
Post by: jacqmans on 07/20/2010 05:52 PM
 July 20, 2010


Cassini Sees Moon Building Giant Snowballs in Saturn Ring

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-240&cid=release_2010-240

While orbiting Saturn for the last six years, NASA's Cassini spacecraft has kept a close eye on the collisions and disturbances in the gas giant's rings. They provide the only nearby natural laboratory for scientists to see the processes that must have occurred in our early solar system, as planets and moons coalesced out of disks of debris.

New images from Cassini show icy particles in Saturn's F ring clumping into giant snowballs as the moon Prometheus makes multiple swings by the ring. The gravitational pull of the moon sloshes ring material around, creating wake channels that trigger the formation of objects as large as 20 kilometers (12 miles) in diameter.

"Scientists have never seen objects actually form before," said Carl Murray, a Cassini imaging team member based at Queen Mary, University of London. "We now have direct evidence of that process and the rowdy dance between the moons and bits of space debris."

Murray discussed the findings today (July 20, 2010) at the Committee on Space Research meeting in Bremen, Germany, and they are published online by the journal Astrophysical Journal Letters on July 14, 2010. A new animation based on imaging data shows how one of the moons interacts with the F ring and creates dense, sticky areas of ring material.

Saturn's thin, kinky F ring was discovered by NASA's Pioneer 11 spacecraft in 1979. Prometheus and Pandora, the small "shepherding" moons on either side of the F ring, were discovered a year later by NASA's Voyager 1. In the years since, the F ring has rarely looked the same twice, and scientists have been watching the impish behavior of the two shepherding moons for clues.

Prometheus, the larger and closer to Saturn of the two moons, appears to be the primary source of the disturbances. At its longest, the potato-shaped moon is 148 kilometers (92 miles) across. It cruises around Saturn at a speed slightly greater than the speed of the much smaller F ring particles, but in an orbit that is just offset. As a result of its faster motion, Prometheus laps the F ring particles and stirs up particles in the same segment once in about every 68 days.

"Some of these objects will get ripped apart the next time Prometheus whips around," Murray said. "But some escape. Every time they survive an encounter, they can grow and become more and more stable."

Cassini scientists using the ultraviolet imaging spectrograph previously detected thickened blobs near the F ring by noting when starlight was partially blocked. These objects may be related to the clumps seen by Murray and colleagues.

The newly-found F ring objects appear dense enough to have what scientists call "self-gravity." That means they can attract more particles to themselves and snowball in size as ring particles bounce around in Prometheus's wake, Murray said. The objects could be about as dense as Prometheus, though only about one-fourteenth as dense as Earth.

What gives the F ring snowballs a particularly good chance of survival is their special location in the Saturn system. The F ring resides at a balancing point between the tidal force of Saturn trying to break objects apart and self-gravity pulling objects together. One current theory suggests that the F ring may be only a million years old, but gets replenished every few million years by moonlets drifting outward from the main rings. However, the giant snowballs that form and break up probably have lifetimes of only a few months.

The new findings could also help explain the origin of a mysterious object about 5 to 10 kilometers (3 to 6 miles) in diameter that Cassini scientists spotted in 2004 and have provisionally dubbed S/2004 S 6. This object occasionally bumps into the F ring and produces jets of debris.

"The new analysis fills in some blanks in our solar system's history, giving us clues about how it transformed from floating bits of dust to dense bodies," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The F ring peels back some of the mystery and continues to surprise us."

The late Kevin Beurle was made the honorary first author on this paper because of his contributions in developing software and designing observation sequences for this research. He died in 2009.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov

#2010-240
Title: Re: NASA - Cassini updates
Post by: jacqmans on 07/29/2010 07:18 PM
Blowing in the Wind: Cassini Helps with Dune Whodunit

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-251&cid=release_2010-251

The answer to the mystery of dune patterns on Saturn's moon Titan did turn out to be blowing in the wind. It just wasn't from the direction many scientists expected.

Basic principles describing the rotation of planetary atmospheres and data from the European Space Agency's Huygens probe led to circulation models that showed surface winds streaming generally east-to-west around Titan's equatorial belt. But when NASA's Cassini spacecraft obtained the first images of dunes on Titan in 2005, the dunes' orientation suggested the sands - and therefore the winds - were moving from the opposite direction, or west to east.

A new paper by Tetsuya Tokano in press with the journal Aeolian Research seeks to explain the paradox. It explains that seasonal changes appear to reverse wind patterns on Titan for a short period. These gusts, which occur intermittently for perhaps two years, sweep west to east and are so strong they do a better job of transporting sand than the usual east-to-west surface winds. Those east-to-west winds do not appear to gather enough strength to move significant amounts of sand.

A related perspective article about Tokano's work by Cassini radar scientist Ralph Lorenz, the lead author on a 2009 paper mapping the dunes, appears in this week's issue of the journal Science.

"It was hard to believe that there would be permanent west-to-east winds, as suggested by the dune appearance," said Tokano, of the University of Cologne, Germany. "The dramatic, monsoon-type wind reversal around equinox turns out to be the key."

The dunes track across the vast sand seas of Titan only in latitudes within 30 degrees of the equator. They are about a kilometer (half a mile) wide and tens to hundreds of kilometers (miles) long. They can rise more than 100 meters (300 feet) high. The sands that make up the dunes appear to be made of organic, hydrocarbon particles. The dunes' ridges generally run west-to-east, as wind here generally sheds sand along lines parallel to the equator.

Scientists predicted winds in the low latitudes around Titan's equator would blow east-to-west because at higher latitudes the average wind blows west-to-east. The wind forces should balance out, based on basic principles of rotating atmospheres.

Tokano re-analyzed a computer-based global circulation model for Titan he put together in 2008. That model, like others for Titan, was adapted from ones developed for Earth and Mars. Tokano added in new data on Titan topography and shape based on Cassini radar and gravity data. In his new analysis, Tokano also looked more closely at variations in the wind at different points in time rather than the averages. Equinox periods jumped out.

Equinoxes occur twice a Titan year, which is about 29 Earth years. During equinox, the sun shines directly over the equator, and heat from the sun creates upwelling in the atmosphere. The turbulent mixing causes the winds to reverse and accelerate. On Earth, this rare kind of wind reversal happens over the Indian Ocean in transitional seasons between monsoons.

The episodic reverse winds on Titan appear to blow around 1 to 1.8 meters per second (2 to 4 mph). The threshold for sand movement appears to be about 1 meter per second (2 mph), a speed that the typical east-to-west winds never appear to surpass. Dune patterns sculpted by strong, short episodes of wind can be found on Earth in the northern Namib sand seas in Namibia, Africa.

"This is a subtle discovery -- only by delving into the statistics of the winds in the model could this rather distressing paradox be resolved," said Ralph Lorenz, a Cassini radar scientist based at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "This work is also reassuring for preparations for proposed future missions to Titan, in that we can become more confident in predicting the winds which can affect the delivery accuracy of landers, or the drift of balloons."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries. JPL is a division of the California Institute of Technology in Pasadena.

More Cassini information is available, at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

#2010-251

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Title: Re: NASA - Cassini updates
Post by: jacqmans on 08/12/2010 08:31 PM
Raisin' Mountains on Saturn's Moon Titan


The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-266&cid=release_2010-266


Saturn's moon Titan ripples with mountains, and scientists have been trying to figure out how they form. The best explanation, it turns out, is that Titan is shrinking as it cools, wrinkling up the moon's surface like a raisin.

A new model developed by scientists working with radar data obtained by NASA's Cassini spacecraft shows that differing densities in the outermost layers of Titan can account for the unusual surface behavior. Titan is slowly cooling because it is releasing heat from its original formation and radioactive isotopes are decaying in the interior. As this happens, parts of Titan's subsurface ocean freeze over, the outermost ice crust thickens and folds, and the moon shrivels up. The model is described in an article now online in the Journal of Geophysical Research.

"Titan is the only icy body we know of in the solar system that behaves like this," said Giuseppe Mitri, the lead author of the paper and a Cassini radar associate based at the California Institute of Technology in Pasadena. "But it gives us insight into how our solar system came to be."

An example of this kind of process can also be found on Earth, where the crumpling of the outermost layer of the surface, known as the lithosphere, created the Zagros Mountains in Iran, Mitri said.

Titan's highest peaks rise up to about two kilometers (6,600 feet), comparable to the tallest summits in the Appalachian Mountains. Cassini was the first to spot Titan's mountains in radar images in 2005. Several mountain chains on Titan exist near the equator and are generally oriented west-east. The concentration of these ranges near the equator suggests a common history.

While several other icy moons in the outer solar system have peaks that reach heights similar to Titan's mountain chains, their topography comes from extensional tectonics -- forces stretching the ice shell -- or other geological processes. Until now, scientists had little evidence of contractional tectonics -- forces shortening and thickening the ice shell. Titan is the only icy satellite where the shortening and thickening are dominant.

Mitri and colleagues fed data from Cassini's radar instrument into computer models of Titan developed to describe the moon's tectonic processes and to study the interior structure and evolution of icy satellites. They also made the assumption that the moon's interior was only partially separated into a mixture of rock and ice, as suggested by data from Cassini's radio science team.

Scientists tweaked the model until they were able to build mountains on the surface similar to those Cassini had seen. They found the conditions were met when they assumed the deep interior was surrounded by a very dense layer of high-pressure water ice, then a subsurface liquid-water-and-ammonia ocean and an outer water-ice shell. So the model, Mitri explained, also supports the existence of a subsurface ocean.

Each successive layer of Titan's interior is colder than the one just inside it, with the outermost surface averaging a chilly 94 Kelvin (minus 290 degrees Fahrenheit). So cooling of the moon causes a partial freezing of the subsurface liquid ocean and thickening of the outer water ice shell. It also thickens the high-pressure ice. Because the ice on the crust is less dense than the liquid ocean and the liquid ocean is less dense than the high-pressure ice, the cooling means the interior layers lose volume and the top "skin" of ice puckers and folds.

Since the formation of Titan, which scientists believe occurred around four billion years ago, the moon's interior has cooled significantly. But the moon is still releasing hundreds of gigawatts of power, some of which may be available for geologic activity. The result, according to the model, was a shortening of the radius of the moon by about seven kilometers (four miles) and a decrease in volume of about one percent.

"These results suggest that Titan's geologic history has been different from that of its Jovian cousins, thanks, perhaps, to an interior ocean of water and ammonia," said Jonathan Lunine, a Cassini interdisciplinary scientist for Titan and co-author on the new paper. Lunine is currently based at the University of Rome, Tor Vergata, Italy. "As Cassini continues to map Titan, we will learn more about the extent and height of mountains across its diverse surface."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries. JPL is a division of the California Institute of Technology in Pasadena.

More Cassini information is available, at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.
Title: Re: NASA - Cassini updates
Post by: Space Pete on 08/16/2010 06:41 PM
JPL: "Cassini Hunting Enceladus 'Tigers' with Night Vision".
www.jpl.nasa.gov/news/news.cfm?release=2010-267

JPL: "Cassini Bags Enceladus 'Tigers'".
www.jpl.nasa.gov/news/news.cfm?release=2010-269

[Images] Enceladus, Tethys and Dione Rev 136 Raw Preview.
www.ciclops.org/view_event/140/Enceladus_Tethys_and_Dione_Rev_136_Raw_Preview?js=1
Title: Re: NASA - Cassini updates
Post by: Space Pete on 09/05/2010 02:26 PM
[Images] Dione Rev 137 Raw Preview. (http://www.ciclops.org/view_event/141/Dione_Rev_137_Raw_Preview?js=1)

Quote
These raw, unprocessed images of Saturn's moon Dione were taken on Sept. 4, 2010. These images include the best views of Dione's north pole region Cassini has yet captured.
Title: Re: NASA - Cassini updates
Post by: Space Pete on 09/22/2010 10:30 PM
Spring on Titan brings sunshine and patchy clouds.

The northern hemisphere of Saturn's moon Titan is set for mainly fine spring weather, with polar skies clearing since the equinox in August last year. The visual and infrared mapping spectrometer (VIMS) aboard NASA's Cassini spacecraft has been monitoring clouds on Titan regularly since the spacecraft entered orbit around Saturn in 2004. Now, a group led by Sébastien Rodriguez, a Cassini VIMS team collaborator based at Université Paris Diderot, France, has analyzed more than 2,000 VIMS images to create the first long-term study of Titan's weather using observational data that also includes the equinox. Equinox, when the sun shone directly over the equator, occurred in August 2009.

Rodriguez is presenting the results and new images at the European Planetary Science Congress in Rome on Sept. 22.

Though Titan's surface is far colder and lacks liquid water, this moon is a kind of "sister world" to Earth because it has a surface covered with organic material and an atmosphere whose chemical composition harkens back to an early Earth. Titan has a hydrological cycle similar to Earth's, though Titan's cycle depends on methane and ethane rather than water.

A season on Titan lasts about seven Earth years. Rodriguez and colleagues observed significant atmospheric changes between July 2004 (early summer in Titan's southern hemisphere) and April 2010 (the very start of northern spring). The images showed that cloud activity has recently decreased near both of Titan's poles. These regions had been heavily overcast during the late southern summer until 2008, a few months before the equinox.

Over the past six years, the scientists found that clouds clustered in three distinct latitude regions of Titan: large clouds at the north pole, patchy clouds at the south pole and a narrow belt around 40 degrees south. "However, we are now seeing evidence of a seasonal circulation turnover on Titan – the clouds at the south pole completely disappeared just before the equinox and the clouds in the north are thinning out," Rodriguez said. "This agrees with predictions from models and we are expecting to see cloud activity reverse from one hemisphere to another in the coming decade as southern winter approaches."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate, Washington, D.C. The visual and infrared mapping spectrometer team is based at the University of Arizona, Tucson.

For a full version of this release, go to: www.europlanet-eu.org/outreach/index.php?option=com_content&task=view&id=288&Itemid=41

For more information about Cassini, go to: www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.


www.jpl.nasa.gov/news/news.cfm?release=2010-308
Title: Re: NASA - Cassini updates
Post by: Space Pete on 09/23/2010 09:50 PM
Cassini Gazes at Veiled Titan.

NASA's Cassini spacecraft will swing high over Saturn's moon Titan on Friday, Sept. 24, taking a long, sustained look at the hazy moon. At closest approach, Cassini will fly within 8,175 kilometers (5,080 miles) above the hazy moon's surface. This flyby is the first in a series of high-altitude Titan flybys for Cassini over the next year and a half.

Cassini's composite infrared spectrometer instrument will be probing Titan's stratosphere to learn more about its vertical structure as the seasons change. Equinox, when the sun shone directly over the equator, occurred in August 2009, and the northern hemisphere is now in spring.

Another instrument, the visual and infrared mapping spectrometer, will be mapping an equatorial region known as Belet at a resolution of 5 kilometers (3 miles) per pixel. This mosaic will complement the mosaics that were obtained in earlier Titan flybys in January and April. This spectrometer will also look for clouds at northern mid-latitudes and near the poles.

Cassin's visible-light imaging cameras will also be taking images of Titan's trailing hemisphere, or the side that faces backward as Titan orbits around Saturn. If Titan cooperates and has a cloudy day, scientists plan to analyze the images for cloud patterns.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C.

More information about the Cassini-Huygens mission is at www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.


www.jpl.nasa.gov/news/news.cfm?release=2010-312
Title: Re: NASA - Cassini updates
Post by: Space Pete on 09/23/2010 11:48 PM
New Views of Saturn's Aurora, Captured by Cassini.

A new movie and images showing Saturn's shimmering aurora over a two-day period are helping scientists understand what drives some of the solar system's most impressive light shows.

The new, false-color images and video are available online at: www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

The movie and images are part of a new study that, for the first time, extracts auroral information from the entire catalogue of Saturn images taken by the visual and infrared mapping spectrometer instrument (VIMS) aboard NASA's Cassini spacecraft. These images and preliminary results are being presented by Tom Stallard, lead scientist on a joint VIMS and Cassini magnetometer collaboration, at the European Planetary Science Congress in Rome on Friday, Sept. 24.

In the movie, the aurora phenomenon clearly varies significantly over the course of a Saturnian day, which lasts around 10 hours 47 minutes. On the noon and midnight sides (left and right sides of the images, respectively), the aurora can be seen to brighten significantly for periods of several hours, suggesting the brightening is connected with the angle of the sun. Other features can be seen to rotate with the planet, reappearing at the same time and the same place on the second day, suggesting that these are directly controlled by the orientation of Saturn's magnetic field.

"Saturn's auroras are very complex and we are only just beginning to understand all the factors involved," Stallard said. "This study will provide a broader view of the wide variety of different auroral features that can be seen, and will allow us to better understand what controls these changes in appearance."
Auroras on Saturn occur in a process similar to Earth's northern and southern lights. Particles from the solar wind are channeled by Saturn's magnetic field toward the planet's poles, where they interact with electrically charged gas (plasma) in the upper atmosphere and emit light. At Saturn, however, auroral features can also be caused by electromagnetic waves generated when the planet's moons move through the plasma that fills Saturn's magnetosphere.

Previous data from Cassini have contributed to a number of detailed snapshots of the aurora. But understanding the overall nature of the auroral region requires a huge number of observations, which can be difficult because Cassini observation time close to Saturn is in high demand, Stallard said.

However, VIMS observations of numerous other scientific targets also include auroral information. Sometimes the aurora can be clearly seen, but sometimes Stallard and colleagues add multiple images together to produce a signal. This wide set of observations allows Cassini scientists to understand the aurora in general, rather than the beautiful specific cases that dedicated auroral observations allow, Stallard said.

Stallard and his colleagues have investigated about 1,000 images from the 7,000 that VIMS has taken to date of Saturn's auroral region.

The new, false-color images show Saturn's aurora glowing in green around the planet's south pole. The auroral information in the two images was extracted from VIMS data taken on May 24, 2007, and Nov. 1, 2008. The video covers about 20 Earth hours of VIMS observations, from Sept. 22 and 23, 2007.

"Detailed studies like this of Saturn's aurora help us understand how they are generated on Earth and the nature of the interactions between the magnetosphere and the uppermost regions of Saturn's atmosphere," said Linda Spilker, Cassini project scientist, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The visual and infrared mapping spectrometer team is based at the University of Arizona, Tucson. Stallard's work on Saturn's auroras is funded by the Science and Technologies Facilities Council, Swindon, U.K.


www.jpl.nasa.gov/news/news.cfm?release=2010-313
Title: Re: NASA - Cassini updates
Post by: Space Pete on 09/24/2010 11:24 PM
Cassini's First Dive Inside Saturn's Aurora.

The Cassini spacecraft has made the first observations from within the radio aurora of another planet than Earth. The measurements, which were taken when the spacecraft flew through an active auroral region in 2008, show some similarities and some contrasts between the radio auroral emissions generated at Saturn and those at Earth.  Results were presented this week by Dr Laurent Lamy at the European Planetary Science Congress in Rome, and recently published in Geophysical Research Letters.

“So far, this is a unique event,” said Lamy (Observatoire de Paris, France).  “Whereas the source region of Earth’s radio aurora has been studied by many missions, this is our first opportunity to observe the equivalent region at Saturn from the inside.  From this single encounter, we have been able to build up a detailed snapshot of auroral activity using three of Cassini’s instruments.  This gives us a fascinating insight into the processes that are generating Saturn’s radio aurora.”

Cassini encountered the auroral region at a distance of 247 million kilometres from Saturn’s cloud tops (about 4 times Saturn’s radius).  Above the spectacular visible-light displays of Saturn’s Northern and Southern Lights, auroral emissions occur this far from the planet at radio wavelengths.  The emissions are generated by fast moving electrons spiralling along Saturn’s magnetic field lines, which are threaded through the auroral region.

On 17 October 2008, Cassini’s MAG (magnetometer), RPWS (radio) and CAPS (electrons) instruments detected three successive curtains of active auroras. An international team of scientists has now combined magnetic, radio and particle in situ observations to build up a picture of the local radio source properties and the surrounding auroral plasma. They also identified the magnetic field lines along which radio aurora are emitted

“The instrument that measures radio waves, RPWS, can tell us the direction that each radio wave detected is travelling. By mapping this information onto magnetic field lines, we can work out the location of each radio source.  In addition, we can project the source locations along the field lines that curve down to Saturn’s southern pole and visualise a radio oval comparable to the auroral features commonly seen at ultraviolet wavelengths. Unusually, the oval observed during this event is strongly distorted, which indicates a particularly enhanced auroral activity,” said Lamy.

Earth also has radio auroral emissions and these new results show that the process that generates radio aurora appears to be the same at both planets. Interestingly, there are two minor differences between the aurora at Earth and Saturn.  At Earth, there is a cavity in the plasma above the auroral oval that rises for several thousand kilometres. The new observations show that this is not seen at Saturn. Secondly, radio sources were crossed at much further distances from the planet. These differences reflect intrinsic differences between the two magnetospheres, in terms of dimensions and planetary rotation speed.

Cassini crossed high latitude auroral field lines during 40 orbits in 2008, but this is the only time that the instruments detected unusually strong electric currents in that region in space with in situ evidence of an active aurora.

“We think that the unusual conditions responsible for these intense electric currents might have been triggered by a solar wind compression squeezing Saturn’s magnetic field and producing the observed auroras”, said Emma Bunce, a team member from the University of Leicester in the UK.


www.europlanet-eu.org/outreach/index.php?option=com_content&task=view&id=312&Itemid=41
Title: Re: NASA - Cassini updates
Post by: Space Pete on 09/25/2010 03:41 AM
New Cassini image: Conjoined Moons.

Looking like half of a figure eight, two of Saturn's moons appear conjoined in this Cassini image.

The moon Dione, at the top in the image, is actually closer to the spacecraft here. However, because of the similar albedo, or reflectivity, of the two moons and because of the location of a particularly large crater near the south polar region of Dione, the moon appears blended seamlessly with Rhea. The large, faint crater Evander is centered at about 57 degrees south latitude, 145 degrees west longitude and can also be seen in the Dione south polar map (see PIA12579 (http://www.ciclops.org/view/6265/Dione_Polar_Maps_-_February_2010)).

Lit terrain seen here is on the anti-Saturn side of Dione (1123 kilometers, 698 miles across) and on the area between the anti-Saturn and leading hemisphere on Rhea (1528 kilometers, 949 miles across).

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 27, 2010. The view was acquired at a distance of approximately 1.1 million kilometers (688,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 78 degrees. The view was acquired at a distance of approximately 1.6 million kilometers (994,000 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 78 degrees. Image scale is 7 kilometers (4 miles) per pixel on Dione and 10 kilometers (6 miles) on Rhea.

The Cassini Equinox Mission is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini Equinox Mission visit http://ciclops.org, www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.


www.ciclops.org/view/6482/Conjoined_Moons?js=1
Title: Re: NASA - Cassini updates
Post by: Space Pete on 09/28/2010 12:40 AM
Hello, Saturn Summer Solstice: Cassini's New Chapter.

Turning a midsummer night's dream into reality, NASA's Cassini spacecraft begins its new mission extension -- the Cassini Solstice Mission -- today. The mission extension will take Cassini a few months past Saturn's northern summer solstice (or midsummer) through September 2017. It will enable scientists to study seasonal changes and other long-term weather changes on Saturn and its moons.

Cassini had arrived just after Saturn's northern winter solstice in 2004, and the extension continues a few months past the northern summer solstice in May 2017. A complete seasonal period on Saturn has never been studied at this level of detail.

Cassini has revealed a bounty of scientific discoveries since its launch in 1997, including previously unknown characteristics of the Earth-like world of Saturn's moon Titan, and the plume of water vapor and organic particles spewing from another moon, Enceladus.

The Cassini Solstice Mission will enable continued study of these intriguing worlds. It will also allow scientists to continue observations of Saturn's rings and the magnetic bubble around the planet, known as the magnetosphere. Near the end of the mission, the spacecraft will make repeated dives between Saturn and its rings to obtain in-depth knowledge of the gas giant. During these dives, the spacecraft will study the internal structure of Saturn, its magnetic fluctuations and ring mass.

Cassini entered orbit around Saturn in 2004. Mission managers had originally planned for a four-year tour of the Saturnian system. In 2008, Cassini received a mission extension through September 2010 to probe the planet and its moons through equinox, when the sun was directly over the equator. Equinox, which occurred in August 2009, marked the turn from southern fall to northern spring. The second mission extension, called the Cassini Solstice Mission, was announced earlier this year.

"After nearly seven years in transit and six years in Saturn orbit, this spacecraft still just hums along," said Bob Mitchell, Cassini program manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "With seven more years to go, the science should be just as exciting as what we've seen so far."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the project for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL.

More Cassini information is available, at www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.


www.jpl.nasa.gov/news/news.cfm?release=2010-314
Title: Re: NASA - Cassini updates
Post by: Space Pete on 10/01/2010 05:32 PM
Check out this amazing new Cassini image (attached)!


Highlighting Plumes.

At least four distinct plumes of water ice spew out from the south polar region of Saturn's moon Enceladus in this dramatically illuminated image.

Light reflected off Saturn is illuminating the surface of the moon while the sun, almost directly behind Enceladus, is backlighting the plumes. See PIA11688 (http://www.ciclops.org/view.php?id=6023) to learn more about Enceladus and its plumes.

This view looks toward the Saturn-facing side of Enceladus (504 kilometers, 313 miles across). North is up.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 25, 2009. The view was obtained at a distance of approximately 617,000 kilometers (383,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 174 degrees. Image scale is 4 kilometers (2 miles) per pixel.

The Cassini Equinox Mission is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini Equinox Mission visit http://ciclops.org, www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.


www.ciclops.org/view/6232/Highlighting_Plumes?js=1
Title: Re: NASA - Cassini updates
Post by: marsavian on 10/01/2010 05:57 PM
That's one active moon ! Saturn definitely has the best moons (e.g Titan) as well as the most spectacular appearance itself.
Title: Re: NASA - Cassini updates
Post by: Robotbeat on 10/01/2010 07:03 PM
That is amazing! It makes me wonder what the galaxy has in store for us...
Title: Re: NASA - Cassini updates
Post by: Space Pete on 10/06/2010 10:53 PM
Saturn's Icy Moon May Keep Oceans Liquid with Wobble.
 
Saturn's icy moon Enceladus should not be one of the most promising places in our solar system to look for extraterrestrial life. Instead, it should have frozen solid billions of years ago. Located in the frigid outer solar system, it's too far from the sun to have oceans of liquid water -- a necessary ingredient for known forms of life -- on its surface.

Some worlds, like Mars or Jupiter's moon Europa, give hints that they might harbor liquid water beneath their surfaces. Mars is about 4,200 miles across and Europa almost 2,000 miles across. However, with a diameter only slightly more than 500 miles, Enceladus just doesn’t have the bulk needed for its interior to stay warm enough to maintain liquid water underground.

With temperatures around 324 degrees below zero Fahrenheit, the surface of Enceladus is indeed frozen. However, in 2005 NASA's Cassini spacecraft discovered a giant plume of water gushing from cracks in the surface over the moon's south pole, indicating that there was a reservoir of water beneath the ice. Analysis of the plume by Cassini revealed that the water is salty, indicating the reservoir is large, perhaps even a global subsurface ocean. Scientists estimate from the Cassini data that the south polar heating is equivalent to a continuous release of about 13 billion watts of energy.

To explain this mysterious warmth, some scientists invoke radiation coupled with tidal heating. As it formed, Enceladus (like all solar system objects) incorporated matter from the cloud of gas and dust left over from our sun’s formation. In the outer solar system, as Enceladus formed it grew as ice and rock coalesced. If Enceladus was able to gather greater amounts of rock, which contained radioactive elements, enough heat could have been generated by the decay of the radioactive elements in its interior to melt the body.

However, in smaller moons like Enceladus, the cache of radioactive elements usually is not massive enough to produce significant heat for long, and the moon should have soon cooled and solidified. So, unless another process within Enceladus somehow generated heat, any liquid formed by the melting of its interior would have frozen long ago.

This led scientists to consider the role of tidal heating as a way to keep Enceladus warm enough for liquid water to remain under its surface. Enceladus' orbit around Saturn is slightly oval-shaped. As it travels around Saturn, Enceladus moves closer in and then farther away. When Enceladus is closer to Saturn, it feels a stronger gravitational pull from the planet than when it is farther away. Like gently squeezing a rubber ball slightly deforms its shape, the fluctuating gravitational tug on Enceladus causes it to flex slightly. The flexing, called gravitational tidal forcing, generates heat from friction deep within Enceladus.

The gravitational tides also produce stress that cracks the surface ice in certain regions, like the south pole, and may be reworking those cracks daily. Tidal stress can pull these cracks open and closed while shearing them back and forth. As they open and close, the sides of the south polar cracks move as much as a few feet, and they slide against each other by up to a few feet as well. This movement also generates friction, which (like vigorously rubbing your hands together) releases extra heat at the surface at locations that should be predictable with our understanding of tidal stress.

To test the tidal heating theory, scientists with the Cassini team created a map of the gravitational tidal stress on the moon's icy crust and compared it to a map of the warm zones created using Cassini's composite infrared spectrometer instrument (CIRS). Assuming the greatest stress is where the most friction occurs, and therefore where the most heat is released, areas with the most stress should overlap the warmest zones on the CIRS map.

"However, they don't exactly match," says Dr. Terry Hurford of NASA's Goddard Space Flight Center, Greenbelt, Md. "For example, in the fissure called the Damascus Sulcus, the area experiencing the greatest amount of shearing is about 50 kilometers (about 31 miles) from the zone of greatest heat."

Hurford and his team believe the discrepancy can be resolved if Enceladus’ rotation rate is not uniform – if it wobbles slightly as it rotates. Enceladus' wobble, technically called "libration," is barely noticeable. "Cassini observations have ruled out a wobble greater than about 2 degrees with respect to Enceladus' uniform rotation rate," says Hurford.

The team created a computer simulation that made maps of the surface stress on Enceladus for various wobbles, and found a range where the areas of greatest stress line up better with the observed warmest zones.

"Depending on whether the wobble moves with or against the movement of Saturn in Enceladus' sky, a wobble ranging from 2 degrees down to 0.75 degrees produces the best fit to the observed warmest zones," said Hurford.

The wobble also helps with the heating conundrum by generating about five times more heat in Enceladus’ interior than tidal stress alone, and the extra heat makes it likely that Enceladus' ocean could be long-lived, according to Hurford. This is significant in the search for life, because life requires a stable environment to develop.

The wobble is probably caused by Enceladus' uneven shape. "Enceladus is not completely spherical, so as it moves in its orbit, the pull of Saturn's gravity generates a net torque that forces the moon to wobble," said Hurford. Also, Enceladus' orbit is kept oval-shaped, maintaining the tidal stress, because of the gravitational tug from a neighboring larger moon Dione. Dione is farther away from Saturn than Enceladus, so it takes longer to complete its orbit. For every orbit Dione completes, Enceladus finishes two orbits, producing a regular alignment that pulls Enceladus' orbit into an oval shape.

The team includes researchers from NASA Goddard, Cornell University, Ithaca, N.Y., Southwest Research Institute, Boulder, Colo., and the University of California, Santa Cruz, Calif. The research was funded by the Cassini Data Analysis Program, which includes contributions from NASA and ESA.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. NASA's Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The composite infrared spectrometer team is based at NASA Goddard, where the instrument was built. Dr. Michael Flasar from NASA Goddard is the composite infrared spectrometer Principal Investigator.

For newly released images and more information about the Cassini-Huygens mission visit: www.nasa.gov/cassini, http://saturn.jpl.nasa.gov or http://ciclops.org.


www.nasa.gov/mission_pages/cassini/whycassini/cassini20100708-b.html
Title: Re: NASA - Cassini updates
Post by: jacqmans on 10/07/2010 07:57 PM
News release: 2010-328                                                                      Oct. 7, 2010

Cassini Catches Saturn Moons in Paintball Fight

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-328&cid=release_2010-328

PASADENA, Calif. – Scientists using data from NASA's Cassini spacecraft have learned that distinctive, colorful bands and splotches embellish the surfaces of Saturn's inner, mid-size moons. The reddish and bluish hues on the icy surfaces of Mimas, Enceladus, Tethys, Dione and Rhea appear to be the aftermath of bombardments large and small.

A paper based on the findings was recently published online in the journal Icarus. In it, scientists describe prominent global patterns that trace the trade routes for material exchange between the moons themselves, an outer ring of Saturn known as the E ring and the planet's magnetic environment. The finding may explain the mysterious Pac-Man thermal pattern on Mimas, found earlier this year by Cassini scientists, said lead author Paul Schenk, who was funded by a Cassini data analysis program grant and is based at the Lunar and Planetary Institute in Houston.

"The beauty of it all is how the satellites behave as a family, recording similar processes and events on their surfaces, each in its own unique way," Schenk said. "I don't think anyone expected that electrons would leave such obvious fingerprints on planetary surfaces, but we see it on several moons, including Mimas, which was once thought to be rather bland."

Schenk and colleagues processed raw images obtained by Cassini's imaging cameras from 2004 to 2009 to produce new, high-resolution global color maps of these five moons. The new maps used camera frames shot through visible-light, ultraviolet and infrared filters which were processed to enhance our views of these moons beyond what could be seen by the human eye.

The new images are available at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

"The richness of the Cassini data set – visible images, infrared images, ultraviolet images, measurements of the radiation belts – is such that we can finally 'paint a picture' as to how the satellites themselves are 'painted,'" said William B. McKinnon, one of six co-authors on the paper. McKinnon is based at Washington University in St. Louis and was also funded by the Cassini data analysis program.

Icy material sprayed by Enceladus, which makes up the misty E ring, appears to leave a brighter, blue signature. The pattern of bluish material on Enceladus, for example, indicates that the moon is covered by the fallback of its own "breath."

Enceladean spray also appears to splatter the parts of Tethys, Dione and Rhea that run into the spray head-on in their orbits around Saturn. But scientists are still puzzling over why the Enceladean frost on the leading hemisphere of these moons bears a coral-colored, rather than bluish, tint.

On Tethys, Dione and Rhea, darker, rust-colored, reddish hues paint the entire trailing hemisphere, or the side that faces backward in the orbit around Saturn. The reddish hues are thought to be caused by tiny particle strikes from circulating plasma, a gas-like state of matter so hot that atoms split into an ion and an electron, in Saturn's magnetic environment. Tiny, iron-rich "nanoparticles" may also be involved, based on earlier analyses by the Cassini visual and infrared mapping spectrometer team.

Mimas is also touched by the tint of Enceladean spray, but it appears on the trailing side of Mimas. This probably occurs because it orbits inside the path of Enceladus, or closer to Saturn, than Tethys, Dione and Rhea.

In addition, Mimas and Tethys sport a dark, bluish band. The bands match patterns one might expect if the surface were being irradiated by high-energy electrons that drift in a direction opposite to the flow of plasma in the magnetic bubble around Saturn. Scientists are still figuring out exactly what is happening, but the electrons appear to be zapping the Mimas surface in a way that matches the Pac-Man thermal pattern detected by Cassini's composite infrared spectrometer, Schenk said.

Schenk and colleagues also found a unique chain of bluish splotches along the equator of Rhea that re-open the question of whether Rhea ever had a ring around it. The splotches do not seem related to Enceladus, but rather appear where fresh, bluish ice has been exposed on older crater rims. Though Cassini imaging scientists recently reported that they did not see evidence in Cassini images of a ring around Rhea, the authors of this paper suggest the crash of orbiting material, perhaps a ring, to the surface of Rhea in the not-too-distant past could explain the bluish splotches.

"Analyzing the image color ratios is a great way to really enhance the otherwise subtle color variations and make apparent some of the processes at play in the Saturn system," said Amanda Hendrix, Cassini deputy project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "The Cassini images highlight the importance and potential effects of so-called 'space weathering' that occurs throughout the solar system – on any surface that isn't protected by a thick atmosphere or magnetic field."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
Title: Re: NASA - Cassini updates
Post by: Space Pete on 10/19/2010 09:56 PM
The (Long) Weekend Warrior: Nine Moons, 62 Hours.

Taking a long-weekend road trip, NASA's Cassini spacecraft successfully glided near nine Saturnian moons, sending back a stream of raw images as mementos of its adrenaline-fueled expedition. The spacecraft sent back particularly intriguing images of the moons Dione and Rhea.

The Dione and Rhea pictures are the highest-resolution views yet of parts of their surfaces. The views of the southern part of Dione's leading hemisphere (the part of the moon that faces forward in its orbit around Saturn) and the equatorial region of Rhea's leading hemisphere are more detailed than the last time we saw these terrains with NASA's Voyager spacecraft in the early 1980s.

Of the five big icy moons of Saturn, Dione and Rhea are often considered a pair because they orbit close to each other, are darker than the others, and exhibit similar patterns of light reflecting off them. These new images, however, highlight the differences between these sister moons.

Both images show similar geographic regions on each satellite. However, scientists can identify differences in geological histories of the two bodies from differences in the numbers and sizes of visible craters on their surfaces. The number and size of craters on a body's surface help indicate the age of that surface – the more craters there are and the larger they are, the older the surface is.

Rhea, for example, shows ancient, intense bombardments throughout this region. However, the same region of Dione is divided into distinct areas that exhibit variations in the number and size of preserved craters. In particular, while parts of Dione are heavily cratered like Rhea, there are other areas covered by relatively smooth plains. Those areas have many small craters, but few large impact scars, which indicates that they are geologically younger than the heavily cratered areas. The smooth plains must have been resurfaced at some point in Dione's past -- an event that seems to be missing from Rhea's geological history on this side of the moon.

Images of the moon Mimas, captured just before it went into shadow behind Saturn, will be compared to thermal maps made earlier this year that showed an unexpected "Pac-Man" heat pattern. (See for more details.)

Cassini also caught a picture of the tiny, 4-kilometer-wide (3-mile-wide) moon Pallene, in front of the planet Saturn, which is more than 120,000 kilometers (75,000 miles) wide at its equator.

Cassini's elliptical orbital pattern around Saturn means it can target moons for flybys about once or twice a month. The flybys on this particular Cassini road trip were "non-targeted" flybys, meaning navigators did not refine Cassini's path to fly over particular points on each moon.

Cassini's long weekend started on Thursday, Oct. 14, at 5:07 p.m. UTC (9:07 a.m. PDT), when it passed by Saturn's largest moon Titan at an altitude of 172,368 kilometers (107,104 miles) above the surface. Then came a whirlwind 21 hours in which Cassini flew by Polydeuces at 116,526 kilometers (72,406 miles), Mimas at 69,950 kilometers (43,465 miles), Pallene at 36,118 kilometers (22,443 miles), Telesto at 48,455 kilometers (30,109 miles), Methone at 105,868 kilometers (65,783 miles), Aegaeon at 96,754 kilometers (60,120 miles) and Dione at 31,710 kilometers (19,704 miles). Cassini's last visit -- Rhea at 38,752 kilometers (24,079 miles) – took place at 6:47 a.m. UTC on Oct. 17 (10:47 p.m. PDT on Oct. 16).

Scientists decided in advance which observations they wanted to make while the spacecraft was cruising past all the moons. They chose to obtain images of Titan, Mimas, Pallene, Dione and Rhea. They also obtained thermal scans of Mimas, Dione and Rhea.

For more raw images, visit: http://saturn.jpl.nasa.gov/photos/raw.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory manages the project for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

More Cassini information is available, at www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.


www.jpl.nasa.gov/news/news.cfm?release=2010-341
Title: Re: NASA - Cassini updates
Post by: Space Pete on 10/20/2010 11:45 PM
Spring Has Sprung ... On Titan.

NASA's Cassini spacecraft has sent back dreamy raw images of Saturn's moon Titan that show the appearance of clouds around the moon's midsection. These bright clouds likely appeared because the moon is changing seasons and spring has arrived in Titan's northern hemisphere. The images were taken from about 2.5 million kilometers (1.5 million miles) away from Titan on Oct. 18, 2010, and also show the faint etchings of Saturn's rings. One of the new raw images also features a cameo from the icy moon Tethys, which looks smaller and brighter than Titan in the image.

More raw images are online at: http://saturn.jpl.nasa.gov/photos/raw.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory manages the project for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

More Cassini information is available at www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.


www.jpl.nasa.gov/news/news.cfm?release=2010-343
Title: Re: NASA - Cassini updates
Post by: robertross on 11/26/2010 01:14 PM
Saturn's moon has atmosphere with oxygen


Saturn's second-largest moon, Rhea, has a thin atmosphere of oxygen and carbon dioxide, according to a new study.



Read more: http://www.cbc.ca/technology/story/2010/11/26/saturn-moon-atmosphere-oxygen-co2.html#ixzz16OjNvTY8


Title: Re: NASA - Cassini updates
Post by: robertross on 11/28/2010 03:26 AM
Cassini Back to Normal, Ready for Enceladus

November 24, 2010

NASA's Cassini spacecraft resumed normal operations today, Nov. 24. All science instruments have been turned back on, the spacecraft is properly configured and Cassini is in good health. Mission managers expect to get a full stream of data during next week's flyby of the Saturnian moon Enceladus.

Cassini went into safe mode on Nov. 2, when one bit flipped in the onboard command and data subsystem computer. The bit flip prevented the computer from registering an important instruction, and the spacecraft, as programmed, went into the standby mode. Engineers have traced the steps taken by the computer during that time and have determined that all spacecraft responses were proper, but still do not know why the bit flipped.

The flyby on Nov. 30 will bring Cassini to within about 48 kilometers (30 miles) of the surface of Enceladus. At 61 degrees north latitude, this encounter and its twin three weeks later at the same altitude and latitude, are the closest Cassini will come to the northern hemisphere surface of Enceladus during the extended Solstice mission. (Cassini's closest-ever approach to the surface occurred in October 2008, when it dipped to an altitude of 25 kilometers, or 16 miles.)

During the closest part of the Nov. 30 flyby, Cassini's radio science subsystem will make gravity measurements. The results will be compared with those from an earlier flyby of the Enceladus south pole to understand the moon's interior structure better. Cassini's fields and particles instruments will sample the charged particle environment around Enceladus. Other instruments will capture images in visible light and other parts of the light spectrum after Cassini makes its closest approach.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C.


http://www.jpl.nasa.gov/news/news.cfm?release=2010-398
Title: Re: NASA - Cassini updates
Post by: jacqmans on 11/30/2010 09:14 AM
Thin Air: Cassini Finds Ethereal Atmosphere at Rhea

 

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-399&cid=release_2010-399

NASA's Cassini spacecraft has detected a very tenuous atmosphere known as an exosphere, infused with oxygen and carbon dioxide around Saturn's icy moon Rhea. This is the first time a spacecraft has directly captured molecules of an oxygen atmosphere – albeit a very thin one -- at a world other than Earth.

The oxygen appears to arise when Saturn's magnetic field rotates over Rhea. Energetic particles trapped in the planet's magnetic field pepper the moon’s water-ice surface. They cause chemical reactions that decompose the surface and release oxygen. The source of the carbon dioxide is less certain.

Oxygen at Rhea's surface is estimated to be about 5 trillion times less dense than what we have at Earth. But the new results show that surface decomposition could contribute abundant molecules of oxygen, leading to surface densities roughly 100 times greater than the exospheres of either Earth's moon or Mercury. The formation of oxygen and carbon dioxide could possibly drive complex chemistry on the surfaces of many icy bodies in the universe.

"The new results suggest that active, complex chemistry involving oxygen may be quite common throughout the solar system and even our universe," said lead author Ben Teolis, a Cassini team scientist based at Southwest Research Institute in San Antonio. "Such chemistry could be a prerequisite for life. All evidence from Cassini indicates that Rhea is too cold and devoid of the liquid water necessary for life as we know it."

Releasing oxygen through surface irradiation could help generate conditions favorable for life at an icy body other than Rhea that has liquid water under the surface, Teolis said. If the oxygen and carbon dioxide from the surface could somehow get transported down to a sub-surface ocean, that would provide a much more hospitable environment for more complex compounds and life to form. Scientists are keen to investigate whether life on icy moons with an ocean is possible, though they have not yet detected it.

The tenuous atmosphere with oxygen and carbon dioxide makes Rhea, Saturn's second largest moon, unique in the Saturnian system. Titan has a thick nitrogen-methane atmosphere, but very little carbon dioxide and oxygen.

"Rhea is turning out to be much more interesting than we had imagined," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "The Cassini finding highlights the rich diversity of Saturn’s moons and gives us clues on how they formed and evolved."

Scientists had suspected Rhea could have a thin atmosphere with oxygen and carbon dioxide, based on remote observations of Jupiter's icy moons by NASA's Galileo spacecraft and Hubble Space Telescope. Other Cassini observations detected oxygen escaping from icy Saturn ring particles after ultraviolet bombardment. But Cassini was able to detect oxygen and carbon dioxide in the exosphere directly because of how close it flew to Rhea – 101 kilometers, or 63 miles – and its special suite of instruments.

In the new study, scientists combined data from Cassini's ion and neutral mass spectrometer and the Cassini plasma spectrometer during flybys on Nov. 26, 2005, Aug. 30, 2007, and March 2, 2010. The ion and neutral mass spectrometer "tasted" peak densities of oxygen of around 50 billion molecules per cubic meter (1 billion molecules per cubic foot). It detected peak densities of carbon dioxide of around 20 billion molecules per cubic meter (about 600 million molecules per cubic foot).

The plasma spectrometer saw clear signatures of flowing streams of positive and negative ions, with masses that corresponded to ions of oxygen and carbon dioxide.

"How exactly the carbon dioxide is released is still a puzzle," said co-author Geraint Jones, a Cassini team scientist based at University College London in the U.K. "But with Cassini's diverse suite of instruments observing Rhea from afar, as well as sniffing the gas surrounding it, we hope to solve the puzzle."

The carbon dioxide may be the result of “dry ice” trapped from the primordial solar nebula, as is the case with comets, or it may be due to similar irradiation processes operating on the organic molecules trapped in the water ice of Rhea. The carbon dioxide could also come from carbon-rich materials deposited by tiny meteors that bombarded Rhea's surface.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The ion and neutral mass spectrometer team and the Cassini plasma spectrometer team are based at Southwest Research Institute, San Antonio.

For more information about the Cassini mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .
Title: Re: NASA - Cassini updates
Post by: jacqmans on 12/30/2010 08:28 AM
Cassini Celebrates 10 Years Since Jupiter Encounter

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-431&cid=release_2010-431

Ten years ago, on Dec. 30, 2000, NASA's Cassini spacecraft made its closest approach to Jupiter on its way to orbiting Saturn. The main purpose was to use the gravity of the largest planet in our solar system to slingshot Cassini towards Saturn, its ultimate destination. But the encounter with Jupiter, Saturn's gas-giant big brother, also gave the Cassini project a perfect lab for testing its instruments and evaluating its operations plans for its tour of the ringed planet, which began in 2004.

"The Jupiter flyby allowed the Cassini spacecraft to stretch its wings, rehearsing for its prime time show, orbiting Saturn," said Linda Spilker, Cassini project scientist based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Ten years later, findings from the Jupiter flyby still continue to shape our understanding of similar processes in the Saturn system."

Cassini spent about six months - from October 2000 to March 2001 - exploring the Jupiter system. The closest approach brought Cassini to within about 9.7 million kilometers (6 million miles) of Jupiter's cloud tops at 2:05 a.m. Pacific Time, or 10:05 a.m. UTC, on Dec. 30, 2000.

Cassini captured some 26,000 images of Jupiter and its moons over six months of continual viewing, creating the most detailed global portrait of Jupiter yet.

While Cassini's images of Jupiter did not have higher resolution than the best from NASA's Voyager mission during its two 1979 flybys, Cassini's cameras had a wider color spectrum than those aboard Voyager, capturing wavelengths of radiation that could probe different heights in Jupiter's atmosphere. The images enabled scientists to watch convective lightning storms evolve over time and helped them understand the heights and composition of these storms and the many clouds, hazes and other types of storms that blanket Jupiter.

The Cassini images also revealed a never-before-seen large, dark oval around 60 degrees north latitude that rivaled Jupiter's Great Red Spot in size. Like the Great Red Spot, the large oval was a giant storm on Jupiter. But, unlike the Great Red Spot, which has been stable for hundreds of years, the large oval showed itself to be quite transient, growing, moving sideways, developing a bright inner core, rotating and thinning over six months. The oval was at high altitude and high latitude, so scientists think the oval may have been associated with Jupiter's powerful auroras.

The imaging team was also able to amass 70-day movies of storms forming, merging and moving near Jupiter's north pole. They showed how larger storms gained energy from swallowing smaller storms, the way big fish eat small fish. The movies also showed how the ordered flow of the eastward and westward jet streams in low latitudes gives way to a more disordered flow at high latitudes.

Meanwhile, Cassini's composite infrared spectrometer was able to do the first thorough mapping of Jupiter's temperature and atmospheric composition. The temperature maps enabled winds to be determined above the cloud tops, so scientists no longer had to rely on tracking features to measure winds. The spectrometer data showed the unexpected presence of an intense equatorial eastward jet (roughly 140 meters per second, or 310 mph) high in the stratosphere, about 100 kilometers (60 miles) above the visible clouds. Data from this instrument also led to the highest-resolution map so far of acetylene on Jupiter and the first detection of organic methyl radical and diacetylene in the auroral hot spots near Jupiter's north and south poles. These molecules are important to understanding the chemical interactions between sunlight and molecules in Jupiter's stratosphere.

As Cassini approached Jupiter, its radio and plasma wave instrument also recorded naturally occurring chirps created by electrons coming from a cosmic sonic boom. The boom occurs when supersonic solar wind - charged particles that fly off the sun - is slowed and deflected around the magnetic bubble surroun ding Jupiter.

Because Cassini arrived at Jupiter while NASA's Galileo spacecraft was still orbiting the planet, scientists were also able to take advantage of near-simultaneous measurements from two different spacecraft. This coincidence enabled scientists to make giant strides in understanding the interaction of the solar wind with Jupiter. Cassini and Galileo provided the first two-point measurement of the boundary of Jupiter's magnetic bubble and showed that it was in the act of contracting as a region of higher solar wind pressure blew on it.

"The Jupiter flyby benefited us in two ways, one being the unique science data we collected and the other the knowledge we gained about how to effectively operate this complex machine," said Bob Mitchell, Cassini program manager based at JPL. "Today, 10 years later, our operations are still heavily influenced by that experience and it is serving us very well."

In celebrating the anniversary of Cassini's visit 10 years ago, scientists are also excited about the upcoming and proposed missions to the Jupiter system, including NASA's Juno spacecraft, to be launched next August, and the Europa Jupiter System Mission, which has been given a priority by NASA.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, Calif., manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute in Boulder, Colo. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md., where the instrument was built. The radio and plasma wave science team is based at the University of Iowa, Iowa City, where the instrument was built.

Title: Re: NASA - Cassini updates
Post by: jacqmans on 02/04/2011 04:29 AM
Surprise Hidden in Titan's Smog: Cirrus-Like Clouds

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2011-040&cid=release_2011-040

Every day is a bad-air day on Saturn's largest moon, Titan. Blanketed by haze far worse than any smog belched out in Los Angeles, Beijing or even Sherlock Holmes' London, the moon looks like a dirty orange ball. Described once as crude oil without the sulfur, the haze is made of tiny droplets of hydrocarbons with other, more noxious chemicals mixed in. Gunk.

Icky as it may sound, Titan is really the rarest of gems: the only moon in our solar system with an atmosphere worthy of a planet. This atmosphere comes complete with lightning, drizzle and occasionally a big, summer-downpour style of cloud made of methane or ethane-hydrocarbons that are best known for their role in natural gas.

Now, thin, wispy clouds of ice particles, similar to Earth's cirrus clouds, are being reported by Carrie Anderson and Robert Samuelson at NASA's Goddard Space Flight Center in Greenbelt, Md. The findings, published this week in the journal Icarus, were made using the composite infrared spectrometer on NASA's Cassini spacecraft.

Unlike Titan's brownish haze, the ice clouds have the pearly white appearance of freshly fallen snow. Their existence is the latest clue to the workings of Titan's intriguing atmosphere and its one-way "cycle" that delivers hydrocarbons and other organic compounds to the ground as precipitation. Those compounds don't evaporate to replenish the atmosphere, but somehow the supply has not run out yet.

"This is the first time we have been able to get details about these clouds," says Samuelson, an emeritus scientist at Goddard and the co-author of the paper. "Previously, we had a lot of information about the gases in Titan's atmosphere but not much about the [high-altitude] clouds."

Compared to the puffy methane and ethane clouds found before in a lower part of the atmosphere by both ground-based observers and in images taken by Cassini's imaging science subsystem and visual and infrared mapping spectrometer, these clouds are much thinner and located higher in the atmosphere. "They are very tenuous and very easy to miss," says Anderson, the paper's lead author. "The only earlier hints that they existed were faint glimpses that NASA's Voyager 1 spacecraft caught as it flew by Titan in 1980."

The full story is online at: http://www.nasa.gov/mission_pages/cassini/whycassini/titan-clouds.html .

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The CIRS team is based at NASA's Goddard Space Flight Center in Greenbelt, Md., where the instrument was built.

Title: Re: NASA - Cassini updates
Post by: robertross on 03/07/2011 11:50 PM
Cassini Finds Enceladus is a Powerhouse

http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20110307.html

PASADENA, Calif. – Heat output from the south polar region of Saturn's moon Enceladus is much greater than was previously thought possible, according to a new analysis of data collected by NASA's Cassini spacecraft. The study was published in the Journal of Geophysical Research on March 4.

Data from Cassini's composite infrared spectrometer of Enceladus' south polar terrain, which is marked by linear fissures, indicate that the internal heat-generated power is about 15.8 gigawatts, approximately 2.6 times the power output of all the hot springs in the Yellowstone region, or comparable to 20 coal-fueled power stations. This is more than an order of magnitude higher than scientists had predicted, according to Carly Howett, the lead author of study, who is a postdoctoral researcher at Southwest Research Institute in Boulder, Colo., and a composite infrared spectrometer science team member.

"The mechanism capable of producing the much higher observed internal power remains a mystery and challenges the currently proposed models of long-term heat production," said Howett.

It has been known since 2005 that Enceladus' south polar terrain is geologically active and the activity is centered on four roughly parallel linear trenches, 130 kilometers (80 miles) long and about 2 kilometers (1 mile) wide, informally known as the "tiger stripes." Cassini also found that these fissures eject great plumes of ice particles and water vapor continually into space. These trenches have elevated temperatures due to heat leaking out of Enceladus' interior.

A 2007 study predicted the internal heat of Enceladus, if principally generated by tidal forces arising from the orbital resonance between Enceladus and another moon, Dione, could be no greater than 1.1 gigawatts averaged over the long term. Heating from natural radioactivity inside Enceladus would add another 0.3 gigawatts.

The latest analysis, which also involved the composite infrared spectrometer team members John Spencer at Southwest Research Institute, and John Pearl and Marcia Segura at NASA's Goddard Space Flight Center in Greenbelt, Md., uses observations taken in 2008, which cover the entire south polar terrain. They constrained Enceladus' surface temperatures to determine the region's surprisingly high output.

A possible explanation of the high heat flow observed is that Enceladus' orbital relationship to Saturn and Dione changes with time, allowing periods of more intensive tidal heating, separated by more quiescent periods. This means Cassini might be lucky enough to be seeing Enceladus when it's unusually active.

The new, higher heat flow determination makes it even more likely that liquid water exists below Enceladus' surface, Howett noted.

Recently, scientists studying ice particles ejected from the plumes discovered that some of the particles are salt-rich, and are probably frozen droplets from a saltwater ocean in contact with Enceladus' mineral-rich rocky core. The presence of a subsurface ocean, or perhaps a south polar sea between the moon's outer ice shell and its rocky interior would increase the efficiency of the tidal heating by allowing greater tidal distortions of the ice shell.

"The possibility of liquid water, a tidal energy source and the observation of organic (carbon-rich) chemicals in the plume of Enceladus make the satellite a site of strong astrobiological interest," Howett said.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The CIRS team is based at NASA's Goddard Space Flight Center in Greenbelt, Md., where the instrument was built.
Title: Re: NASA - Cassini updates
Post by: robertross on 03/19/2011 03:09 PM
Cassini Sees Seasonal Rains Transform Titan's Surface

March 17, 2011

PASADENA, Calif. -- As spring continues to unfold at Saturn, April showers on the planet's largest moon, Titan, have brought methane rain to its equatorial deserts, as revealed in images captured by NASA's Cassini spacecraft. This is the first time scientists have obtained current evidence of rain soaking Titan's surface at low latitudes.

Extensive rain from large cloud systems, spotted by Cassini's cameras in late 2010, has apparently darkened the surface of the moon. The best explanation is these areas remained wet after methane rainstorms. The observations released today in the journal Science, combined with earlier results in Geophysical Research Letters last month, show the weather systems of Titan's thick atmosphere and the changes wrought on its surface are affected by the changing seasons.

"It's amazing to be watching such familiar activity as rainstorms and seasonal changes in weather patterns on a distant, icy satellite," said Elizabeth Turtle, a Cassini imaging team associate at the Johns Hopkins University Applied Physics Lab in Laurel, Md., and lead author of today's publication. "These observations are helping us to understand how Titan works as a system, as well as similar processes on our own planet."

The Saturn system experienced equinox, when the sun lies directly over a planet's equator and seasons change, in August 2009. (A full Saturn "year" is almost 30 Earth years.) Years of Cassini observations suggest Titan's global atmospheric circulation pattern responds to the changes in solar illumination, influenced by the atmosphere and the surface, as detailed in the Geophysical Research Letters paper. Cassini found the surface temperature responds more rapidly to sunlight changes than does the thick atmosphere. The changing circulation pattern produced clouds in Titan's equatorial region.

Clouds on Titan are formed of methane as part of an Earth-like cycle that uses methane instead of water. On Titan, methane fills lakes on the surface, saturates clouds in the atmosphere, and falls as rain. Though there is evidence that liquids have flowed on the surface at Titan's equator in the past, liquid hydrocarbons, such as methane and ethane, had only been observed on the surface in lakes at polar latitudes. The vast expanses of dunes that dominate Titan's equatorial regions require a predominantly arid climate. Scientists suspected that clouds might appear at Titan's equatorial latitudes as spring in the northern hemisphere progressed. But they were not sure if dry channels previously observed were cut by seasonal rains or remained from an earlier, wetter climate.

An arrow-shaped storm appeared in the equatorial regions on Sept. 27, 2010 -- the equivalent of early April in Titan's "year" -- and a broad band of clouds appeared the next month. As described in the Science paper, over the next few months, Cassini's imaging science subsystem captured short-lived surface changes visible in images of Titan's surface. A 193,000-square-mile (500,000-square-kilometer) region along the southern boundary of Titan's Belet dune field, as well as smaller areas nearby, had become darker. Scientists compared the imaging data to data obtained by other instruments and ruled out other possible causes for surface changes. They concluded this change in brightness is most likely the result of surface wetting by methane rain.

These observations suggest that recent weather on Titan is similar to that over Earth's tropics. In tropical regions, Earth receives its most direct sunlight, creating a band of rising motion and rain clouds that encircle the planet.

"These outbreaks may be the Titan equivalent of what creates Earth's tropical rainforest climates, even though the delayed reaction to the change of seasons and the apparently sudden shift is more reminiscent of Earth's behavior over the tropical oceans than over tropical land areas," said Tony Del Genio of NASA's Goddard Institute for Space Studies, New York, a co-author and a member of the Cassini imaging team.

On Earth, the tropical bands of rain clouds shift slightly with the seasons but are present within the tropics year-round. On Titan, such extensive bands of clouds may only be prevalent in the tropics near the equinoxes and move to much higher latitudes as the planet approaches the solstices. The imaging team intends to watch whether Titan evolves in this fashion as the seasons progress from spring toward northern summer.

"It is patently clear that there is so much more to learn from Cassini about seasonal forcing of a complex surface-atmosphere system like Titan's and, in turn, how it is similar to, or differs from, the Earth's," said Carolyn Porco, Cassini imaging team lead at the Space Science Institute, Boulder, Colo. "We are eager to see what the rest of Cassini's Solstice Mission will bring."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.
Title: Re: NASA - Cassini updates
Post by: robertross on 03/19/2011 03:11 PM
Northern Reaches
March 14, 2011

The Cassini spacecraft watches over the northern latitudes of Saturn's geologically active moon Enceladus while the planet's rings peek through in the distance in this snapshot.
See Enceladus' Leading Hemisphere to learn more about the surface of the moon. This view looks toward the northern latitudes of the anti-Saturn side of Enceladus (504 kilometers, or 313 miles across). North on Enceladus is up and rotated 21 degrees to the left.

This view looks toward the northern, sunlit side of the rings from just above the ringplane.

The image was taken with the Cassini spacecraft narrow-angle camera on Dec. 21, 2010 using a spectral filter sensitive to wavelengths of near-infrared light centered at 752 nanometers. The view was obtained at a distance of approximately 34,000 kilometers (21,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 15 degrees. Image scale is 202 meters (663 feet) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .
Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/22/2011 07:29 PM
March 22, 2011

Cassini Finds Saturn Sends Mixed Signals

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2011-091&cid=release_2011-091

Like a petulant adolescent, Saturn is sending out mixed signals.

Recent data from NASA's Cassini spacecraft show that the variation in radio waves controlled by the planet's rotation is different in the northern and southern hemispheres. Moreover, the northern and southern rotational variations also appear to change with the Saturnian seasons, and the hemispheres have actually swapped rates. These two radio waves, converted to the human audio range, can be heard in a new video available online at: http://www.nasa.gov/multimedia/videogallery/index.html?media_id=74390781

"These data just go to show how weird Saturn is," said Don Gurnett, Cassini's radio and plasma wave science instrument team lead and professor of physics at the University of Iowa, Iowa City. "We thought we understood these radio wave patterns at gas giants, since Jupiter was so straightforward. Without Cassini's long stay, scientists wouldn't have understood that the radio emissions from Saturn are so different."

Saturn emits radio waves known as Saturn Kilometric Radiation, or SKR for short. To Cassini, they sound a bit like bursts of a spinning air raid siren, since the radio waves vary with each rotation of the planet. This kind of radio wave pattern had been previously used at Jupiter to measure the planet's rotation rate, but at Saturn, as is the case with teenagers, the situation turned out to be much more complicated.

When NASA's Voyager spacecraft visited Saturn in the early 1980s, the radiation emissions indicated the length of Saturn's day was about 10.66 hours. But as its clocking continued by a flyby of the joint ESA-NASA Ulysses spacecraft and Cassini, the radio burst varied by seconds to minutes. A paper in Geophysical Research Letters in 2009 analyzing Cassini data showed that the Saturn Kilometric Radiation was not even a solo, but a duet, with two singers out of sync. Radio waves emanating from near the north pole had a period of around 10.6 hours; radio waves near the south pole had a period of around 10.8 hours.

A new paper led by Gurnett that was published in Geophysical Research Letters in December 2010 shows that, in recent Cassini data, the southern and northern SKR periods crossed over around March 2010, about seven months after equinox, when the sun shines directly over a planet's equator. The southern SKR period decreased from about 10.8 hours on Jan. 1, 2008 and crossed with the northern SKR period around March 1, 2010, at around 10.67 hours. The northern period increased from about 10.58 hours to that convergence point.

Seeing this kind of crossover led the Cassini scientists to go back into data from previous Saturnian visits. With a new eye, they saw that NASA's Voyager data taken in 1980, about a year after Saturn's 1979 equinox, showed different warbles from Saturn's northern and southern poles. They also saw a similar kind of effect in the Ulysses radio data between 1993 and 2000. The northern and southern periods detected by Ulysses converged and crossed over around August 1996, about nine months after the previous Saturnian equinox.

Cassini scientists don't think the differences in the radio wave periods had to do with hemispheres actually rotating at different rates, but more likely came from variations in high-altitude winds in the northern and southern hemispheres. Two other papers involving Cassini investigators were published in December, with results complementary to the radio and plasma wave science instrument -- one by Jon Nichols, University of Leicester, U.K., in the same issue of Geophysical Research Letters, and the other led by David Andrews, also of University of Leicester, in the Journal of Geophysical Research.

In the Nichols paper, data from the NASA/ESA Hubble Space Telescope showed the northern and southern auroras on Saturn wobbled back and forth in latitude in a pattern matching the radio wave variations, from January to March 2009, just before equinox. The radio signal and aurora data are complementary because they are both related to the behavior of the magnetic bubble around Saturn, known as the magnetosphere. The paper by Andrews, a Cassini magnetometer team associate, showed that from mid-2004 to mid-2009, Saturn's magnetic field over the two poles wobbled at the same separate periods as the radio waves and the aurora.

"The rain of electrons into the atmosphere that produces the auroras also produces the radio emissions and affects the magnetic field, so scientists think that all these variations we see are related to the sun's changing influence on the planet," said Stanley Cowley, a co-author on both papers, co-investigator on Cassini's magnetometer instrument, and professor at the University of Leicester.

As the sun continues to climb towards the north pole of Saturn, Gurnett's group has continued to see the crossover trend in radio signals through Jan. 1, 2011. The period of the southern radio signals continued to decrease to about 10.54 hours, while the period of the northern radio signals increased to 10.71 hours.

"These papers are important in helping to explain the complicated dance between the sun and Saturn's magnetic bubble, something normally invisible to the human eye and imperceptible to the human ear," said Marcia Burton, a Cassini fields and particles scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., who was not involved in the work. "Cassini will continue to keep an eye on these changes."

Title: Re: NASA - Cassini updates
Post by: jacqmans on 04/08/2011 04:32 AM
April 07, 2011

New Theory: Titan Shaped By Weather, Not Ice Volcanoes

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2011-111&cid=release_2011-111

Have the surface and belly of Saturn's smog-shrouded moon, Titan, recently simmered like a chilly, bubbling cauldron with ice volcanoes, or has this distant moon gone cold? In a newly published analysis, a pair of NASA scientists analyzing data collected by the Cassini spacecraft suggest Titan may be much less geologically active than some scientists have thought.

In the paper, published in the April 2011 edition of the journal Icarus, scientists conclude Titan's interior may be cool and dormant and incapable of causing active ice volcanoes.

"It would be fantastic to find strong evidence that clearly shows Titan has an internal heat source that causes ice volcanoes and lava flows to form," said Jeff Moore, lead author of the paper and a planetary scientist at NASA's Ames Research Center, Moffett Field, Calif. "But we find that the evidence presented to date is unconvincing, and recent studies of Titan's interior conducted by geophysicists and gravity experts also weaken the possibility of volcanoes there."

Scientists agree that Titan shows evidence of having lakes of liquid methane and ethane, and valleys carved by these exotic liquids, as well as impact craters. However, a debate continues to brew about how to interpret the Cassini data on Titan. Some scientists theorize ice volcanoes exist and suggest energy from an internal heat source may have caused ice to rise and release methane vapors as it reached Titan's surface.

But in the new paper, the authors conclude that the only features on Titan's surface that have been unambiguously identified were created by external forces -- such as objects hitting the surface and creating craters; wind and rain pummeling its surface; and the formation of rivers and lakes.

"Titan is a fascinating world," said Robert Pappalardo, a research scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and former project scientist for NASA's Cassini mission. "Its uniqueness comes from its atmosphere and organic lakes, but in this study, we find no strong evidence for icy volcanism on Titan."

In December 2010, a group of Cassini scientists presented new topographic data on an area of Titan called Sotra Facula, which they think makes the best case yet for a possible volcanic mountain that once erupted ice on Titan. Although Moore and Pappalardo do not explicitly consider this recent topographic analysis in their paper, they do not find the recent analysis of Sotra Facula to be convincing so far. It remains to be seen whether ongoing analyses of Sotra Facula can change minds.

Titan, Saturn's largest moon, is the only known moon to have a dense atmosphere, composed primarily of nitrogen, with two to three percent methane. One goal of the Cassini mission is to find an explanation for what, if anything, might be maintaining this atmosphere.

Titan's dense atmosphere makes its surface very difficult to study with visible-light cameras, but infrared instruments and radar signals can peer through the haze and provide information about both the composition and shape of the surface.

"Titan is most akin to Jupiter's moon Callisto, if Callisto had weather," Moore added. "Every feature we have seen on Titan can be explained by wind, rain and meteorite impacts, rather than from internal heating."

Callisto is almost the exact same size as Titan. It has a cratered appearance, and because of its cool interior, its surface features are not affected by internal forces. Moore and Pappalardo conclude that Titan also might have a cool interior, with only external processes like wind, rain and impacts shaping its surface.

The Cassini spacecraft, currently orbiting Saturn, continues to make fly-bys of Titan. Scientists will continue to explore Titan's mysteries, including investigations of the changes in the landscapes.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and several of its instruments were designed, developed and assembled at JPL.

For more information about the Cassini-Huygens mission, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Fore more information about possible ice volcanoes on Titan, visit http://www.jpl.nasa.gov/news/news.cfm?release=2010-416 and http://www.jpl.nasa.gov/news/news.cfm?release=2008-237 .

Title: Re: NASA - Cassini updates
Post by: jacqmans on 04/20/2011 07:53 PM
RELEASE: 11-115

CASSINI PROBE SEES ELECTRIC LINK WITH SATURN AND ONE OF ITS MOONS

PASADENA, Calif. -- NASA is releasing the first images and sounds of
an electrical connection between Saturn and one of its moons. The
data collected by the agency's Cassini spacecraft enable scientists
to improve their understanding of the complex web of interaction
between the planet and its numerous moons. The results of the data
analysis are published in the journals Nature and Geophysical
Research Letters.

Scientists previously theorized an electrical circuit should exist at
Saturn. After analyzing data that Cassini collected in 2008,
scientists saw a glowing patch of ultraviolet light emissions near
Saturn's north pole that marked the presence of a circuit, even
though the moon is 150,000 miles (240,000 kilometers) away from the
planet.

The patch occurs at the end of a magnetic field line connecting Saturn
and its moon Enceladus. The area, known as an auroral footprint, is
the spot where energetic electrons dive into the planet's atmosphere,
following magnetic field lines that arc between the planet's north
and south polar regions.

"The footprint discovery at Saturn is one of the most important fields
and particle revelations from Cassini and ultimately may help us
understand Saturn's strange magnetic field," said Marcia Burton, a
Cassini fields and particles scientist at NASA's Jet Propulsion
Laboratory in Pasadena, Calif. "It gives us the first visual
connection between Saturn and one of its moons."

The auroral footprint measures approximately 750 miles (1,200
kilometers) by less than 250 miles (400 kilometers), covering an area
comparable to California or Sweden. At its brightest, the footprint
shone with an ultraviolet light intensity far less than Saturn's
polar auroral rings, but comparable to the faintest aurora visible at
Earth without a telescope in the visible light spectrum. Scientists
have not found a matching footprint at the southern end of the
magnetic field line.

"Cassini fields and particles instruments found particle beams aligned
with Saturn's magnetic field near Enceladus, and scientists started
asking if we could see an expected ultraviolet spot at the end of the
magnetic field line on Saturn," said Wayne Pryor, a lead author of
the Nature study released today, and Cassini co-investigator at
Central Arizona College in Coolidge, Ariz. "We were delighted to find
the glow close to the 'bulls-eye' at the center of our target."

Jupiter's active moon Io creates glowing footprints near Jupiter's
north and south poles, so scientists suspected there was an analogous
electrical connection between Saturn and Enceladus. It is the only
known active moon in the Saturn system with jets spraying water vapor
and organic particles into space. For years, scientists used space
telescopes to search Saturn's poles for footprints, but none were
found.

In 2008, Cassini detected a beam of energetic protons near Enceladus
aligned with the magnetic field and field-aligned electron beams. A
team of scientists analyzed the data and concluded the electron beams
had sufficient energy flux to generate a detectable level of auroral
emission at Saturn. A few weeks later, Cassini captured images of an
auroral footprint in Saturn's northern hemisphere. In 2009, a group
of Cassini scientists led by Donald Gurnett at the University of Iowa
in Iowa City detected more complementary signals near Enceladus
consistent with currents that travel from the moon to the top of
Saturn's atmosphere, including a hiss-like sound from the magnetic
connection. That paper was published in March in Geophysical Research
Letters.

The water cloud above the Enceladus jets produces a massive, ionized
"plasma" cloud through its interactions with the magnetic bubble
around Saturn. This cloud disturbs the magnetic field lines. The
footprint appears to flicker in these new data, so the rate at which
Enceladus is spewing particles may vary.

"The new data are adding fuel to the fire of some long-standing
debates about this active little moon," said Abigail Rymer, the other
lead author of the Nature study and a Cassini team scientist based at
the Johns Hopkins University Applied Physics Laboratory in Laurel,
Md. "Scientists have been wondering whether the venting rate is
variable, and these new data suggest that it is."

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. JPL manages the
mission for NASA's Science Mission Directorate in Washington.

To see a video and hear the sounds of the electrical connection,
visit:



http://www.nasa.gov/cassini

Title: Re: NASA - Cassini updates
Post by: jacqmans on 05/19/2011 09:54 PM
RELEASE: 11-151

CASSINI SPACECRAFT AND GROUND TELESCOPE SEE VIOLENT SATURN STORM

WASHINGTON -- NASA's Cassini spacecraft and a European Southern
Observatory ground-based telescope tracked the growth of a giant
early-spring storm in Saturn's northern hemisphere so powerful it
stretches around the entire planet. The rare storm has been wreaking
havoc for months and shot plumes of gas high into the planet's
atmosphere.

Cassini's radio and plasma wave science instrument first detected the
large disturbance, and amateur astronomers tracked its emergence in
December 2010. As it rapidly expanded, its core developed into a
giant, powerful thunderstorm. The storm produced a 3,000-mile-wide
(5,000-kilometer-wide) dark vortex, possibly similar to Jupiter's
Great Red Spot, within the turbulent atmosphere.

The dramatic effects of the deep plumes disturbed areas high up in
Saturn's usually stable stratosphere, generating regions of warm air
that shone like bright "beacons" in the infrared. Details are
published in this week's edition of Science Magazine.

"Nothing on Earth comes close to this powerful storm," says Leigh
Fletcher, the study's lead author and a Cassini team scientist at the
University of Oxford in the United Kingdom. "A storm like this is
rare. This is only the sixth one to be recorded since 1876, and the
last was way back in 1990."

This is the first major storm on Saturn observed by an orbiting
spacecraft and studied at thermal infrared wavelengths, where
Saturn's heat energy reveals atmospheric temperatures, winds and
composition within the disturbance.

Temperature data were provided by the Very Large Telescope (VLT) on
Cerro Paranal in Chile and Cassini's composite infrared spectrometer
(CIRS) operated by NASA's Goddard Space Flight Center in Greenbelt,
Md.

"Our new observations show that the storm had a major effect on the
atmosphere, transporting energy and material over great distances,
modifying the atmospheric winds -- creating meandering jet streams
and forming giant vortices -- and disrupting Saturn's slow seasonal
evolution," said Glenn Orton, a paper co-author, based at NASA's Jet
Propulsion Laboratory (JPL) in Pasadena, Calif.

The violence of the storm -- the strongest disturbances ever detected
in Saturn's stratosphere -- took researchers by surprise. What
started as an ordinary disturbance deep in Saturn's atmosphere
punched through the planet's serene cloud cover to roil the high
layer known as the stratosphere.

"On Earth, the lower stratosphere is where commercial airplanes
generally fly to avoid storms which can cause turbulence," says
Brigette Hesman, a scientist at the University of Maryland in College
Park who works on the CIRS team at Goddard and is the second author
on the paper. "If you were flying in an airplane on Saturn, this
storm would reach so high up, it would probably be impossible to
avoid it."

Other indications of the storm's strength are the changes in the
composition of the atmosphere brought on by the mixing of air from
different layers. CIRS found evidence of such changes by looking at
the amounts of acetylene and phosphine, both considered to be tracers
of atmospheric motion. A separate analysis using Cassini's visual and
infrared mapping spectrometer, led by Kevin Baines of JPL, confirmed
the storm is very violent, dredging up larger atmospheric particles
and churning up ammonia from deep in the atmosphere in volumes
several times larger than previous storms. Other Cassini scientists
are studying the evolving storm, and a more extensive picture will
emerge soon.

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The mission is
managed by JPL for NASA's Science Mission Directorate in Washington.
The European Southern Observatory in Garching, Germany operates the
VLT in Chile.

For information about Cassini, visit:


http://www.nasa.gov/cassini 

Title: Re: NASA - Cassini updates
Post by: jacqmans on 06/22/2011 05:22 PM
RELEASE: 11-196

NASA CASSINI SPACECRAFT CAPTURES OCEAN-LIKE SPRAY AT SATURN MOON

WASHINGTON -- NASA's Cassini spacecraft has discovered the best
evidence yet for a large-scale saltwater reservoir beneath the icy
crust of Saturn's moon Enceladus. The data came from the spacecraft's
direct analysis of salt-rich ice grains close to the jets ejected
from the moon.

Data from Cassini's cosmic dust analyzer show the grains expelled from
fissures, known as tiger stripes, are relatively small and usually
low in salt far away from the moon. But closer to the moon's surface,
Cassini found that relatively large grains rich with sodium and
potassium dominate the plumes. The salt-rich particles have an
"ocean-like" composition and indicate that most, if not all, of the
expelled ice and water vapor comes from the evaporation of liquid
salt-water. The findings appear in this week's issue of the journal
Nature.

"There currently is no plausible way to produce a steady outflow of
salt-rich grains from solid ice across all the tiger stripes other
than salt water under Enceladus's icy surface," said Frank Postberg,
a Cassini team scientist at the University of Heidelberg, Germany,
and the lead author on the paper. When water freezes, the salt is
squeezed out, leaving pure water ice behind. If the plumes emanated
from ice, they should have very little salt in them.

The Cassini mission discovered Enceladus' water-vapor and ice jets in
2005. In 2009, scientists working with the cosmic dust analyzer
examined some sodium salts found in ice grains of Saturn's E ring,
the outermost ring that gets its material primarily from Enceladean
jets. But the link to subsurface salt water was not definitive.

The new paper analyzes three Enceladus flybys in 2008 and 2009 with
the same instrument, focusing on the composition of freshly ejected
plume grains. The icy particles hit the detector target at speeds
between 15,000 and 39,000 mph (23,000 and 63,000 kilometers per
hour), vaporizing instantly. Electrical fields inside the cosmic dust
analyzer separated the various constituents of the impact cloud.

The data suggest a layer of water between the moon's rocky core and
its icy mantle, possibly as deep as about 50 miles (80 kilometers)
beneath the surface. As this water washes against the rocks, it
dissolves salt compounds and rises through fractures in the overlying
ice to form reserves nearer the surface. If the outermost layer
cracks open, the decrease in pressure from these reserves to space
causes a plume to shoot out. Roughly 400 pounds (200 kilograms) of
water vapor is lost every second in the plumes, with smaller amounts
being lost as ice grains. The team calculates the water reserves must
have large evaporating surfaces, or they would freeze easily and stop
the plumes.

"This finding is a crucial new piece of evidence showing that
environmental conditions favorable to the emergence of life can be
sustained on icy bodies orbiting gas giant planets," said Nicolas
Altobelli, the European Space Agency's project scientist for Cassini.


Cassini's ultraviolet imaging spectrograph also recently obtained
complementary results that support the presence of a subsurface
ocean. A team of Cassini researchers led by Candice Hansen of the
Planetary Science Institute in Tucson, Ariz., measured gas shooting
out of distinct jets originating in the moon's south polar region at
five to eight times the speed of sound, several times faster than
previously measured. These observations of distinct jets, from a 2010
flyby, are consistent with results showing a difference in
composition of ice grains close to the moon's surface and those that
made it out to the E ring. The paper was published in the June 9
issue of Geophysical Research Letters.

"Without an orbiter like Cassini to fly close to Saturn and its moons
-- to taste salt and feel the bombardment of ice grains -- scientists
would never have known how interesting these outer solar system
worlds are," said Linda Spilker, NASA's Cassini project scientist at
the Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The mission is
managed by JPL for NASA's Science Mission Directorate in Washington.

For more information about Cassini, visit:



http://www.nasa.gov/cassini

Title: Re: NASA - Cassini updates
Post by: Robotbeat on 06/22/2011 05:43 PM
Fascinating! Move over, Europa...
Title: Re: NASA - Cassini updates
Post by: jacqmans on 07/06/2011 06:29 PM
July 6, 2011

Cassini Spacecraft Captures Images and Sounds of Big Saturn Storm

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2011-203&cid=release_2011-203

PASADENA, Calif. -- Scientists analyzing data from NASA's Cassini spacecraft now have the first-ever, up-close details of a Saturn storm that is eight times the surface area of Earth.

On Dec. 5, 2010, Cassini first detected the storm that has been raging ever since. It appears approximately 35 degrees north latitude of Saturn. Pictures from Cassini's imaging cameras show the storm wrapping around the entire planet covering approximately 2 billion square miles (4 billion square kilometers).

The storm is about 500 times larger than the biggest storm previously seen by Cassini during several months from 2009 to 2010. Scientists studied the sounds of the new storm's lightning strikes and analyzed images taken between December 2010 and February 2011. Data from Cassini's radio and plasma wave science instrument showed the lightning flash rate as much as 10 times more frequent than during other storms monitored since Cassini's arrival to Saturn in 2004. The data appear in a paper published this week in the journal Nature.

"Cassini shows us that Saturn is bipolar," said Andrew Ingersoll, an author of the study and a Cassini imaging team member at the California Institute of Technology in Pasadena, Calif. "Saturn is not like Earth and Jupiter, where storms are fairly frequent. Weather on Saturn appears to hum along placidly for years and then erupt violently. I'm excited we saw weather so spectacular on our watch."

At its most intense, the storm generated more than 10 lightning flashes per second. Even with millisecond resolution, the spacecraft's radio and plasma wave instrument had difficulty separating individual signals during the most intense period. Scientists created a sound file from data obtained on March 15 at a slightly lower intensity period.

Cassini has detected 10 lightning storms on Saturn since the spacecraft entered the planet's orbit and its southern hemisphere was experiencing summer, with full solar illumination not shadowed by the rings. Those storms rolled through an area in the southern hemisphere dubbed "Storm Alley." But the sun's illumination on the hemispheres flipped around August 2009, when the northern hemisphere began experiencing spring.

"This storm is thrilling because it shows how shifting seasons and solar illumination can dramatically stir up the weather on Saturn," said Georg Fischer, the paper's lead author and a radio and plasma wave science team member at the Austrian Academy of Sciences in Graz. "We have been observing storms on Saturn for almost seven years, so tracking a storm so different from the others has put us at the edge of our seats."

The storm's results are the first activities of a new "Saturn Storm Watch" campaign. During this effort, Cassini looks at likely storm locations on Saturn in between its scheduled observations. On the same day that the radio and plasma wave instrument detected the first lightning, Cassini's cameras happened to be pointed at the right location as part of the campaign and captured an image of a small, bright cloud. Because analysis on that image was not completed immediately, Fischer sent out a notice to the worldwide amateur astronomy community to collect more images. A flood of amateur images helped scientists track the storm as it grew rapidly, wrapping around the planet by late January 2011.

The new details about this storm complement atmospheric disturbances described recently by scientists using Cassini's composite infrared spectrometer and the European Southern Observatory's Very Large Telescope. The storm is the biggest observed by spacecraft orbiting or flying by Saturn. NASA's Hubble Space Telescope captured images in 1990 of an equally large storm.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena manages the mission for the agency's Science Mission Directorate in Washington. The radio and plasma wave science team is based at the University of Iowa, Iowa City, where the instrument was built. The imaging team is based at the Space Science Institute in Boulder, Colo. JPL is a division of the California Institute of Technology, Pasadena.

For images and an audio file of the storm, visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini.

Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/12/2011 09:58 AM
Quote
The most recent spacecraft telemetry was acquired on Aug. 8 from the Deep Space Network tracking complex at Goldstone, California.  The Cassini spacecraft is in an excellent state of health and all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at:
http://saturn.jpl.nasa.gov/mission/presentposition/ .

Wednesday, Aug. 3 (DOY 215)

Last week, the Downlink Ground System (DGS) team successfully made the switch from Broadcast to Multicast, the new real-time transfer mechanism for project data coming from the DSN.  Data Monitor and Display (DMD) units were updated to receive telemetry via Multicast, and Cassini has now been receiving its telemetry via Multicast since July 27.  Dual streams of both Broadcast and Multicast have been running during this time to provide a backup option. However, on Monday, Aug. 15, the Broadcast data flow will be turned off for Cassini, and telemetry will only be delivered via Multicast.

Thursday, Aug. 4 (DOY 216)

Highlights in science data acquisition this week include the following items: an Extreme Ultraviolet/Far Ultraviolet (EUV/FUV) observation completed by the Ultraviolet Imaging Spectrograph Subsystem (UVIS), which involved slow scans across Saturn's visible hemisphere to form spectral images, a calibration activity for determination of magnetometer sensor offsets, a magnetospheric survey campaign observation performed by the Magnetosphere and Plasma Science (MAPS) instruments, and two Saturn mid-infrared (mid-IR) maps by the Composite Infrared Spectrometer (CIRS), which help determine Saturn's upper troposphere and tropopause temperature.

Friday, Aug. 5 (DOY 217)

Cassini Outreach supported the Juno launch outreach activities at Kennedy Space Center (KSC) by publicizing a star party and viewing tips for the moon, Saturn and Jupiter on the days surrounding the successful Aug. 5th launch.

Saturday, Aug. 6 (DOY 218)

This month's What's Up podcast features Saturn and Jupiter viewing, windy worlds in the solar system, and Cassini and Juno mission news.  To explore, visit:
http://solarsystem.nasa.gov/news/whatsup-archive.cfm

Sunday, Aug. 7 (DOY 219)

The Navigation Team continued preparations for Orbit Trim Maneuver (OTM) #288 which is scheduled to execute on Aug. 22.  OTM-288 will be a Reaction Control Subsystem (RCS) maneuver estimated to be around 90 mm/s in magnitude, and will target to the 5,821 km altitude Titan flyby (T78) on Sept. 12.

Monday, Aug. 8 (DOY 220)

A feature story called "Putting it All Together on Titan" is available on the Cassini web site.  It showcases three of Titan's major surface features -- dunes, craters and the enigmatic Xanadu -- in a Radar image from the Cassini spacecraft taken on June 21, 2011.   For images and more information on this subject, link to:
http://saturn.jpl.nasa.gov/news/cassinifeatures/feature200110808/ .

The second VIMS instrument expanded block (IEB) reload mini-sequence for S69 was radiated to the spacecraft today over Goldstone's DSS-15 station.  The commands will begin executing around 224/19:30:39 SCET, when VIMS will move this IEB load from spacecraft to instrument memory.
 
Tuesday, Aug. 9 (DOY 221)

The Cassini Project Scientist gave an in-reach talk today.  The presentation provided an update on the Cassini Science results and highlights from the past quarter.

The Science Planning and Sequencing Team (SPST) held another meeting today for instrument teams that would be affected by the proposed alternative T79 timeline being considered if the Cassini Plasma Spectrometer (CAPS) instrument remains off for the Titan 79 flyby.  The S71 sequence team and Titan Orbiter Science Team (TOST) representatives from CIRS, VIMS, ISS, UVIS, CAPS and the Radio and Plasma Wave Science (RPWS) instruments were asked to call in to discuss the schedule for the additional product deliveries, the file naming convention, and to address any questions.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/15/2011 05:02 PM
Images from Aug 13th are up

http://saturn.jpl.nasa.gov/photos/raw/index.cfm?start=1&storedQ=2370009
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/15/2011 05:16 PM
Whats happening Aug 12 - Sep 3 2011

Quote
Cassini begins the three-week Rev152 on August 12 at its farthest distance from Saturn, called apoapse. At this point, Cassini is 2.71 million kilometers (1.68 million miles) from Saturn's cloud tops. The spacecraft is in the middle of the first equatorial phase of the Cassini Solstice Mission, which lasts until May 2012.

...

http://www.ciclops.org/view/6846/Rev152
Title: Re: NASA - Cassini updates
Post by: ugordan on 08/15/2011 05:37 PM
I don't usually look at the Looking Ahead page because I find out there's some cool observation planned, then wait for it and for some reason it gets lost - either at the spacecraft or downlink. I prefer just being surprised by going to the raw page and seeing what's on the table that day.

That said...

Quote
On August 25 at 16:48 UTC, Cassini will perform a non-targeted encounter with the irregularly shaped moon, Hyperion. Cassini will pass the icy moon at a distance of 24,978 kilometers (15,520 miles). During the encounter, ISS will take several, multi-filter mosaics of the satellite. The first, three-frame mosaic covers the crescent of Hyperion as Cassini approaches.

Mmmm, Hyperion.

The approach 3-frame mosaic might look something like this (http://www.flickr.com/photos/ugordan/4595629549/sizes/o/in/photostream/).

Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/16/2011 08:14 PM
2 New Images

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4340

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4341
Title: Re: NASA - Cassini updates
Post by: ugordan on 08/16/2011 08:35 PM
2 New Images

"new". The Helene encounter was 2 months ago.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/16/2011 08:42 PM
2 New Images

"new". The Helene encounter was 2 months ago.

Ahh, my mistake. NASA has them under "Latest Images" on the photos page

http://saturn.jpl.nasa.gov/photos/

Title: Re: NASA - Cassini updates
Post by: ugordan on 08/16/2011 08:47 PM
Yes, it *was* published today. Usually it takes them about a month to publish an image advisory, this time they outdid themselves I'd say. Could have at least made a color composite in the meantime.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/19/2011 08:47 PM
Quote
Cassini Significant Events 08/10/11 - 08/16/11


The most recent spacecraft telemetry was acquired on August 16 from the Deep Space Network tracking complex at Goldstone, California. The Cassini spacecraft is in an excellent state of health and all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Wednesday, Aug. 10 (DOY 222)

This week in science was dominated by observations of Saturn by the Composite Infrared Spectrometer (CIRS), the Imaging Science Subsystem (ISS), and the Visual and Infrared Mapping Spectrometer (VIMS) while the spacecraft was near apoapsis in its orbit. The observations were designed to track wind speeds and study atmospheric composition. The Ultraviolet Imaging Spectrograph (UVIS) also performed an observation to study the upper atmosphere of Saturn, and ISS and VIMS observed Titan twice (1.5 hr each) as part of the cloud monitoring campaign. ISS made a 14-hour observation of the small irregular outer moon Tarqeq to study its light curve.

Thursday, Aug. 11 (DOY 223)

In the last week, 771 ISS images and 43 VIMS cubes were generated and distributed.

Monday, Aug. 15 (DOY 227)

The Navigation Team delivered an orbit determination (OD) solution today in support of an unplanned Saturn/Hyperion live Inertial Vector Propagator (IVP) update, tentatively scheduled for uplink on DOY 230. The need for this live IVP update was not predicted at the start of S69, but pointing offsets were discovered resulting from small execution errors at OTM-287 that propagated as trajectory dispersions over the nearly two months since OTM-287.
 
Tuesday, Aug. 16 (DOY 228)

Commands were uplinked to the spacecraft today over Goldstone’s DSS-15 station in support of S69 for the Cosmic Dust Analyzer (CDA) parameter update due to execute on DOY 234. This parameter adjustment is done to avoid saturating one of the instrument's detectors.
 
The Spacecraft Operations (SCO) team delivered the Cassini Operations Reference Encyclopedia (CORE) V6.1 software today. This is the command and flight rules dictionary. Analysts are given the opportunity to view command and flight rule information associated with a particular sequence through formatted Oracle queries. CORE was updated to remove unused telemetry channel hyperlinks in displayed commands and printed reports.
 
A kickoff meeting was held today for the S72 Sequence Implementation Process. Port 1 for the first set of input files from the teams occurs August 31.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/23/2011 12:24 PM
NASA has published a new image...

Dione Decoration
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4342
Title: Re: NASA - Cassini updates
Post by: apace on 08/23/2011 12:26 PM
Wow! Cool, love this pictures... what a stunning view... want to be there in real!
Title: Re: NASA - Cassini updates
Post by: kevin-rf on 08/23/2011 12:32 PM
...The profanity filter just filtered out my response ... now to get my drink off the monitor and the drool out of the keyboard ;) WOW!
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/25/2011 09:51 PM
Quote
Cassini Significant Events 08/17/11 - 08/23/11

The most recent spacecraft telemetry was acquired on August 23 from the Deep Space Network tracking complex at Madrid, Spain. The Cassini spacecraft is in an excellent state of health and all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Wednesday, Aug. 17 (DOY 229)

Science highlights this week focused on Saturn atmospheric observations while on approach to periapsis. The Composite Infrared Spectrometer (CIRS) measured oxygen compounds in Saturn’s stratosphere as a function of latitude and performed a mid-IR limb scan to measure stratospheric thermal structure. The Imaging Science Subsystem (ISS) and the Visual and Infrared Mapping Spectrometer (VIMS) built up their Saturn wind speed measurements by observing every ten minutes to make a mosaic in longitude. The Ultraviolet Imaging Spectrograph (UVIS) completed two EUV/FUV observations, slow scans across Saturn's visible hemisphere to form spectral images, and probe the upper atmosphere. VIMS observed an occultation of the star omiCet by Saturn. VIMS also made a nearly-20 hour observation at periapsis to measure the time variability of winds and study temporal variations of features comprising the String of Pearls (clearings in the clouds), the Saturn Ribbon feature, and the “smoke rings." These observations over two Saturn rotations will provide valuable information on the oscillatory nature of the pearls.

Thursday, Aug. 18 (DOY 230)

The Saturn/Hyperion live Inertial Vector Propagator (IVP) update sequence was uplinked today over Canberra’s DSS-43 station. The sequence is registered and activated on board and will begin execution on 234/17:18:19 SCET.

Friday, Aug. 19 (DOY 231)

An Autorad session was approved, enabled and frozen in preparation for an uplink demo on Wednesday, Aug. 24. Autorad is a tool used for the auto-radiation of some of the command files being sent to the spacecraft. A problem publishing the Autorad List XML file to the Data Systems Operations Team (DSOT) Distributed Object Manager (DOM) was discovered in the process, indicating a parameter change on the DSOT DOM since the last use of Autorad by Cassini real time operations.

Monday, Aug. 22 (DOY 234)

Orbit Trim Maneuver (OTM) #288 was performed today. This was the periapsis maneuver setting up for the Titan 78 encounter on Sept. 12. The Reaction Control Subsystem (RCS) burn began at 9:30 AM PDT. Telemetry immediately after the maneuver showed a burn duration of 83.75 seconds, giving a delta-V of 0.092 m/s. All subsystems reported nominal performance after the maneuver. The next maneuver, OTM288a, is scheduled to execute on September 1; still targeting T-78, it will clean up any dispersions resulting from OTM288.

The Mission Sequence System (MSS) team delivered the D14.3.1 software patch today. MSS software is used to generate sequence files and timelines for distribution as intermediate review products, and Sequence of Events, DSN Keyword File and the Space Flight Operations Schedule as formal review products. Also generated are the Command Packet File and the Command DSN file, which is the command file radiated to the spacecraft. This minor delivery was to identify and alert MSS users of improperly constructed array parameters in the Spacecraft Activity Sequence File (SASF).

Tuesday, Aug. 23 (DOY 235)

A mission planning forum was held today to discuss the official release of the updated reference trajectory by the navigation team. This update covers fiscal years 2013 and 2014 and allows for minor changes in DSN tracks and maneuver locations as well as minimizing changes to targeted flybys. This reference trajectory will be implemented starting with S72 which begins execution in January 2012.

The Spacecraft Operations Team (SCO) held an internal meeting today to review the progress on the Cassini Plasma Spectrometer (CAPS) problem. A Project follow-up meeting with the CAPS instrument team is tentatively scheduled for Sept. 22.

Non-targeted flybys of Epimetheus and Atlas occurred today.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/26/2011 05:56 PM
Quote
Cassini Closes in on Saturn's Tumbling Moon Hyperion

NASA's Cassini spacecraft captured new views of Saturn's oddly shaped moon Hyperion during its encounter with this cratered body on Thursday, Aug. 25. Raw images were acquired as the spacecraft flew past the moon at a distance of about 15,500 miles (25,000 kilometers), making this the second closest encounter.

Hyperion is a small moon -- just 168 miles (270 kilometers) across. It has an irregular shape and surface appearance, and it rotates chaotically as it tumbles along in orbit. This odd rotation prevented scientists from predicting exactly what terrain the spacecraft's cameras would image during this flyby.

However, this flyby's closeness has likely allowed Cassini's cameras to map new territory. At the very least, it will help scientists improve color measurements of the moon. It will also help them determine how the moon's brightness changes as lighting and viewing conditions change, which can provide insight into the texture of the surface. The color measurements provide additional information about different materials on the moon's deeply pitted surface.

The latest raw images of Hyperion are online at: http://saturn.jpl.nasa.gov/photos/raw/ .

Cassini's closest encounter with Hyperion was on September 26, 2005, when the spacecraft flew approximately 310 miles (500 kilometers) above the moon's surface.
Cassini's next flyby of Hyperion will be on Sept. 16, 2011, when it passes the tumbling moon at a distance of about 36,000 miles (58,000 kilometers).

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .


http://www.jpl.nasa.gov/news/news.cfm?release=2011-266&cid=release_2011-266&msource=11266&tr=y&auid=9384568
Title: Re: NASA - Cassini updates
Post by: Robotbeat on 08/26/2011 06:06 PM
Love the raw images!

I wish we had them for Dawn, too.

I'm excited about having "raw" color images from MSL!
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/26/2011 07:53 PM
Heres a sample of some of the images

Title: Re: NASA - Cassini updates
Post by: ugordan on 08/27/2011 04:19 PM
Hyperion in approximately natural color:
Title: Re: NASA - Cassini updates
Post by: NavySpaceFan on 08/27/2011 04:31 PM
Quote from: CAPT Spock
Hyperion is class "D'. It consists of various unremarkable ores. Essentially, a great rock in space.

 ;D
Title: Re: NASA - Cassini updates
Post by: ugordan on 08/27/2011 08:22 PM
Quote from: CAPT Spock
Hyperion is class "D'. It consists of various unremarkable ores. Essentially, a great rock in space.

 ;D

For most other rocks you might be right, but you couldn't be more off on this one. With a density of just over 1/2 that of ice, it's neither rock nor unremarkable  ;D
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/30/2011 07:00 PM
A new image has been released!

A New Crater for Titan
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4354

Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/02/2011 11:39 AM
Quote
Cassini Significant Events 08/24/11 - 08/30/11

The most recent spacecraft telemetry was acquired on August 30 from the Deep Space Network tracking complex at Goldstone, California. The Cassini spacecraft is in an excellent state of health and all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Wednesday, Aug. 24 (DOY 236)

The Autorad test scheduled for today was cancelled due to Master Equatorial Controller (MEC) problems at the DSN’s Goldstone DSS-14 station, resulting in the antenna being unable to move to the required azimuthal position. This test will be re-scheduled once the Distributed Object Manager (DOM) changes are complete and DSS-14 is operational.

A non-targeted flyby of Titan occurred today.

Thursday, Aug. 25 (DOY 237)

A flyby of Hyperion occurred today. It was non-targeted, but at a distance of 25,000 kilometers (about 16,000 miles), it was still the second closet encounter with Hyperion in the mission.

Highlights in science data acquisition this week included an observation of Saturn’s aurora by the Ultraviolet Imaging Spectrograph (UVIS) followed by a two hour UVIS calibration activity using the star Spica. A relatively close Hyperion flyby (24,979 km) was used for imaging and spectroscopic observations by Imaging Science (ISS), the Composite Infrared Spectrometer (CIRS), the Visual and Infrared Mapping Spectrometer (VIMS), and UVIS. This was followed by a 15 hour observation of the E and G rings, and a 14.5 hour observation of the faint rings at low elevation angles and low phase performed by VIMS, CIRS and ISS. The Magnetometer performed an 8 hour calibration while the spacecraft rolled about its X-axis, and the Cosmic Dust Analyzer (CDA) completed a 22 hour interstellar dust observation. ISS, CIRS and VIMS performed an observation in support of the Titan monitoring campaign, and ISS performed astrometric observations of a selection of Saturn's small inner moons.

Friday, Aug. 26 (DOY 238)

A feature story called “Cassini Closes in on Saturn’s Tumbling Moon Hyperion” is available on the Cassini web site. It describes how the spacecraft captured new views of Saturn’s oddly shaped moon Hyperion during its encounter with this cratered body on Thursday, Aug. 25. Detailed images were acquired as the spacecraft flew past the moon at a distance of about 25,000 kilometers, making this the second closest encounter with Hyperion in the mission. For images and more information on this subject, link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20110826/.

Saturday, Aug. 27 (DOY 239)

The videos that accompany the Cassini Scientist for a Day essay contest are now live and available on the Cassini website. The three essay topics this year are Hyperion, Rhea and Titan, and Saturn.

The contest is open to students in grades 5-12 and the deadline for submissions is Oct. 26, 2011. For more information on this subject, go to: http://saturn.jpl.nasa.gov/education/scientistforaday10thedition/targets/.

Monday, Aug. 29 (DOY 241)

The first set of five instrument expanded block (IEB) files was radiated to the spacecraft today over Madrid’s DSS-65 station in support of the S70 background sequence. The S70 sequence will be uplinked on DOY 247 and goes active on DOY 250

The Downlink Ground System (DGS) team successfully completed the DOM Virtual Internet Protocol (IP) changes today. The Cassini Operational DOM was temporarily unavailable in order to update the DOM with a virtual IP and related configuration changes. And since there are several Cassini tools with dependencies on the OPS DOM, aliveness testing was performed prior to the OPS DOM resuming normal operations.

The Science Forum for S72 was held today. Topics included an overview of science planned for this sequence followed by highlights, unique activities, and highest priority observations as described by the Target Working Team (TWT) and Orbiter Science Team (OST) leads, with comments from the Investigation Scientists and other instrument team representatives.

Tuesday, Aug. 30 (DOY 242)

A mission planning forum was held today to discuss an analysis of trajectory dispersions and uncertainties for the F-ring and proximal orbits performed by the Navigation team. The analysis showed the range of timing and position dispersions which may occur during these orbits. The science and engineering teams will use this information to plan for the F-ring and proximal orbit sequences.

The DGS team completed Data Monitor and Display (DMD) cleanup updates which were installed on all DMD machines in a Cassini test environment, in preparation for user testing. In order to see the DMD page updates on the DMDs, users were instructed to use a "root menu" to bring up the desired DMD. The DMD pages have updated labels, fixed plots, and undefined channels removed, and Broadcast telemetry tools have been replaced with Multicast on the root menus.

The most recent Cassini-Huygens Analysis and Results of the Mission (CHARM) teleconference was held today. The topic: "Cassini Huygens Mission to Saturn Seventh Anniversary -- Part 2 – Highlights of Rings and Dust Science." A PDF of the presentation package may be obtained at: http://saturn.jpl.nasa.gov/video/products/MultimediaProductsCharm/.

An audio recording of the presentation was made and will be linked to the same location within a few days

Orbit Trim Maneuver (OTM) #288a, an apoapsis maneuver scheduled for Sept. 1, was cancelled today based on the current trajectory estimate being very close to the desired orbit for the upcoming Titan encounter on Sept. 12.

The final set of IEB files was radiated to the spacecraft today over Goldstone’s DSS-14 station in support of the S70 background sequence. Files were verified and confirmed to have been properly uploaded to the Solid State Recorder (SSR).
Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/02/2011 04:40 PM
Rev153: Sep 3 - Sep 22 '11

http://www.ciclops.org/view/6866/Rev153?js=1
Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/05/2011 04:10 PM
Dione Up Front

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4355
Title: Re: NASA - Cassini updates
Post by: ugordan on 09/05/2011 04:34 PM
Here's a color version of that:
Title: Re: NASA - Cassini updates
Post by: robertross on 09/06/2011 12:35 AM
Here's a color version of that:

imagine being on a spacecraft, and you're coming up on that....wow.
Title: Re: NASA - Cassini updates
Post by: Nomadd on 09/08/2011 08:06 PM
Ok. I've been looking at Saturn since I was six and have never seen anything like this before.
http://www.tecca.com/news/2011/09/08/nasa-cassini-saturn-photograph/
Title: Re: NASA - Cassini updates
Post by: aquanaut99 on 09/08/2011 08:10 PM
Ok. I've been looking at Saturn since I was six and have never seen anything like this before.
http://www.tecca.com/news/2011/09/08/nasa-cassini-saturn-photograph/

Oh. My. God.

Simply the most awesome pic of Saturn I've ever seen.
Title: Re: NASA - Cassini updates
Post by: robertross on 09/09/2011 01:56 AM
Ok. I've been looking at Saturn since I was six and have never seen anything like this before.
http://www.tecca.com/news/2011/09/08/nasa-cassini-saturn-photograph/

Oh. My. God.

Simply the most awesome pic of Saturn I've ever seen.

I'll second that!

wow.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/09/2011 06:46 AM
Quote

Cassini Significant Events 08/31/11 - 09/06/11

The most recent spacecraft telemetry was acquired on September 6 from the Deep Space Network tracking complex at Goldstone, California. The Cassini spacecraft is in an excellent state of health and all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Wednesday, Aug. 31 (DOY 243)


This week, members of the Cassini Outreach team are supporting the GRAIL Mission launch Education and Public Outreach activities at the Kennedy Space Center.

Today, the Instrument Operations System (IOS) Multi-Mission T2 hardware which hosts the File Exchange Interface (FEI), the Spacecraft, Planet, Instruments, C-matrix, and Events (SPICE) software and password servers crashed, possibly related to an Information Technology (IT) Security scan. The host was rebooted, and servers were restarted throughout the day. Users running FEI subscriptions were required to restart their processes.

Thursday, Sept. 1 (DOY 244)

 
An encounter strategy meeting was held today to cover the period from Sept. 12 to Oct. 1, Titan flyby T-78 to Enceladus encounter E-14, and maneuvers 290-292.

Port 1 products were due today as part of the S72 Sequence Implementation Process (SIP). The products will be merged and sent out to the flight team for review.

A Cassini System Engineering Team (CSET) meeting was held today to discuss ground system plans for next Fiscal Year (FY12). Each team / office discussed its activities for the coming year including hardware adjustments, software deliveries, any other changes, and loose ends from this year's efforts that will be tied up next year.

Sunday, Sept. 4 (DOY 247)

 
The S70 background sequence was uplinked today over Goldstone’s DSS-15 station. S70 has been properly registered on-board the spacecraft and will start executing on 2011-250T00:48:00.

Monday, Sept. 5 (DOY 248)


In this week’s science observations, the Cosmic Dust Analyzer (CDA) performed three 13.5 hour interstellar dust observations in the apoapsis portion of the orbit. Imaging Science (ISS), the Composite Infrared Spectrometer (CIRS) and the Visual and Infrared Mapping Spectrometer (VIMS) performed an observation in the Titan monitoring campaign, and ISS made astrometric observations of several of Saturn's small inner moons. ISS also performed a satellite search in the L5 Lagrangian region of Iapetus; this is the region in Iapetus's orbit, 60 degrees behind Iapetus, that is a stable location for additional moons. Tethys and Dione have moons at their corresponding Lagrangian points. Finally, several of the fields-and-particles instruments completed a 9-hour dedicated measurement of the outer portion of Saturn's magnetosphere. These activities concluded the S69 sequence science activities.

Tuesday, Sept. 6 (DOY 249)

 
Orbit Trim Maneuver (OTM) #289, the final T-78 targeting maneuver scheduled for Sept. 8, was cancelled today. The delta-V predictions for two reaction wheel biases that preceded the maneuver were accurate and the current trajectory estimate came close to the desired target; hence, OTM-289 was not needed.

Title: Re: NASA - Cassini updates
Post by: kevin-rf on 09/09/2011 05:23 PM
Here's a color version of that:

imagine being on a spacecraft, and you're coming up on that....wow.

That's why I have always believed Saturn would be the best tourism destination in the solar system. (Of course, you will really appreciate it after riding through space with nothing but a starry sky for several years).

Anyone know what the little blip in the ring above Dione is?
Title: Re: NASA - Cassini updates
Post by: Nomadd on 09/09/2011 08:26 PM
 Turns out I'm a little out of date on that backlit Saturn photo. Yahoo News' version of "Stunning new image" apparently includes pictures from 2006.
Title: Re: NASA - Cassini updates
Post by: Robotbeat on 09/09/2011 08:32 PM
Turns out I'm a little out of date on that backlit Saturn photo. Yahoo News' version of "Stunning new image" apparently includes pictures from 2006.
Yeah, it's a new "Astronomy Picture of the Day" (APOD), but it was taken years ago. I saw this much earlier, and yes, it is amazing!
Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/13/2011 10:11 AM
Quintet of Moons

http://photojournal.jpl.nasa.gov/jpegMod/PIA14573_modest.jpg
Title: Re: NASA - Cassini updates
Post by: Robotbeat on 09/13/2011 04:09 PM
Wow, that is poetic!
Title: Re: NASA - Cassini updates
Post by: ugordan on 09/13/2011 04:37 PM
Here's one fresh off the raw page by yours truly. Narrow-angle camera RGB shot of Titan's south polar haze taken from a distance of 116 thousand km. I think the reddish star visible might be "Chi Aquarii, a 4.93-magnitude, red-giant star in the constellation Aquarius" as per the Looking Ahead article.

I love the contrast in hues between the high altitude blue haze and the "smog" layers below.
Title: Re: NASA - Cassini updates
Post by: Jason1701 on 09/13/2011 06:07 PM
I used a Titan atmosphere picture taken by Huygens as a background for a poster once. Pictures like that are beautiful.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/16/2011 07:52 AM
Quote
Cassini Significant Events 09/07/11 - 09/13/11

The most recent spacecraft telemetry was acquired on September 13 from the Deep Space Network tracking complex at Canberra, Australia. The Cassini spacecraft is in an excellent state of health and with the exception of one science instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Wednesday, Sept. 7 (DOY 250)

The S70 sequence began execution today at 2011-250T00:48. The sequence will run for 69 days and conclude on November 15. During that time there will be ten segments; four cross-discipline, four Satellite Orbiter Science Team (SOST), one Titan Orbiter Science Team (TOST) and one Magnetospheric and Plasma Science (MAPS) segment, with four targeted encounters – one Titan (T-78) and three Enceladus (E-14, E-15, and E-16). Also, eleven Orbit Trim Maneuvers (OTMs) are scheduled, numbered 289 through 299.

Friday, Sept. 9 (DOY 252)

This week in science began with the S70 background sequence going active, and included two observations in the Titan monitoring campaign and two sets of astrometric observations of several of Saturn's small inner moons by Imaging Science (ISS). Also, many of the fields-and-particles instruments performed two sets of dedicated measurements of the outer portion of Saturn's magnetosphere. ISS made a 21 hour light curve observation of the outer irregular moon Paaliaq. Leading up to the T-78 flyby, the Composite Infrared Spectrometer (CIRS) made a 12 hour observation of Saturn to measure oxygen compounds in the stratosphere. Following T-78 and approaching periapsis, ISS, CIRS and the Ultraviolet Imaging Spectrograph (UVIS) observed the plume of Enceladus and then the disk of Enceladus from ~42,000 km, and UVIS made measurements of Enceladus' footprint in the auroral region of Saturn.

Saturday, Sept. 10 (DOY 253)

The main engine cover was closed today; performance was normal.

Monday, Sept. 12 (DOY 255)

Cassini encountered Titan (T-78) today at an altitude of 5,821 kilometers and a speed of 5.8 km/sec. The primary observations of the T-78 flyby included CIRS far-IR limb sounding at high latitudes. In addition, UVIS performed a solar occultation experiment, and the visible and infrared mapping spectrometer (VIMS) observed a stellar occultation by Titan's atmosphere of the star R-Aqr. The measurements taken will allow scientists to constrain the composition and the spectral properties of Titan's atmosphere.

The Enceladus/Pallene live Inertial Vector Propagator (IVP) update mini-sequence was uplinked today over Goldstone’s DSS-14 station in support of S70. The mini-sequence is registered and activated on board and will begin execution on 2011-256T08:32:31 SCET.

Port 3 products were due today as part of the S71 Sequence Implementation Process (SIP). The products will be merged and sent out to the flight team for review for both the original sequence with CAPS turned on, and the alternate T-79 flyby sequence to be used in case the CAPS instrument is not turned back on prior to the T-79 flyby.

Tuesday, Sept. 13 (DOY 256)

The Spacecraft Operations Team (SCO) held a meeting today to update the Cassini Plasma Spectrometer (CAPS) personnel on the most recent results from JPL analysis of the Cassini bus voltage imbalance (reference ISA 48671, PFR 49275). Analysis is still on-going, but CAPS remains off for now.

A mission planning forum was held today to discuss operations concepts for the F-ring and proximal orbits. Given the trajectory dispersions and uncertainties predicted for these orbits, concepts such as more frequent live updates, a shorter sequence process, and accepting new orbit determination solutions during the sequencing process were discussed. Feedback on these concepts was requested from all teams. The feedback will be used in establishing the final operations processes to be used for the F-ring and proximal orbits.

Non-targeted flybys of Rhea, Tethys, Pandora, Enceladus, and Janus occurred today.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/19/2011 10:06 AM
A few new images are up

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4365
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4364
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4363
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4362
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4361
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4360
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4359
Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/20/2011 12:12 PM
Another new image

Rhea Lit at Night
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4366
Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/23/2011 08:52 AM
Quote
Cassini Significant Events 09/14/11 - 09/20/11

The most recent spacecraft telemetry was acquired on September 20 from the Deep Space Network tracking complex at Canberra, Australia. The Cassini spacecraft is in an excellent state of health and with the exception of one science instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Wednesday, Sept. 14 (DOY 257)

The main engine cover was closed on Saturday, Sept. 10, for dust hazard avoidance, and was opened today. This was the 65th in-flight cycle of the cover.

Non-targeted flybys of Methone, Pallene, and Telesto occurred today.

Thursday, Sept. 15 (DOY 258)

Orbit Trim Maneuver (OTM) #290, the T78 cleanup maneuver scheduled for execution today, was found to be unnecessary and was canceled.

Port 2 products were due today as part of the S72 Sequence Implementation Process (SIP). The products will be merged and sent out to the flight team for review.

A non-targeted flyby of Hyperion occurred today.
 
Friday, Sept 16 (DOY 259)

A feature story called “Cassini Presents Saturn Moon Quintet” is available on the Cassini web site. It describes how with the artistry of a magazine cover shoot, the Cassini spacecraft captured a portrait of five of Saturn’s moons poised along the planet’s rings in a single image. The image was taken in visible green light with the Cassini spacecraft narrow-angle Camera on July 29, 2011. The view was acquired at a distance of approximately 1,100,000 km from Rhea and 1,800,000 km from Enceladus. For more information on this subject and to see the image, link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature200110916/.

Saturday, Sept. 17 (DOY 260)
 
Science activities this week kicked off with Cassini's best-ever opportunity to observe the tiny moon Pallene (at ~26,000 km altitude) by the remote sensing instruments (ISS, UVIS, CIRS and VIMS), followed by two observations of Tethys to study the leading hemisphere of this moon and understand interactions with the energetic electrons in the system. Three observations in the Titan monitoring campaign were performed. Imaging Science (ISS), the Composite Infrared Spectrometer (CIRS) and the Visual and Infrared Mapping Spectrometer (VIMS) performed observations of Saturn's faint outer rings (the E ring and the G ring arc) while close to the ring plane. A relatively close flyby of Hyperion (observations made as close as ~90,000 km altitude) followed; observations were made as part of the Scientist for a Day (SFAD) Program. SFAD observations were also made of the transit of the icy moon Tethys across the giant moon Titan. ISS later performed astrometric observations of some of Saturn's small inner moons, and the Magnetometer (MAG) performed an 8 hour calibration with the spacecraft rolling about its X-axis. ISS observed the transits of Enceladus and then Dione across Titan for satellite orbit determination purposes, and then two interstellar dust observations were performed by the Cosmic Dust Analyzer (CDA). The Ultraviolet Imaging Spectrograph (UVIS) performed a 16 hour scan of Saturn’s magnetosphere to study the distribution of the neutral species oxygen and hydrogen.

Monday, Sept. 19 (DOY 262)

Orbit Trim Maneuver (OTM) #291 was performed today. This was the apoapsis maneuver setting up for the Enceladus 14 encounter on Oct. 1. The main engine burn began at 9:45 PM PDT. Telemetry immediately after the maneuver showed a burn duration of 29.42 seconds, giving a delta-V of 5.054 m/s. All subsystems reported normal performance after the maneuver.

Tuesday, Sept. 20 (DOY 263)

Members of the Science Planning and Sequencing Team (SPST) presented early results on some initial modeling of CIRS and VIMS heating violations during the proximal orbits in preparation for a presentation at the upcoming Cassini Project Science Group Meeting (PSG) #55, scheduled for the week of Oct. 24-28, 2011.

Non-targeted flybys of Rhea, Tethys, Pandora, Enceladus, and Janus occurred today.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/23/2011 09:43 AM
Rev154: Sep 22 - Oct 10 '11

http://www.ciclops.org/view/6911/Rev154
Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/26/2011 07:55 PM
East of Huygens

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4369
Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/29/2011 03:30 PM
The Dione Atlas

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4370
Title: Re: NASA - Cassini updates
Post by: racshot65 on 09/29/2011 03:47 PM
Quote
Cassini Significant Events 09/21/11 - 09/27/11

The most recent spacecraft telemetry was acquired on September 27 from the Deep Space Network tracking complex at Madrid, Spain. The Cassini spacecraft is in an excellent state of health and with the exception of one science instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.


Wednesday, Sept. 21 (DOY 264)

An encounter strategy meeting was held today to cover the period between Oct. 1 and Oct. 19, Enceladus encounters E-14 and E-15, and maneuvers 294 and 295 in S70.

A feature story called “Saturn’s Moon Enceladus Spreads Its Influence” is available on the Cassini web site. It describes how the small, dynamic moon spews out plumes of water vapor and ice, first detected by the magnetometer on the Cassini spacecraft in 2005. Enceladus has simple organic particles and may house liquid water beneath its surface. Its geyser-like jets create a gigantic halo of ice, dust and gas around Enceladus that helps feed Saturn’s E ring. Thanks to those icy jets, Enceladus is the only moon in our solar system known to substantially influence the chemical composition of its parent planet. For more information on this subject, link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20110921/.

A software point delivery for the Cassini Information Management System (CIMS) was delivered and installed today. Several enhancements were provided as part of this CIMS V3.7 release, which are referenced in approved engineering change requests (ECRs) 111988, 111990, 112011, 112010, and 112008.


Thursday, Sept. 22 (DOY 265)

The post Orbit Trim Maneuver 291 orbit solution was completed, and based on its results the Navigation team recommended that OTM-292 be executed. OTM-292 is the Enceladus (E-14) approach maneuver, scheduled to execute Wednesday, Sept. 28. OTM294 and OTM295 follow on Oct. 4 and Oct. 9, respectively. There is no OTM293 maneuver, this number was skipped to maintain the “modulo 3” numbering nomenclature.

The command loss timer reset command sent to the spacecraft today was received with a frame header error. A double error was detected and a single error was corrected; nevertheless, the command loss timer was properly reset.

The Multi-mission Ground Systems and Services Office (MGSS) conducted the Software Delivery and Deployment Review (DDR) for the Instrument Operations System/Multi Mission Image Processing Laboratory (IOS/MIPL) D40 today, where the delivery was approved for Cassini operations.


Friday, Sept. 23 (DOY 266)

Science highlights this week included satellite searches near the Rhea and Dione L5 Lagrange points performed by the Imaging Science (ISS) and the Visual and Infrared Mapping Spectrometer (VIMS). The Ultraviolet Imaging Spectrograph (UVIS) made two system scan measurements, mapping out the neutral oxygen and hydrogen in the inner Saturn system. ISS performed astrometric observations of some of Saturn's small inner moons as well as a Saturn observation as part of the Scientist for a Day (SFAD) program. The Cosmic Dust Analyzer (CDA) performed two interstellar dust observations, and ISS observed Titan for six hours as part of a long range monitoring campaign. The Composite Infrared Spectrometer (CIRS) made measurements of the composition of Titan’s atmosphere for six hours, and ISS and UVIS concluded the week with a 15 hour observation of the outer irregular moon Skoll.


Saturday, Sept. 24 (DOY 267)

Today a downlink processing job stalled while interacting with the IO/MIPL database, apparently due to simultaneous attempts to access a data set in the database. This froze interactions to some of the tables and prevented automated jobs from running. Processes were killed in order to free up the access, and processing was manually recovered on Monday.


Monday, Sept. 26 (DOY 269)

The Cassini Project is preparing to release a new set of Dione Atlas images and PDFs on Wednesday, Sept. 28. They’ll be available at the following link, as well as in the Photojournal, JPL’s image website:

http://saturn.jpl.nasa.gov/video/products/MultimediaProductsDetailCartography/dioneglobalmaps/.


Tuesday, Sept. 27 (DOY 270)

A mission planning forum was held today to discuss dust hazards and propellant budgets status. The dust hazards for the remainder of the mission and changes in the hazards due to the 110818 reference trajectory release were reviewed. Dust hazards occur when the spacecraft flies through a region which may contain dust particles large enough to cause damage to the spacecraft and the risk is sufficient to warrant protective measures. A consumables status is provided on a regular basis so the Project can maintain cognizance of propellant usage and end of mission margins.

The most recent Cassini-Huygens Analysis and Results of the Mission (CHARM) teleconference was held today. The topic: "A Year in the Life of Cassini." A PDF of the presentation package may be obtained at: http://saturn.jpl.nasa.gov/video/products/MultimediaProductsCharm/. An audio recording of the presentation was made and will be linked to the same location within a few days.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 10/03/2011 07:21 PM
Some images are up from the Enceladus flyby

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4373
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4374
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4378
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4377
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4375
Title: Re: NASA - Cassini updates
Post by: racshot65 on 10/06/2011 09:17 PM
Quote
Cassini Significant Events 09/28/11 - 10/04/11

The most recent spacecraft telemetry was acquired on Oct.4 from the Deep Space Network tracking complex at Canberra, Australia. The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.


Wednesday, Sept. 28 (DOY 271)

Orbit Trim Maneuver (OTM) #292 was performed today. This was the approach maneuver setting up for the Enceladus 14 encounter on Oct. 1. The Reaction Control Subsystem (RCS) burn began at 7:30AM PDT. Telemetry immediately after the maneuver showed a burn duration of 26.75 seconds, giving a delta-V of 0.033 m/s. This OTM required two reaction wheel biases to avoid the low RPM region. All subsystems reported nominal performance after the maneuver.

The alternate timeline for the T-79 encounter was selected in time for the S71 Sequence Change Requests (SCRs) being submitted for the Preliminary Sequence Integration and Validation (PSIV) step, which were due today. The Project Scientist decided to recommend the alternate, non-Cassini Plasma Spectrometer (CAPS) option for the T-79 flyby, with careful consideration given to the one or two other Titan flybys existing in the remainder of the Solstice mission that provide similar geometries for CAPS Titan science. Titan's environment is temporally variable, however, and the loss of the T-79 flyby for CAPS will result in the loss of key Titan magnetospheric science. Until a final decision is made regarding future CAPS turn-ons, the plan is for CAPS to schedule observations and request data volume in all future sequences assuming that it will be on, with case-by-case dual options such as the T-79 flyby if schedule and workforce resources permit. It has also been recommended that, at the appropriate point in the sequencing process, if it is clear that CAPS will not be on for that sequence, the CAPS downlink bits are reallocated to other instruments as sponge bits.

A non-targeted flyby of Titan occurred today.


Thursday, Sept. 29 (DOY 272)

This week's science observations included a 10 hour observation of Saturn in order to measure oxygen compounds (H2O, CO2) in the stratosphere by the Composite Infrared Spectrometer (CIRS). The Ultraviolet Imaging Spectrograph (UVIS) later performed a 9 hour observation of Saturn’s aurora and the remote sensing instruments made measurements of Dione and its trailing hemisphere "wispy terrain." The E-14 Enceladus flyby followed with Enceladus observations during the encounter. This was then followed by further observations of Dione, this time of the leading hemisphere, and searches for objects in the L4 Lagrangian regions of Enceladus' and Titan's orbits. On the final day of the week, astrometric observations were made of some of Saturn's small inner moons, Rhea was observed passing in front of Titan, Titan itself was observed as part of the cloud monitoring campaign, and CIRS made an additional stratospheric compositional measurement of Saturn.

The Attitude and Articulation Control Subsystem (AACS) Safe Table value was updated to -30 degrees today.


Friday, Sept. 30 (DOY 273)

Cassini Real Time Operations (RTO) conducted the final Autorad demonstration and Ace procedure validation today. Autorad is now considered an operational command utility for Cassini. First use of the Autorad tool in operations will begin in S71. The S71 sequence team leads will use Autorad for the uplink of the S71 Instrument Expanded Block (IEB) files. Autorad is a tool used for the autonomous radiation of some of the command files being sent to the spacecraft.

A non-targeted flyby of Titan occurred today.


Saturday, Oct. 1 (DOY 274)

Today Cassini flew by Enceladus at an altitude of 99 kilometers and a speed of 7.4 km/sec. This close flyby of the south pole featured fields and particles instruments learning more about the nature and density of the particles in the plumes, with high-phase observations of the south polar plume and jets, and the Ion and Neutral Mass Spectrometer (INMS) measurements of plume & jet gas density, with measurements by other fields-and-particles instruments as well. On the outbound leg of the flyby, CIRS and the other remote sensing instruments made thermal and compositional measurements of Enceladus' equatorial and northern regions during and after eclipse. Remote sensing instruments also looked for changes in the level of activity on Enceladus. For more information and raw images, link to: http://saturn.jpl.nasa.gov/mission/flybys/enceladus20111001/.

Non-targeted flybys of Epimetheus and Calypso occurred today.


Sunday, Oct. 2 (DOY 275)

The main engine cover was closed on Thursday, Sept. 29, for dust hazard avoidance and was opened today. This was the 66th in-flight cycle of the cover.

IO/MIPL provided members of the Cassini Media Relations team file transfer software (FEI5) and access to the Imaging Science Subystem (ISS) web JPEG index file. This file provides the mapping between products the ISS team delivers to Media Relations and the metadata needed to describe those products. This file was successfully used to expedite posting flyby images from the E-14 flyby on the Cassini website (http://saturn.jpl.nasa.gov/).


Monday, Oct. 3 (DOY 276)

A feature story called “Saturn’s Geyser Moon Enceladus Shows Off for NASA’s Cassini” is available on the Cassini web site. It describes how the Cassini spacecraft successfully completed its Oct. 1 flyby of Saturn's moon Enceladus and its jets of water vapor and ice. For images and more information on this subject, link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature200111003/.

The Division for Planetary Sciences (DPS) of the American Astronomical Society is holding its annual meeting this week in Nantes, France (Oct 3-7); many Cassini scientists are in attendance reporting on their most recent results. This meeting is to bring together the international community of specialists in the planetary sciences to present and discuss the latest results of research on the solar system.

AACS Periodic Engineering Maintenance was done today. This activity, performed approximately every 90 days, spins up the backup reaction wheel assembly to 100 rpm for lubrication purposes and exercises the back-up Engine Gimbal Actuator.

The S73 Engineering Activities Review was held today. At this review, Spacecraft Office personnel took a look at all spacecraft activities to be performed during the S73 sequence.


Tuesday, Oct. 4 (DOY 277)

OTM #294 was performed today. This was the clean up maneuver following Enceladus 14 and setting up for the Enceladus 15 encounter on Oct. 19. The Reaction Control Subsystem (RCS) burn began at 8:45PM PDT. Telemetry immediately after the maneuver showed a burn duration of 66.125 seconds, giving a delta-V of 0.074 m/s. All subsystems reported nominal performance after the maneuver.

OTM 295, the E15 approach maneuver, is scheduled to execute on Sunday, October 9. Afterwards, for four days beginning on Oct. 11, the spacecraft attitude control mode changes from a Reaction Wheel Assembly (RWA) mode to RCS mode as the spacecraft passes through solar conjunction with a minimum Sun Earth Probe (SEP) angle of 2.2 degrees.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 10/10/2011 07:46 PM
Pendent Pair

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4380
Title: Re: NASA - Cassini updates
Post by: racshot65 on 10/11/2011 03:06 PM
Rev155: Oct 10 - Oct 28 '11

http://www.ciclops.org/view/6923/Rev155
Title: Re: NASA - Cassini updates
Post by: racshot65 on 10/14/2011 08:26 AM
Quote
Cassini Significant Events 10/04/11 - 10/11/11

The most recent spacecraft telemetry was acquired on Oct. 11 from the Deep Space Network tracking complex at Canberra, Australia. The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.


Wednesday, Oct. 5 (DOY 278)

On Oct. 4-5, JPL held a teacher professional development workshop in Jonesborough, Tennessee. Twenty-five teachers from Washington County, Sullivan County, and Kingsport City schools participated in the two-day workshop. Members of the Cassini Spacecraft Operations Office (SCO), Outreach, and Program staff led hands-on activities using "Our Solar System Through the Eyes of Scientists" and other Cassini educational products and programs.

In support of the S73 sequence development, the Radar Team agreed to an early delivery of Pointing Design Tool (PDT) designs for Titan encounters T-83 and T-84 so the Attitude and Articulation Control Subsystem (AACS) Team can assess whether or not there are any control authority issues for these upcoming relatively low altitude flybys on thrusters. Similar concerns for future low Titan flybys will need to be resolved as soon as possible, before integrated segments are due.


Thursday, Oct. 6 (DOY 279)

Cassini Outreach and SCO team members conducted classroom visits at David Crockett High School in Jonesborough, Tennessee and University School in Johnson City, Tennessee, today.

Preliminary Sequence Integration and Validation (PSIV) Spacecraft Activity Sequence File (SASF) products were due today as part of the S71 Sequence Implementation Process (SIP). The products will be merged and the Science Planning Assessment (of the) Merge (SPAM) is due on Monday, Oct. 10.


Friday, Oct. 7 (DOY 280)

A telemetry mode overlay real time command was executed today to avoid losing playback data due to the loss of 2 hours and 25 minutes of DSN tracking time as a consequence of a late tracking schedule change.

Orbit Trim Maneuver (OTM) #295, the Enceladus 15 (E-15) approach maneuver scheduled for Sunday, Oct. 9, was cancelled at the preliminary Navigation Review meeting today. There was no science impact or propellant usage cost resulting from the cancellation.

The spacecraft will pass through solar conjunction next week, with a minimum Sun Earth Probe (SEP) angle of 2.2 degrees on Thursday, Oct. 13, about 1.95 degrees off the solar limb.

OTM 296, the E-15 cleanup maneuver, is scheduled to execute on Oct. 20.


Saturday, Oct. 8 (DOY 281)

The Instrument Operations System/Multi Mission Image Processing Laboratory (IOS/MIPL) completed development of upcoming Cassini Delivery 40 (CAS D40). The delivery will proceed to Integration and Test, and is scheduled to become operational in December 2011.


Monday, Oct. 10 (DOY 283)

This week, while the spacecraft approached apoapsis, science activities included an eight hour calibration performed by the Magnetometer (MAG) while the spacecraft rolled about its X-axis. This was followed by a series of five 12-hour scans of Saturn’s inner magnetosphere by the Ultraviolet Imaging Spectrograph (UVIS), the Imaging Science Subsystem (ISS), and the Visual and Infrared Mapping Spectrometer (VIMS), with the primary objective of mapping neutral species such as oxygen. ISS performed two sets of astrometric observations of some of Saturn's small inner moons, and the week concluded with Cassini entering the solar conjunction period.


Tuesday, Oct. 11 (DOY 284)

Solar conjunction begins today and continues through Sunday, Oct. 16. The Sun-Earth-Spacecraft angle is less than 3 degrees during this time. Attitude control was switched from reaction wheels to thrusters to facilitate a possible redistribution of lubrication in the wheel bearings during this time.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 10/17/2011 07:40 PM
The New South

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4382
Title: Re: NASA - Cassini updates
Post by: racshot65 on 10/19/2011 01:23 PM
Orion's Belt Lights Up Cassini's View of Enceladus

Quote
NASA's Cassini mission will take advantage of the position of two of the three stars in Orion's belt when the spacecraft flies by Saturn's moon Enceladus on Wed., Oct. 19. As the hot, bright stars pass behind the moon's icy jets, Cassini's ultraviolet imaging spectrograph will acquire a two-dimensional view of these dramatic plumes of water vapor and icy material erupting from the moon's southern polar region. This flyby is the mission's first-ever opportunity to probe the jets with two stars simultaneously, a dual stellar occultation. 

...

http://www.jpl.nasa.gov/news/news.cfm?release=2011-321
Title: Re: NASA - Cassini updates
Post by: racshot65 on 10/20/2011 07:33 PM
Some images from the Enceladus Flyby are up

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4389
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4394
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4393
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4390
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4387
Title: Re: NASA - Cassini updates
Post by: robertross on 10/21/2011 12:19 AM
The New South

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4382

SO interesting that this image has quite a few parallels to the images of Vesta.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 10/21/2011 07:32 AM
Quote
The most recent spacecraft telemetry was acquired on Oct. 18 from the Deep Space Network tracking complex at Madrid, Spain.  The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.


Wednesday, Oct. 12 (DOY 285)

A beautiful image of Saturn's rings forming a sundial on the planet's surface was Astronomy Picture of the Day today. It is available at:
http://apod.nasa.gov/apod/ap111012.html.
 
An encounter strategy meeting was held today to cover the period between Oct. 19 and Nov. 6, Enceladus encounters E15 and E16, and maneuvers 296-298 in S70.
 
The S71 Science Planning and Sequence Team (SPST) leads held a project tag-up meeting today to discuss the potential impact of incomplete DSN resource allocations by the Final Sequence Integration and Validation (FSIV) Sequence Change Request (SCR) need date later this month.  The Spacecraft Operations Office (SCO) agreed to plan real-time commands once final allocations are available in late November in order to protect high priority data such as T80 and the Saturn periapsis data.
 
Today the Attitude and Articulation Control Subsystem (AACS) control mode was changed from Reaction Wheel Assembly (RWA) to Reaction Control Subsystem (RCS) for solar conjunction. The attitude control system went into low rate mode for the first time since a flight software patch was loaded on July 7, 2011, to change the low rate timer from 10 minutes to 40 minutes.

 
Thursday, Oct. 13 (DOY 286)

Today the spacecraft passed through the mid-point of solar conjunction with a minimum Sun-Earth-Probe (SEP) angle of 2.2 degrees.  Ranging data was not used for navigation due to expected biases and the Doppler data was significantly de-weighted. Tracking data should be back to normal by Monday, Oct. 24, when the SEP angle rises above 10 degrees.
 
Target Working Team and Orbiter Science Team (TWT/OST) integrated products for S73, covering orbits 164 through 168 in April 2012 through June 2012, were delivered today. The integrated products include the first inclined revs of IN-1.
 
The Instrument Operations System/Multi Mission Image Processing Laboratory (IOS/MIPL) Kerberos server was upgraded to IOS D40 today, with no interruption to operations.

 
Friday, Oct. 14 (DOY 287)

Cassini Outreach and the JPL Public Service Office supported Pasadena ArtNight with two Art/Science activities at Pasadena's Kidspace Museum.  Over 1,000 kids took home their own chalk Saturn moon drawings and Solar System/Constellation art and stories.  This is a free evening event held in the fall, consisting of art, music and entertainment as Pasadena's most prominent arts and cultural institutions swing open their doors to the community.

 
Saturday, Oct. 15 (DOY 288)

The Downlink Ground System (DGS) team successfully completed testing of Acelog V2.0.1 in preparation for an upcoming Delivery Coordination Meeting (DCM) scheduled for Thursday, Oct. 27.  The DGS team also took over maintenance responsibility of the Instrument Operations (IO) Gap Summary Tool, a tool that identifies data gaps, by either Earth Received Time (ERT) or Spacecraft Event Time (SCET), that are greater than the specified time delta between adjacent records from an input file.

 
Sunday, Oct. 16 (DOY 289)

This week in science continued from last week with the spacecraft remaining Earth-pointed during solar conjunction when the Sun-Earth-Spacecraft angle is less than 3 degrees.  After Cassini exited solar conjunction, the Ultraviolet Imaging Spectrograph (UVIS), the Composite Infrared Spectrometer (CIRS) and the Visual and Infrared Mapping Spectrometer (VIMS) performed a 12 hour observation of Saturn's aurora, and the Imaging Science Subsystem (ISS), CIRS and VIMS performed two monitoring observations of Titan. Next up is the Enceladus (E15) flyby on Oct. 19.

 
Monday, Oct. 17 (DOY 290)

The main engine cover was closed today; performance was normal.

 
Tuesday, Oct. 18 (DOY 291)

A feature story called "Orion's Belt Lights Up Cassini's View of Enceladus" is available on the Cassini web site.  It describes how the Cassini spacecraft will take advantage of the position of two of the three stars in Orion's belt when the spacecraft flies by Enceladus on Wed., Oct. 19.  As the hot, bright stars pass behind the moon's icy jets, Cassini's ultraviolet imaging spectrograph will acquire a two-dimensional view of these dramatic plumes of water vapor and icy material erupting from the moon's southern polar region.  This flyby is the mission's first-ever opportunity to probe the jets with two stars simultaneously, a dual stellar occultation.  For images and more information on this subject, link to:
http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20111018/.
 
The next maneuver, Orbit Trim Maneuver (OTM) 296, the E15 cleanup maneuver, is scheduled to execute on Oct. 20.  OTM-297, targeting the 500 km altitude Enceladus 16 flyby on November 6, is scheduled for Oct. 28.

Title: Re: NASA - Cassini updates
Post by: racshot65 on 10/26/2011 03:03 PM
Map of Titan from April

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4396
Title: Re: NASA - Cassini updates
Post by: racshot65 on 10/28/2011 07:38 AM
Quote
Cassini Significant Events 10/19/11 - 10/25/11

The most recent spacecraft telemetry was acquired on October 25 from the Deep Space Network tracking complex at Madrid, Spain. The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Wednesday, Oct. 19 (DOY 292)

Today Cassini flew by Enceladus at an altitude of 1,231 kilometers and a speed of 7.4 km/sec. This flyby featured a dual stellar occultation in which the ultraviolet spectrograph observed two of the three stars that make up Orion's belt as they passed behind the moon's plumes. Scientists hope to better understand the density, composition, and variability of the jets from these observations. Infrared instruments and cameras also monitored activity on the moon. For more information and raw images, link to: http://saturn.jpl.nasa.gov/mission/flybys/enceladus20111019/.

Today the Instrument Operations System/Multi Mission Image Processing Laboratory (IO/MIPL) group expedited processing for the Enceladus 15 flyby, delivering images to the science team and raw image website during the downlink.

The main engine cover was closed on Monday, Oct. 17, for dust hazard avoidance, and was reopened today. This was the 67th in-flight cycle of the cover.

A non-targeted flyby of Telesto occurred today.

Thursday, Oct. 20 (DOY 293)

The Navigation Team found that the latest orbit solution had the spacecraft close enough to the reference trajectory after the E-15 flyby on Oct. 19 that execution of Orbit Trim Maneuver (OTM) #296, the E-15 cleanup maneuver, was not needed. OTM-296 was therefore canceled.
The next maneuver, OTM-297, targeting the 500 kilometer altitude Enceladus 16 flyby on November 6, is scheduled to execute on Oct. 28, and then is followed by OTM-298 and OTM-299, the E-16 approach and cleanup maneuvers, scheduled to execute Nov. 2 and Nov. 8 respectively. There's a possibility of canceling OTM-297 as well if the planned science observations can tolerate an ~70 kilometer miss at E-16. The Navigation team will give the science teams the current trajectory estimate to decide if it's close enough for their observations.

A number of Cassini scientists attended the Outer Planets Assessment Group (OPAG) meeting Oct. 19-20 in Pasadena, CA. This is a NASA-supported forum for scientists and engineers to discuss exploration of the outer solar system and to enhance communication between the science community and NASA.

The Cassini Project Scientist gave a Cassini Solstice Mission status report, and the slides are now available via direct link at: https://cassini.jpl.nasa.gov/projscimtg/docs/OPAG_Cassini_Report_Oct2011.pdf.  Additional links to the agenda and presentations are available on the OPAG website at: http://www.lpi.usra.edu/opag/.

Monday, Oct. 24 (DOY 297)
A week-long series of presentations and discussions begins today at the 55th meeting of the Cassini Project Science Group (PSG) held at JPL. The meeting objective and key theme is the Senior Review preparation and team budget discussions, and to review the status of the Solstice Mission activities.

Tuesday, Oct. 25 (DOY 298)

Science activities on the spacecraft this week began with Enceladus E-15 flyby observations as the suite of optical instruments observed the surface of the moon as well as its dramatic plume and jets. Half an hour before closest approach, the Ultraviolet Imaging Spectrograph (UVIS) took control of the spacecraft to observe two stars in Orion’s Belt, epsilon Ori and zeta Ori, as they passed behind the plume of Enceladus. This observation gave a measurement of the vertical structure in the plume, and will help in pinning down collimation of gas in the jets.

Once the occultation was completed, the Composite Infrared Spectrometer (CIRS) observed the surface of Enceladus as the spacecraft receded from the moon. Observations continued when Enceladus was in eclipse, i.e., in Saturn’s shadow, which provided a good opportunity for CIRS to investigate how different parts of Enceladus cool down during the eclipse and warm up again once sunlight returns.
After the Enceladus flyby, Imaging Science (ISS), CIRS, and the Visual and Infrared Mapping Spectrometer (VIMS) observed the G ring arc at low elevation and low phase angle for 10 hours, and UVIS performed a three hour calibration using the star Spica. ISS, CIRS and VIMS then performed a Titan monitoring observation, and ISS performed another couple of observations in its Satellite Orbit Campaign, making astrometric measurements of some of Saturn's small inner moons.

ISS made a 15-hour observation of the lightcurve of the outer irregular moon, Loge, and CIRS later created a 23 hour mid-infrared map of Saturn to determine upper troposphere and tropopause temperatures.
Cassini lastly began a new phase of Titan observations known as Titan Exploration at Apoapsis, or TEA, whose primary objective is to acquire ISS and VIMS images at low phase angle in order to detect and monitor the evolution of clouds on Titan, and to detect new molecules and their isotopes in Titan's stratosphere using long integrations with the CIRS instrument.

TEAs are continuous observations over periods of up to 37 hours and repeated over the course of one week. This series of TEAs was primarily dedicated to atmospheric composition and began with a 19 hour and a 13 hour observation by CIRS and ISS, ending this week’s observations.
The S71 Final Sequence Integration and Validation (FSIV) Sequence Change Request (SCR) approval meeting was held today.

There is ongoing work to get the latest DSN station allocations in as soon as possible to minimize real time commanding for any DSN changes coming in after the SCR approval date.

Title: Re: NASA - Cassini updates
Post by: racshot65 on 10/28/2011 08:16 AM
Rev156: Oct 28 - Nov 15 '11

http://www.ciclops.org/view/6957/Rev156
Title: Re: NASA - Cassini updates
Post by: racshot65 on 11/03/2011 03:46 PM
Quote
Cassini Significant Events 10/26/11 - 11/01/11

The most recent spacecraft telemetry was acquired on Nov.1 from the Deep Space Network tracking complex at Madrid, Spain. The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.


Wednesday, Oct. 26 (DOY 299)

An image of Saturn's rings with Titan, Dione, Pandora and Pan is today's Astronomy Picture of the Day. It is available at: http://apod.nasa.gov/apod/ap111026.html.  The original post is here: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4384.


Thursday, Oct. 27 (DOY 300)

Today the Imaging Science Subsystem (ISS) narrow angle camera had an unplanned warm start during an idle period and recovered nominally. No images were lost, however, incident surprise anomaly (ISA) #50468 was issued.


Friday, Oct. 28 (DOY 301)

Today a member of the Cassini Outreach team led a teacher professional development workshop for 27 teachers from New York, New Jersey, New Hampshire, Connecticut, and Massachusetts at the National Science Teachers' Association regional conference in Hartford, CT. The workshop was entitled "Our Solar System Through the Eyes of Scientists", and included hands-on activities as well as videos, web content, and an introduction to a new NASA solar system thematic curriculum for students in grades 1-6. This curriculum is a follow-on to Cassini's "Reading, Writing & Rings" science and language arts curriculum.

Orbit Trim Maneuver (OTM) #297 was performed today. This was the apoapsis maneuver setting up for the Enceladus 16 encounter on Nov. 6. The Reaction Control Subsystem (RCS) burn began at 5:45AM PDT. Telemetry immediately after the maneuver showed a burn duration of 40.25 seconds, giving a delta-V of 0.046 m/s, and making an 80 km correction in the Enceladus 16 B-plane. All subsystems reported nominal performance after the maneuver. The next maneuver, OTM-298, is scheduled to execute on Wednesday, November 2, and is the final targeting maneuver for E-16. Following OTM298, OTM-299, the post E-16 clean-up maneuver, is scheduled to execute on Tuesday, Nov. 8, with a deterministic delta-V of 2.2 m/s.


Sunday, Oct. 30 (DOY 303)

This week while the spacecraft was near apoapsis, science observations were dominated by Titan observations, with a series of three 13.5 hour and one 4.75 hour observations by the Composite Infrared Spectrometer (CIRS) and Imaging Science Subsystem (ISS). The Cosmic Dust Analyzer (CDA) performed two 15 hour and one 13 hour interstellar dust observations.


Monday, Oct. 31 (DOY 304)

S72 Sequence Implementation Process (SIP) port 3 products were due today. The products will be merged and sent out to the flight team for review.

A kickoff meeting was held today for the S73 Sequence Implementation Process. Port 1 for the first set of input files from the teams occurs on Nov. 14.


Tuesday, Nov. 1 (DOY 305)

The Radio Science (RSS) Team completed Solar Corona Experiment #8; the experiment went well overall. The next RSS data collection occurs on DOY 325.

In support of S73 sequence development, the Attitude and Articulation Control Subsystem (AACS) Team completed its analysis of Titan flybys T-83 and T-84, now that these pointing designs are considered "frozen". This analysis was performed to assess whether or not there are any control authority issues for these upcoming relatively low altitude flybys on thrusters.

The Downlink Ground System (DGS) team delivered Acelog V2.0.1 via a Delivery Coordination Meeting (DCM) held Thursday, Oct. 27, and installed this latest patch release into operations today. The DGS team also installed Mission Control, Data Mgmt, & S/C Analysis (MDAS) V5.0.6 today, to provide an Automatic Alarm Notification (AAN) hysteresis fix.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 11/04/2011 09:15 AM
NASA's Cassini Makes a New Pass at Enceladus

http://www.jpl.nasa.gov/news/news.cfm?release=2011-340
Title: Re: NASA - Cassini updates
Post by: racshot65 on 11/08/2011 03:21 PM
Images from the Enceladus pass

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4400
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4401
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4402
Title: Re: NASA - Cassini updates
Post by: racshot65 on 11/11/2011 07:34 AM
Quote
Cassini Significant Events 11/02/11 - 11/08/11

The most recent spacecraft telemetry was acquired on November 8 from the Deep Space Network tracking complex at Canberra, Australia. The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.


Wednesday, Nov.2 (DOY 306)

An encounter strategy meeting was held today to cover the period between Nov. 6 and Dec. 13, Enceladus, Dione and Titan encounters E-16, D-3 and T-79, and maneuvers 299-301.

Navigation Team and Science Planning and Sequencing Team members reviewed current trajectories with and without Orbit Trim Maneuver 298 (OTM-298), the final targeting maneuver for E-16 scheduled to execute today, and determined that OTM-298 was not needed. Consequently, OTM-298 was canceled.


Thursday, Nov. 3 (DOY 307)

Science activities this week began with the final 15 hour Titan Exploration at Apoapsis (TEA) observation (in the set of TEAs begun last week) by the Composite Infrared Spectrometer (CIRS) and Imaging Science Subsystem (ISS). This was followed by a set of ISS astrometric observations of some of Saturn's small inner moons, and a CIRS 12 hour observation of Saturn to measure oxygen compounds (H2O, CO2) in the stratosphere. The Ultraviolet Imaging Spectrograph (UVIS), CIRS, and the Visual and Infrared Mapping Spectrometer (VIMS) completed an 11 hour observation of Saturn’s aurora, which was followed by the E-16 Enceladus flyby at 496 km altitude. The primary goal of this flyby was to perform the first close Synthetic Aperture Radar (SAR) measurements of an icy satellite to understand the structure and composition of the regolith directly below the surface, and to compare these data with similar measurements of Titan. In addition to the Radar observations, remote sensing measurements were made of Enceladus' plume on the inbound leg to aid in understanding the structure and morphology, temporal variability, and relationship to geological features and hot spots on the surface; on the outbound leg the surface of Enceladus was observed to obtain thermal and compositional data. UVIS made a long (5.25 hr) Dione observation to measure its UV spectral albedo and search for an exosphere, and then performed a calibration measurement of the star Spica. ISS made searches for objects in the L5 Lagrange regions of both Enceladus and Rhea. Lastly, Saturn auroral observations were led by UVIS, with repeated slews across the auroral oval, and ISS then performed a satellite search in the region around the Titan L4 Lagrange point.
 

Friday, Nov. 4 (DOY 308)

The main engine cover was closed today and will re-open on Sunday, Nov. 6. This was the 68th in-flight cycle of the cover.


Saturday, Nov. 5 (DOY 309)

Real Time Operations (RTO) uplinked the S71 Instrument Expanded Block (IEB) files over the weekend using the new Autorad tool successfully.


Sunday, Nov. 6 (DOY 310)

Today Cassini flew by Enceladus at an altitude of 496 kilometers and a speed of 7.4 km/sec. This flyby was designed to obtain the first detailed radar observations of Enceladus. This was also the first close radar pass of any icy moon besides Titan. The results will enable a comparison of the radar properties of a moon with a known composition (Enceladus) with that of Titan. The segment also included plume observations, the composite infrared spectrometer (CIRS) monitoring of hotspot activity, ultraviolet imaging spectrograph (UVIS) observations of Dione and its environment, and searches for Lagrangian companions of Enceladus and Rhea. For more information and raw images, link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20111107/ .

Non-targeted flybys of Methone, Pandora, and Calypso occurred today.


Monday, Nov. 7 (DOY 311)

The Science Forum for S73 was held today. Topics included an overview of science planned for this sequence followed by highlights, unique activities, and highest priority observations as described by the Target Working Team (TWT) and Orbiter Science Team (OST) leads, with comments from the Investigation Scientists and other instrument team representatives.


Tuesday, Nov. 8 (DOY 312)

Orbit Trim Maneuver (OTM) #299 was performed today. This was the clean-up maneuver following the Enceladus 16 encounter on Nov. 6. The main engine burn began at 5:45PM PDT. Telemetry immediately after the maneuver showed a burn duration of 12.029 seconds, giving a delta-V of 2.09 m/s. All subsystems reported nominal performance after the maneuver.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 11/14/2011 07:58 PM
Hiding Little Brother

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4404
Title: Re: NASA - Cassini updates
Post by: racshot65 on 11/17/2011 02:48 PM
Rev157: Nov 15 - Dec 3 '11

http://www.ciclops.org/view/6965/Rev157
Title: Re: NASA - Cassini updates
Post by: racshot65 on 11/18/2011 07:38 AM
Quote
Cassini Significant Events 11/9/11 - 11/15/11

The most recent spacecraft telemetry was acquired on November 15 from the Deep Space Network tracking complex at Canberra, Australia. The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.


Wednesday, Nov. 9 (DOY 313)

Science activities this week while the spacecraft was approaching apoapsis were dominated by Magnetospheric and Plasma Science (MAPS) investigations. The MAPS instruments acquired nearly continuous measurements of Saturn's outer magnetosphere and magnetosheath. By doing this once every four to six months, the MAPS instruments are able to observe Saturn’s magnetosphere over a solar cycle, from one solar minimum to the next, and investigate magnetospheric periodicities and how the Saturn kilometric radiation (SKR) period is imposed on the magnetosphere.

Thursday, Nov. 10 (DOY 314)
An article called “Saturn and the Solar Wind Send Tiny Particles Flying” was posted on the Cassini web site today. It describes how dust particles act in an unusual way around Saturn. Instead of being attracted to the giant planet as might be expected, dust particles are ejected away from Saturn in streams that move at speeds of more than 100 kilometers per second. Using data from the Cassini mission, a team of scientists has now successfully modeled these dust streams. For more information on this subject, link to: http://saturn.jpl.nasa.gov/news/cassiniscienceleague/science20111110/.
Today the Imaging Science Subsystem (ISS) narrow angle camera encountered a machine error and warm start during an idle period and recovered nominally, with no images lost. A new Incident Surprise Anomaly (ISA) report will be opened.
 

Friday, Nov. 11 (DOY 315)

The S71 background sequence was signed off and approved on Tuesday, Nov. 8, in preparation for uplink scheduled for today via the Autorad tool.
 

Sunday, Nov. 13 (DOY 317)

The Navigation Team is preparing for Orbit Trim maneuver 300 (OTM-300), which is scheduled to execute Wed., Nov. 23. It sets up the trajectory for the dual Dione/Titan flybys. Because this maneuver has a relatively large deterministic delta-V cost (3 m/s) and is executed only 45 minutes from periapsis, delaying to the backup maneuver location would be very costly in terms of delta-V. Due to this sensitivity, the maneuver will be designed early enough to enable six uplink opportunities, thereby eliminating the possibility of a delay to the backup time due to DSN transmitter failure.


Monday, Nov. 14 (DOY 318)

Port 1 products were due today as part of the S73 Sequence Implementation Process (SIP). The products will be merged and sent out to the flight team for review. Redelivery was requested of two teams to correct pointing designs that stepped outside of their allocated time window.
 

Tuesday, Nov. 15 (DOY 319)

In support of S74, the Science Planning and Sequencing (SPST) Team continued work on shifting the sequence boundary between S74 and S75 by approximately 8 hours to fall after Cassini’s Goldstone 70 meter pass on DOY 238 instead of the Madrid 70m pass on DOY 237, to avoid a 70m conflict with the Mars Science Laboratory (MSL) Project during their 30-day-post-Entry-Descent-Landing conditioning phase. This occurs within a Saturn Target Working Team (TWT) segment which spans across the S74-S75 sequence boundary.

Title: Re: NASA - Cassini updates
Post by: racshot65 on 11/18/2011 08:52 AM
Cassini Chronicles Life of Saturn's Giant Storm

http://www.jpl.nasa.gov/news/news.cfm?release=2011-359&cid=release_2011-359&msource=11359&tr=y&auid=9882435


Images

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4420
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4409
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4410
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4415
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4413
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4412
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4411
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4419
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4420
Title: Re: NASA - Cassini updates
Post by: racshot65 on 11/21/2011 07:08 PM
Odd Hyperion

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4421
Title: Re: NASA - Cassini updates
Post by: racshot65 on 11/24/2011 07:40 AM
Quote
Cassini Significant Events 11/16/11 - 11/22/11

The most recent spacecraft telemetry was acquired on November 22 from the Deep Space Network tracking complex at Canberra, Australia. The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.
 

Wednesday, Nov.16 (DOY 320)

The S71 sequence began execution today at 2011-320T03:02. The sequence will run for 70 days and conclude on Jan. 24. During that time there will be nine segments; three cross-discipline, one Satellite Orbiter Science Team (SOST), two Saturn, two Titan Orbiter Science Team (TOST), and one Magnetospheric and Plasma Science (MAPS) segment, with three targeted encounters – two Titan (T-79 and T-80) and one Dione flyby (D-3). Also, six Orbit Trim Maneuvers (OTMs) are scheduled, numbered 300 through 306 (300, 300a, 301, 303, 304, and 306).
 

Thursday, Nov. 17 (DOY 321)

A feature story called “Cassini Chronicles the Life and Times of Saturn’s Giant Storm” is available on the Cassini web site. It describes how new images and animated movies from the Cassini spacecraft chronicle the birth and evolution of the colossal storm that ravaged the northern face of Saturn for nearly a year. These new full-color mosaics and animations show the storm from its emergence as a tiny spot in a single image almost one year ago, on Dec. 5, 2010, through its subsequent growth into a storm so large it completely encircled the planet by late January 2011. For images and more information on this subject, link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20111117/.
A stellar reference unit calibration took place today.
 

Friday, Nov. 18 (DOY 322)

Science activities this week, as the spacecraft approached periapsis, were primarily a continuation from last week and focused on Magnetospheric and Plasma Science (MAPS) investigations, with MAPS instruments acquiring nearly continuous measurements of Saturn's magnetosphere. A break in the magnetospheric measurements was made when ISS performed an 8-hour observation of the outer irregular satellite Suttungr.

 
Saturday, Nov. 19 (DOY 323)

The Cassini web site has four new Really Simple Syndication (RSS) feeds. In addition to the original RSS feed, which gathers the latest excerpts from the Cassini home page, the four new feeds include All News, Features, the latest images in the Image Gallery, and the latest Raw Images. An RSS feed is a family of web feed formats used to publish frequently updated works. For access to Cassini RSS feeds link to: http://saturn.jpl.nasa.gov/news/latest-cassini-huygens.xml, http://saturn.jpl.nasa.gov/news/latest-cassini-huygens-news-releases.xml, http://saturn.jpl.nasa.gov/news/latest-cassini-huygens-features.xml, and http://saturn.jpl.nasa.gov/news/latest-cassini-huygens-pressimages.xml.
 

Sunday, Nov. 20 (DOY 324)

Cassini's twitter account @CassiniSaturn is now live streaming from the Cassini web site. A page is dedicated to the Cassini Saturn personification within the Cassini Mission site. For short and timely newsbytes, click on Twitter "Read The Feed" box at: http://saturn.jpl.nasa.gov/ or link to http://saturn.jpl.nasa.gov/news/twitter/.
 

Monday, Nov. 21 (DOY 325)

Twenty three Cassini team members and Outreach staff judged the entries for the Cassini Scientist for a Day 2011 essay contest. The winning students are 5th-12th grade students from Hillsborough, CA, Glen Ellyn, IL, Phoenix, AZ, Paris, KY, Waikoloa, HI, Boston, MA, Orlando, FL, and Fairport, NY. Teachers of the winning students have been notified. The United States edition of the contest included 568 students from 75 classes in 26 states. Internationally, 31 countries are running and participating in their own Cassini scientist for a Day contest.
 

Tuesday, Nov. 22 (DOY 326)

The Cassini Tour Atlas was delivered on Thursday, Nov. 17, and successfully re-run for the latest reference trajectory over the weekend. The Tour Atlas examines a Cassini trajectory for a wide variety of scientific opportunities. New products for tour 110818 were posted to the Science Planning and Sequence Team web site today.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 11/29/2011 07:54 AM
Titan's Kraken Mare

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4422
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/02/2011 07:49 AM
Quote
Cassini Significant Events 11/23/11 - 11/29/11

The most recent spacecraft telemetry was acquired on Nov. 29 from the Deep Space Network tracking complex at Goldstone, California.  The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.
 

Wednesday, Nov. 23 (DOY 327)
 
Orbit Trim Maneuver (OTM) #300 was performed today.  This was the periapsis maneuver setting up for the Titan 79 encounter on Dec. 13.  The main engine burn began at 10:45 PM PST.  Telemetry immediately after the maneuver showed a burn duration of 17.175 seconds, giving a delta-V of 2.969 m/s. While the maneuver targets to T79, the next encounter is actually a 100 km flyby of Dione (D3), taking place one day before the T79 encounter. Additional effort is required to make sure T79 should be targeted rather than D3, since not both can be independently targeted, and to make sure the resulting untargeted flyby is still safe.  All subsystems reported nominal performance after the maneuver.
 
Today the backup Sun Sensor Assembly (SSA B) was powered on in preparation for tomorrow's dust crossing; it will be turned off via real time command (RTC) on DOY 331.
 
A non-targeted flyby of Helene occurred today.
 

Thursday, Nov. 24 (DOY 328)

This week, while the spacecraft was near periapsis, science observations began with the Imaging Science (ISS ) and other optical remote sensing instruments monitoring clouds in Titan's atmosphere from a range of 2.1 million kilometers.  The Ultraviolet Imaging Spectrograph (UVIS), ISS and the Visual and Infrared Mapping Spectrometer (VIMS) observed Saturn's auroral oval for 10 hours.  Around periapsis, the Cosmic Dust Analyzer (CDA) made measurements of the dust environment during the ring plane crossing.  UVIS then performed a 3 hour calibration using the star Spica.  The Composite Infrared Spectrometer (CIRS), ISS, and VIMS completed an 18 hour observation of the faint ring arcs at low elevation and low phase, followed by a 14.5 hour light-curve observation of the outer irregular moon Thrymr performed by ISS and VIMS.  CIRS, ISS and VIMS later performed a 15.5 hour Titan composition observation, and CDA made a 13 hour interstellar dust observation.   Concluding the week, ISS observed a set of some of Saturn's small inner moons, including Epimetheus and Methone.
 
Non-targeted flybys of Enceladus, Epimetheus, and Titan occurred today.
 

Friday, Nov. 25 (DOY 329)
 
The main engine cover was closed yesterday prior to the dust crossing for dust hazard avoidance and was opened today.  This was the 69th in-flight cycle of the cover.
 

Saturday, Nov. 26 (DOY 330)
 
OTM-300A and OTM-301, both statistical maneuvers targeting to T79, are scheduled to execute on December 1 and 9 respectively.  After the post OTM-300 orbit determination solution is available, one of these maneuvers will likely end up with a deterministic component.
 

Sunday, Nov. 27 (DOY 331)
 
A non-targeted encounter of Titan occurred today.
 

Monday, Nov. 28 (DOY 332)
 
The CDA - High Rate Detector (HRD) recovery command file was uplinked today over Goldstone's DSS-14 station and is due to execute on the spacecraft on 2011-334T15:30.  This is in response to two separate recent incidents.  The HRD instrument stopped generating data after 2011-310T23:26; this is currently under investigation.  The CDA instrument also underwent a known anomaly on DOY 2011-327T21:59 when a checksum showed an error. The spacecraft was in the E-ring at the time and the CDA instrument has seen this occur there before.  A reset/reload activity is needed to get CDA back into a normal operating state.  Execution of the command going up on DOY 334/335 includes reset/reload, HRD calibration, and other tests.  Once the results are on the ground, additional real time commanding will ensure proper functioning of the instrument for the upcoming Dione flyby on Dec. 12.
 
An insider's feature story called "Dr. Jean-Pierre Lebreton, Huygens, and a Salute to the Mars Science Laboratory" is available on the Cassini web site.  It describes an interview with Jean-Pierre Lebreton, the European Space Agency (ESA) Project Scientist for the Huygens mission, just as he retired from a decades-long career with ESA. Though he remains active in research, Dr. Lebreton's departure from ESA is a noteworthy milestone, and this article also honors his many contributions to space science in general and Cassini-Huygens in particular.  For images and more information on this subject, link to:  http://saturn.jpl.nasa.gov/news/cassiniinsider/insider20111128/.
 

Tuesday, Nov. 29 (DOY 333)
 
The most recent Cassini-Huygens Analysis and Results of the Mission (CHARM) teleconference was held today.  The topic: "Powerhouses to PacPeople: An update on the recent discoveries by Cassini/CIRS on the nature of the Saturnian satellite surfaces."  A PDF of the presentation package is available at: http://saturn.jpl.nasa.gov/video/products/MultimediaProductsCharm/
An audio recording of the presentation was made and will be linked to the same location within a few days.
 
In June, the decision to turn off the Cassini Plasma Spectrometer (CAPS) was made as a precautionary measure in light of shifting spacecraft bus voltages attributed to malfunctions in the instrument.  An analysis of this situation has been initiated at the NASA Engineering and Safety Center (NESC), with a report expected in January 2012.  The final decision regarding whether or not to turn the instrument back on will be made some time after the release of this report.

Preliminary Sequence Integration and Validation (PSIV) Spacecraft Activity Sequence File (SASF) products were due today as part of the S72 Sequence Implementation Process (SIP).
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/02/2011 07:56 AM
What's That Sparkle in Cassini's Eye?

http://www.jpl.nasa.gov/news/news.cfm?release=2011-370


http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4424
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4426
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4427
Title: Re: NASA - Cassini updates
Post by: spectre9 on 12/02/2011 12:33 PM
That's totally awesome.

Cassini is underrated.  8)

Are we looking at ice rocks reflecting light back?

I'm very interested in Enceladus. It's an exciting place to explore even if it is so small.
Title: Re: NASA - Cassini updates
Post by: ugordan on 12/02/2011 01:00 PM
Cassini is underrated.  8)

It's not.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/03/2011 10:05 AM
Rev158: Dec 3 - Dec 23 '11

http://www.ciclops.org/view/6991/Rev158
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/09/2011 09:28 AM
Quote
Cassini Significant Events 11/30/11 - 12/06/11

The most recent spacecraft telemetry was acquired on Dec. 6 from the Deep Space Network tracking complex at Canberra, Australia. The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.


Wednesday, Nov. 30 (DOY 334)

The Composite Infrared Spectrometer (CIRS) Flight Software (FSW) 6.0.1 patch was installed onboard today. Prior to this patch, the only timing information for CIRS scans was a time stamp for when the first science sample of each scan was obtained from the detectors and stored into the instrument’s internal memory; however, each scan consists of both a forward and backward motion of the scan mechanism. There was no information on the timing of when the scan mechanism completed scanning forward, obtaining science data, and when it was beginning to travel backward in preparation for the next scan. The patch created a new telemetry point and added new data to the science telemetry stream. This new information is provided for each scan and allows the CIRS team to compute the exact time at which the scan mechanism switches directions and begins traveling backward. It also allows for a derived telemetry point to be generated on the ground to let engineers know the true raw sampling rate of the detectors. The detector sampling is hardware controlled and in normal conditions it is constant. When there is interference at certain reaction wheel rates, the CIRS scan mechanism’s velocity varies and sampling is not at a constant rate. This new information provides the calibration team an improved ability to detect anomalous science data that sometimes results from external mechanical interference.


The S74 Engineering Activities Review took place today. At this review, Spacecraft Office personnel take a look at all spacecraft activities to be performed during the S74 sequence.

A software patch delivery for the Cassini Information Management System (CIMS) was delivered today and deployed into operations on Thursday, Dec. 1. Several enhancements were provided as part of this release, which are referenced in approved engineering change request (ECR) 112488.

Port 2 products were due today as part of the S73 Sequence Implementation Process (SIP). The products were merged and sent out to the flight team for review.

 

Thursday, Dec. 1 (DOY 335)

Orbit Trim Maneuver (OTM) #300a was performed today. This was the apoapsis maneuver setting up for the Dione 3 encounter on Dec. 12 and the Titan 79 encounter on Dec. 13. The Reaction Control Subsystem (RCS) burn began at 4:30 PM PST. Telemetry immediately after the maneuver showed a burn duration of 13.75 seconds, giving a delta-V of 0.021 m/s. All subsystems reported normal performance after the maneuver.

A feature story called “What’s That Sparkle in Cassini’s Eye?” is available on the Cassini web site. It describes how the moon Enceladus, one of the jewels of the Saturn system, sparkles particularly bright in new images obtained by the Cassini spacecraft. The images of the moon, the first ever taken of Enceladus with Cassini's synthetic aperture radar, reveal new details of some of the grooves in the moon's south polar region and unexpected textures in the ice. These images, obtained on Nov. 6, are the highest-resolution images of this region obtained so far. For images and more information on this subject, link to: http://saturn/news/newsreleases/newsrelease20111201/.


Friday, Dec. 2 (DOY 336)

The Navigation Team is in the process of determining if the next scheduled maneuver, OTM-301, will be needed; it’s scheduled to execute on Dec. 9. OTM-303, scheduled to execute on Dec. 17, is the cleanup maneuver for the Dione 3/Titan 79 dual flyby.

 
Saturday, Dec. 3 (DOY 337)

This week’s science highlights included three interstellar dust observations performed by the Cosmic Dust Analyzer (CDA). The Imaging Science Subsystem (ISS) performed astrometric observations of some of Saturn's small moons including Helene, Calypso and Epimetheus, followed by five images taken for optical navigation purposes. CIRS made a 23-hour mid-infrared (mid-IR) observation of Saturn to measure upper troposphere and tropopause temperatures. Finally, the Magnetometer (MAG) performed an 8 hour calibration while the spacecraft rolled about its X-axis.

Today a member of the Cassini Outreach team received a Visionary Award from the Women’s International Film and Television Showcase (WIFTS). The award is in recognition of her invention, the Blissymbol Printer, which was created for a seventh grade science fair project over 25 years ago.

 
Sunday, Dec. 4 (DOY 338)

The U.S. Cassini Scientist for a Day winners, finalists, and honorable mention winners have been officially notified, and the names will be posted on the Cassini website next week.
 
In preparation for the upcoming Dione 3 encounter on Monday, Dec. 12, a ‘‘D-3’ flyby page is now available on the Cassini web site along with promotional art. Any noteworthy results from the D-3 flyby as well as additional links and images will be posted at: http://saturn.jpl.nasa.gov/mission/flybys/dione20111212/.
 

Monday, Dec. 5 (DOY 339)

An encounter strategy meeting was held today to cover the period between Dec. 12 and Jan. 2, Dione and Titan encounters D-3, T-79, and T-80, and maneuvers 303 and 304 in S71.

Preliminary Sequence Integration and Validation (PSIV) Spacecraft Activity Sequence File (SASF) – Merge 1 products were published last week as part of the S72 Sequence Implementation Process (SIP). The PSIV-Merge 2 was published today in support of the S72 split needed due to the sequence size. The split of the S72 sequence is planned to fall on DOY-062.
 

Tuesday, Dec. 6 (DOY 340)

A mission planning forum was held today to review propellant use in S70 and the status of the propellant budgets. A consumables status is provided on a regular basis so the Project can maintain cognizance of propellant usage and end of mission margins.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/10/2011 09:51 AM
Cassini to Make a Double Play

http://www.jpl.nasa.gov/news/news.cfm?release=2011-381
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/12/2011 05:05 PM
East of Wisps

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4432
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/13/2011 08:57 AM
Portraits of Moons Captured by Cassini

http://www.jpl.nasa.gov/news/news.cfm?release=2011-385


http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4433
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4434
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4438
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4437
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4436
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4435
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/16/2011 09:18 PM
Quote
Cassini Significant Events 12/7/11 - 12/13/11

The most recent spacecraft telemetry was acquired on Dec. 13 from the Deep Space Network tracking complex at Canberra, Australia. The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.


Wednesday, Dec. 7 (DOY 341)

This week’s science observations included two observations in the Titan monitoring campaign performed by the Imaging Science Subsystem (ISS), Composite Infrared Spectrometer (CIRS), and the Visual and Infrared Mapping Spectrometer (VIMS). ISS made astrometric observations of some of Saturn's smaller moons including Helene and Telesto, along with three sets of mutual event observations - the transit of Rhea across Dione, the transit of Dione across Titan, and the transit of Tethys across Titan. Later, the Cosmic Dust Analyzer (CDA) performed a 14.5 hour interstellar dust observation, and CIRS performed a 12 hour observation of Saturn in order to measure oxygen compounds (H2O, CO2) in the stratosphere. The Ultraviolet Imaging Spectrograph (UVIS) made an observation of the star Spica for calibration purposes, then ISS observed Titan for a double mutual event opportunity - a transit of Titan across Tethys followed by transit of Rhea across Titan, and to make measurements of Titan's atmospheric haze layer. UVIS made repeated slow slews across Saturn's auroral zone, monitoring the Enceladus footprint. CDA took measurements of the E ring during the ring shadow crossing at 4 Rs.


Friday, Dec. 9 (DOY 343)

Orbit Trim Maneuver (OTM) #301 was performed today. This was an approach maneuver setting up for the Dione 3/Titan 79 encounters on Dec. 12 and 13. The Reaction Control Subsystem (RCS) burn began at 2:14 PM PST. Telemetry immediately after the maneuver showed a burn duration of 11.25 seconds, giving a delta-V of 0.018 m/s. All subsystems reported normal performance after the maneuver.

Many Cassini scientists attended the American Geophysical Union meeting in San Francisco Dec 5-9, where numerous sessions highlighted Cassini science results.

A telecon was held today with personnel from the NASA Engineering and Safety Center and the Southwest Research Institute who are working to better understand the nature of the electrical problems with CAPS and the spacecraft. Progress is being made on the problem, but a final decision on turning the instrument back on is still some time off.

 
Saturday, Dec. 10 (DOY 344)

The next maneuver, OTM-303, is scheduled to execute on December 17, and is the cleanup maneuver following the Dione 3/Titan 79 flybys. OTM-304 follows on December 22, targeting to the Titan 80 encounter.


Monday, Dec. 12 (DOY 346)

Cassini encountered Dione today at an altitude of 99 kilometers and a speed of 8.7 km/sec to examine the moon’s internal structure. The design of this close encounter also provided the ion and neutral mass spectrometer (INMS) a good sample opportunity, and before closest approach there was also time for the optical remote sensing (ORS) instruments to observe Enceladus from a relatively near distance. For more information on this subject link to: http://saturn.jpl.nasa.gov/mission/flybys/dione20111212/ and http://saturn/news/cassinifeatures/feature20111212/.

Today the Cassini Radio Science (RSS) Team completed the S71 Rev 158 Dione (D-3) gravity observation. D-3 is the first Dione flyby with tracking at closest approach. In spite of the relatively small mass of the satellite, the spacecraft acceleration will be clearly detected in the Doppler data. The accuracy of range rate measurements provides good sensitivity not only to the monopole, but also to the quadrupole field, which will be determined for the first time. The observation consisted of three segments (inbound, closest approach, and outbound), and was covered by Beam Wave Guide (BWG) antennae at all three complexes starting with Canberra’s DSS-34, followed by Madrid's DSS-55, and ending with Goldstone's DSS-25. The radio science measurements will add insight into how highly structured the interior of the small moon is, which in turn should provide clues about its recent history and possible activity.

The Instrument Operations System/Multi Mission Image Processing Laboratory (IOS/MIPL) expedited processing for the Dione 3 flyby, delivering images to the science team and raw image website during the downlink.

The main engine cover was closed on Dec. 10 prior to the dust crossing for dust hazard avoidance and was opened today. This was the 70th in-flight cycle of the cover.

Non-targeted flybys of Calypso, Enceladus, and Tethys occurred today.


Tuesday, Dec. 13 (DOY 347)

Cassini encountered Titan at an altitude of 3,586 kilometers and a speed of 5.8 km/sec today. The composite infrared spectrometer (CIRS) was prime during the Titan flyby, about 36 hours after the Dione encounter. This flyby was originally planned to be a Cassini Plasma Spectrometer (CAPS) flyby, but was switched to an Optical Remote Sensing flyby since CAPS was powered off in June due to a power bus short. For more information on the
Titan flyby, link to:

http://saturn.jpl.nasa.gov/mission/flybys/titan20111213/.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/20/2011 10:04 AM
Tiny by the Terminator

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4439
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/21/2011 12:51 PM
Rev159: Dec 23 '11 - Jan 16 '12

http://www.ciclops.org/view/7042/Rev159
Title: Re: NASA - Cassini updates
Post by: jacqmans on 12/22/2011 06:38 PM
News release: 2011-393                                                                     Dec. 22, 2011

NASA's Cassini Delivers Holiday Treats From Saturn

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2011-393&cid=release_2011-393

The release includes images of satellite conjunctions in which one moon passes in front of or behind another. Cassini scientists regularly make these observations to study the ever-changing orbits of the planet’s moons. But even in these routine images, the Saturnian system shines. A few of Saturn’s stark, airless, icy moons appear to dangle next to the orange orb of Titan, the only moon in the solar system with a substantial atmosphere. Titan’s atmosphere is of great interest because of its similarities to the atmosphere believed to exist long ago on the early Earth.

The images are online at: http://www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://ciclops.org .

While it may be wintry in Earth’s northern hemisphere, it is currently northern spring in the Saturnian system and it will remain so for several Earth years. Current plans to extend the Cassini mission through 2017 will supply a continued bounty of scientifically rewarding and majestic views of Saturn and its moons and rings, as spectators are treated to the passage of northern spring and the arrival of summer in May 2017.

"As another year traveling this magnificent sector of our solar system draws to a close, all of us on Cassini wish all of you a very happy and peaceful holiday season, ” said Carolyn Porco, Cassini imaging team lead at the Space Science Institute, Boulder, Colo.

More information about Cassini mission is online at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/23/2011 09:34 AM
Quote

Cassini Significant Events 12/14/11 - 12/20/11

The most recent spacecraft telemetry was acquired on Dec. 20 from the Deep Space Network tracking complex at Madrid, Spain.  The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.


Wednesday, Dec. 14 (DOY 348)

Real-time commands were uplinked today and verified over Canberra's DSS-43 track in support of S71's Imaging Science Subsystem (ISS) Real Time (RT) Memory Readout (MRO) and the telemetry mode changes in response to the DSN station allocation changes.  The commands will execute on the spacecraft on DOY 354T12:02:59 and 2012-003T22:13:41 respectively.


Thursday, Dec. 15 (DOY 349)

The ISS team performed memory readouts of the error/mark table and heap/stack registers.  These memory readouts may provide more information about recent Narrow Angle Camera warm starts.


Friday, Dec. 16 (DOY 350)

In support of S72 activities, the Science Planning and Sequencing Team (SPST) delayed the Final Sequence Integration and Validation (FSIV) Sequence Change Request (SCR) meeting from this week to January 5, 2012, to allow more time for the effects of DSN station allocation changes to be worked.


Saturday, Dec. 17 (DOY 351)

Orbit Trim Maneuver#303 was performed today.  This was a cleanup maneuver following the Dione 3/Titan 79 flybys and setting up for the Titan 80 encounter on January 2.   The main engine burn began at 1:44 AM PST.  Telemetry immediately after the maneuver showed a burn duration of 2.923 seconds, giving a delta-V of 0.489 m/s.  All subsystems reported normal performance after the maneuver.


Sunday, Dec. 18 (DOY 352)

The Navigation Team is in the process of determining if the next scheduled maneuver, OTM-304, the T80 approach maneuver, will be needed; it's scheduled to execute on Dec. 22.  OTM-306, scheduled to execute on January 16, is the cleanup maneuver for the Titan 80 flyby.

The new Cassini Mission Assurance Manager (MAM) met with team leads to understand their roles and responsibilities, and continued working old Incident Surprise Anomaly (ISA) reports while supporting sequence activities and becoming familiarized with the Project Risk Database.


Monday, Dec. 19 (DOY 353)

A Delivery Coordination Meeting for the Maneuver Automation Software (MAS) v9.2 took place today.  This latest version of MAS included a number of operational enhancements which are referenced in approved engineering change request (ECR) 112360.

Preliminary agendas and a calendar have been posted on the newly revamped Project Science web site in preparation for the upcoming Project Science Group (PSG) meeting #56, the week of Jan. 30-Feb. 3, 2012.


Tuesday, Dec. 20 (DOY 354)

Weekly meetings with the NASA Engineering and Safety Center review board are being held to investigate the Cassini Plasma Spectrometer (CAPS) and Radioisotope Thermoelectric Generator (RTG) power subsystem anomaly.  Meetings will continue until a recommendation can be made regarding whether or not to turn the CAPS instrument back on.

This week's science activities began with finishing up the T79 Titan flyby observations, including a temperature map to monitor seasonal changes in the Titan stratosphere performed by the Composite Infrared Spectrometer (CIRS), and global mapping of cloud coverage at 100 km/pixel resolution conducted by the Visual and Infrared Mapping Spectrometer (VIMS).  The Imaging Science Subsystem (ISS) then monitored Titan for changes in cloud coverage, with a brief interruption for a RADAR calibration.  Further Titan monitoring was performed by the Optical Remote Sensing (ORS) instruments from a more distant vantage point while the spacecraft was on approach to apoapsis.  The Cosmic Dust Analyzer (CDA) completed one 15 hour and two 13 hour interstellar dust observations, and ISS made astrometric measurements of some of Saturn's small moons, including Janus, Pandora and Atlas.  The Ultraviolet Imaging Spectrograph (UVIS) concluded the week with a 15 hour scan of the system to measure hydrogen in Saturn's inner magnetosphere.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/23/2011 09:52 AM
Cassini Top Images of 2011

http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20111223b/
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/23/2011 09:54 AM
Some nice colour images

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4442
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4445
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4444
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4443
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4441
Title: Re: NASA - Cassini updates
Post by: racshot65 on 12/27/2011 10:10 AM
Brilliant Enceladus

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4447
Title: Re: NASA - Cassini updates
Post by: racshot65 on 01/06/2012 07:39 AM
Quote

Cassini Significant Events 12/21/11 - 1/3/12

The most recent spacecraft telemetry was acquired on January 3 from the Deep Space Network tracking complex at Canberra, Australia.  The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at:
http://saturn.jpl.nasa.gov/mission/presentposition/.
 

Wednesday, Dec. 21 (DOY 355)
 
Science observations over the past two weeks included a series of observations in the Titan monitoring campaign by the Imaging Science (ISS), the Composite Infrared Spectrometer (CIRS), and the Visual and Infrared Mapping Spectrometer (VIMS).  ISS also performed a number of astrometric observations of some of Saturn's small moons, as well as a 15 hour observation of the outer irregular moon Suttungr.  The Ultraviolet Imaging Spectrograph (UVIS) performed two long slow scans of the inner magnetosphere to map hydrogen, and also observed Saturn's aurora for 11 hours.  The Magnetometer performed a 7 hour calibration while the spacecraft rolled about its X-axis.  CIRS completed a 23 hour mid-infrared (mid-IR) map of Saturn to determine upper troposphere and tropopause temperature, followed by a 13 hour interstellar dust observation performed by the Cosmic Dust Analyzer (CDA).  Later, CIRS performed a 12 hour observation of Saturn in order to measure oxygen compounds (H2O, CO2) in the stratosphere.
 

Thursday, Dec. 22 (DOY 356)
 
A feature story called "NASA's Cassini Delivers Holiday Treats from Saturn" is available on the Cassini web site.  It describes how radio signals from the Cassini spacecraft have delivered a holiday package of images. The pictures, from Cassini's imaging team, show Saturn's largest, most colorful ornament, Titan, and other icy baubles in orbit around the planet.  For images and more information on this subject, link to:
http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20111222/.
 
Orbit Trim Maneuver (OTM) #304 was performed today.  This was the apoapsis maneuver setting up for the Titan 80 encounter on January 2.  The Reaction Control Subsystem (RCS) burn began at 3:14 PM PST.  Telemetry immediately after the maneuver showed a burn duration of 10.125 seconds, giving a delta-V of 0.0164 m/s.  All subsystems reported normal performance after the maneuver.
 
An encounter strategy meeting was held today to cover the period between Jan. 2 and Jan. 30, Titan flybys T80 and T81, and maneuver OTM-306 in S71.
 
A Delivery Coordination Meeting for the Instrument Operations (IO) /Multi-Mission Image Processing Laboratory (MIPL) ground software delivery CAS D40 took place today.  This latest version included multi-mission updates, enhancements and new capabilities for the Cassini Solstice mission, bug fixes, and documentation updates which are referenced in approved engineering change request (ECR) 112079. This delivery transitioned smoothly to operations on Dec. 23.
 

Friday, Dec. 23 (DOY 357)
 
No signal was detected from the spacecraft today at the beginning of track at Deep Space Station (DSS) DSS-43, the Canberra 70 meter station.  Additional tracking was obtained at Canberra's DSS-45 and Goldstone's DSS-14 to no avail. The 2-way coherent signal was acquired at the one round trip light-time point into the track as usual, indicating it was a spacecraft problem and not a ground system error.  Incident Surprise Anomaly (ISA) #50901 and Discrepancy Report (DR) C108400 were submitted to document this spacecraft anomaly. Commands were sent on Dec. 25 to inhibit the ultra-stable oscillator (USO) and use the auxiliary oscillator as the frequency source for the downlink signal. The spacecraft has operated in this mode for every pass starting on Dec. 27, and telemetry is being received for entire passes again. Data loss was limited to two round-trip light time periods. Analysis of the problem has been delayed because of the holidays with many of the key engineers being unavailable, but it is now well underway.
 
A feature story called "Cassini Top Images of 2011" is available on the Cassini web site.  It showcases the Cassini scientists' picks of the top images from 2011 with many close-up views of Saturn and its storm. For images and more information on this subject, link to:
http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20111223/
 

Saturday, Dec. 24 (DOY 358)
 
The IO/ISS team has completed further analysis of recent memory readouts of the error/mark table and heap/stack registers.  The recent machine error (ISA-50585) was discovered to have been caused by a Bus Interface Unit (BIU) memory issue, which has been observed in the past.
 

Monday, Dec. 26 (DOY 360)
 
An image of a raging storm system on Saturn was Astronomy Picture of the Day today. It is available at: http://apod.nasa.gov/apod/ap111226.html.
 

Tuesday, Dec. 27 (DOY 361)
 
The Attitude and Articulation Control Subsystem (AACS) Periodic Engineering Maintenance was completed today.  This activity, performed approximately once every three months, spins up the backup reaction wheel assembly for lubrication purposes and exercises the back-up engine gimbal actuator.
 

Wednesday, Dec. 28 (DOY 362)
 
A glimpse at the year ahead is now available on the "Saturn Tour Dates" page.  For details on the subject link to: http://saturn.jpl.nasa.gov/mission/saturntourdates/.
 

Thursday, Dec. 29 (DOY 363)
 
Earlier this month, the U.S. Cassini Scientist for a Day winners, finalists, and honorable mention winners were officially notified, and their names were posted on the Cassini website.  The winners and their photos and essays are now posted on the "Meet the Winners" page at:
http://saturn.jpl.nasa.gov/education/scientistforaday10thedition/winners2011/.
 

Monday, January 2 (DOY 2)
 
Cassini encountered Titan at an altitude of 29,415 kilometers and a speed of 5.5 km/sec today.  On this high-altitude encounter, the imaging science subsystem (ISS) performed high-resolution observations around closest-approach along the anti-Saturnian and trailing hemispheres at mid- to high southern latitudes.  This is one of ISS's so-called "10-pointer" flybys, i.e. one of the two scientifically most significant Titan flybys for ISS during the Solstice mission.  For more information on the flyby, link to:
http://saturn.jpl.nasa.gov/mission/flybys/titan20120102/.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 01/06/2012 10:28 AM
Before Wide Shadows

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4448
Title: Re: NASA - Cassini updates
Post by: racshot65 on 01/09/2012 08:34 PM
Welcome Disruption

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4451
Title: Re: NASA - Cassini updates
Post by: racshot65 on 01/13/2012 04:46 PM
Quote
Cassini Significant Events 1/4/12 - 1/10/12

The most recent spacecraft telemetry was acquired on Jan. 9 from the Deep Space Network tracking complex at Goldstone, California. The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

 
Wednesday, Jan. 4 (DOY 004)

A news release called “New Computer Model Explains Lakes and Storms on Titan” is available on the Caltech Media Relations web site. Saturn's largest moon, Titan, is an intriguing, alien world that's covered in a thick atmosphere with abundant methane. With an average surface temperature of a brisk -300 degrees Fahrenheit and a diameter just less than half of Earth's, Titan boasts methane clouds and fog, as well as rainstorms and plentiful lakes of liquid methane. It's the only place in the solar system, other than Earth, that has large bodies of liquid on its surface. Using a combination of ground-based and Cassini data, researchers at Caltech have developed a computer model of Titan's atmosphere and methane cycle that explains many of these phenomena in a relatively simple and coherent way. For more information on this subject link to: http://media.caltech.edu/press_releases/13484.


Thursday, Jan. 5 (DOY 005)

Science activities this week focused on a number of observations by the Imaging Science Subsystem (ISS) and other Optical Remote Sensing (ORS) instruments. On approach to periapsis, ISS took a look at Enceladus’ plumes and the Composite Infrared Spectrometer (CIRS) performed a Saturn Limb Map observation to obtain stratospheric thermal structure by means of limb sounding in the mid-infrared. ISS and VIMS performed two Saturn emission angle scans by observing different emission angles in different latitude bands; these data will help to understand the photometric characteristics of Saturn at different wavelengths. ISS took a look at Titan as part of the Titan monitoring campaign, while CIRS recorded a Saturn mid-IR map to determine upper troposphere and tropopause temperatures. Concluding the week, the ORS teams made further observations of Titan, and a set of complementary observations by ISS and CIRS measured Saturn winds and composition. Meanwhile, back on Earth, members of the UVIS team met for a team meeting at Caltech, Jan 5-7, to discuss science results and plans for future observations.


Friday, Jan. 6 (DOY 006)

The Cassini Navigation team accepted formal delivery of Monte, the replacement tool for its legacy navigation software, and began using it in operations today. The purpose of the Monte software is to provide all navigation-related functions in a single, integrated system.

 
Saturday, Jan. 7 (DOY 007)

Members of the Science Planning and Sequence Team (SPST) supported multiple meetings with DSN schedulers and Section 317 representatives to discuss issues related to late DSN station allocation deliveries and scheduling software issues.

The Cassini Mission Assurance Manager started reviewing the Project Risk database and scheduled a meeting with the Instrument Operations Team lead to go over instrument-related risks; these risk descriptions were last updated in 2009. The MAM will work with each team lead to update the rationale and risk rating, and for next few weeks will start scheduling meetings with each team lead, while continuing to support sequence development activities as needed.

 
Sunday, Jan. 8 (DOY 008)

The Navigation Team is in the process of determining if the next scheduled maneuver, Orbit Trim Maneuver (OTM) #306, is needed; it’s scheduled to execute on Jan. 16. OTM-306 is the sole maneuver between Titan flyby T-80 and T-81, a situation made possible by the fact that both of these are high altitude flybys.


Monday, Jan. 9 (DOY 009)

The Ultra Stable Oscillator (USO) was powered off today for 30 minutes. This was a diagnostic step in the investigation of the USO anomaly that occurred on Dec. 23. The telemetry received while turning the USO equipment off and back on was as expected. Further analysis of this anomaly is still ongoing.

Both ISS and VIMS lost some data and encountered degraded products due to the USO anomaly that started on DOY 357. The carrier tracking loop bandwidth has been changed to 10 Hz over the one-way portion of each tracking pass for which the auxiliary oscillator is now used, and as result, data quality has improved to where it was previously on the USO.

 
Tuesday, Jan. 10 (DOY 010)

A feature story called “Cassini Top 10 Science Highlights -- 2011” is available on the Cassini web site. All throughout 2011, the Cassini spacecraft collected science data at a rapid pace. Mission scientists provided exciting results all year long, from scrutinizing a huge new storm on Saturn, to discovering salty particles in Enceladus’ plumes, to studying Saturn’s rings with radio science experiments. For images and a look at last year’s best science, link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20120110/.

The Instrument Operations (IO) /Multi-Mission Image Processing Laboratory (MIPL) had a planned downtime today to switch two operations servers to backup hardware. This was done to allow firmware and patch updates to the T2 Logical Domains (LDOMs) hosting the operations and data storage (ZFS) servers
Title: Re: NASA - Cassini updates
Post by: racshot65 on 01/13/2012 05:16 PM
Cassini Testing Part of Its Radio System

http://www.jpl.nasa.gov/news/news.cfm?release=2012-013
Title: Re: NASA - Cassini updates
Post by: racshot65 on 01/13/2012 05:16 PM
Rev160: Jan 16 - Feb 9 '12

http://www.ciclops.org/view/7051/Rev160
Title: Re: NASA - Cassini updates
Post by: racshot65 on 01/16/2012 06:21 PM
Closest Dione Flyby

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4453
Title: Re: NASA - Cassini updates
Post by: racshot65 on 01/20/2012 07:34 AM
Quote
Cassini Significant Events 01/11/2012 - 01/17/2012

The most recent spacecraft tracking and telemetry data were acquired Jan. 17 from the Deep Space Network 70 meter diameter Deep Space Station 63 at Madrid, Spain. The Cassini spacecraft is in an excellent state of health, with the exception of the Cassini Plasma Spectrometer remaining powered off, and the anomalous Radio Frequency Subsystem's Ultrastable Oscillator. (The next Radio Science Occultation experiment, which normally would use the Ultrastable Oscillator, is not until June.) All of Cassini's other subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Science activities this week involved the Imaging Science Subsystem (ISS) and other Optical Remote Sensing instruments observing Titan throughout the week to monitor cloud activity while the spacecraft coasted toward apoapsis. ISS also observed Saturn to measure lingering atmospheric activity in the northern hemisphere storm. The Ultraviolet Imaging Spectrograph imaged Titan and Saturn in the extreme- and far-ultraviolet parts of the spectrum. The Composite Infrared Spectrometer observed Saturn to measure oxygen compounds (H2O, CO2) in the stratosphere as a function of latitude, while ISS measured the winds. The Magnetometer instrument performed a calibration activity by having the spacecraft execute a roll about its X-axis.
 

Wednesday, Jan. 11 (DOY 011)

The Realtime Operations team discovered that the Autorad tool was inoperative. Autorad is a Command System tool that assists the Mission Controller and Sequence Implementation Process Lead when uplinking Cassini's Instrument-Expanded Block commands (IEBs) once per sequence. Incident-Surprise-Anomaly report #50976 documents the failure. Troubleshooting today identified a suspected cause.
 

Thursday, Jan. 12 (DOY 012)

The Orbit Trim Maneuver #306 design and associated trajectories that were released today marked the first operational delivery using the new navigation software called Monte.

The Cassini Science Planning Team participated in a discussion of issues that are slowing down the process of allocating Deep Space Network (DSN) tracking resources to Cassini. Participants included representatives from the JPL Multimission Resource Scheduling Service team, JPL Interplanetary Network Science Policy Office, and Scheduling Subsystem software developers.
 
The suspected cause of the Autorad failure was confirmed and corrected, and the tool was reinstated for use with the S72 IEB load uplinks.

The Radio Science Subsystem team conducted a DSN Monopulse Calibration on the 34 meter Deep Space Station 55 in Madrid. Monopulse is a ground-antenna fine-pointing system that provides precise control and monitor for Ka-band Radio Science experiments with Cassini.

A status report was published today regarding the problem with Cassini's Ultrastable Oscillator:

http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20120112/
 
Finally, today's news feature on the ecology of Saturn's ring particles appears here:

http://saturn.jpl.nasa.gov/news/cassiniscienceleague/science20120112/
 

Friday, Jan. 13 (DOY 013)
 
The Orbit Trim Maneuver (OTM) #306 for Jan. 15 was built and commands approved this afternoon. They were uplinked this evening over the 34 meter Deep Space Station 65 in Madrid. Also uplinked were commands to test the Ultrastable Oscillator's output on Jan. 20, including turning Cassini's S-band transmitter on, and a command to set Two-Way Non-Coherent mode on for Jan. 22, when Cassini will participate in a special DSN uplink polarization test for the benefit of the New Horizons mission.

Cassini's 2007 image of Iapetus ("The Other Side of Iapetus," or PIA08384) made the Astronomy Picture of the Day today:

http://apod.nasa.gov/apod/ap120113.html
 

Saturday, Jan. 14 (DOY 014)

Seven IEB command loads for Sequence S72 were uplinked using Autorad over Deep Space Station 55 in Madrid. Memory readouts from the spacecraft confirmed proper receipt.
 

Sunday, Jan. 15 (DOY 015)

The last two IEB command loads for Sequence S72 were uplinked using Autorad over Deep Space Station 55 in Madrid. Memory readouts from the spacecraft confirmed proper receipt.

OTM #306 executed today (the nomenclature "OTM #305" was not used). This was the apoapsis maneuver setting up for the Titan-81 encounter on Jan. 30. The Reaction Control Subsystem (RCS) thrusters began their burn at 11:59 PM PST (Earth-receive time). Telemetry immediately after the maneuver showed a burn duration of 44.125 seconds, giving a delta-V of 0.0498 meters per second. All subsystems reported normal performance after the maneuver.

 
Monday, Jan. 16 (DOY 360)

Apoapsis passage this morning, at 2.96 million kilometers altitude, marked the start of Cassini's 160th orbit of Saturn. The spacecraft's speed relative to Saturn was approximately 5,240 kilometers per hour at this slowest point in the orbit.

The Attitude and Articulation Control Subsystem executed a Reaction Wheel Bias maneuver. Using thrusters to maintain attitude, keeping Cassini's High-Gain Antenna on Earth-point, the reaction wheel speeds were adjusted to the required values.
 
If you looked south before dawn today, you'd have seen Saturn in a triangle with the Moon below and the star Spica to the right. The reddish object to the right of the trio was Mars.


Tuesday, Jan. 17 (DOY 361)

The background sequence S72 was approved today; it will be uplinked Jan.20 and begin executing on Jan. 24. Allocations of Deep Space Network station assignments for Cassini had not been completed prior to sequence approval, so the need for real-time commands to minimize science data loss will be determined after final DSN allocations have been made; these are expected at the end of January.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 01/23/2012 02:12 PM
The two faces of Titan's dunes
 
23 January 2012

A new analysis of radar data from the international Cassini spacecraft has revealed regional variations amongst Titan's sand dunes. The result yields new clues to the giant moon's climatic and geological history.

http://www.esa.int/esaCP/SEMX5NH8RXG_index_0.html
Title: Re: NASA - Cassini updates
Post by: jacqmans on 01/23/2012 02:28 PM
News release: 2012-021                                                                     Jan. 23, 2012

Cassini Sees the Two Faces of Titan's Dunes

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2012-021&cid=release_2012-021

A new analysis of radar data from NASA's Cassini mission, in partnership with the European Space Agency and the Italian Space Agency, has revealed regional variations among sand dunes on Saturn's moon Titan. The result gives new clues about the moon's climatic and geological history.

Dune fields are the second most dominant landform on Titan, after the seemingly uniform plains, so they offer a large-scale insight into the moon's peculiar environment. The dunes cover about 13 percent of the surface, stretching over an area of 4 million square miles (10 million square kilometers). For Earthly comparison, that's about the surface area of the United States.

Though similar in shape to the linear dunes found on Earth in Namibia or the Arabian Peninsula, Titan's dunes are gigantic by our standards. They are on average 0.6 to 1.2 miles (1 to 2 kilometers) wide, hundreds of miles (kilometers) long and around 300 feet (100 meters) high. However, their size and spacing vary across the surface, betraying the environment in which they have formed and evolved.

Using radar data from the Cassini spacecraft, Alice Le Gall, a former postdoctoral fellow at NASA's Jet Propulsion Laboratory, Pasadena, Calif., who is currently at the French research laboratory LATMOS, Paris, and collaborators have discovered that the size of Titan's dunes is controlled by at least two factors: altitude and latitude.

In terms of altitude, the more elevated dunes tend to be thinner and more widely separated. The gaps between the dunes seem to appear to Cassini's radar, indicating a thinner covering of sand. This suggests that the sand needed to build the dunes is mostly found in the lowlands of Titan.

Scientists think the sand on Titan is not made of silicates as on Earth, but of solid hydrocarbons, precipitated out of the atmosphere. These have then aggregated into grains 0.04 inch in size by a still unknown process.

In terms of latitude, the sand dunes on Titan are confined to its equatorial region, in a band between 30 degrees south latitude and 30 degrees north latitude. However, the dunes tend to be less voluminous toward the north. Le Gall and colleagues think that this may be due to Saturn's elliptical orbit.

Titan is in orbit around Saturn, and so the moon's seasons are controlled by Saturn's path around the sun. Because Saturn takes about 30 years to complete an orbit, each season on Titan lasts for about seven years. The slightly elliptical nature of Saturn's orbit means that the southern hemisphere of Titan has shorter but more intense summers. So the southern regions are probably drier, which implies they have less ground moisture. The drier the sand grains, the more easily they can be transported by the winds to make dunes. "As one goes to the north, we believe the soil moisture probably increases, making the sand particles less mobile and, as a consequence, the development of dunes more difficult." says Le Gall.

Backing this hypothesis is the fact that Titan's lakes and seas are not distributed symmetrically by latitude. These reserves of liquid ethane and methane are predominantly found in the northern hemisphere, suggesting again that the soil is moister toward the north and so, again, the sand grains are less easy to transport by the wind.

"Understanding how the dunes form as well as explaining their shape, size and distribution on Titan's surface is of great importance to understanding Titan's climate and geology because the dunes are a significant atmosphere-surface exchange interface", says Nicolas Altobelli, ESA's Cassini-Huygens project scientist. "In particular, as their material is made out of frozen atmospheric hydrocarbon, the dunes might provide us with important clues on the still puzzling methane/ethane cycle on Titan, comparable in many aspects with the water cycle on Earth."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the U.S. and several European countries.

For more information about the Cassini mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .
Title: Re: NASA - Cassini updates
Post by: racshot65 on 01/23/2012 05:30 PM
Closest Dione Flyby

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4453


Past Night

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4454
Title: Re: NASA - Cassini updates
Post by: racshot65 on 01/27/2012 06:45 AM
Quote
Cassini Significant Events 01/18/2012 - 01/24/2012

Capture of the telemetry data that is carried on Cassini's 1-way downlink signal, whose frequency is based on the Auxiliary Oscillator in the absence of an operable Ultrastable Oscillator (USO), continues to be normal. The most recent spacecraft tracking and telemetry data were acquired on Jan. 24 from the Deep Space Network 70 meter Deep Space Station 43 at Canberra, Australia. The Cassini spacecraft is in an excellent state of health with all subsystems operating normally except for the Cassini Plasma Spectrometer remaining powered off and the anomalous USO. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

While the spacecraft started inward from apoapsis, Saturn and Titan were again observed with the Optical Remote Sensing (ORS) instruments. The Cassini Infrared Spectrometer (CIRS) measured oxygen compounds (H2O, CO2) in Saturn's stratosphere as a function of latitude, and the Imaging Science Subsystem (ISS) measured winds. The Ultraviolet Imaging Spectrograph imaged Titan and Saturn in the extreme- and far-ultraviolet parts of the spectrum, and ISS led a joint-ORS photometric measurement of Saturn known as an emission-angle scan. CIRS acquired a Saturn mid-infrared map to determine upper troposphere and tropopause temperatures. On Tuesday, ISS observed the small, irregular moon Siarnaq from approximately 26 million kilometers away. Preparations were made for the 56th Project Science Group meeting to be held next week at JPL.
 

Wednesday, Jan. 18 (DOY 018)

Today the Spacecraft Operations Office opened Incident-Surprise-Anomaly report (ISA) #51031, "Z-Sigma Spike on 2012-013" to document an incident that occurred on Jan. 13. In Cassini's Attitude & Articulation Control Subsystem, the Z-sigma ratio compares the measured brightness of a star in the Stellar Reference Unit (SRU) to that expected. It reached a high value of 11, and persisted for 41 realtime interrupts (1/8 second each) during a rotation of the spacecraft. There were no bright bodies in the SRU field of view at the time, which is usually the cause for Z-sigma excursions. The excursion was not sufficient to trigger a fault response, and analysis of the event is continuing.

The Encounter Strategy Meeting for Titan encounters T-81 and T-82 was held today.


Thursday, Jan. 19 (DOY 019)

This week, the Navigation team has been re-converging Cassini's trajectory solution based on tracking data acquired after execution of Orbit Trim Maneuver #306.


Friday, Jan. 20 (DOY 020)

The S72 Background Sequence Part 1 was uplinked today. Its 6,743 timed commands will execute over a period of 37 days. A Reaction Wheel Bias activity for DOY 024 was uplinked separately.

As part of the investigation of ISA #50901, "Loss of Cassini spacecraft 1-way Downlink Signal", the Ultrastable Oscillator (USO) was enabled today for about an hour (recall the USO was power cycled Jan. 9). Deep Space Station 43 in Canberra, Australia, was tracking Cassini, but observed no normal signal from the USO. The Radio Science team observed a wide swath of the radio spectrum at X-band and S-band frequencies using Station 43's Radio Science Receiver, and their results were as expected for a nonfunctioning USO. There was no loss of science telemetry data since the playback had been commanded to pause.
 

Sunday, Jan. 22 (DOY 022)

Cassini's X-band radio receiver was utilized today in a test of the Deep Space Network's uplink polarization isolation. This test was designed to troubleshoot problems experienced with the New Horizons Spacecraft Radio Science Experiment in 2011 (New Horizons encounters Pluto in 2015). The uplink from Station 14 at Goldstone, California, was configured four ways: right- and left-hand circular, each with and without the dichroic plate (a frequency-band separating device) extended into the microwave path. The test provided data that, along with design analysis of the dichroic plate, will be used to characterize DSN performance.

 
Monday, Jan. 23 (DOY 023)

The feature "Cassini Sees the Two Faces of Titan's Dunes" was published on the Cassini public website:

http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20120123/


Tuesday, Jan. 24 (DOY 024)

Background command sequence S71 completed execution today. The start of S72, expected at 4:14 p.m. PST Earth-receive time, could not be verified because of a shortened tracking station allocation.

Contingency S72-deactivate commands were approved and placed on the shelf, as standard preparation in case of an anomaly.

The Attitude and Articulation Control Subsystem executed a Reaction Wheel Bias activity while Cassini's High-Gain Antenna was off Earth-point.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 01/30/2012 05:27 PM
Dione on a Diagonal

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4457
Title: Re: NASA - Cassini updates
Post by: racshot65 on 02/03/2012 04:10 PM
Quote
Cassini Significant Events 01/25/2012 - 01/31/2012

The most recent spacecraft tracking and telemetry data in this reporting period were acquired on Feb. 1 from the Deep Space Network 34 meter Station 26 at Goldstone, California. The Cassini spacecraft is in an excellent state of health with all subsystems operating normally except for the known issues with the Cassini Plasma Spectrometer and the Ultrastable Oscillator. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

This week, command sequence S72 started its science observations with a Titan Meteorological Campaign, in which the Imaging Science Subsystem (ISS) looked for cloud events. The Ultraviolet Imaging Spectrograph (UVIS) then executed slow scans in the extreme- and far-ultraviolet across Saturn's illuminated hemisphere. The Visual and Infrared Mapping Spectrometer (VIMS) concentrated on the remains of the storm in Saturn's northern hemisphere, which has been raging since December 2010. Scientists think the String of Pearls (http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20061011/) may be hidden beneath the storm, and after the storm wanes will try to discover whether the feature may have been destroyed by the tempest. ISS then acquired images over a range of latitudes at low, medium, and high emission angles as the planet rotated. (Emission angle is the angle between the camera boresight and a line normal to the surface point being imaged; straight down is zero degrees.)

The Composite Infrared Spectrometer (CIRS) mapped Saturn's prime meridian from the north pole to the equator to determine the upper troposphere and tropopause temperatures with spatial resolutions of about two degrees of latitude and longitude. Following this, VIMS acquired a high spatial resolution map of the dynamics of Saturn's deep atmosphere. VIMS imaged the same area twice, measuring winds via motions of the clouds. Since these observations were made while the spacecraft was near periapsis, clouds as small as 300 kilometers wide were detectable.

RADAR mapped the same deep region at and around periapsis, obtaining radiometry data at microwave wavelengths much longer than those seen by VIMS. These RADAR maps looked for ammonia gas to reveal the variability of this condensable constituent over the same area where VIMS mapped clouds (formed either via chemical reaction with hydrogen sulfide, thus forming ammonia hydrosulfide clouds, or via direct condensation into ammonia clouds). Unfortunately, this carefully collected RADAR data set and most of the corresponding VIMS data were lost when heavy Australian summer rainstorms drowned out Cassini's signal while it was arriving at Earth on Sunday, January 29.

Targeted Titan encounter T-81 then executed perfectly on January 30, as detailed below.


Wednesday, Jan. 25 (DOY 025)

The S72 background command sequence went active on the spacecraft today. The Cosmic Dust Analyzer instrument turned on heaters to perform a routine 15-hour long decontamination activity.


Thursday, Jan. 26 (DOY 026)

JPL flags flew at half-mast as a NASA-wide Day of Remembrance was observed in honor of the Apollo 1, Challenger, and Columbia crews, as well as other members of the NASA family who have died supporting NASA's mission.

The S74 Sequence Implementation Process kick-off meeting was held today.

 
Attitude and Articulation Control Subsystem (AACS) engineers read out the spacecraft's Reaction Wheel Assembly revolution counter, and then reset it to 0 counts. This is done about every six months to maintain an accurate accounting of wheel usage and avoid rollover of the counter.

It was discovered that the Cassini remote Science Operations Planning Computers in the ground system were unable to obtain data from some of the servers at JPL that were upgraded last week. Additional server upgrades have been postponed, and the previous version of software was re-installed to restore service.


Friday, Jan. 27 (DOY 027)

Orbit Trim Maneuver 308, the Titan T-81 cleanup maneuver, is being prepared this week to execute on Feb. 2 local time.


Saturday, Jan. 28 (DOY 028)

Cassini passed through periapsis this morning, about 206,000 kilometers above Saturn's cloud tops, which is the closest point to the planet for this orbit. Relative to Saturn, Cassini was traveling 58,187 kilometers per hour.


Sunday, Jan. 29 (DOY 029)

AACS executed a Reaction Wheel Bias maneuver while Cassini was not being tracked from Earth. Using thrusters to maintain attitude, the reaction wheel speeds were set to the required values.


Monday, Jan. 30 (DOY 030)

During the high-altitude Titan T-81 encounter, ISS performed high-resolution observations around closest approach (31,131 kilometers) along Titan's leading hemisphere at high southern latitudes, including a late view of Ontario Lacus before the Sun sets for southern winter. ISS also "rode along" (took advantage of instrument pointing) with CIRS inbound high-phase angle observations and outbound observations over Titan's anti-Saturnian hemisphere at low phase angles. This encounter provided one of Cassini's last views of Titan's high southern latitudes. VIMS rode along with ISS looking for lakes in the south polar region.

Inbound and outbound UVIS observations obtained an image cube of Titan's atmosphere at extreme- and far-ultraviolet wavelengths by sweeping its slit across the disk. These cubes provided spectral and spatial information on nitrogen emissions, hydrogen emission and absorption, absorption by simple hydrocarbons, and the scattering properties of haze aerosols. This was one of many such cubes gathered over the course of the mission to provide latitude and seasonal coverage of Titan's middle atmosphere and stratosphere.

During the flyby, the Radio and Plasma Wave Science instrument (RPWS) measured thermal plasmas in Titan's ionosphere and surrounding environment, searched for lightning in Titan's atmosphere, and investigated the interaction of Titan with Saturn's magnetosphere.

More details about this encounter are available at: http://saturn.jpl.nasa.gov/mission/flybys/titan20120130/.

Back on Earth, Cassini's 56th Project Science Group meeting convened at JPL today; about 130 scientists are in attendance at various meetings and workshops throughout the week.

Near the end of the day, AACS executed a Reaction Wheel Bias maneuver while Cassini's high-gain antenna was off Earth-point.
 

Tuesday, Jan. 31 (DOY 031)

Starting at midnight Pacific time, Deep Space Station 14, the 70 meter aperture at Goldstone, California, began capturing realtime tracking data (Doppler and range for navigation), and playback of the telemetry that had been stored on Cassini's Solid-State Recorder during the Titan T-81 encounter. All of the data were safely down by 11:00 a.m. local. For background on telecommunications in general, see: http://www.jpl.nasa.gov/basics/bsf10-1.php.

Since approach science began in January, 2004, there have been 258,340 ISS images planned, commanded, acquired, and downlinked. Of these, only 8 percent have suffered any missing data. VIMS has acquired 128,946 cubes in the same time frame, with a similar rate of loss. Raw images from ISS are always posted online soon after receipt at: http://saturn.jpl.nasa.gov/photos/raw/.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 02/08/2012 12:39 PM
Rings and Enceladus

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4458
Title: Re: NASA - Cassini updates
Post by: racshot65 on 02/09/2012 08:31 AM
Rev161: Feb 9 - Mar 1 '12

http://www.ciclops.org/view/7080/Rev161
Title: Re: NASA - Cassini updates
Post by: racshot65 on 02/10/2012 08:18 AM
Quote
Cassini Significant Events 02/01/2012 - 02/07/2012

The most recent spacecraft tracking and telemetry data in this reporting period were acquired on Feb. 8 from the Deep Space Network 70 meter Station 14 at Goldstone, California. The Cassini spacecraft is in an excellent state of health with all subsystems operating normally except for the known issues with the Cassini Plasma Spectrometer and the Ultrastable Oscillator. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

This week's science activities began with multi-instrument observations of Titan from as far as 2.8 million kilometers away, as Cassini continued moving towards apoapse. These activities included a RADAR radiometry observation and a calibration, and observations by the Composite Infrared Spectrometer (CIRS), Imaging Science Subsystem (ISS) and the Visual and Infrared Mapping Spectrometer (VIMS) for atmospheric and cloud monitoring. Following this, the Cosmic Dust Analyzer (CDA) made a 13.5 hour interstellar dust observation.

Later, ISS performed observations of some of Saturn's small inner moons (part of the Satellite Orbit Campaign), including Janus and Polydeuces, to improve understanding of the orbits of these small satellites. This was followed by a 9.5 hour search for Trojan satellites around the L5 Lagrange point, 60 degrees behind Titan in its orbit.

Finally, ISS made some additional observations in the Satellite Orbit Campaign, and then CIRS, ISS and VIMS made an 11 hour Titan observation from a distance of more than 3.6 million kilometers.
 

Wednesday, Feb. 1 (DOY 032)

Yesterday the second half of the column celebrating the work of Dr. Jean-Pierre Lebreton, who before retiring was the European Space Agency Project Scientist and Mission Manager for the Huygens mission to Titan, was posted to the Cassini web site. See:

http://saturn.jpl.nasa.gov/news/cassiniinsider/insider20120131/

Today Deep Space Station 26, a 34 meter Beam Waveguide antenna at Goldstone, performed a monopulse calibration of value to Radio Science Ka-band experiments. The calibration caused unexpected antenna movement and a short loss of Cassini data.

The Reaction Wheel Assembly Bias Optimization Tool identified a segment in the S74 command sequence, which is under construction, that had to be reworked to avoid placing a redundant bias in the Radio Science Enceladus observation keep-out zone. Negotiations for Deep Space Network resource allocations for this sequence have started; the first two days of the ten-week sequence are completed.
 

Thursday, Feb. 2 (DOY 033)

Orbit Trim Maneuver #308, the Titan 81 cleanup maneuver, was successfully executed today Pacific Time (Feb. 3 Universal Time). With a burn duration of 124.37 seconds on Reaction Control Subsystem thrusters, it provided the spacecraft a delta-V of 0.137 m/sec, targeting Cassini to the T-82 aimpoint. This was the second maneuver designed using the new Monte software, and the first prepared with Maneuver Automation Software v9.2. This version of the software allows the main engine assembly heaters to be powered off for the backup maneuver opportunity, avoiding a thermal cycle.

The Instrument Operations (IO) team and Multi Mission Image Processing Laboratory (MIPL) swapped processes to and from computer hardware requiring patch and firmware upgrades. During this activity, the MIPL database, servers, Cassini Atlas, and MIPL file system were unavailable.
 

Friday, Feb. 3 (DOY 034)

Nominal IO and MIPL operations resumed.

The Attitude and Articulation Control Subsystem executed a Reaction Wheel Bias maneuver while Cassini was being tracked from Earth following the Orbit Trim Maneuver. While thrusters maintained attitude, the reaction wheel speeds were set to the required values.

On the ground, a new suite of Telemetry Channel Parameter Tables, called Tour-12, has been installed on test workstations, and on one operations workstation for "soak" testing. Plans are to distribute the files to all users next week pending a successful outcome of the testing.


Saturday, Feb. 4 (DOY 035)

JPL conducted a 5-hour training session in partnership with the California Afterschool Network for 60 leaders and site coordinators of San Bernardino Unified School District's "Creative Before and Afterschool Programs for Success" (CAPS). The attendees pursued hands-on activities from the NASA/JPL "Jewel of the Solar System" activity guide on Saturn and Cassini for grades 4 and 5. The workshop was visited by the CAPS leadership.


Monday, Feb. 6 (DOY 037)

A Y-thruster-pair calibration took place today. This annual event allows Navigation and Attitude Control teams to validate the force-balance of the coupled Y-thruster pairs. Navigation will analyze Doppler tracking data as part of the T-81 to T-82 spacecraft ephemeris reconstruction, looking for indications of any unevenness, important because the Y-Bias maneuvers are performed so often. Those maneuvers are described here:

http://saturn.jpl.nasa.gov/news/cassiniinsider/insider20091027/
 

Tuesday, Feb. 7 (DOY 038)

The Radio Science Subsystem Team performed a Radio Frequency Instrument Subsystem Periodic Instrument Maintenance activity today. The spacecraft's Ka-band transmitter was turned on and observed. Normally this kind of activity also measures performance of the Ultrastable Oscillator, but due to the current anomaly only the Auxillary Oscillator was seen.

Seventy-five packages were mailed today to the teachers whose students participated in the Cassini Scientist for a Day essay contest. Each student and teacher received a certificate of participation, and all teachers received a package of Cassini educational materials. Winners, finalists, and honorable mention recipients received special certificates as well. To see the winning essays, visit: http://saturn.jpl.nasa.gov/education/scientistforaday10thedition/winners2011/
Title: Re: NASA - Cassini updates
Post by: racshot65 on 02/13/2012 05:17 PM
Rhea Before Titan

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4462
Title: Re: NASA - Cassini updates
Post by: racshot65 on 02/17/2012 06:47 PM
Quote
Cassini Significant Events 02/08/2012 - 02/14/2012

The most recent spacecraft tracking and telemetry data in this reporting period were acquired on Feb. 14 from the Deep Space Network 34 meter Station 55 in Madrid, Spain. The Cassini spacecraft is in an excellent state of health. All subsystems are operating normally except for the issues being worked with the Cassini Plasma Spectrometer and the Ultrastable Oscillator. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

This week the Cassini science instruments made several observations called TEAs - Titan Exploration from Apoapsis. This campaign makes frequent distant observations over periods of days to weeks under illumination at low to moderate phase angles. Rain clouds are infrequent on Titan, so TEA observations provide a good chance to document coincident atmospheric and surface changes. The Imaging Science Subsystem (ISS), the Composite Infrared Spectrometer (CIRS), and the Visual and Infrared Mapping Spectrometer (VIMS) participate in TEAs.

The ISS team performed another observation in its Satellite Orbit Campaign, observing several small inner moons, and the VIMS team conducted several observations in the Saturn Storm Watch series and the Titan Monitoring Campaign.


Wednesday, Feb. 8 (DOY 039)

The Attitude and Articulation Control Subsystem team performed a calibration of the prime Inertial Reference Unit, which required rotating Cassini about its X, Y, and Z axes. Gyro calibrations such as this are done about once per year as a system performance check.

The Magnetometer (MAG) performed a calibration while the spacecraft was rolling about its Z axis and keeping Cassini's High-Gain Antenna pointed on Earth for communications.

The Ultraviolet Imaging Spectrograph (UVIS) conducted an interplanetary hydrogen survey from out near apoapsis in Saturn orbit.


Thursday, Feb. 9 (DOY 040)

Today Cassini passed through apoapsis at 5,276 kilometers per hour with respect to Saturn, at an altitude of 2.9 million kilometers. This marks the start of Saturn Orbit #161, which has a period of 23.5 days and near-equatorial inclination.

The Cosmic Dust Analyzer (CDA) took advantage of Cassini's distance from Saturn to undertake several long-duration observations of the interstellar dust passing through the solar system.

The Attitude and Articulation Control Subsystem executed a reaction wheel Y-bias maneuver to adjust wheel speeds, while Cassini was off Earth point.
 
The Cassini Spacecraft Operations Office met with JPL Division 33 (Communications, Tracking & RADAR) personnel today to discuss further troubleshooting on Cassini's anomalous Ultrastable Oscillator (USO). A review will be held soon to propose a test designed to check out the USO using Deep Space Transponder-B (DST-B) on the spacecraft without turning off DST-A, which is prime.
 

Friday, Feb. 10 (DOY 041)

Orbit trim maneuver #309 was planned for today, but it was deemed unnecessary and cancelled. The Navigation team's orbit determination solution estimated Cassini to be only about 3 kilometers from its aimpoint for the upcoming Titan T-82 flyby and 0.5 seconds off in timing without the maneuver.

MAG performed an 8-hour calibration while rotating the spacecraft about its X-axis.


Sunday, Feb. 12 (DOY 043)

The Deep Space Network conducted seven 9-hour tracking sessions with Cassini during the week without any losses of Telemetry, Tracking (Doppler and Ranging), Command or Radio Science data.


Monday, Feb. 13 (DOY 044)

The Navigation team took five images of Enceladus against the background stars for purposes of Optical Navigation.

Simulation coordination and procedure review meetings were held this week to discuss RADAR tests for the upcoming Titan T-83 and T-84 flybys in the S73 command sequence which is currently in development. In the Cassini Integration and Test Lab, command testing was conducted for both activities, and the test report for T-83 was released today. An Encounter Strategy Meeting for the Titan T-82 through Enceladus E-17 encounters also took place today.


Tuesday, Feb. 14 (DOY 045)

Today, visitors to the Cassini website http://saturn.jpl.nasa.gov/ were greeted with a fine bouquet of red roses. The artwork was later archived here: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4463.

A mission planning forum was held to review propellant usage during the S71 sequence, and the status of the propellant budgets. A "consumables" status is provided on a regular basis so the Project can remain informed of propellant usage and end-of-mission margins.

In anticipation of the Titan T-82 encounter coming up Sunday, a flyby web page was set up. As usual, related images and news will be posted to it. View the page here: http://saturn.jpl.nasa.gov/mission/flybys/titan20120219/.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 02/20/2012 04:41 PM
Cut-Off Rings

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4465
Title: Re: NASA - Cassini updates
Post by: racshot65 on 02/23/2012 08:05 PM
Quote
Cassini Significant Events 02/15/2012 - 02/21/2012

The most recent spacecraft tracking and telemetry data in this reporting period were acquired on Feb. 21 from the Canberra, Australia, Deep Space Network 70 meter Station 43. The Cassini spacecraft is in an excellent state of health. All subsystems are operating normally except for the issues being worked with the Cassini Plasma Spectrometer and the Ultrastable Oscillator. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

The highlight for this week was the flyby of Saturn's largest moon, Titan, on Sunday. Flyby altitude was 3,803 kilometers.

The week included four PIEs -- Pre-Integrated Events. In the first two, the Imaging Science Subsystem (ISS) conducted Enceladus plume observations. In second pair, the Visual and Infrared Mapping Spectrometer (VIMS) observed two Saturn stellar occultations, acquiring spectral data while Cassini's motion caused the distant stars to go behind Saturn's upper atmosphere.


Wednesday, Feb.15 (DOY 046)

An Engineering Activities Review was held today for the S75 background sequence which is currently in development.


Thursday, Feb. 16 (DOY 047)

ISS, VIMS, and the Composite Infrared Spectrometer (CIRS) performed another observation in the Titan monitoring campaign. CIRS then observed Saturn for 12 hours to measure oxygen compounds (H2O and CO2) in the stratosphere.

Orbit Trim Maneuver 310, the T-82 approach maneuver, was commanded to execute during its backup window tonight (Feb. 17 Universal Time). This was a Reaction Control Subsystem (RCS thruster) burn with a duration of 12.88 seconds and delta-V of approximately 0.02 meters per second. The maneuver was done during the backup window because the reaction wheel speed solution was more favorable, and the need for a time of flight bias in the targeting was avoided.
 

Friday, Feb. 17 (DOY 048)

ISS, CIRS and VIMS made a 19-hour edge-on observation of the E ring at moderate phase illumination.

The main engine cover was deployed to its closed position.

The NASA Engineering and Safety Center (NESC) team, the Cassini Spacecraft Operations Office, and the CAPS team at the Southwest Research Institute in San Antonio have been meeting weekly since November 2011, to discuss the Cassini Plasma Spectrometer (CAPS) and Radioisotope Thermoelectric Generator (RTG) power bus imbalance anomaly. A preliminary assessment was given orally today. Cassini is now in the process of convening a briefing to JPL upper management for next month.
 

Saturday, Feb. 18 (DOY 049)

On approach to Titan, CIRS measured stratospheric temperatures and chemical species in Titan's atmosphere. ISS had a one-hour unilluminated prime observation primarily for photometry, i.e. measuring Titan's nighttime brightness, while VIMS stared at Titan for global mapping.


Sunday, Feb. 19 (DOY 050)

Titan encounter T-82 took place today.

CIRS performed a wide variety of observations, including limb sounding and mapping of surface and atmospheric temperatures. Far-infrared limb sounding near closest approach reached the most northerly latitude of the Solstice Mission so far, at 75 degrees. This provides insights into the atmospheric circulation in Titan's north polar region as it transitions from spring to summer, and helps search for possible condensates. VIMS rode along to detect clouds, monitoring climatic changes after the equinox.
 
T-82 was a dusk sector equatorial flyby across Titan's magnetic tail. Similar in geometry, but at a lower altitude than T-78 last September, it enables Cassini to better characterize the magnetotail by sampling it at different radial distances from Titan at a fixed local time.

In addition to scientific investigation of Titan, each targeted Titan flyby also provides an orbital momentum exchange that modifies Cassini's orbit about Saturn according to plan. T-82 reduced Cassini's orbit period from 23.5 days to 17.9 days.

The T-82 page will be populated with data from the encounter, available here: http://saturn.jpl.nasa.gov/mission/flybys/titan20120219/.


Monday, Feb. 20 (DOY 051)

Cassini passed through periapse of Saturn Orbit #161 at 68,375 kilometers per hour early today. At this closest point to Saturn, the spacecraft was about 54,000 kilometers outside the F ring.

Cassini turned its High-Gain Antenna toward Earth and downlinked all the T-82 telemetry data in 9.5 hours. Deep Space Station 63 at Madrid, Spain, captured every bit.

The Ultraviolet Imaging Spectrograph (UVIS) was prime for observations of Saturn's aurorae.
 

Tuesday, Feb. 21 (DOY 052)

The Ion and Neutral Mass Spectrometer (INMS) measured neutral molecules in Saturn's equatorial plane.

The main engine cover was stowed in its open position. This marks the 71st in-flight cycle.

During the week, 312 VIMS cubes were generated and distributed, as were 343 ISS images, including one image for optical navigation and 64 for support imaging.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 02/26/2012 09:06 AM
The Many Moods of Titan

http://www.jpl.nasa.gov/news/news.cfm?release=2012-048
Title: Re: NASA - Cassini updates
Post by: racshot65 on 02/27/2012 04:14 PM
Beside a Giant

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4470
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/01/2012 08:25 AM
Rev162: Mar 1 - Mar 18 '12

http://www.ciclops.org/view/7097/Rev162
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/02/2012 07:14 AM
Quote
Cassini Significant Events 02/22/2012 - 02/28/2012

The most recent spacecraft tracking and telemetry data in this reporting period were acquired on Feb. 29 from the Goldstone, California, Deep Space Network 34 meter Station 26. The Cassini spacecraft is in an excellent state of health. All subsystems are operating normally except for the issues being worked with the Cassini Plasma Spectrometer and the Ultrastable Oscillator. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

During Cassini's current orbit of Saturn, many observations have centered on Magnetospheric and Plasma Science (MAPS). Measurements made this week by these direct-sensing instruments included equatorial inner magnetosphere sampling, low latitude prime pointing for MAPS as the spacecraft nears apoapsis, and Cassini Apoapses for Kronian Exploration (CAKE) observations. The objective is to acquire nearly complete and continuous measurements of Saturn's outer magnetosphere and magnetosheath. By doing this once every four to six months, MAPS can sample and measure Saturn's magnetosphere over a solar cycle, from one solar minimum to the next, and investigate magnetospheric periodicities and how the Saturn kilometric radiation (SKR) period is imposed on the magnetosphere.
 

Wednesday, Feb. 22 (DOY 053)

The Ultraviolet Imaging Spectrograph (UVIS) and the Visual and Infrared Mapping Spectrometer (VIMS) enjoyed a period of fixed pointing at Saturn's auroral oval, then UVIS surveyed interplanetary hydrogen from its vantage point a million kilometers above Saturn's atmosphere.

An Attitude & Articulation Control Subsystem Reaction Wheel bias maneuver was executed today, setting wheel speeds as needed while thrusters maintained the spacecraft's attitude. Last week's report skipped mention of three such maneuvers during that period.

Today's Orbit Trim Maneuver 311, a cleanup maneuver for last week's Titan T-82 flyby, was canceled. Cancellation was made possible by the T-82 miss being small and in a favorable direction.

Cassini Instrument Operations Multi Mission Image Processing Laboratory (MIPL) used a downtime today to swap the database and File Exchange Interface servers to alternate hardware to continue firmware and patch updates.
 

Thursday, Feb. 23 (DOY 054)

Normal MIPL processing resumed.

The feature "The Many Moods of Titan" was published on the Cassini website:

http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20120223/

The S73 command sequence developers held a Sequence Change Request (SCR) disposition meeting. Four SCRs were approved.

A Cassini-internal meeting was held today to discuss procedure and scheduling options for turning the Cassini Plasma Spectrometer (CAPS) instrument back on (recall it was turned off last June due to concerns over some problems internal to the instrument and others associated with RTG #3). Final approval will depend on the outcome of a review with JPL upper management next week.
 

Friday, Feb. 24 (DOY 055)

The Composite Infrared Spectrometer (CIRS), the Imaging Science Subsystem (ISS), and VIMS carried out Titan Monitoring Campaign observations to look for long term cloud activity, then VIMS and ISS conducted Saturn Storm Watch observations. The Navigation team acquired an Optical Navigation image of Enceladus with two cataloged stars in the background. It has since been processed on the ground in preparation for the March 27 flyby of Enceladus at 75 kilometer altitude.
 

Saturday, Feb. 25 (DOY 056)

Viewed from anywhere on Earth these days, Saturn and Titan are a delight to see in a small telescope. With good optics you might also see moons Dione, Tethys, Rhea, and even Iapetus if it happens to have enough of its bright side facing Earth. Saturn rises in the east before midnight, and is well placed for viewing in the hours before dawn, sharing the sky with bright red Mars. Find out more about this month's night sky here: http://www.jpl.nasa.gov/video/index.cfm?id=1060


Sunday, Feb. 26 (DOY 057)

During the week the Deep Space Network carried out Cassini tracking activities from all three of its worldwide complexes using 70 and 34 meter apertures, and had zero data loss. The one-way light time to Cassini is currently one hour and fifteen minutes, and is decreasing as Earth moves closer to Saturn in its orbit around the sun.


Monday, Feb. 27 (DOY 058)

The Realtime Operations team uplinked Part 2 of the S72 background sequence and verified that the spacecraft properly received and stored all 6,114 of its commands.

A unique image is featured today. "Beside a Giant" shows Titan next to Saturn, and the small F ring shepherd moon Prometheus with its shadow on Saturn, and the shadow of the other shepherd Pandora, along with shadows of the main rings and the thin F ring. View the image here:

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4470

Cassini is discussed in a PBS OpEd article as an example of international collaboration in space:

http://to.pbs.org/wXVGpM
 

Tuesday, Feb. 28 (DOY 059)

During the week, 454 ISS images and 41 VIMS cubes were received and distributed.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/03/2012 09:03 AM
Cassini Detects Hint of Fresh Air at Dione

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2012-056&cid=release_2012-056

NASA’s Cassini spacecraft has “sniffed” molecular oxygen ions around Saturn’s icy moon Dione for the first time, confirming the presence of a very tenuous atmosphere. The oxygen ions are quite sparse – one for every 0.67 cubic inches of space (one for every 11 cubic centimeters of space) or about 2,550 per cubic foot (90,000 per cubic meter) – show that Dione has an extremely thin neutral atmosphere.

At the Dione surface, this atmosphere would only be as dense as Earth’s atmosphere 300 miles (480 kilometers) above the surface. The detection of this faint atmosphere, known as an exosphere, is described in a recent issue of the journal Geophysical Research Letters.

“We now know that Dione, in addition to Saturn’s rings and the moon Rhea, is a source of oxygen molecules,” said Robert Tokar, a Cassini team member based at Los Alamos National Laboratory, Los Alamos, N.M., and the lead author of the paper. “This shows that molecular oxygen is actually common in the Saturn system and reinforces that it can come from a process that doesn’t involve life.”

Dione’s oxygen appears to derive from either solar photons or energetic particles from space bombarding the moon’s water ice surface and liberating oxygen molecules, Tokar said. But scientists will be looking for other processes, including geological ones, that could also explain the oxygen.

“Scientists weren’t even sure Dione would be big enough to hang on to an exosphere, but this new research shows that Dione is even more interesting than we previously thought,” said Amanda Hendrix, Cassini deputy project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., who was not directly involved in the study. “Scientists are now digging through Cassini data on Dione to look at this moon in more detail.”

Several solid solar system bodies – including Earth, Venus, Mars and Saturn’s largest moon Titan – have atmospheres. But they tend to be typically much denser than what has been found around Dione. However, Cassini scientists did detect a thin exosphere around Saturn’s moon Rhea in 2010, very similar to Dione. The density of oxygen at the surfaces of Dione and Rhea is around 5 trillion times less dense than that at Earth’s surface.

Tokar said scientists suspected molecular oxygen would exist at Dione because NASA’s Hubble Space Telescope detected ozone. But they didn’t know for sure until Cassini was able to measure ionized molecular oxygen on its second flyby of Dione on April 7, 2010 with the Cassini plasma spectrometer. On that flyby, the spacecraft flew within about 313 miles (503 kilometers) of the moon’s surface.

Cassini scientists are also analyzing data from Cassini’s ion and neutral mass spectrometer from a very close flyby on Dec. 12, 2011. The ion and neutral mass spectrometer made the detection of Rhea’s thin atmosphere, so scientists will be able to compare Cassini data from the two moons and see if there are other molecules in Dione’s exosphere.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The Cassini plasma spectrometer team and the ion and neutral mass spectrometer team are based at Southwest Research Institute, San Antonio.

For more information about the Cassini mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .
Title: Re: NASA - Cassini updates
Post by: bolun on 03/05/2012 03:25 PM
Saturn and Titan

05 Mar 2012

Titan, Saturn's largest moon at 5150 km across, looks small here, pictured to the right of the gas giant in this infrared image taken by the Cassini spacecraft.

http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50112

and

http://www.esa.int/esaCP/SEMPWD7YBZG_index_0.html
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/06/2012 09:11 AM
Across to Prometheus

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4471
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/10/2012 10:25 AM
Cassini's E-12 through E-21 Trajectories

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4472
Title: Re: NASA - Cassini updates
Post by: dsmillman on 03/10/2012 12:04 PM
There is a spectacular flyover video of Enceladus at:

    vimeo.com/37689757



Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/12/2012 07:19 PM
Quote
Cassini Significant Events 02/29/2012 - 03/06/2012

The most recent spacecraft tracking and telemetry data were collected March 7 using the Deep Space Network's 34 meter Beam-Waveguide Station 25 at Goldstone in the California desert. The Cassini spacecraft is in an excellent state of health. All subsystems are operating normally except for the issues being worked with the Cassini Plasma Spectrometer and the Ultrastable Oscillator. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Twice this week, Cassini rotated to point its Imaging Science Subsystem (ISS), Composite Infrared Spectrometer (CIRS), and Visual and Infrared Mapping Spectrometer (VIMS) telescopes toward Saturn's largest satellite for more Titan Monitoring Campaign observations. At other times, the instruments were pointed toward Saturn for the Ultraviolet Imaging Spectrograph (UVIS) and ISS to measure and monitor the planet's aurorae.


Wednesday, Feb. 29 (DOY 060)

UVIS surveyed the abundance of interplanetary hydrogen by remote sensing from 2.4 million kilometers above Saturn.
Commands were sent to the spacecraft to do a "live" update of the running Inertial Vector Propagator. This ensures best instrument pointing for an observation of Saturn's large icy satellite Rhea next week.


Thursday, March 1 (DOY 061)

Apoapsis passage early today (Universal Time) marked the start of Cassini's 162nd orbit of Saturn. Having slowed to 5,463 kilometers per hour relative to the planet, the spacecraft begins its nine-day plunge, still in the equatorial plane, gathering speed on its arc back toward Saturn.


Friday, March 2 (DOY 062)

The Cosmic Dust Analyzer made direct measurements of interstellar dust particles as they interacted with the instrument. ISS carried out an 18-hour observation of the outer irregular satellite Thrymr to measure the rotational phase curve.

The feature "Cassini Detects Hint of Fresh Air at Dione" was posted online: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20120302/
The Attitude and Articulation Control Subsystem executed a Reaction Wheel Y-Bias maneuver to adjust wheel speeds while Cassini was off Earth point.


Saturday, March 3 (DOY 063)

The spacecraft rolled about its Z axis to perform a Magnetometer (MAG) calibration. There is an animation of a typical MAG roll here: http://1.usa.gov/xlYR7U


Sunday, March 4 (DOY 064)

Still some 2.2 million kilometers from Saturn, UVIS again surveyed the hydrogen in interplanetary space.

Cassini rolled for several hours to perform another MAG calibration, this time keeping its High-Gain Antenna dish trained on Earth to maintain two-way communications.

Commands for Orbit Trim Maneuver 312 were uplinked to the spacecraft using Deep Space Station 14 at Goldstone, California. The maneuver will execute March 9, but was uplinked early as a precaution; there would be a heavy delta-V cost if it were delayed.


Monday, March 5 (DOY 065)

Commands for the Cassini Plasma Spectrometer (CAPS) are still being issued from the S72 background sequence that is running, but since the instrument is turned off, there are no results. Pending the outcome of a review next week, it may be possible to turn CAPS back on before the sequence ends.
 

Tuesday, March 6 (DOY 066)

Cassini passed 717,800 kilometers from Titan on its way inbound toward Saturn; this occurred during a Deep Space Network tracking pass.

An "Insider's Cassini" article, "How to Plan Your Flyby" was published here:
http://saturn.jpl.nasa.gov/news/cassiniinsider/insider20120306/
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/12/2012 07:24 PM
Cassini Captures New Images of Icy Moon

http://www.jpl.nasa.gov/news/news.cfm?release=2012-069


The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2012-069&cid=release_2012-069

These raw, unprocessed images of Saturn's second largest moon, Rhea, were taken on March 10, 2012, by NASA's Cassini spacecraft. This was a relatively distant flyby with a close-approach distance of 26,000 miles (42,000 kilometers), well suited for global geologic mapping.

During the flyby, Cassini captured these distinctive views of the moon’s cratered surface, creating a 30-frame mosaic of Rhea's leading hemisphere and the side of the moon that faces away from Saturn. The observations included the large Mamaldi (300 miles, or 480 kilometers, across) and Tirawa (220 miles, or 360 kilometers, across) impact basins and the 29-kilometer (47-kilometer) ray crater Inktomi, one of the youngest surface features on Rhea (about 950 miles, or 1,530 kilometers, across).

All of Cassini's raw images can be seen at http://saturn.jpl.nasa.gov/photos/raw/ .

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena manages the mission for the agency's Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations team is based at the Space Science Institute in Boulder, Colo. JPL is a division of Caltech.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini .



Images
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4474
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4477
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4476
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4475
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4473
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/14/2012 07:42 PM
Cassini Spies Wave Rattling Jet Stream on Jupiter

http://www.jpl.nasa.gov/news/news.cfm?release=2012-070
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/14/2012 07:44 PM
Cassini Garners Top Honor From Air and Space Museum

http://www.jpl.nasa.gov/news/news.cfm?release=2012-071
Title: Re: NASA - Cassini updates
Post by: robertross on 03/15/2012 12:24 AM
There is a spectacular flyover video of Enceladus at:

    vimeo.com/37689757

Oh yes, indeed! Thanks for the link.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/16/2012 07:46 AM
Quote
Cassini Significant Events 03/07/2012 - 03/13/2012

The most recent spacecraft tracking and telemetry data were collected March 14 using the Deep Space Network's 70 meter Station 43 at Canberra, Australia. The Cassini spacecraft is in an excellent state of health. All subsystems are operating normally except for the issues being worked with the Cassini Plasma Spectrometer and the Ultrastable Oscillator. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

There were two Earth-based highlights this week. First, a review with JPL upper management Thursday of a recommendation made by the Cassini Project, the NASA Engineering and Safety Center, and the CAPS instrument team resulted in the decision to proceed with turning the Cassini Plasma Spectrometer (CAPS) back on. (Recall the instrument was turned off last June due to concerns over some problems internal to the instrument and others associated with Radioisotope Thermoelectric Generator #3.) Commands to turn CAPS on were prepared and approved, and will be sent to the spacecraft on March 16.

Second, the Cassini Mission was named the recipient of the top group honor from the Smithsonian's National Air and Space Museum, the Trophy for Current Achievement. Representatives from Cassini will receive the trophy on March 21 at a black-tie dinner in Washington, D.C. The full story appears here: http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20120314/.


Wednesday, March 7 (DOY 067)

The Optical Remote Sensing (ORS) instruments were pointed toward Saturn for the Ultraviolet Imaging Spectrograph (UVIS) and Imaging Science Subsystem (ISS) to measure and monitor the planet's aurorae.

The Sequence Implementation Process leads released Instrument Expanded Block command files in support of the S73 background sequence for the team to review.

The Downlink Ground Systems team set up a second Distributed Object Manager server and a client workstation for testing version A19.0 of the Advanced Multi-mission Operations System.
 

Thursday, March 8 (DOY 068)

ISS made an observation of Saturn's small irregular moon Jarnsaxa, which is about 6 kilometers in diameter, to characterize its rotation.

A graphic was published today showing Cassini's trajectories for upcoming targeted encounters of the icy moon Enceladus out through October 2015, which will include passes through the icy plumes for in-situ sampling by Cassini's direct-sensing instruments. It also illustrates the previous flybys E-12 through E-16. It can be viewed here: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4472
 

Friday, March 9 (DOY 069)

The small, dark irregular moon Mundilfari, which is about the same size as Jarnsaxa, was ISS's target for characterizing its rotation.

The closest approach to Titan for this orbit of Saturn occurred today, a "non-targeted" flyby at a distance of 864,013 kilometers. Titan Monitoring Campaign observations were performed today and will continue over the next few days.

Today's routine communications through the Deep Space Network were interrupted as planned when Cassini turned to use its High-Gain Antenna (HGA) as a shield for two hours while it passed through the potentially hazardous E ring. The backup Sun Sensor Assembly (SSA), whose aperture faces forward through the HGA, was powered on for this event and then back off again when no adverse effects were noted on the prime (or the backup) SSA from the dust hazard.
 

Saturday, March 10 (DOY 070)

If you noticed the Moon tonight, the creamy-white planet just up to its left was indeed Saturn, 1.33 billion kilometers from Earth.

Cassini passed through Saturn periapsis early today, going by at 68,215 kilometers per hour.

Orbit Trim Maneuver #312 was timed to occur right at periapsis to take advantage of the orbital "leverage" uniquely available there, minimizing propellant use. Firing the main engine provided a delta-V of 3.6 meters per second, targeting to the Enceladus E-17 flyby coming up on March 27. This maneuver was large enough to satisfy the requirement for at least a 5 second burn in any 400 day period for propellant line flushing.

Analysis for the Feb. 6 Y-thruster calibration was completed and documented. Results indicate that thrust mismatches are smaller than 2 percent.

The Attitude and Articulation Control Subsystem (AACS) executed a Reaction Wheel Assembly (RWA) bias maneuver to adjust wheel speeds while Cassini was on Earth point and being tracked by the Deep Space Network.

Cassini took advantage of three sequential non-targeted encounters today and turned the ORS instruments to Enceladus, then to Titan, and then to the large icy moon Rhea. The Rhea observations provided for regional mapping and a search for ring particles. Commands had been sent last week to update instrument pointing for the Rhea observations. See the feature, "Cassini Captures New Images of Icy Moon": http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20120312/
 

Sunday, March 11 (DOY 071)

UVIS performed an instrument calibration by observing the well-characterized star Spica (alpha Virginis). The Composite Infrared Spectrometer (CIRS) then observed Saturn for 12 hours, measuring oxygen compounds (H2O, CO2) in the stratosphere.

From Cassini's vantage point, Rhea transited in front of Dione while ISS observed for orbit determination purposes.

Following the recent RWA-driven pointing for science data collection, AACS performed another RWA bias maneuver while being tracked from Earth.
 

Monday, March 12 (DOY 072)

ISS observed a transit of Enceladus across Titan, again for orbit determination purposes. The Cosmic Dust Analyzer (CDA) performed a 13.5 hour observation of dust moving in a retrograde direction about Saturn.

The feature "Cassini Spies Wave Rattling Jet Stream on Jupiter" was published today, based on data collected when Cassini flew by Jupiter in 2000:

http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20120313/


Tuesday, March 13 (DOY 073)

The Magnetometer executed an 8 hour calibration while the spacecraft was rolling about its X-axis.

The Mission Planning Team delivered updates to its software today. One update incorporated a new leap-seconds file into the software. The other corrected a Daylight Saving Time bug in Deep Space Network tracking pass scheduling.

A Saturn atmosphere model was delivered for use in spacecraft analyses for the "proximal orbits" planned to begin in 2017. Periapsis for these 6.5-day orbits will be much closer than a spacecraft has ever come to Saturn before – passing between the upper atmosphere and the D ring's inner edge.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/16/2012 09:15 AM
Rev163: Mar 18 - Apr 5 '12

http://www.ciclops.org/view/7112/Rev163
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/20/2012 09:30 AM
Cassini Plasma Spectrometer Resumes Operations

http://www.jpl.nasa.gov/news/news.cfm?release=2012-078
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/20/2012 09:30 AM
Cassini Sees Saturn Stressing out Enceladus

http://www.jpl.nasa.gov/news/news.cfm?release=2012-079
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/23/2012 06:06 PM
Cassini Mission Receives Air and Space Museum Award

http://www.jpl.nasa.gov/news/news.cfm?release=2012-085
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/26/2012 02:16 PM
Quieted Storm

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4488
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/26/2012 04:21 PM
Quote
Cassini Significant Events 03/14/2012 - 03/20/2012

The most recent spacecraft tracking and telemetry data were collected March 21 using the Deep Space Network's 34 meter Station 25 at Goldstone, California. The Cassini spacecraft is in an excellent state of health. All subsystems are operating normally except for the issue being worked with the Ultrastable Oscillator. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

The Cassini Plasma Spectrometer (CAPS, off since June 2011) was powered back on on March 16 based on the unanimous agreement of the review board at the CAPS turn-on review held on March 8. All went as planned for both the instrument and the spacecraft during the turn-on. The high rail to chassis short internal to the instrument that was part of what prompted it to be turned off last June was not present, and no changes were seen in the bus voltages or currents when the turn-on occurred. On Tuesday, March 20, the high rail to chassis short in the CAPS instrument returned, generating the same condition that existed at the time the instrument was turned off. However, based on the tin whisker model developed by the NESC team, this condition is believed to be understood and is not expected to cause any problems for either the instrument or the spacecraft. The CAPS instrument has been left powered on and is sequenced to operate as originally planned for the 75 kilometer Enceladus flyby coming up on March 27.

Repeating observations this week included two by the Imaging Science Subsystem (ISS) and Visual and Infrared Mapping Spectrometer (VIMS) in the Titan Monitoring Campaign, seven by ISS and VIMS in the Saturn Storm Watch, and three by ISS in the Satellite Orbit Campaign. In the latter, Cassini points toward specific patches of sky near Saturn where small satellites may be found, including some discovered in recent years. Astrometric observations are made of their location in orbit about the planet to refine knowledge of their orbits. These observations can also catch small satellites never seen before.

While the spacecraft was near apoapsis, the Cosmic Dust Analyzer (CDA) made two multi-hour measurements of interstellar dust.
 

Wednesday, March 14 (DOY 074)

ISS observed the transit of Tethys across Dione for orbit determination purposes.

The Composite Infrared Spectrometer (CIRS) began a 23-hour mapping activity to determine temperatures in Saturn's upper troposphere and tropopause.

 
Thursday, March 15 (DOY 075)

During the past week, 3191 ISS images and 155 VIMS cubes were generated and distributed.
 

Friday, March 16 (DOY 076)

Orbit Trim Maneuver (OTM)-312A, an apoapsis maneuver using the Reaction Control Subsystem thrusters, provided Cassini a delta-V of approximately 100 mm/sec, targeting it to the Enceladus-17 encounter coming up on March 27.

CAPS was powered on via realtime command. The power-on activity was successful and the short circuit seen previously from the high rail to chassis was not present.

Realtime commands were sent to update the Sun-to-Saturn vector in the Inertial Vector Propagator.


Saturday, March 17 (DOY 077)

The Ultraviolet Imaging Spectrograph (UVIS) began an 8-hour scan of Saturn's magnetosphere in order to image hydrogen and oxygen.
 

Sunday, March 18 (DOY 078)

The Magnetometer (MAG) performed a 5-hour calibration using the Science Calibration Subsystem, which measures alignment of the individual MAG sensors.

Cassini passed through apoapsis today, marking the beginning of Saturn orbit #163. At an altitude of 2.4 million kilometers above Saturn and approximately in its equatorial plane, the spacecraft had slowed to 5,493 kilometers per hour relative to the planet.
 

Monday, March 19 (DOY 079)

UVIS began a 16-hour magnetosphere scan, again imaging hydrogen and oxygen.
 
Reaction-Wheel Assembly Bias Optimization Tool (RBOT) results were analyzed in the S74 RBOT meeting today, then an Encounter Strategy meeting for Enceladus encounters E-17 and E-18 took place.
 
JPL Division 33 (Communications, Tracking, & Radar) held a mini-review of Cassini's Deep Space Transponder/Ultra Stable Oscillator test proposal. Several actions were identified to be worked before moving on to the next step.


Tuesday, March 20 (DOY 080)

Just prior to returning to full science data collection, CAPS experienced another high rail short-circuit causing the spacecraft's electrical power subsystem to exhibit the same voltage-imbalanced state it had last June when CAPS was turned off. An anomaly meeting was held, and the decision was to continue as planned based on the current understanding of the phenomenon that is believed to be causing the shorts. The power subsystem design makes it fully compatible with operating in this condition. The decision to turn CAPS off last June was based on not understanding what was causing the shorts.

Eight command files were approved for the Instrument-Expanded Blocks that will be invoked by background sequence S73, which will be uplinked and start execution next month.

The Attitude and Articulation Control Subsystem (AACS) performed a Periodic Engineering Maintenance activity. As part of the routine exercise, Reaction Wheel #3 was powered on, spun up, and powered off again.

AACS executed a Reaction Wheel Assembly (RWA) bias maneuver to adjust wheel speeds; it completed just before turning to Earthpoint.

Radio Science executed a High-Gain Antenna boresight calibration by turning the spacecraft slightly and recording the variations in signal strength seen in the Deep Space Network receivers a one-way light-time (1 hour 13 minutes) later.
Title: Re: NASA - Cassini updates
Post by: bolun on 03/27/2012 12:01 PM
Cassini-Huygens Participating Scientists Research Announcement 2012

21 Mar 2012

The scientific community is invited to respond to the current Research Announcement to submit proposals for Participating Scientists to the Cassini-Huygens mission. This Research Announcement is published jointly by ESA, NASA and ASI. The deadline for submission of proposals is 4 May 2012.

 http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50171
Title: Re: NASA - Cassini updates
Post by: bolun on 03/27/2012 12:11 PM
How Cassini will end its days

http://www.bbc.co.uk/news/science-environment-17471128
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/27/2012 02:52 PM
Cassini to Make Closest Pass Yet over Enceladus South Pole

http://www.jpl.nasa.gov/news/news.cfm?release=2012-087
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/29/2012 12:34 PM
Icy Moons through Cassini's Eyes

http://www.jpl.nasa.gov/news/news.cfm?release=2012-091

Images:
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4490
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4491
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4492
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4493
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4494
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4495
Title: Re: NASA - Cassini updates
Post by: bolun on 03/29/2012 01:52 PM
Enceladus plumes and Dione

29 March 2012

The international Cassini spacecraft was on its way to its lowest pass yet over the south polar region of Saturn’s moon Enceladus when it took this image of the impressive plumes.
 
The plumes are jets of water ice and vapour, mixed with organic compounds. With this flyby coming within a mere 74 km, scientists hope to learn more about the composition, density and variability of these remarkable features of Enceladus. 

A day after the flyby, Cassini imaged Dione, another of Saturn’s moons. From a distance of 44 000 km, features like impact craters are clearly visible on the side of the moon that faces away from the Sun.

http://www.esa.int/export/SPECIALS/Cassini-Huygens/SEMZ6YGY50H_0.html
Title: Re: NASA - Cassini updates
Post by: Archibald on 03/29/2012 04:52 PM
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=1829.0;attach=387276;image

That's what I call a picture straight of a sci-fi movie. Amazing !
Title: Re: NASA - Cassini updates
Post by: racshot65 on 03/30/2012 04:14 PM
Quote
Cassini Significant Events 03/21/2012 - 03/27/2012

The most recent spacecraft tracking and telemetry data were collected on March 28 using the Deep Space Network's 70 meter Station 43 at Canberra, Australia; data from the Enceladus E-17 encounter were captured successfully. Aside from the issue in work with the Ultrastable Oscillator (see the Jan. 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health and all subsystems are operating normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

The Enceladus encounter E-17 occurred Tuesday, and by the end of the day, all the encounter observations resided as telemetry on Cassini's Solid-State Recorder. The playback to Earth didn't begin until Wednesday; it will be listed among next week's significant events. The E-17 webpage will include the data as they become available: http://saturn.jpl.nasa.gov/mission/flybys/enceladus20120306/
 

Wednesday, March 21 (DOY 081)

The Imaging Science Subsystem (ISS) spent 12 hours searching for possible satellites near the zone of stability 60 degrees ahead of Titan in its orbit about Saturn, known as the L4 Lagrange point.


Thursday, March 22 (DOY 082)

The Cosmic Dust Analyzer (CDA) spent 13.5 hours collecting data on interstellar dust.

An image was posted today showing the Cassini Program Manager accepting the 2012 Smithsonian National Air and Space Museum's Trophy for Current Achievement for the Cassini Team on Wednesday, with the 1903 Wright Flyer in the background: http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20120322/

Negotiations for Deep Space Network antenna allocations to support the S73 sequence continue to run quite late. This will require either commanding spacecraft telemetry modes in real time to compensate for allocation changes after the sequence has been uplinked to the spacecraft, or losing the data for lack of a DSN station during the downlink.


Friday, March 23 (DOY 083)

ISS conducted another observation in the Satellite Orbit Campaign, looking near Saturn where small satellites ("rocks") may be found, hoping to improve knowledge of their orbits or make new discoveries. More accurate orbit determinations lead to better predictions of the satellites' future positions for observation planning and potentially even spacecraft safety purposes.

The Navigation Team acquired five images for Optical Navigation purposes, and the Ultraviolet Imaging Spectrograph (UVIS) made scans of Saturn's magnetosphere for 16 hours in order to image hydrogen and oxygen, while VIMS and ISS performed a Saturn Storm Watch observation.
 

Saturday, March 24 (DOY 084)

Orbit Trim Maneuver (OTM)-313, the E-17 approach maneuver, was executed by turning the spacecraft and firing the Reaction Control Subsystem thrusters for 10 seconds, providing a delta-V of approximately 16.3 mm/s.

After the OTM, the Attitude and Articulation Control Subsystem executed a Reaction Wheel Assembly (RWA) bias maneuver to adjust wheel speeds. When this was completed, ISS did another Satellite Orbit Campaign observation while VIMS did more storm watch observations. UVIS and VIMS then started an 11 hour watch of Saturn's aurorae.
 

Sunday, March 25 (DOY 085)

ISS began a 13 hour observation of the edge of Saturn's shadow on the Phoebe ring, which is likely composed of particles ejected during micrometeoroid impacts on the small moon. Orbiting Saturn nearly 13 million kilometers out, Phoebe and its ring particles go around the planet in a retrograde direction.

The main engine cover was deployed to its closed position.
 

Monday, March 26 (DOY 086)

ISS, CIRS, and VIMS made Titan Monitoring Campaign observations that showed cloud features and how they change over time across the Senkyo dune field from a distance of 1.44 million kilometers. ISS and VIMS then searched the L5 Lagrange point 60 degrees behind Titan, again looking for any new satellites.

A feature on the upcoming Enceladus E-17 encounter was published:

http://www.jpl.nasa.gov/news/news.cfm?release=2012-087

An image dubbed "Quieted Storm" was highlighted today:

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4488

Tiny Enceladus, visible as a small dot in this image, perhaps illustrates the challenge of conducting a low-altitude flyby, although the Cassini flight team accomplishes such technical feats routinely.


Tuesday, March 27 (DOY 087)

Cassini flew by Enceladus at an altitude of 74 kilometers, with the Optical Remote Sensing instruments as well as the direct sensing instruments in play. ISS imaged the icy satellite's south polar plume while Enceladus was just a thin crescent. Next, the Composite Infrared Spectrometer (CIRS) acquired a series of mid-infrared scans across the night side as well as a pair of scans across the south polar terrain, which is home to numerous thermal hotspots, and then did a far-infrared raster scan. For the two hours surrounding closest approach, the Ion and Neutral Mass Spectrometer (INMS) was prime, while CDA and CAPS contributed to measuring the plume's composition as the spacecraft flew through it along the length of Baghdad Sulcus. These instruments were poised to resolve individual jets from this "tiger stripe" fracture. Finally, ISS acquired nine frames forming a mosaic of Enceladus's leading hemisphere as the spacecraft receded.

ISS then acquired a series of 29 images of one of Saturn's smaller satellites, Janus, with Saturn as a backdrop, at a closest approach distance of 43,850 kilometers.

Leaving Enceladus behind, Cassini passed through periapsis going 68,120 kph, and slightly closer to Saturn than Mimas's orbit.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 04/05/2012 12:44 PM
Rev164: Apr 5 - Apr 23 '12

http://www.ciclops.org/view/7142/Rev164
Title: Re: NASA - Cassini updates
Post by: go4mars on 04/05/2012 08:16 PM
I didn't realize Cassini was equiped with "Genesis Torpedoes"!    8)
Title: Re: NASA - Cassini updates
Post by: racshot65 on 04/09/2012 01:13 PM
Smudge of a Shadow

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4496
Title: Re: NASA - Cassini updates
Post by: racshot65 on 04/09/2012 05:40 PM
Quote
Cassini Significant Events 03/28/2012 - 04/03/2012

The most recent spacecraft tracking and telemetry data were collected on April 4 using the Deep Space Network's 34 meter Station 15 at Goldstone, California. Aside from the issues in work with the Ultrastable Oscillator (see the Jan. 5, 2012 Significant Events) and the Cosmic Dust Analyzer, the Cassini spacecraft is in an excellent state of health and its subsystems are operating normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Telemetry data from the targeted Enceladus encounter E-17 on March 27 were transmitted 1.3 billion kilometers to Earth on Wednesday; every bit was captured successfully by the Deep Space Network. The Ion and Neutral Mass Spectrometer (INMS) was able to discern variations in CO2 density among the individual gas jets as the spacecraft dove through the Enceladus south polar plume. The Cassini Plasma Spectrometer (CAPS), which was recently powered back on, acquired excellent data in and near the plume, along with the Cosmic Dust Analyzer (CDA) and INMS. A spectacular image of the south polar plume may be seen here, along with images of the icy moons Janus, taken March 27, and Dione, taken March 28: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20120328/

 
Wednesday, March 28 (DOY 088)

The Instrument Operations Team and the Multi-mission Image Processing Laboratory expedited processing of Cassini's data, delivering images to the science team and to the raw-image website during the downlink.

Cassini turned to point its high-gain antenna to the icy moon Dione for the RADAR instrument to make scatterometry and radiometry observations of its surface, then the Imaging Science Subsystem (ISS) took images of Dione at a distance of 44,000 kilometers and compiled a nine-frame mosaic showing the side of the moon that faces away from Saturn during its 2.7-day orbit.

ISS made observations in the Titan Monitoring Campaign while the target was about 1.2 million kilometers away. Then ISS conducted a search for possible satellites around Rhea's stable L5 Lagrange point, 60 degrees behind the satellite as it orbits Saturn.

The Attitude and Articulation Control Subsystem (AACS) executed a Reaction Wheel Assembly (RWA) bias maneuver to adjust wheel speeds.

The Realtime Operations Team sent a total of 9,506 "Instrument-Expanded Block" commands to the spacecraft in eight separate files using the Autorad utility for convenience. Every command was properly received and stored on-board. They will be called during execution of the S73 sequence, which begins next week.

The main engine cover was opened to its stowed position; this was the 72nd in-flight cycle of the flexible micro-meteoroid shield.
 

Thursday, March 29 (DOY 089)
 
After pointing to Saturn's icy satellite Rhea to do an observation by the Optical Remote-Sensing instruments and a photometric calibration of ISS, Cassini turned to train its optical telescopes on the bright star Alpha Centauri for a 7 hour calibration of the Visual and Infrared Mapping Spectrometer (VIMS).

CDA was turned off, and its replacement heater turned on, by realtime commands after valid science data and instrument engineering data packets unexpectedly stopped coming from the instrument. After a round-trip light time of 2 hours 26 minutes, telemetry indicated that the commands had the desired effect.
 

Friday, March 30 (DOY 090)

Realtime commands were sent to power CDA back on and its replacement heater off.

VIMS performed another 7 hour calibration using Fomalhaut, one of the brightest stars in the sky.

Orbit Trim Maneuver (OTM)-314, the post-E17 cleanup maneuver, turned the spacecraft and fired the Reaction Control Subsystem thrusters for 133.8 seconds, providing a delta-V of 143.8 mm/s. After the OTM was complete, AACS executed another RWA bias maneuver.

For the 34th time since launch, a Solid-State Power Switch (SSPS) experienced a circuit trip, attributed to being hit by a cosmic ray particle. This time, it set the backup helium latch-valve power circuit from the "off" state to "tripped." An on-board fault-protection routine sensed this and set the line back to "off" with no effect on spacecraft operations. The last SSPS trip occurred about 18 months ago.
 

Saturday, March 31 (DOY 091)

Cassini rotated to the attitude needed by the Cassini Plasma Spectrometer (CAPS) so it could perform an 11 hour observation of charged particles in its immediate environment. This was followed by a four hour calibration of the instrument's ion beam spectrometer and its ion mass spectrometer.
 

Sunday, April 01 (DOY 092)

CIRS performed a 20 hour mid-infrared map of Saturn to determine temperatures in the upper troposphere and tropopause.

Saturn and its moons figure prominently in the video "What's Up for April":

http://solarsystem.nasa.gov/news/whatsup-view.cfm?WUID=1144
 

Monday, April 02 (DOY 093)

The S73 final sequence integration and validation approval meeting and command approval meeting were held this morning. Later in the day, S73 sequence Part-1 was uplinked. All 6683 of its commands were received and registered on the spacecraft.

CDA performed a 13.5 hour interstellar dust observation today, a few days before the spacecraft reached apoapsis.

The "Hazy Orange Orb" of Saturn's giant moon Titan is featured in this natural-color image today. The north polar hood is clearly visible above Titan's dense atmosphere:

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4489

 
Tuesday, April 03 (DOY 094)

ISS, CIRS, and VIMS performed another observation in the Titan Monitoring Campaign, and ISS performed another observation in the Satellite Orbit Campaign. ISS then conducted a 9.5 hour observation of the irregular moon Thrymr, a "rock" about 6 kilometers wide in a very distant, retrograde orbit.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 04/13/2012 09:19 AM
Quote
Cassini Significant Events 04/04/2012 - 04/10/2012

The most recent spacecraft tracking and telemetry data were collected April 11 using the Deep Space Network's 34 meter High-Efficiency Station 45 at Canberra, Australia. Aside from the issues in work with the Ultrastable Oscillator (see the January 5, 2012 Significant Events) and the Cosmic Dust Analyzer, the Cassini spacecraft is in an excellent state of health. Its subsystems are operating normally as the spacecraft orbits, nearly in Saturn's equatorial plane, once every 17.8 days.

The S73 command sequence began execution onboard the spacecraft this week, representing the culmination of a long and involved process. Only after scientists' working teams had decided how to allocate spacecraft pointing control time to the various instrument teams did the Sequence Implementation Process begin, about five months ago. On Friday, S73 took control of the spacecraft.
 

Wednesday, April 04 (DOY 095)

Realtime commands were uplinked to perform a test of the Cosmic Dust Analyzer (CDA) to determine the cause of the instrument's packet errors seen last week. At the end of the test, the commands turned CDA off. The instrument remained off for the rest of this week, but will be turned back on prior to the Enceladus encounter coming up on Saturday.
 

Thursday, April 05 (DOY 096)

Cassini passed through apoapsis today, having slowed to 5,496 kilometers per hour relative to Saturn. This marked the beginning of Cassini's 164th orbit.

Orbit Trim Maneuver (OTM) 315 was cancelled because the optimum delta-V was too small to be implemented. Instead, OTM-316 on April 11 will accomplish the final orbit correction for the Enceladus E-18 flyby on April 14.

A realtime command was sent to clear the Solid State Power Switch (SSPS) trip counter following the unexpected trip last week of the Helium Latch Valve Driver-B switch.

The Encounter Strategy Meeting for the Enceladus E-18 and E-19 fly-bys was held today.

On the last day under control of the S72 sequence, the Visible and Infrared Mapping Spectrometer (VIMS), the Imaging Science Subsystem (ISS), and the Composite Infrared Spectrometer (CIRS) performed a 15 hour observation of Saturn's G ring and E ring; the latter is made up of icy particles ejected in jets from the moon Enceladus.


Friday, April 06 (DOY 097)

Realtime commands were sent to execute an end-of-sequence Reaction Wheel Assembly (RWA) bias to adjust the wheel speeds.

The S73 Sequence began execution. The Radio and Plasma Wave Science instrument (RPWS), the Ultraviolet Imaging Spectrograph (UVIS), ISS, and VIMS loaded their instrument-expanded-block commands from Cassini's solid-state data recorder; they will come into play as S73 continues during the next ten weeks.
 

Saturday, April 07 (DOY 098)

The Magnetometer performed an eight hour calibration while rotating the spacecraft about its X-axis; this head-over-heels motion is called pitch, as compared with roll and yaw.


Sunday, April 08 (DOY 099)

ISS, CIRS and VIMS performed an observation in the Titan monitoring campaign, the first of 26 such observations scattered throughout the S73 sequence to generate a long time baseline of cloud activity. For this observation, Titan was at a distance of 1.8 million kilometers. ISS then performed another observation in the Satellite Orbit Campaign.
 

Monday, April 09 (DOY 100)

The Deep Space Network station 55 in Madrid, Spain, participated in an Operations Readiness Test in preparation for a Radio Science Enceladus gravity experiment coming up on May 2. Station 25 at Goldstone, California, performed a calibration of monopulse, which is a fine-pointing capability used in Radio Science experiments.

The image "Smudge of a Shadow" was highlighted today, showing an elongated shadow of the small icy moon Mimas on Saturn's cloud tops.

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4496
 

Tuesday, April 10 (DOY 101)

A web page was created for the upcoming Enceladus E-18 flyby:

http://saturn.jpl.nasa.gov/mission/flybys/eenceladus20120414/
Title: Re: NASA - Cassini updates
Post by: racshot65 on 04/16/2012 01:54 PM
The Tale Continues...

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4497
Title: Re: NASA - Cassini updates
Post by: robertross on 04/16/2012 03:27 PM
The Tale Continues...

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4497

I mean seriously, how can one not be in awe at an image like that (or many of the images on this thread!). Incredible.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 04/17/2012 11:52 AM
Wow !

Cassini Successfully Flies over Enceladus
http://www.jpl.nasa.gov/news/news.cfm?release=2012-106#4


Images:

Tethys Surface (Raw Image) - http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4502

Tethys Portrait (Raw Image) - http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4501

Enceladus Terrain (Raw image) - http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4500

Arc of Enceladus (Raw Image) - http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4499
Title: Re: NASA - Cassini updates
Post by: bolun on 04/18/2012 07:42 PM
Rings, Titan and Enceladus

18 April 2012

Saturn’s icy moon Enceladus hangs below the gas giant’s rings while Titan lurks in the background, in this new image taken by the Cassini spacecraft.
 
Faint detail of the tiger stripe markings can be seen on Enceladus’ surface, which is framed against Titan, Saturn’s largest moon. With jets of water ice and vapour streaming from Enceladus’ south pole, and liquid hydrocarbon lakes pooling beneath Titan’s thick atmosphere, these are two of Saturn’s most enigmatic moons.

The northern, sun-lit side of Saturn’s rings are seen from just above the ring plane in this image, which was taken in visible green light by Cassini’s narrow-angle camera on 12 March while it was approximately one million kilometres from Enceladus. The image scale is six kilometres per pixel on Enceladus.

http://www.esa.int/esaSC/SEMBGCKWZ0H_index_0.html
Title: Re: NASA - Cassini updates
Post by: racshot65 on 04/19/2012 02:55 PM
Cassini Finds Titan Lake is like a Namibia Mudflat

http://www.jpl.nasa.gov/news/news.cfm?release=2012-108
Title: Re: NASA - Cassini updates
Post by: racshot65 on 04/20/2012 05:32 PM
Rev165: Apr 23 - May 11 '12

http://www.ciclops.org/view/7190/Rev165
Title: Re: NASA - Cassini updates
Post by: corrodedNut on 04/20/2012 08:19 PM
This also has Voyager and/or Jupiter images, but a lot from Cassini:

http://vimeo.com/40234826"
Title: Re: NASA - Cassini updates
Post by: Robotbeat on 04/20/2012 09:00 PM
Thanks! The sequence with the little moon dipping into the ring and scattering the particles there was jaw-dropping. Most beautiful!
Title: Re: NASA - Cassini updates
Post by: ugordan on 04/21/2012 12:59 PM
Yes, lovely video. I loved the first couple of seconds showing how certain ring sections are not symmetrical around the planet, but elliptical/disturbed.

The sequence with the little moon dipping into the ring and scattering the particles there was jaw-dropping.

Prometheus and the F ring.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 04/23/2012 04:39 PM
Quote
Cassini Significant Events 04/11/2012 - 04/17/2012

The most recent spacecraft tracking and telemetry data were collected April 18 using the Deep Space Network's 34 meter Beam-Waveguide Station 55 at Madrid, Spain. Beyond the issues in work with the Ultrastable Oscillator (see the January 5, 2012 Significant Events) and the Cosmic Dust Analyzer, the Cassini spacecraft is in an excellent state of health. Its subsystems are operating normally as the spacecraft orbits, nearly in Saturn's equatorial plane, once every 17.8 days. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

E-18, the targeted flyby of Enceladus on Saturday, was this week's highlight. The Ion and Neutral Mass Spectrometer (INMS) and the other Magnetospheric and Plasma Science (MAPS) instruments were prime for closest approach and flight through the plume. View the E-18 web page here: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20120416/.

Among Cassini's routine activities this week were three observations in the Titan monitoring campaign to look for cloud activity over a long time baseline. There were also two observations in the Satellite Orbit Campaign, in which the Imaging Science Subsystem (ISS) measures positions of small satellites, improving knowledge of their orbits. One reason for these frequent observations is that over the mission's duration it may be possible to measure small changes in their orbits. Such changes could potentially provide an independent determination of the mass of Saturn's rings or of certain of the icy satellites such as Mimas.

ISS also undertook searches at the L4 and L5 Lagrange points in Rhea's orbit about Saturn, looking for any small satellites that might be trapped in these stable points 60 degrees ahead and behind Rhea, respectively. So far, none has been discovered.
 

Wednesday, April 11 (DOY 102)

Orbit Trim Maneuver (OTM) 316, the Enceladus 18 approach maneuver, was performed today. As usual, the maneuver was designed based on the latest navigation data, and translated into commands that were transmitted to the spacecraft only a few hours before they would execute. The RCS thrusters fired for 25.5 seconds, providing Cassini 31 mm/s of delta-V. In the target plane, the aim-point was intentionally biased by about 4 kilometers off the nominal trajectory because doing so would save propellant and simplify implementation.

Realtime commands were uplinked today that will turn on the Cosmic Dust Analyzer (CDA) shortly before the E-18 encounter on Saturday. Commands in the background sequence (S73) turned on CDA heaters for roughly ten hours today to perform a routine decontamination of the instrument.


Thursday, April 12 (DOY 103)

The Navigation Team took five images of Saturn's moon Dione against the background stars for optical navigation purposes, then the Ultraviolet Imaging Spectrograph (UVIS) began a 13 hour observation of Saturn's aurora.

The main engines' protective cover was deployed to its closed position.
 

Friday, April 13 (DOY 104)

When UVIS completed its aurora observation, the spacecraft turned to point its high-gain antenna (HGA) to Earth, and downlinked all the telemetry data that had been stored on the Solid-State Recorders (SSRs). The Canberra, Australia, 70 meter diameter Deep Space Network (DSN) station captured every bit. This was one of seven routine DSN tracking activities for the week.

The E-18 flyby filled up the SSRs with new data. It began with long Enceladus plume observations led by the Visible and Infrared Mapping Spectrometer (VIMS) and ISS at a low latitude and at a variety of spatial scales, to be used for morphological studies and context.
 

Saturday, April 14 (DOY 105)

As the E-18 encounter continued, the Composite Infrared Spectrometer (CIRS) led Optical Remote-Sensing (ORS) viewing of Enceladus's night-side anti-Saturn-facing hemisphere, with dark sky behind, to search for possible hot spots away from the "tiger stripe" crevasses. At this time, the commands uplinked on Wednesday took effect, powering CDA on for the encounter.

Closing in on the icy target, the spacecraft turned to give INMS prime status for closest approach, going 27,000 km/h with respect to Enceladus. The purpose of this series of observations was to understand variability in Enceladus's activity and to map the plume's three-dimensional structure. As the spacecraft then proceeded outbound from Enceladus (though still inbound to Saturn), CIRS made observations to complete its coverage and to search for additional hot spots on the day-side Saturn-facing hemisphere.

Following the E-18 encounter, VIMS performed a stellar occultation experiment. This means that VIMS kept its telescope trained on the bright star Procyon (alpha Canis Minoris) and watched it for 2 hours 40 minutes while Cassini's motion caused the star to set slowly into Saturn's atmosphere, to gain information about the atmosphere.

Before the stellar occultation was finished, Cassini passed through periapsis, the low point in its orbit about Saturn, going 68,123 km/h. (Compare this to its Saturn-relative speed of 5,496 km/h at the high point in its orbit last week.)

Next came a series of observations of the moon Tethys from a close-approach distance of 9,053 kilometers by various ORS instruments. These observations will provide data to extend the mapping of Tethys's geologic features, and to understand the interaction of the E ring and energetic electrons with the icy moon's surface. The observations from this non-targeted flyby should help refine mapping of Tethys's "pacman" feature, similar to that seen on Mimas, caused by the varying thermal inertia across the surface. For reference, see http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=3919.
 

Sunday, April 15 (DOY 106)

Today's task was to downlink all the E-18 telemetry data at rates up to 142,201 bits (binary digits) per second. Thanks to the 70 meter diameter DSN stations in Canberra, Australia and Madrid, Spain, the data were captured flawlessly.

After the E-18 flyby, CDA stopped producing data. It was turned off by real-time command today after members of the flight team held an anomaly meeting.

Cassini's ORS instruments made an observation of Saturn's icy moon Rhea as a small dark crescent with dark sky behind.

The main engine cover was stowed to its open position. This was the 73rd in-flight cycle.
 
Saturn comes closest to Earth today as Saturn and Earth orbit the Sun. The ringed planet is at opposition, so it rises in the East at sunset, and sets near dawn. This highlights a season of great viewing opportunities for anyone who has access to even a small telescope. See "Viewing Saturn in 2012": http://saturn.jpl.nasa.gov/education/saturnobservation/viewingsaturn/.
 

Monday, April 16 (DOY 107)

CIRS began a 12 hour Saturn observation to measure oxygen compounds (H2O, CO2) in the stratosphere, then the magnetometer executed a calibration while rolling the spacecraft about its Z-axis, keeping the HGA facing Earth all the while for communication.

The DSN station 34 in Canberra, Australia, acquired the Ka-band (32 GHz) signal from Cassini to perform a calibration of monopulse, the fine-pointing capability used in Radio Science experiments. This occurred at the same time as X-band (8 GHz) communications and tracking were in progress.

Sequence Implementation Process team members held a Science Forum meeting for development of the S75 command sequence, which is scheduled to be uplinked in August.

OTM-317, the E-18 clean-up maneuver that was scheduled for April 18, was cancelled today. This was because the propellant cost of making the maneuver implementable was found to be about equal to the downstream cost of canceling it.

An image of Enceladus in front of Titan and Saturn's rings is featured today:

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4497

 
Tuesday, April 17 (DOY 108)

The Navigation Team took five images of Saturn's moon Iapetus against the background stars for optical navigation purposes.

JPL software developers identified a fix in an upcoming delivery of ground software for a problem that prevented remote Science Operations Planning Computers from querying the JPL-based Telemetry Delivery System.
Title: Re: NASA - Cassini updates
Post by: bolun on 04/23/2012 08:34 PM
Far-off cousin of part-time African lake found on Titan

19 Apr 2012

A region on Saturn's moon Titan has been found to be similar to the Etosha Pan in Namibia, Africa. Both are ephemeral lakes - large, shallow depressions that sometimes fill with liquid.

Ontario Lacus is the largest lake in the southern hemisphere of Saturn's moon, Titan. It is a little smaller than its namesake, Lake Ontario in North America, but otherwise differs from it in some major ways.

It is filled with liquid hydrocarbons, not water, and it is only a few metres deep at most, located in an extremely shallow depression in a flat sedimentary basin, surrounded by small mountain ranges.

In addition, a new study shows that these landforms and the climatic conditions in the region are similar to those of semi-arid regions on Earth, such as the salt pans of southern Africa.

The observations were made by the Cassini orbiter, part of the NASA, ESA and Italian Space Agency Cassini-Huygens mission to Saturn's system.

http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50282
Title: Re: NASA - Cassini updates
Post by: jacqmans on 04/24/2012 07:54 AM
RELEASE: 12-128

CASSINI SPACECRAFT SEES NEW OBJECTS BLAZING TRAILS IN SATURN RING

WASHINGTON -- Scientists working with images from NASA's Cassini
spacecraft have discovered strange, half-mile-sized objects punching
through one of Saturn's rings and leaving glittering trails behind
them. The results will be presented tomorrow at the European
Geosciences Union meeting in Vienna, Austria.

The penetration occurred in the outermost of Saturn's main rings,
called the F ring, which has a circumference of 550,000 miles
(881,000 kilometers). Scientists are calling the trails in the F ring
"mini-jets." Cassini scientists combed through 20,000 images and
found 500 examples of these rogues during the seven years Cassini has
been at Saturn.

"Beyond just showing us the strange beauty of the F ring, Cassini's
studies of this ring help us understand the activity that occurs when
solar systems evolve out of dusty disks that are similar to, but
obviously much grander than, the disk we see around Saturn," said
Linda Spilker, Cassini project scientist at NASA's Jet Propulsion
Laboratory (JPL) in Pasadena, Calif.

Scientists have known relatively large objects can create channels,
ripples and snowballs, or clumps of icy material, in the F ring.
However, scientists did not know what happened to these snowballs
after they were created. Some were broken up by collisions or tidal
forces in their orbit around Saturn. Scientists now have evidence
some of the smaller ones survived, and their differing orbits mean
they go on to strike through the F ring on their own.

"I think the F ring is Saturn's weirdest ring, and these latest
Cassini results go to show how the F ring is even more dynamic than
we ever thought," said Carl Murray, a Cassini imaging team member
based at Queen Mary University of London, U.K. "These findings show
us that the F ring region is like a bustling zoo of objects from a
half-mile (0.8-kilometer) in size to moons like Prometheus a hundred
miles (160.9 kilometers) in size, creating a spectacular show."

These small objects appear to collide with the F ring at gentle speeds
about 4 mph (2 meters per second). The collisions drag glittering ice
particles out of the F ring with them, leaving a trail of 20-110
miles (40-180 kilometers) long.

In some cases, the objects traveled in packs, creating mini-jets that
looked exotic, like the barb of a harpoon. Other new images show
grand views of the entire F ring and the swirls and eddies from the
different kinds of objects moving through and around it.

Saturn's rings are comprised primarily of water ice. The chunks of ice
that make up the main rings spread out 85,000 miles (140,000
kilometers) from the center of Saturn. Scientists believe the rings'
average thickness is approximately 30 feet (10 meters).

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. JPL manages the
mission for NASA's Science Mission Directorate in Washington. The
imaging team is based at the Space Science Institute in Boulder,
Colo.

New images and movies of the mini-jets are available at:

http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20120423.html

For information about Cassini, visit:

http://www.nasa.gov/cassini
Title: Re: NASA - Cassini updates
Post by: jacqmans on 04/27/2012 05:16 AM
RELEASE: 12-136

NASA'S CASSINI FINDS SATURN'S MOON PHOEBE HAS PLANET-LIKE QUALITIES

WASHINGTON -- Data from NASA's Cassini mission reveal Saturn's moon
Phoebe has more planet-like qualities than previously thought.

Scientists had their first close-up look at Phoebe when Cassini began
exploring the Saturn system in 2004. Using data from multiple
spacecraft instruments and a computer model of the moon's chemistry,
geophysics and geology, scientists found Phoebe was a so-called
planetesimal, or remnant planetary building block. The findings
appear in the April issue of the Journal Icarus.

"Unlike primitive bodies such as comets, Phoebe appears to have
actively evolved for a time before it stalled out," said Julie
Castillo-Rogez, a planetary scientist at NASA's Jet Propulsion
Laboratory (JPL) in Pasadena, Calif. "Objects like Phoebe are thought
to have condensed very quickly. Hence, they represent building blocks
of planets. They give scientists clues about what conditions were
like around the time of the birth of giant planets and their moons"

Cassini images suggest Phoebe originated in the far-off Kuiper Belt,
the region of ancient, icy, rocky bodies beyond Neptune's orbit. Data
show Phoebe was spherical and hot early in its history, and has
denser rock-rich material concentrated near its center. Its average
density is about the same as Pluto, another object in the Kuiper
Belt. Phoebe likely was captured by Saturn's gravity when it somehow
got close to the giant planet.

Saturn is surrounded by a cloud of irregular moons that circle the
planet in orbits tilted from Saturn's orbit around the sun, the
so-called equatorial plane. Phoebe is the largest of these irregular
moons and also has the distinction of orbiting backward in relation
to the other moons. By comparison, Saturn's large moons appear to
have formed from gas and dust around the planet's equatorial plane
and orbit in that same plane.

"By combining Cassini data with modeling techniques previously applied
to other solar system bodies, we've been able to go back in time and
clarify why Phoebe is so different from the rest of the Saturn
system," said Jonathan Lunine, a co-author on the study and a Cassini
team member at Cornell University.

Analyses suggest that Phoebe was born within the first 3 million years
of the birth of the solar system, which occurred 4.5 billion years
ago. The moon originally may have been porous but appears to have
collapsed in on itself as it warmed up. Phoebe developed a density 40
percent higher than the average inner Saturnian moon.

Objects of Phoebe's size have long been thought to form as
potato-shaped bodies and remain that way over their lifetimes. If
such an object formed early enough in the solar system's history, it
could have harbored the kinds of radioactive material that would
produce substantial heat over a short timescale. This would warm the
interior and reshape the moon.

"From Cassini images and models, we were able to see that Phoebe
started with a nearly spherical shape, rather than an irregular shape
later smoothed into a sphere by impacts," said co-author Peter
Thomas, a Cassini team member at Cornell.

Phoebe likely stayed warm for tens of millions of years before
freezing up. The study suggests the heat also would have enabled the
moon to host liquid water at one time. This could explain the
signature of water-rich material on Phoebe's surface previously
detected by Cassini.

The new study also is consistent with the idea that several hundred
million years after Phoebe cooled, the moon drifted toward the inner
solar system in a solar-system-wide rearrangement. Phoebe was large
enough to survive this turbulence.

More than 60 moons are known to orbit Saturn, varying drastically in
shape, size, surface age and origin. Scientists using both
ground-based observatories and Cassini's cameras continue to search
for others.

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. JPL manages the
mission for the agency's Science Mission Directorate in Washington.

For more information, visit:

www.nasa.gov/cassini
Title: Re: NASA - Cassini updates
Post by: Robotbeat on 04/27/2012 09:51 PM
RELEASE: 12-128

CASSINI SPACECRAFT SEES NEW OBJECTS BLAZING TRAILS IN SATURN RING

WASHINGTON -- Scientists working with images from NASA's Cassini
spacecraft have discovered strange, half-mile-sized objects punching
through one of Saturn's rings and leaving glittering trails behind
them. The results will be presented tomorrow at the European
Geosciences Union meeting in Vienna, Austria.

The penetration occurred in the outermost of Saturn's main rings,
called the F ring, which has a circumference of 550,000 miles
(881,000 kilometers). Scientists are calling the trails in the F ring
"mini-jets." Cassini scientists combed through 20,000 images and
found 500 examples of these rogues during the seven years Cassini has
been at Saturn.

"Beyond just showing us the strange beauty of the F ring, Cassini's
studies of this ring help us understand the activity that occurs when
solar systems evolve out of dusty disks that are similar to, but
obviously much grander than, the disk we see around Saturn," said
Linda Spilker, Cassini project scientist at NASA's Jet Propulsion
Laboratory (JPL) in Pasadena, Calif.

Scientists have known relatively large objects can create channels,
ripples and snowballs, or clumps of icy material, in the F ring.
However, scientists did not know what happened to these snowballs
after they were created. Some were broken up by collisions or tidal
forces in their orbit around Saturn. Scientists now have evidence
some of the smaller ones survived, and their differing orbits mean
they go on to strike through the F ring on their own.

"I think the F ring is Saturn's weirdest ring, and these latest
Cassini results go to show how the F ring is even more dynamic than
we ever thought," said Carl Murray, a Cassini imaging team member
based at Queen Mary University of London, U.K. "These findings show
us that the F ring region is like a bustling zoo of objects from a
half-mile (0.8-kilometer) in size to moons like Prometheus a hundred
miles (160.9 kilometers) in size, creating a spectacular show."

These small objects appear to collide with the F ring at gentle speeds
about 4 mph (2 meters per second). The collisions drag glittering ice
particles out of the F ring with them, leaving a trail of 20-110
miles (40-180 kilometers) long.

In some cases, the objects traveled in packs, creating mini-jets that
looked exotic, like the barb of a harpoon. Other new images show
grand views of the entire F ring and the swirls and eddies from the
different kinds of objects moving through and around it.

Saturn's rings are comprised primarily of water ice. The chunks of ice
that make up the main rings spread out 85,000 miles (140,000
kilometers) from the center of Saturn. Scientists believe the rings'
average thickness is approximately 30 feet (10 meters).

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. JPL manages the
mission for NASA's Science Mission Directorate in Washington. The
imaging team is based at the Space Science Institute in Boulder,
Colo.

New images and movies of the mini-jets are available at:

http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20120423.html

For information about Cassini, visit:

http://www.nasa.gov/cassini

That is pretty cool. I recommend that people watch that video.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 04/30/2012 01:21 PM
Moon Specks

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4516
Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/01/2012 04:57 PM
Cassini to Probe Enceladus Gravity, Take Pictures

http://www.jpl.nasa.gov/news/news.cfm?release=2012-121
Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/03/2012 01:37 PM
Enceladus Crescent (Raw Image)

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4518


Enceladus Spray (Raw Image)

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4517
Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/03/2012 04:46 PM
Quote
Cassini Significant Events 04/25/2012 - 05/01/2012

The most recent spacecraft tracking and telemetry data were collected on May 2 using the Deep Space Network's 34 meter high-efficiency Station 34 at Canberra, Australia. Aside from the issue in work with the Ultrastable Oscillator (see the January 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health. Its subsystems are operating normally as the spacecraft orbits Saturn, nearly in the equatorial plane, once every 17.8 days. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

This week's events included preparations for the Enceladus E-19 targeted flyby on May 2, which will bring the spacecraft to within 74 kilometers of the icy satellite and make measurements of its gravity field. More information on E-19 may be found here: http://saturn.jpl.nasa.gov/mission/flybys/enceladus20120502/.

On the ground, Cassini flight team members made progress working on science observation plans for sequences S74, which goes active in June, S75 (August), S76 (November), and S77 (January 2013).
 

Wednesday, April 25 (DOY 116)

The Spacecraft Operations Office held an Engineering Activities Review for the S76 command sequence. The Radio Science Support team held a meeting with members of the DSN and Realtime Operations teams to finalize operations for the E-19 gravity observation.
 

Thursday, April 26 (DOY 117)

A 34 meter diameter Deep Space Network (DSN) station in Canberra, Australia, participated in an Operational Readiness Test, preparing for the E-19 realtime Radio Science gravity measurement during closest approach on May 2.

A news release titled, "Cassini Finds Saturn Moon Has Planet-Like Qualities" describes new findings about Saturn's outer, retrograde moon Phoebe. It may be viewed here:

http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20120426/


Friday, April 27 (DOY 118)

The Attitude and Articulation Control (AACS) team performed a reaction-wheel assembly (RWA) bias maneuver, stabilizing the spacecraft via thrusters and setting the RWAs to the required speeds while the DSN was tracking the spacecraft. AACS also performed a calibration of the spacecraft's backup inertial reference unit (gyros). These calibrations are performed about once per year and require rotating the spacecraft about its X, Y and Z axes.
 

Saturday, April 28 (DOY 119)

ISS performed another observation in the Satellite Orbit Campaign. VIMS performed a Saturn storm watch observation.

Commands were sent to the spacecraft that were time-tagged to power the Cosmic Dust Analyzer (CDA) back on just prior to the E-19 flyby. Additional commands were sent to do a live update within the AACS Inertial Vector Propagator to refine pointing information on the location of Dione, which will be observed during the non-targeted encounter following E-19.

Orbit Trim Maneuver (OTM) 319, the E-19 approach maneuver, operated the Reaction Control Subsystem thrusters for 29.5 seconds, resulting in a delta-V of 0.034 meters per second.

Saturn was the featured attraction at two local Astronomy Day activities attended by Cassini outreach specialists.
 

Sunday, April 29 (DOY 120)

The DSN provided eight tracking sessions for Cassini using stations in Canberra, Australia, and Goldstone, California this week. There were several small data outages.
 

Monday, April 30 (DOY 121)

The Ultraviolet Imaging Spectrograph (UVIS) performed a 10 hour observation of Saturn's aurora.

The main engine protective cover was deployed to its closed position.

The Attitude and Articulation Control Subsystem executed an RWA Y-bias maneuver to adjust wheel speeds while Cassini was off Earth point, out of communication.

An image titled "Moon Specks", showing Tethys and Enceladus, is featured here:

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4516.
 

Tuesday, May 1 (DOY 122)

ISS observed an irregular outer satellite for nearly 10 hours to gather data for a light curve to give further information on the collisional environment in the outer Saturnian system. VIMS performed a 3-hour solar-port calibration activity.

DSN station 25, a 34 meter aperture at Goldstone, California, began a gravity science enhancement observation prior to tomorrow's E-19 flyby. Station 25's X-band (8 GHZ) uplink provided for an X-band and Ka-band (32 GHz) coherent downlink from Cassini. The Doppler data contained in these signals will add to knowledge of Enceladus's gravity field.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/04/2012 10:17 AM
Bright Bits on Dione (Raw Image)

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4525


Dione Up Close (Raw Image)

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4523


Radiant Dione (Raw Image)

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4524

Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/11/2012 09:03 AM
Quote
Cassini Significant Events 05/02/2012 - 05/08/2012

The most recent spacecraft tracking and telemetry data were collected on May 9 using the Deep Space Network's 70 meter Station 43 at Canberra, Australia. Aside from the issues in work with the Cosmic Dust Analyzer (CDA) and the Ultrastable Oscillator (see the January 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health and its subsystems are operating normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

This week's highlight was the targeted E-19 close encounter with Saturn's 500 kilometer diameter snow-white moon Enceladus on Wednesday. The flyby delivered the final in a set of three Enceladus encounters designed to give real-time Radio Science measurements of Enceladus's gravity field. It also included another pass through the plume from the geysers. More information on E-19 may be found here: http://saturn.jpl.nasa.gov/mission/flybys/enceladus20120502/ .


Wednesday, May 2 (DOY 123)

During the Enceladus E-19 flyby, the spacecraft turned frequently under control of the Attitude and Articulation Control (AACS) Reaction Wheel Assemblies (RWA) to properly point the Optical Remote Sensing (ORS) instruments and the Magnetospheric and Plasma Science (MAPS) instruments. All the telemetry data from their many observations went to the Solid-State Recorder (SSR) for later playback to Earth. Radio Science experiments operate differently. For long periods around and during closest approach to Enceladus (74 kilometers), Cassini was oriented to keep its high-gain antenna dish pointed to Earth while receiving a frequency-stable signal from the Deep Space Network (DSN). Cassini's downlink, locked to this reference signal, was received on Earth an hour and 13 minutes later. Its Doppler shift was accurately measured, providing the Radio Science data that contains information about mass distribution within Enceladus. Not to waste any Earth-pointed time, though, telemetry data were also played back from the SSR during the Radio Science experiment.

Cassini passed periapsis, this orbit's closest point to Saturn at 136,000 kilometers above the clouds, going 68,213 kilometers per hour relative to the planet.

The busy day concluded with Cassini turning its ORS instruments to Dione 8,000 kilometers away (for which pointing vectors were updated last week via realtime command). With Dione squarely in view, the Composite Infrared Spectrometer (CIRS) and Imaging Science Subsystem (ISS) scanned its equatorial latitudes on the leading hemisphere, with a chance to observe the fractured region and do further searches for evidence of out-gassing or recent activity.

The illustrated feature "Cassini, Saturn Moon Photographer" was published on the Cassini website:

http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20120502/ .
 

Thursday, May 3 (DOY 124)

The Cosmic Dust Analyzer (CDA) exhibited telemetry packet production problems again, and was powered off by realtime command following an anomaly meeting today.

The Ultraviolet Imaging Spectrograph (UVIS) performed an instrument calibration, and ISS made a 9-hour observation of one of Saturn's outer irregular satellites, Ymir, a tiny, dark body in a retrograde orbit 23 million kilometers away.

The AACS team performed an RWA Y-bias maneuver, stabilizing the spacecraft via thrusters and setting the RWAs to the required speeds. Thrusters usually impart a small delta-V. Since the spacecraft was out of communication with Earth, the Navigation team relied on telemetry played back later to estimate the effect on Cassini's orbit.

The main engines' protective cover was stowed to its open position.
 

Friday, May 4 (DOY 125)

The Cassini Plasma Spectrometer (CAPS), a direct-sensing instrument, measured the ambient co-rotating plasma at low latitude in Saturn's magnetosphere for half the day. The spacecraft was 1.5 million kilometers from Saturn as it continued coasting outbound from periapsis.
 

Saturday, May 5 (DOY 126)

Playback of telemetry from the icy satellite observations, including Enceladus and Dione, was completed this morning after three daily sessions with the DSN's 70 meter aperture station at Goldstone.

The MAPS instruments, directly sensing ambient conditions, continued to acquire measurements in Saturn's outer magnetosphere and magnetosheath. By doing this once every four to six months, these instruments are able to observe Saturn's magnetosphere over a solar cycle, from one solar minimum to the next, and investigate periodicities and how the Saturn kilometric radiation period is imposed on the magnetosphere.
 

Sunday, May 6 (DOY 127)

OTM-320, the E-19 clean-up maneuver scheduled for today, was found to be unnecessary because of the small E-19 target miss, and was canceled.
 

Monday, May 7 (DOY 128)

The MAPS instruments continued their observations in Saturn's outer magnetosphere.

An image of Saturn's 200 kilometer wide, cratered moon Janus, which orbits outside the F ring, is featured at:

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4519 .


Tuesday, May 08 (DOY 129)

On three days this week including today, ISS monitored distant Titan, with CIRS and the Visible and Infrared Mapping Spectrometer (VIMS) also taking measurements.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/11/2012 09:10 AM
Rev166: May 11 - May 28 '12

http://www.ciclops.org/view/7206/Rev166
Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/14/2012 04:12 PM
Ring Moons' Effects

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4526
Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/21/2012 05:04 PM
Quote
Cassini Significant Events 05/09/2012 - 05/15/2012

The most recent spacecraft tracking and telemetry data were collected on May 15 using the Deep Space Network's 70 meter Station 14 at Goldstone, California. Aside from the issues in work with the Ultrastable Oscillator (see the Jan. 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health with all its subsystems operating normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

As the spacecraft proceeded out toward apoapsis, Magnetospheric and Plasma Science (MAPS) observations again made in-situ measurements of Saturn's outer magnetosphere and magnetosheath at low latitude, which means near Saturn's equatorial plane where the spacecraft is currently orbiting. These observations continued through Monday. Interspersed with these activities, the Imaging Science Subsystem (ISS) led the pointing for the optical remote sensing instruments to take repeated measurements of Titan this week to monitor cloud formations at different phase angles and distances.
 

Wednesday, May 9 (DOY 130)

Part 2 of the 10-week S73 background sequence was uplinked through the Deep Space Network (DSN) to the spacecraft today; its 7649 commands were confirmed aboard after one round-trip light time of 2 hours, 27 minutes.
 

Thursday, May 10 (DOY 131)

Negotiations for DSN antenna allocations to support the ten-week S74 sequence that is in work were completed for the first six weeks of the sequence. Work also continued on the ten-week sequences S75, S76, and S77.
 

Friday, May 11 (DOY 132)

Cassini's orbit count incremented to 166 with apoapsis passage at 2.4 million kilometers from Saturn (about twice the distance of Titan's orbit) going 5,488 kilometers per hour with respect to the planet.

S73 Part-2 commands began controlling the spacecraft.

ISS observed Saturn's moon Erriapus for 8 hours. This dark body is less than 10 kilometers in diameter, and orbits the planet once each 871 days at a distance of more than 17 million kilometers from Saturn.
 

Saturday, May 12 (DOY 133)

After approval of the maneuver and the command file, Orbit Trim Maneuver (OTM) 321 was uplinked to the spacecraft.

Realtime commands were sent to the spacecraft that will power the Cosmic Dust Analyzer (CDA) back on this Tuesday.
 

Sunday, May 13 (DOY 134)

Five optical navigation images were taken of Rhea against the background stars.

OTM 321 successfully turned the spacecraft and fired the main engine, providing 8.3 meters per second delta-V. This brought Cassini onto the planned trajectory for the Titan T-83 flyby at 955 kilometers above its surface on May 22.
 

Monday, May 14 (DOY 135)

The Magnetometer executed a sensor-offset calibration by rotating the spacecraft about its X axis.

The Ultraviolet Imaging Spectrograph began a series of observations that will continue over the next several days, with the Visible and Infrared Mapping Spectrometer, ISS, and the Composite Infrared Spectrometer riding along, to study Saturn's aurora by performing a mixture of slews and fixed pointings at the auroral oval.


Tuesday, May 15 (DOY 136)

The CDA power-on commands executed, and the instrument began operating normally.

The Cassini Plasma Spectrometer team updated some of its instrument's parameters by realtime command using the automated sequence processor.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/21/2012 07:51 PM
Tethys Surface (Raw Image)

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4531


Tiny Methone (Raw Image)

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4529


Tethys in View (Raw Image)

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4530
Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/22/2012 03:59 PM
Cassini Spots Tiny Moon, Begins to Tilt Orbit

http://www.jpl.nasa.gov/news/news.cfm?release=2012-140
Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/24/2012 04:49 PM
Rev167: May 28 - Jun 17 '12

http://www.ciclops.org/view/7216/Rev167 (http://www.ciclops.org/view/7216/Rev167)
Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/25/2012 04:11 PM
Quote
Cassini Significant Events 05/16/2012 - 05/22/2012

The most recent spacecraft tracking and telemetry data were collected on May 23 using the Deep Space Network's 70 meter Station 14 at Goldstone, California. Aside from the Ultrastable Oscillator (see the Jan. 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health with all its subsystems operating normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

This week's highlight was the Titan encounter (T-83), which included acquiring another high-resolution Synthetic Aperture Radar (SAR) image strip about 6,000 kilometers long. Among ongoing observations in the days before Tuesday morning's encounter, the Ultraviolet Imaging Spectrograph (UVIS) continued its series of observations, with the Visible and Infrared Mapping Spectrometer (VIMS), the Imaging Science Subsystem (ISS), and the Composite Infrared Spectrometer (CIRS) riding along, to study Saturn's aurora with slews and fixed pointings at the auroral oval.
 

Wednesday, May 16 (DOY 137)

Today, as on nearly every day, the Realtime Operations Team sent commands to reset the command-loss timer, which is one of several fault-protection programs running aboard the spacecraft.

The Radio Science Subsystem performed periodic instrument maintenance activities on the Radio Frequency Instrument Subsystem.


Thursday, May 17 (DOY 138)

Today and the next day, ISS led the pointing with CIRS and VIMS also taking measurements in the Titan Monitoring Campaign, watching cloud formations at different phase angles and ranges.
 

Friday, May 18 (DOY 139)

Commands were sent to overlay telemetry-rate commands in the S73 sequence. This was necessary because Deep Space Network (DSN) antenna allocations were incomplete even as S73 began executing last month. Other command data sent to Cassini made a "live" update to the Inertial Vector Propagator to refine pointing directions for Saturn's satellite Methone. Finally, commands were sent that would perform Orbit Trim Maneuver (OTM) 322 the next day.
 

Saturday, May 19 (DOY 140)

Nearing periapsis, the Cassini Plasma Spectrometer (CAPS) led spacecraft pointing for Magnetospheric and Plasma Science (MAPS) measurements of the equatorial inner magnetosphere.

OTM-322, the T-83 approach maneuver, executed during its backup window. This was a reaction control subsystem thruster burn with a duration of 73.5 seconds, providing approximately 83 millimeters per second delta-V. The maneuver was delayed to the backup window to allow orbit determination solutions more time to converge.
 

Sunday, May 20 (DOY 141)

There were three major observing campaigns today. First came high spatial resolution optical studies of Tethys, the third major moon out from Saturn. CIRS took the lead in mapping its leading hemisphere to confirm the previously detected thermal anomaly, to determine thermal surface properties inside and outside of the anomaly, and to characterize the anomaly's shape and spatial extent. The higher daytime temperatures provided enough signal for CIRS to use its FP3 (focal-plane 3) high spatial resolution detector. The CIRS scans allowed ISS and VIMS to mosaic the surface to contribute to a global map of the moon; UVIS rode along to measure variations in Tethys' albedo across its surface.

Going 68,460 kilometers per hour relative to Saturn while viewing Tethys, Cassini passed through periapsis just outside the orbit of Mimas, the innermost of Saturn's major satellites.

ISS then viewed the tiny moon Methone, for which new pointing vectors were uplinked Friday. This close flyby, less than 2,000 kilometers, offered the first opportunity to characterize Methone's geology, to obtain compositional information, and to understand the relationship of the moon to Saturn's ring system. Its orbit lies about 8,500 kilometers outside that of Mimas.

Finally, CAPS took control and turned Cassini to an attitude that allowed optimal measurements of ions and electrons in Saturn's inner magnetosphere. These observations were taken in parallel with higher time resolution measurements by all the MAPS instruments. These latter observations, performed roughly every six months on equatorial orbits, are for the purpose of studying long-term solar cycle and seasonal variability in Saturn's magnetosphere. They are also used to investigate magnetospheric periodicities and their coupling to the ionosphere.
 

Monday, May 21 (DOY 142)

The image "Serene Scene" with Saturn and Tethys was featured here today:

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4527.

Cassini pointed the Optical Remote Sensing instruments to the growing disk of Titan to start conducting many observations, which are detailed on the T-83 encounter page (see below).
 

Tuesday, May 22 (DOY 143)

During the Titan encounter today, the spacecraft rotated repeatedly about all three axes to aim its telescopes, point the large dish antenna for Radar observations, and expose in-situ instruments in desired directions. For closest approach, attitude control switched from reaction wheels to thrusters for increased control authority over atmosphere-generated torques around closest approach. Full information may be found here on the T-83 encounter page:

http://saturn.jpl.nasa.gov/mission/flybys/titan20120522/.

By flying closely over Titan's north pole, gravity enabled an "elastic collision" connecting Cassini with some of Titan's orbital momentum. The result of this gravity-assist flyby increased the inclination of the spacecraft's orbit plane from near-equatorial (0.4 degrees) to 15.8 degrees. This is the first of eight gravity-assisted steps that will bring Cassini's inclination to a maximum of 61.7 degrees above the equatorial plane about a year from now. More information on the inclined orbits, and on Methone, may be found here:

http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20120521/.

The DSN's 70 meter aperture stations in Madrid, Spain, and Goldstone, California, captured every bit of telemetry that was stored on the solid-state recorders during T-83, while providing Doppler and ranging data for navigation. At the same time, both stations participated in an Operations Readiness Test (ORT) preparing for an upcoming Radio Science ring and atmosphere occultation experiment, which is possible to do now that Cassini's orbital plane has been rotated somewhat out of the ring plane. Cassini's S-band (2 GHz), X-band (8 GHz), and Ka-band (32 GHz) transmissions were received during the ORT.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 05/29/2012 05:22 PM
Splitting Titan

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4536
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/01/2012 07:12 AM
Quote
Cassini Significant Events 05/23/2012 - 05/29/2012

The most recent spacecraft tracking and telemetry data were collected on May 30 by the Deep Space Network's 34 meter Station 15 at Goldstone, California. Aside from the Ultrastable Oscillator (see the Jan. 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health with all its subsystems operating normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Cassini began a year-long phase, starting with the Titan flyby on May 22, during which Titan flybys will continue to increase the spacecraft's orbital inclination. Periapses will continue coming about as close to Saturn as the broad E ring. This plan is designed to provide opportunities for ring occultation experiments by Radio Science and the Ultraviolet Imaging Spectrograph (UVIS), as well as optical remote sensing observations of the rings.

The Imaging Science Subsystem (ISS) performed three observations in the ongoing Satellite Orbit Campaign this week, measuring positions of small satellites to improve knowledge of their orbits. ISS, the Composite Infrared Spectrometer (CIRS), and the Visible and Infrared Mapping Spectrometer (VIMS) performed two observations in the Titan monitoring campaign.

Negotiations to schedule Deep Space Network (DSN) antennas to support Cassini's S74 sequence, which goes active June 18, are proving difficult due to contentions related to Mars Science Laboratory's requirements for support during atmospheric entry, descent, landing, and initial surface operations early this August.
 

Wednesday, May 23 (DOY 144)

The Navigation Team took five images for optical navigation purposes.

ISS, CIRS, UVIS and VIMS performed a joint observation of the faint D and G rings at low phase angle.
 

Thursday, May 24 (DOY 145)

The Cosmic Dust Analyzer (CDA) performed a 5 hour measurement of interstellar dust.

Using the Automated Sequence Processor, the Cassini Plasma Spectrometer team sent commands that reconfigured their ion beam spectrometer settings to adapt the instrument to current environmental conditions.

ISS and VIMS telemetry processing halted because of erroneously set flags in data from the DSN regarding earth-receive times. A labor-intensive workaround was devised so that processing can continue while this ground-based anomaly is resolved. The Instrument Operations team initiated Incident-Surprise-Anomaly report (ISA) #52211 to document the problem.
 

Friday, May 25 (DOY 146)

ISS observed the star Vega for 15 hours to perform a photometric calibration.
 

Saturday, May 26 (DOY 147)

CDA performed a 13.5 hour interstellar dust observation.
 

Sunday, May 27 (DOY 148)

Station 25, one of the DSN's 34 meter diameter antennas at Goldstone, California, participated in an Operations Readiness Test (ORT) preparing for the Radio Science ring and atmosphere occultation experiment on June 4.

The Magnetometer Team performed an instrument calibration by rolling the spacecraft about its Z-axis during DSN communications with the high-gain antenna pointed to Earth.
 

Monday, May 28 (DOY 149)

Cassini passed apoapsis at about 2.3 million kilometers from Saturn, having slowed to 5,771 kilometers per hour relative to the planet.

CDA took advantage of the spacecraft's distance from Saturn to perform another 13.5 hour interstellar dust observation.

An image titled "Splitting Titan" was featured on the Cassini website, illustrating seasonal atmospheric changes in Titan's northern and southern hemispheres. The image may be seen at: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4536 .
 

Tuesday, May 29 (DOY 150)

ISS spent 11 hours observing the irregular moon Ymir. The tiny dark body is in a retrograde orbit 23 million kilometers from Saturn.

Station 25 participated in another Radio Science ORT preparing for the June 4 experiment.

Orbit Trim Maneuver 324, a 21.4 second maneuver using the main engine, was performed just before midnight, targeting to the Titan encounter on June 7. It provided a delta-V of 3.71 m/s.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/01/2012 04:00 PM
Enceladus Plume is a New Kind of Plasma Laboratory

http://www.jpl.nasa.gov/news/news.cfm?release=2012-149
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/04/2012 03:39 PM
Line of Craters

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4537

Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/07/2012 09:21 AM
Cassini Plasma Spectrometer Turns Off

http://www.jpl.nasa.gov/news/news.cfm?release=2012-159
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/08/2012 05:11 PM
Quote

Significant Events 05/30/2012 - 06/05/2012

The most recent spacecraft tracking and telemetry data were collected on June 6 by the Deep Space Network's 70 meter Station 14 at Goldstone, California. Aside from CAPS, which is off, and the Ultrastable Oscillator the Cassini spacecraft is in an excellent state of health with all its subsystems operating normally.

This week's highlight was a Radio Science occultation experiment. On Monday, telemetry was turned off and the spacecraft's radio emissions actively probed Saturn's rings and atmosphere as they passed through the rings and atmosphere en route to Earth while the spacecraft passed behind them as seen from Earth.

Negotiations to schedule Deep Space Network (DSN) antennas to support Cassini's next command sequence, S74, continue to pose a significant challenge.


Wednesday, May 30 (DOY 151)

Orbit Trim Maneuver (OTM) 324, which was covered in last week's report, finished executing early this morning.

The Magnetometer performed an eight-hour calibration while rotating the spacecraft about its X-axis.


Thursday, May 31 (DOY 152)

The 70-meter diameter Deep Space Station 63 participated in an Operations Readiness Test in preparation for Monday's Radio Science occultation experiment. As usual, the station also sent commands, acquired telemetry, and provided Doppler and range data for navigation. This was one of a total of ten DSN tracking activities for Cassini this week.

A feature titled, "Enceladus Plume is a New Kind of Plasma Laboratory" was posted today, describing the "dusty plasma" that issues from the small icy moon:
http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20120531/


Friday, June 01 (DOY 153)

The Cassini Plasma Spectrometer Subsystem (CAPS) perfomed a 4 hour calibration of its ion beam spectrometer and its ion mass spectrometer.

Commands were sent to update Cassini's Inertial Vector Propagator (IVP) to refine pointing information for an observation of Mimas on Tuesday.


Saturday, June 02 (DOY 154)

Yesterday and again today, the Imaging Science Subsystem (ISS), the Composite Infrared Spectrometer (CIRS), and the Visible and Infrared Mapping Spectrometer (VIMS) performed observations in the Titan monitoring campaign, and ISS and VIMS made observations in the Satellite Orbit Campaign.
During the American Cancer Society Relay for Life Walk-a-thon in Monrovia, California, Cassini Outreach offered views of Saturn and Titan to hundreds of participants. Saturn will continue to be a great viewing target in small telescopes though August.


Sunday, June 03 (DOY 155)

Telemetry showed that CAPS was powered off yesterday when the instrument began to draw excess current, which tripped off the solid state power switch (SSPS) that provides electrical power to the instrument. The Realtime Operations Team notified the CAPS instrument team, the Spacecraft Operations team, and the Sequence Implementation Process lead, and an anomaly meeting was arranged for the following morning. More information may be found in this news release:
http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20120606/

The Ultraviolet Imaging Spectrograph (UVIS) carried out a 13 hour observation of Saturn's aurora.
OTM-325, the Titan 84 approach maneuver, executed today using the Reaction Control Subsystem thrusters. The burn provided a delta-V of about 37 millimeters per second.


Monday, June 04 (DOY 156)

An anomaly meeting was held to deliberate on yesterday's CAPS shutoff. It was decided to conduct further analysis and not turn the instrument back on until such time as the anomaly is better understood.

ISS had one of its first looks at the rings in nearly two years, now that Cassini's orbit is inclined somewhat out of the ring plane. Part one of the observations began an azimuthal survey of the region where propeller-shaped objects had been found. More information on these features can be found here: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4045

VIMS observed the unlit side of the rings for composition data.
The Radio Science Subsystem team performed an ingress occultation experiment, probing Saturn's rings, ionosphere, and upper troposphere using Cassini's three radio-frequency bands: S, X, and Ka. Since the Ultrastable Oscillator is inoperative, the DSN provided the reference frequency via uplink; this use of coherent mode is a first for an occultation experiment. The spacecraft's downlink was received and recorded at 70- and 34 meter stations in Madrid, Spain, and Goldstone, California.


Tuesday, June 05 (DOY 157)

Cassini passed through periapsis just outside the orbit of Mimas going 69,739 kilometers per hour relative to Saturn.

UVIS led an egress solar occultation observation as the Sun rose, by virtue of spacecraft motion, through Saturn's upper atmosphere.

Thanks to the IVP update commanded on Friday, CIRS found Mimas well centered in its field of view and made observations of the small moon to better define its thermally anomalous "pacman" feature. The other ORS instruments observed in ride-along mode. The unusual surface feature is illustrated here: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=3919

VIMS made a ring composition lit-face study. Finally, ISS performed part two of the propeller survey.

Yesterday and again today, the Attitude and Articulation Control Subsystem team executed reaction-wheel bias maneuvers.

The S74 sequence Instrument Expanded Block commands were processed and approved for uplink starting on Thursday.

A web page detailing the upcoming Titan T84 encounter was posted here:
http://saturn.jpl.nasa.gov/mission/flybys/titan20120607/
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/11/2012 02:52 PM
Epimetheus Beyond Rings

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4539
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/14/2012 06:14 PM
Cassini Sees Tropical Lakes on Saturn Moon

http://www.jpl.nasa.gov/news/news.cfm?release=2012-172
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/14/2012 07:49 PM
Quote

Cassini Significant Events 06/06/2012 - 06/12/2012

The most recent spacecraft tracking and telemetry data were collected on June 13 by the Deep Space Network's 70 meter Station 43 at Canberra, Australia. Aside from CAPS, which is off, and the Ultrastable Oscillator (see the January 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health with all its subsystems operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Wednesday's targeted Titan encounter, T84, was this week's highlight. The 959 kilometer flyby of Saturn's largest satellite increased Cassini's orbital inclination from 15.8 to 21.1 degrees with respect to Saturn's equatorial plane, and increased the orbit period from 16 to 24.9 days. More information may be found on the T84 page here: http://saturn.jpl.nasa.gov/mission/flybys/titan20120607/
On Saturday and again on Monday, the Imaging Science Subsystem (ISS) performed observations in the Satellite Orbit Campaign, looking near Saturn where small satellites ("rocks") may be found, seeking to improve knowledge of their orbits or make new discoveries.


Wednesday, June 6 (DOY 158)

Inbound to Titan, the Composite Infrared Spectrometer (CIRS) observed vertical profiles of atmospheric temperatures and the presence and abundance of trace gasses. The Visible and Infrared Mapping Spectrometer (VIMS) acquired data to monitor climatic changes, and to look for specular reflection of the Sun on northern lakes. A previously acquired VIMS image illustrates the latter concept here: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=3777

For closest approach, attitude control was commanded to switch from reaction wheels to thrusters to provide increased control authority over atmosphere-generated torques. The maximum duty cycle was about 29%, less than predicted and indicating a less dense atmosphere than expected.

The Radar instrument acquired high-resolution Synthetic Aperture Radar (SAR) imaging around closest approach, and altimetry and lower-resolution SAR imaging from higher altitudes. Information on these Radar techniques may be found here: http://www2.jpl.nasa.gov/basics/bsf12-1.php#sar

The Radio and Plasma Wave Science instrument (RPWS) measured thermal plasmas in Titan's ionosphere and surrounding environment, searched for lightning in Titan's atmosphere, and investigated Titan's interaction with Saturn's magnetosphere.

The Magnetospheric Imaging Instrument (MIMI) measured the energetic ion and electron energy input to Titan's atmosphere.
Attitude and Articulation Control Subsystem Flight Software version A8.9.0 was approved at a Project Change Control Board meeting. The new software will be installed on the spacecraft in December.


Thursday, June 7 (DOY 159)

Outbound from Titan, the Ultraviolet Imaging Spectrograph (UVIS) obtained an image cube of Titan's atmosphere at extreme- and far-ultraviolet wavelengths by sweeping its slit across the disk. ISS rode along (took advantage of spacecraft pointing) and acquired low-phase-angle observations of Adiri and the region where extensive surface changes were observed in Fall 2010.


Friday, June 08 (DOY 160)

The 70 meter diameter Deep Space Network (DSN) stations in California and Spain successfully captured all the telemetry data that Cassini played back from the T84 encounter.

ISS monitored Titan to track clouds and their evolution for an extra day after T84. CIRS and VIMS rode along with ISS to monitor seasonal change. Radar performed a radiometry calibration.
The Instrument Expanded Block commands to support the S74 sequence were uplinked yesterday and today. All 10,777 commands from nine files were confirmed aboard the spacecraft.


Saturday, June 09 (DOY 161)

CIRS observed Saturn for 12 hours to measure oxygen compounds (H2O, CO2) in the stratosphere. The Navigation team took five images of the small satellite Mimas for Optical Navigation.


Sunday, June 10 (DOY 162)

Orbit Trim Maneuver 326, the T84 cleanup maneuver, was performed using the main engine. The 2.4 second burn provided a delta-V of 420 millimeters per second.

CDA performed a 12.5 hour interstellar dust observation.
Two dozen Cassini flight team members participated in this year's Open House at JPL, which drew record crowds.


Monday, June 11 (DOY 163)

ISS, CIRS, and VIMS performed another observation in the Titan monitoring campaign, then CIRS began a 33.5 hour mid-infrared map of Saturn to determine upper troposphere and tropopause temperature.
The S74 command sequence was approved today for uplink Thursday night.


Tuesday, June 12 (DOY 164)

The DSN telemetry processing issue that introduced packet timing error flags has been fixed. Ground data processing for ISS and VIMS products is back to normal.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/15/2012 01:42 PM
Rev168: Jun 17 - Jul 10 '12

http://www.ciclops.org/view/7229/Rev168
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/18/2012 02:11 PM
Hazy Ring

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4540
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/22/2012 06:40 AM
Quote

Cassini Significant Events 06/13/2012 - 06/19/2012

The most recent spacecraft tracking and telemetry data were collected on June 20 by the Deep Space Network's 34 meter Station 15 at Goldstone, California. Aside from CAPS, which is off, and the Ultrastable Oscillator, the Cassini spacecraft is in an excellent state of health with all its subsystems operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at:
http://saturn.jpl.nasa.gov/mission/presentposition/.


The S73 on-board command sequence completed execution and S74 began running on Monday afternoon; it will control the spacecraft through Aug. 25. While still running S73 commands this week, the Imaging Science Subsystem (ISS), the Composite Infrared Spectrometer (CIRS), and the Visible and Infrared Mapping Spectrometer (VIMS) performed two Titan monitoring campaign observations, and ISS accomplished two observations in the Satellite Orbit Campaign. More details about these campaigns appear in previous weeks' reports.


Wednesday, June 13 (DOY 165)

CIRS completed a 33.5 hour mid-infrared map of Saturn to determine upper troposphere and tropopause temperature. The Cosmic Dust Analyzer (CDA) began a 37.5 hour interstellar dust observation.

The Attitude and Articulation Control Subsystem (AACS) team performed a Reaction Wheel Assembly (RWA) bias maneuver. While off Earth-point and not being tracked, thrusters stabilized the spacecraft so the RWA speeds could be adjusted.
A feature titled, "Cassini Sees Tropical Lakes on Saturn Moon" was published today, describing methane lakes located far from Titan's poles. It may be viewed here: http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20120613/ .


Thursday, June 14 (DOY 166)

The Realtime Operations team uplinked the S74 background sequence this evening using the 70 meter DSN station at Canberra, Australia. All of the 9488 commands were confirmed onboard the spacecraft after a round-trip light time of 2 hours 32 minutes.


Friday, June 15 (DOY 167)

CIRS began another mid-infrared map of Saturn; this one lasted 23 hours.


Saturday, June 16 (DOY 168)

ISS performed a 10 hour satellite search around the Titan L5 Lagrange point 60 degrees behind Titan where it is possible for objects to exist in orbital equilibrium.


Sunday, June 17 (DOY 169)

Taking advantage of its 2.9 million kilometer distance from Saturn, CDA began another interstellar dust observation; it executed for 23.5 hours.

Cassini passed through apoapsis today going 5680 kilometers per hour relative to Saturn. This marked the start of orbit #168, which has a period of 24.9 days and an inclination of 21.1 degrees.
A 34 meter Deep Space Network (DSN) station at Canberra, Australia, participated in an Operations Readiness Test (ORT) in preparation for the Radio Science ring occultation experiment coming up on June 28. This was the third such ORT this week involving various Canberra DSN stations.


Monday, June 18 (DOY 170)

An RWA bias maneuver was executed via realtime command in preparation for the new background sequence. AACS then executed its Periodic Engineering Maintenance, which included spinning RWA3 to + and - 100 rpm for lubrication purposes, and a main-engine gimbal assembly exercise.

This afternoon the S74 Sequence began executing on the spacecraft.
An image of Titan blocking the Sun, titled "Hazy Ring", was featured today. It may be viewed here: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4540 .


Tuesday, June 19 (DOY 171)

VIMS, CIRS, ISS and UVIS jointly observed the dark side of Saturn's rings for 12 hours.

The Spacecraft Operations Office held a review of plans for powering on Deep Space Transponder B, the spacecraft's redundant radio receiver, for troubleshooting the apparently anomalous Ultrastable Oscillator early next month.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/25/2012 03:19 PM
Enormous Saturn

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4542
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/25/2012 04:42 PM
Cassini Shows why Jet Streams Cross-Cut Saturn

http://www.jpl.nasa.gov/news/news.cfm?release=2012-186&cid=release_2012-186&msource=12186
Title: Re: NASA - Cassini updates
Post by: racshot65 on 06/27/2012 12:07 PM
Eddy-Powered Jet stream

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4544
Title: Re: NASA - Cassini updates
Post by: jacqmans on 06/28/2012 06:15 PM
RELEASE: 12-218

NASA'S CASSINI FINDS PROBABLE SUBSURFACE OCEAN ON SATURN MOON

WASHINGTON -- Data from NASA's Cassini spacecraft have revealed
Saturn's moon Titan likely harbors a layer of liquid water under its
ice shell.

Researchers saw a large amount of squeezing and stretching as the moon
orbited Saturn. They deduced that if Titan were composed entirely of
stiff rock, the gravitational attraction of Saturn would cause
bulges, or solid "tides," on the moon only 3 feet (1 meter) in
height. Spacecraft data show Saturn creates solid tides approximately
30 feet (10 meters) in height, which suggests Titan is not made
entirely of solid rocky material. The finding appears in today's
edition of the journal Science.

"Cassini's detection of large tides on Titan leads to the almost
inescapable conclusion that there is a hidden ocean at depth," said
Luciano Iess, the paper's lead author and a Cassini team member at
the Sapienza University of Rome, Italy. "The search for water is an
important goal in solar system exploration, and now we've spotted
another place where it is abundant."

Titan takes only 16 days to orbit Saturn, and scientists were able to
study the moon's shape at different parts of its orbit. Because Titan
is not spherical but slightly elongated like a football, its long
axis grew when it was closer to Saturn. Eight days later, when Titan
was farther from Saturn, it became less elongated and more nearly
round. Cassini measured the gravitational effect of that squeeze and
pull.

Scientists were not sure Cassini would be able to detect the bulges
caused by Saturn's pull on Titan. By studying six close flybys of
Titan from Feb. 27, 2006, to Feb. 18, 2011, researchers were able to
determine the moon's internal structure by measuring variations in
the gravitational pull of Titan using data returned to NASA's Deep
Space Network (DSN).

"We were making ultrasensitive measurements, and thankfully Cassini
and the DSN were able to maintain a very stable link," said Sami
Asmar, a Cassini team member at NASA's Jet Propulsion Laboratory
(JPL) in Pasadena, Calif. "The tides on Titan pulled up by Saturn
aren't huge compared to the pull the biggest planet, Jupiter, has on
some of its moons. But, short of being able to drill on Titan's
surface, the gravity measurements provide the best data we have of
Titan's internal structure."

An ocean layer does not have to be huge or deep to create these tides.
A liquid layer between the external, deformable shell and a solid
mantle would enable Titan to bulge and compress as it orbits Saturn.
Because Titan's surface is mostly made of water ice, which is
abundant in moons of the outer solar system, scientists infer Titan's
ocean is likely mostly liquid water.

On Earth, tides result from the gravitational attraction of the moon
and sun pulling on our surface oceans. In the open oceans, those can
be as high as two feet (60 centimeters). While water is easier to
move, the gravitational pulling by the sun and moon also causes
Earth's crust to bulge in solid tides of about 20 inches (50
centimeters).

The presence of a subsurface layer of liquid water at Titan is not
itself an indicator for life. Scientists think life is more likely to
arise when liquid water is in contact with rock, and these
measurements cannot tell whether the ocean bottom is made up of rock
or ice. The results have a bigger implication for the mystery of
methane replenishment on Titan.

"The presence of a liquid water layer in Titan is important because we
want to understand how methane is stored in Titan's interior and how
it may outgas to the surface," said Jonathan Lunine, a Cassini team
member at Cornell University. "This is important because everything
that is unique about Titan derives from the presence of abundant
methane, yet the methane in the atmosphere is unstable and will be
destroyed on geologically short timescales."

A liquid water ocean, "salted" with ammonia, could produce buoyant
ammonia-water liquids that bubble up through the crust and liberate
methane from the ice. Such an ocean could serve also as a deep
reservoir for storing methane.
The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The mission is
managed by JPL for NASA's Science Mission Directorate in Washington.
DSN, also managed by JPL, is an international network of antennas
that supports interplanetary spacecraft missions and radio and radar
astronomy observations for the exploration of the solar system and
the universe. The network also supports selected Earth-orbiting
missions. Cassini's radio science team is based at Wellesley College
in Massachusetts.

For more information about the mission, visit:

http://www.nasa.gov/cassini

Title: Re: NASA - Cassini updates
Post by: bolun on 06/29/2012 01:17 PM
Titan's tides point to hidden ocean

28 Jun 2012

Nothing like it has been seen before beyond our own planet: large tides have been found on Saturn's moon Titan that point to a liquid ocean  most likely water  swirling around below the surface.

http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50517
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/02/2012 05:57 PM
Quote
Cassini Significant Events 06/20/2012 - 06/26/2012

The most recent spacecraft tracking and telemetry data were collected on June 27 by the Deep Space Network's70 meter Station 63 at Madrid, Spain. Aside from the Cassini Plasma Spectrometer, which is off, and the Ultrastable Oscillator (see the January 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health with all subsystems functioning normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Senior JPL management and Division 33 (Communications, Tracking, and Radar) gave the Cassini Flight Team the go-ahead for powering on Deep Space Transponder B, the spacecraft's redundant radio receiver, on July 4 to troubleshoot the apparently anomalous Ultrastable Oscillator.

Negotiations to schedule Deep Space Network (DSN) antennas to support Cassini's next background sequence, S75, are proving to be difficult. Since the Cassini Plasma Spectrometer instrument (CAPS) is powered off, CAPS-earmarked data volume in the Solid State Recorders is being used to help absorb DSN station allocation cuts.


Wednesday, June 20 (DOY 172)

The Magnetometer performed an 8 hour calibration while rotating the spacecraft about its X-axis. An animation of this pitching maneuver may be seen here: http://1.usa.gov/IEJlc1

Orbit Trim Maneuver 325, the Titan 85 approach maneuver, was executed today using the main engine. The 58 second burn provided a delta-V of about 10 meters per second.


Thursday, June 21 (DOY 173)

The Cosmic Dust Analyzer performed a 15 hour interstellar dust observation.


Friday, June 22 (DOY 174)

The Imaging Science Subsystem (ISS) and the Ultraviolet Imaging Spectrograph (UVIS) began a 37 hour observation of the irregular moon Ymir. This is a tiny dark object in a retrograde orbit 23 million kilometers from Saturn.


Saturday, June 23 (DOY 175)

A live update to Cassini's Inertial Vector Propagator was uplinked to provide updated instrument pointing commands for next week's observations of Titan, Tethys, and Saturn.


Sunday, June 24 (DOY 176)

ISS observed the sunlit face of the rings for 19 hours at high phase in order to create a movie, searching for periodicities in the spokes. A discussion of ring "spokes" accompanies this image: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=3893


Monday, June 25 (DOY 177)

ISS performed another observation in the Satellite Orbit Campaign. ISS, the Composite Infrared Spectrometer (CIRS), and UVIS then observed the F ring for 15.5 hours to create a low resolution movie.

The Visible and Infrared Mapping Spectrometer made three short Saturn Storm Watch observations while other instruments had control of spacecraft pointing.

A feature titled "Cassini Shows Why Jet Streams Cross-cut Saturn" was published today. It may be seen here: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20120625/


Tuesday, June 26 (DOY 178)

ISS made a 14.8 hour observation of Titan from a distance of 740,000 kilometers as part of a long range monitoring campaign.
Title: Re: NASA - Cassini updates
Post by: Robotbeat on 07/02/2012 08:04 PM
Titan's tides point to hidden ocean

28 Jun 2012

Nothing like it has been seen before beyond our own planet: large tides have been found on Saturn's moon Titan that point to a liquid ocean  most likely water  swirling around below the surface.

http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50517
Crazy. How thick is the top icy layer?

Very interesting... Here we have a big, liquid water ocean and all the sorts of organic materials needed for life in absolute abundance...
Title: Re: NASA - Cassini updates
Post by: ugordan on 07/02/2012 08:26 PM
Very interesting... Here we have a big, liquid water ocean and all the sorts of organic materials needed for life in absolute abundance...

Yes, except the liquid water and organic materials aren't really in proximity. The liquid layer is thought to be sandwitched between two layers of ice, one preventing ready contact with surface organics, the other preventing contact with the core and its minerals.
Title: Re: NASA - Cassini updates
Post by: go4mars on 07/03/2012 06:04 AM
Very interesting... Here we have a big, liquid water ocean and all the sorts of organic materials needed for life in absolute abundance...
Yes, except the liquid water and organic materials aren't really in proximity. The liquid layer is thought to be sandwitched between two layers of ice, one preventing ready contact with surface organics, the other preventing contact with the core and its minerals.
Very interesting.  But Sean Connery had life on Titan well characterized back in 1981.  ;)

http://www.youtube.com/watch?v=Ez2XfvN8XSc
Title: Re: NASA - Cassini updates
Post by: MarsMethanogen on 07/04/2012 01:22 AM
Very interesting... Here we have a big, liquid water ocean and all the sorts of organic materials needed for life in absolute abundance...
Yes, except the liquid water and organic materials aren't really in proximity. The liquid layer is thought to be sandwitched between two layers of ice, one preventing ready contact with surface organics, the other preventing contact with the core and its minerals.
Very interesting.  But Sean Connery had life on Titan well characterized back in 1981.  ;)

http://www.youtube.com/watch?v=Ez2XfvN8XSc

Uhh, afraid not.  That takes place on "one of Jupiter's moons".  Last time I checked, Titan was orbiting Saturn.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/06/2012 10:13 AM
Quote
Cassini Significant Events 06/27/2012 - 07/03/2012

The most recent spacecraft tracking and telemetry data were collected on July 2 by the Deep Space Network's 34 meter Station 55 at Madrid, Spain. Aside from the Cassini Plasma Spectrometer, which is off, and the Ultrastable Oscillator (see the Jan. 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health with all its subsystems functioning normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at:
http://saturn.jpl.nasa.gov/mission/presentposition/.

Now that Cassini's orbit is inclined 21 degrees out of Saturn's equatorial plane, many different observations of the splendid ring system have been taking center stage. Thursday's Radio Science ring occultation experiment, in which the Deep Space Network (DSN) itself comprised part of the science instrumentation, was not the least of them. Leading up to Thursday, the DSN participated in three Operations Readiness Tests to help ensure the successful Radio Science data capture.
 

Wednesday, June 27 (DOY 179)
 
The Imaging Science Subsystem (ISS), Composite Infrared Spectrometer (CIRS), and Visible and Infrared Mapping Spectrometer (VIMS) completed a 15 hour Titan observation as part of the Long Range Monitoring Campaign.
 
The ISS narrow-angle camera pointed to the F ring ansa and took 45 images while ring material passed through the field of view. The images will be used to make a movie of the narrow ring to monitor its time variable structure. Resolution was roughly twice as good as typical F ring observations. A previous F ring movie may be seen here:
http://saturn.jpl.nasa.gov/video/videodetails/?videoID=241
 

Thursday, June 28 (DOY 180)
 
ISS observed the ansa of Saturn's innermost ring, the D ring, for the full orbital period of its particles -- about 5 hours. One goal was to monitor corrugations in the outer part of this ring. These corrugations, which arose after a disturbance in 1983, are discussed at more length here:
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=3664
Another goal of this moderately high phase observation was to see patterns generated by resonances with Saturn's magnetic field.
 
The Radio Science Subsystem team performed an ingress occultation experiment, probing Saturn's rings using Cassini's three radio-frequency bands: S, X, and Ka. Since the Ultrastable Oscillator (USO) is inoperative, the DSN provided the reference frequency via uplink. The spacecraft's downlink was received and recorded at 70- and 34 meter stations at Canberra, Australia. This was the second of four such experiments designed to sample new values of ring opening angles, about 12.5 to 13.5 degrees. The experiments are expected to yield radial profiles of ring structure, shedding more light on the variability with ring longitude, opening angle, and wavelength of dynamical features such as waves, wakes, edges, gaps, and narrow ringlets. In addition, measurements of the strength and shape of the collective forward scattering of Cassini's radio energy will shed more light on physical properties of ring features such as particle sizes, aggregate sizes or wakes, wake orientation, packing fraction, and ring thickness.
 
The feature "Cassini Finds Likely Subsurface Ocean on Saturn Moon" was released today. It may be viewed here:
http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20120628/
 

Friday, June 29 (DOY 181)
 
The flight team uplinked a command that will turn on Cassini's S-band transmitter during a special USO test Tuesday night.
 
The F ring's structure has been seen to vary during Cassini's mission, so detailed measurements of it are valuable. The Ultraviolet Imaging Spectrograph (UVIS) observed a grazing occultation as the bright star Sirius passed behind the F ring and the outer A ring due to Cassini's motion. This observation measured the distribution and sizes of individual ring particles to a scale of one meter and larger.
 
VIMS obtained high-resolution spectral observations of the sunlit side of the rings at a moderately low phase angle, running roughly parallel to the planet's shadow across the rings to minimize the effect of scattered light from Saturn.
 
ISS searched for moonlets in the Cassini Division, which separates the A ring from the B ring.
 
 
Saturday, June 30 (DOY 182)
 
ISS took a 10.5 hour movie of the outer B ring to study edge waves that have been previously detected there. ISS then stared at the D ring ansa for about 5 hours, examining the corrugation patterns from a different viewing geometry to help quantify the amplitude of vertical motions in this region. This lower phase angle observation helped probe the distribution of larger particles, complementing the data obtained from Thursday's observation. Larger particles in this ring may be the source of the fine dust seen in higher-phase images.
 
 
Sunday, July 01 (DOY 183)
 
Today and yesterday ISS led observations in the Titan Monitoring Campaign.
 
UVIS, with VIMS and CIRS riding along (taking advantage of pointing), observed Saturn's polar aurora with repeated slews across the auroral oval for 12 hours.
 
 
Monday, July 02 (DOY 184)
 
Final preparations involving the Cassini Spacecraft Operations Office, Radio Science Subsystem team, Realtime Operations team, and the DSN were made today for the test late tomorrow night with Deep Space Transponder B, the spacecraft's redundant radio receiver, to troubleshoot the apparently anomalous Ultrastable Oscillator.
 
UVIS, with VIMS as a rider, observed Saturn's aurora for 14.5 hours. ISS, CIRS and VIMS then monitored Titan at a distance of 3.1 million kilometers.
 
 
Tuesday, July 03 (DOY 185)
 
ISS tracked the orbits of individual known "propeller" shaped features in the rings. UVIS, with VIMS riding along, then started a 23.5 hour observation of Saturn's auroral oval.
 
Videotaping for the 2012 Cassini Scientist for a Day essay contest took place today. Four Cassini flight team members introduced the contest and advocated their chosen targets for the upcoming contest. Videos will be edited over the next few weeks in preparation for announcing the contest on the Cassini website in mid-August.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/09/2012 04:06 PM
Bright Ejecta

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4551
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/10/2012 09:35 AM
Hello Again

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4594
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/10/2012 09:35 AM
Return to the Rings

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4590
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/10/2012 09:35 AM
Rev169: Jul 10 - Aug 2 '12

http://www.ciclops.org/view/7240/Rev169
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/11/2012 10:38 AM
The Titanian Seasons Turn, Turn, Turn

http://www.jpl.nasa.gov/news/news.cfm?release=2012-200
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/13/2012 11:15 AM
Quote
Cassini Significant Events 07/04/2012 - 07/10/2012

The most recent spacecraft tracking and telemetry data were collected on July 10 by the Deep Space Network's 70 meter Station 43 at Canberra, Australia. Aside from the Cosmic Dust Analyzer (CAPS), which is off, and the Ultrastable Oscillator (see the Jan. 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health with all its subsystems functioning normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

This week the Cassini flight team and the Deep Space Network (DSN) coordinated closely to conduct a definitive engineering test on the spacecraft which confirmed that the Ultra Stable Oscillator (USO) is inoperative, rather than other in-line telecommunications subsystem components. This will have no effect on engineering operations, but will impose some degradation on the accuracy of Radio Science occultation experiments.

With Cassini's orbits now inclined about 21 degrees with respect to Saturn's equatorial plane, not only are ring observations possible, but the polar regions of Saturn and its satellites are again in view. This geometry led to the news releases linked below.


Wednesday, July 4 (DOY 186)

Yesterday, a Cassini ground-system database issue halted Imaging Science Subsystem (ISS) and Visible and Infrared Mapping Spectrometer (VIMS) product generation from the downlinked data. Flight team members restored the processes before the holiday and no data were lost.

Cassini's S-band transmitter came on today, the result of a timed command sent last week. Realtime commands were then uplinked to power on Deep Space Transponder (DST)-B for the first time in flight. Manipulating the DSN uplink frequency from the ground provided a chance for DST-B to operate from a USO reference, had it been operable, without having to turn off DST-A. DST-B appeared healthy, but there was no evidence of a USO-based signal. The spacecraft was then re-configured for normal operations.

ISS, VIMS and the Composite Infrared Spectrometer (CIRS) monitored Titan from a distance of 3.2 million kilometers, then the Ultraviolet Imaging Spectrograph (UVIS) and VIMS began a 35 hour observation of Saturn's south polar auroral oval while the planet rotated three and a half times.
 

Thursday, July 5 (DOY 187)

Round-trip light-time with Cassini, as close to "realtime" as we can get, is 2 hours 38 minutes and increasing as Earth moves farther from Saturn.

Since Approach Science began in January, 2004, there have been 272,652 ISS images and 142,355 VIMS cubes acquired, downlinked, and processed.
 

Friday, July 6 (DOY 188)

ISS, CIRS and VIMS monitored Titan from 2.9 million kilometers, then UVIS and VIMS began another long duration Saturn aurora observation.


Saturday, July 7 (DOY 189)

The Attitude and Articulation Control Subsystem team performed a Reaction Wheel Assembly (RWA) bias maneuver while being tracked by the DSN. Thrusters stabilized the spacecraft attitude so the RWA speeds could be adjusted. An RWA bias maneuver was also performed during the busy 4th of July holiday while off Earth-point and not being tracked.


Sunday, July 8 (DOY 190)

UVIS and VIMS began another long aurora observation.
 

Monday, July 9 (DOY 191)

The feature "Saturn's Rings are Back" was made available here: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20120709/ .

A member of the Cassini Navigation team published a blog entry called, "A Different Slant: Cassini Has a Special View of Saturn These Days - How Did It Get There?" It can be seen here: http://blogs.jpl.nasa.gov/2012/07/a-different-slant/ .


Tuesday, July 10 (DOY 192)

Apoapsis in an orbit around Saturn can also be called "apokrone". Cassini passed through this point today at more than twice the "height" of Titan's orbit, going 5,695 kilometers per hour relative to the planet. This marked the start of orbit #169, which has a period of 24 days and an inclination of 21.2 degrees.

ISS, CIRS and VIMS monitored Titan from 1.8 million kilometers. The Magnetometer then executed a sensor offset calibration by rotating the spacecraft about its X axis.

Heavy rain over the DSN station at Canberra, Australia, drowned out Cassini's incoming signal for more than six hours, causing loss of science telemetry for large portions of the last two aurora observations.

Compelling images of a high-altitude vortex on Titan were released today and discussed in a feature titled, "The Titanian Seasons Turn, Turn, Turn": http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20120710/ .
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/16/2012 02:37 PM
Eclipsing a Moon

http://forum.nasaspaceflight.com/index.php?action=post;topic=1829.300;num_replies=338
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/19/2012 09:48 AM
Cassini Spots Daytime Lightning on Saturn

http://www.jpl.nasa.gov/news/news.cfm?release=2012-212
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/20/2012 04:20 PM
Quote
Cassini Significant Events 07/11/2012 - 07/17/2012

The most recent spacecraft tracking and telemetry data were collected on July 18 by the Deep Space Network's 34 meter Station 45 at Canberra, Australia. Aside from the Cassini Plasma Spectrometer, which is off, and the Ultrastable Oscillator (see the Jan. 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health with all its subsystems functioning normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Having passed through apoapsis the previous day, Cassini spent this week more than 2 million kilometers from Saturn making in-situ measurements in the outer magnetosphere and magnetosheath, remotely observing Saturn's aurora and monitoring Titan. On the ground, preparations were conducted for a busy period around periapsis next week, when the rings will again be observed by remote sensing, and actively probed in another Radio Science occultation experiment.


Wednesday, July 11 (DOY 193)

The Imaging Science Subsystem (ISS) observed the small dark moon Ymir in its retrograde orbit 23 million kilometers from Saturn.

Sequence planners for S75, which goes active in September, are evaluating whether there will be a need to do a Live Inertial Vector Propagator Update to ensure adequate instrument pointing accuracy for observations of the outer irregular satellite Bestla, based on newly delivered ephemeris data.
 

Thursday, July 12 (DOY 194)

Deep Space Network (DSN) tracking allocations to Cassini were changed late in the S74 sequence process after the sequence had been built, so commands were uplinked today to change downlink telemetry rates to accommodate a short DSN tracking pass on Monday.

The Attitude and Articulation Control Subsystem team performed a Reaction Wheel Assembly (RWA) bias maneuver. While off Earth-point and not being tracked, thrusters stabilized the spacecraft so the RWA speeds could be adjusted.

The 70 meter DSN station in Canberra, Australia, participated in an Operations Readiness Test (ORT) for next week's Radio Science rings and atmosphere occultation experiment.


Friday, July 13 (DOY 195)

The Navigation team took images of Saturn's moon Iapetus against a background star field to be used in support of optical navigation.

Today, and again on July 15 and 17, the Ultraviolet Imaging Spectrograph (UVIS) observed Saturn's aurora by performing a mixture of slews and fixed pointings at the southern auroral oval. The visible and infrared mapping spectrometer (VIMS), the Composite Infrared Spectrometer (CIRS), and ISS took advantage of the pointing to also make auroral observations.


Saturday, July 14 (DOY 196)

A 34 meter DSN station in Canberra, Australia, participated in an ORT for next week's Radio Science experiment.
 

Sunday, July 15 (DOY 197)

Saturn and Titan are still prominent for viewing in small telescopes; look toward the southwest as soon as it's dark. You might notice Mars is in the same part of the sky. This affects Cassini in that many of the same DSN antennas that might otherwise be tracking Cassini are needed for communications with the Mars Science Laboratory, which is due to land on Mars on Aug. 5 Pacific time.
 

Monday, July 16 (DOY 198)

ISS led the pointing, with CIRS and VIMS also taking measurements, to monitor Titan as part of the Titan Meteorological Campaign.

The navigation team released a trajectory update in support of the Live Moveable Block that will execute during next week's Radio Science experiment.

 
Tuesday, July 17 (DOY 199)

A Mission Planning forum was held today to review propellant use in the S73 sequence and the status of the propellant budgets. This status is provided on a regular basis so the Project can maintain cognizance of propellant usage and end-of-mission margins.

Work began today on realtime commands that make up what is known as a Live Moveable Block that will ensure the best possible timing of spacecraft activities during the RS occultation experiment next week.
 
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/27/2012 08:10 AM
Quote
Cassini Significant Events 07/18/2012 - 07/24/2012

The most recent spacecraft tracking and telemetry data were collected on July 25 by the Deep Space Network's 70 meter Station 14 at Goldstone, California. Aside from the Cassini Plasma Spectrometer, which is off, and the Ultrastable Oscillator (see the Jan. 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health with all its subsystems functioning normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

A 21-day period wrapped up on Saturday that was focused on Magnetospheric and Plasma Science observations of Saturn's magnetosphere and magnetosheath. Another Radio Science rings and atmosphere occultation experiment took place on Sunday. Finally, the Titan T85 encounter occurred on Tuesday as described here: http://saturn.jpl.nasa.gov/mission/flybys/titan20120724/
 

Wednesday, July 18 (DOY 200)

The Imaging Science Subsystem (ISS) led spacecraft pointing as part of the Titan Meteorological Campaign while the Composite Infrared Spectrometer (CIRS) and the Visible and Infrared Mapping Spectrometer (VIMS) also took measurements.

The feature "Cassini Spots Daytime Lightning on Saturn" was released today. It may be viewed here: http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20120718/


Thursday, July 19 (DOY 201)

A 34 meter Deep Space Network (DSN) station in Canberra, Australia, participated in an Operations Readiness Test for Sunday's Radio Science rings and atmosphere occultation experiment. During this pass, the flight team uplinked "Live Moveable Block" commands to refine the timing of spacecraft activities during Sunday's experiment.
 

Friday, July 20 (DOY 202)

A meeting with the NASA Engineering and Safety Center, the Cassini spacecraft team, and staff from the Southwest Research Institute was held to begin an investigation into the Cassini Plasma Spectrometer instrument anomaly that caused a solid state power switch to shut it off on June 3 of this year.


Saturday, July 21 (DOY 203)

Orbit Trim Maneuver (OTM) 328, the Titan 85 approach maneuver, was performed today using the Reaction Control Subsystem thrusters. The 161 second burn provided a delta-V of about 172 millimeters per second.


Sunday, July 22 (DOY 204)

The Radio Science Subsystem team performed an ingress occultation experiment, probing Saturn's rings and then atmosphere, using Cassini's 3-frequency radio beam. The DSN again provided the reference frequency via uplink because Cassini's Ultrastable Oscillator is inoperable. This time the spacecraft performed a limb-tracking maneuver, rotating as it went behind Saturn to keep its antenna pointing in such a way that it would still be received on Earth when atmospheric refraction began to bend the signal. The spacecraft's downlink was received and recorded at 70 meter and 34 meter stations at Canberra, Australia.

With the Sun eclipsed behind Saturn, Cassini was free to safely point its instruments toward the backlit rings. VIMS observed the unlit side at up to 175 degrees phase angle, looking for clouds from impacts of interplanetary debris on the A ring. Unusually high resolution should reveal most of the narrow gaps in the Cassini Division and narrow ringlets in the tenuous D ring. Riding on the VIMS observation, ISS took advantage of the opportunity to image the rings at high resolution and very high phase.

As Cassini crossed through the ring plane, the Cosmic Dust Analyzer measured particle count rates. CIRS then made a unique, high priority observation of the rings at high phase angles. VIMS observed the bright star Sirius rising through Saturn's atmosphere. Finally, UVIS observed another star behind the rings, providing a virtually microscopic view of ring densities including locations where the A ring opens into the Cassini Division.

 
Monday, July 23 (DOY 205)

UVIS observed the bright star Spica passing near Saturn's moon Dione due to Cassini's motion to search for evidence of Dione's exosphere in absorption spectra.

ISS searched for moonlets in gaps in the Cassini Division. CIRS carried out an infrared temperature mapping of Titan's atmosphere, and then the spacecraft performed a reaction-wheel bias maneuver.

An image called "Wave Maker" was featured today, showing Saturn's moon Daphnis causing out-of-plane structures in the A ring. It can be viewed here: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4601


Tuesday, July 24 (DOY 206)

As planned years ago by Cassini's tour designers, today's close northerly flyby of Titan (see the T-85 page linked above) took advantage of that body's gravitation and orbital momentum to increase the spacecraft's orbital inclination from 21.2 to 32.2 degrees with respect to Saturn's equatorial plane.

For closest approach, attitude control was commanded to switch from reaction wheels to thrusters to provide increased control authority over atmosphere-generated torques. The spacecraft rotated about its three axes to point optical remote-sensing and in-situ instruments. Telemetry data from all the instruments were stored aboard the Solid State Recorder. Playback will be complete Friday morning after three tracking periods with DSN's 70 meter stations at Goldstone and Canberra. Cassini transmits its telemetry to Earth at rates up to about 165,000 bits per second.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/30/2012 01:35 PM
Peeping Mimas

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4603
Title: Re: NASA - Cassini updates
Post by: racshot65 on 07/30/2012 01:35 PM
Wave Maker

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4601
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/02/2012 10:13 AM
Rev170: Aug 2 - Aug 23 '12

http://www.ciclops.org/view/7290/Rev170
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/03/2012 09:38 AM
Quote
Cassini Significant Events 07/25/2012 - 07/31/2012

The most recent spacecraft tracking and telemetry data were collected on July 31 by the Deep Space Network's 70 meter Station 63 at Madrid, Spain. Except for the Cassini Plasma Spectrometer, which is off, and the inoperative Ultrastable Oscillator, the Cassini spacecraft is in an excellent state of health with all its subsystems functioning normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

The Titan T-85 flyby executed normally yesterday. All of the radiometric tracking data and telemetry data were successfully collected without any loss. The spacecraft was so close to its nominal trajectory that the Cassini Navigation team was able to cancel the "cleanup" Orbit Trim Maneuver (OTM), which was planned for three days past the encounter. More information on T-85 is available here: http://saturn.jpl.nasa.gov/mission/flybys/titan20120724/
 

Wednesday, July 25 (DOY 207)

With Titan 177,000 kilometers away and receding, medium resolution capability was available for the Visible and Infrared Mapping Spectrometer (VIMS) to detect clouds and monitor post-equinox climatic changes. The Imaging Science Subsystem (ISS) and Composite Infrared Spectrometer (CIRS) observed Titan's atmosphere, riding along while VIMS controlled spacecraft pointing.
 

Thursday, July 26 (DOY 208)

The Ultraviolet Imaging Spectrograph (UVIS) performed a 17 hour system scan of Saturn's magnetosphere in order to image hydrogen and oxygen.
 

Friday, July 27 (DOY 209)

The Magnetometer (MAG) performed an 8 hour calibration while rotating the spacecraft about its X-axis.
 

Saturday, July 28 (DOY 210)

Today and the next twelve days are dedicated to UVIS system scans to image magnetospheric hydrogen and oxygen.


Sunday, July 29 (DOY 211)

A DSN track completed early today. This was one of six this week to carry out two-way digital data communications with Cassini, while making high-precision measurements of the incoming signal's Doppler shift for radial speed information, and the two-way light time to determine distance. Today it was Station 45, a 34 meter diameter "X-band high-efficiency" antenna at the Canberra Deep Space Communications Complex near Canberra, Australia.


Monday, July 30 (DOY 212)

An image titled "Peeping Mimas" was featured today, showing the small icy moon rising over the limb of the much larger moon Dione. http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4603


Tuesday, July 31 (DOY 213)

The Attitude and Articulation Control Subsystem (AACS) team updated a parameter in the spacecraft's AACS Flight Computer that affects main engine performance. The commands, which were approved for uplink this morning, first read out the memory location, made the change, and then read it out again. The change was confirmed 2 hours 46 minutes later. The new value will come into play during the main engine burn for OTM-330 on Aug. 7.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/06/2012 07:19 PM
Southern Swirl

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4605
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/10/2012 10:07 AM
Quote
Cassini Significant Events 08/01/2012 - 08/07/2012

The most recent spacecraft tracking and telemetry data were collected on Aug. 8 by the Deep Space Network's 34 meter Station 45 at Canberra, Australia. Except for the Cassini Plasma Spectrometer, which is off, and the inoperative Ultrastable Oscillator, the Cassini spacecraft is in an excellent state of health with all of its subsystems functioning normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

This week, Cassini was dedicated to primarily one kind of science data gathering activity. The Ultraviolet Imaging Spectrograph continued to control spacecraft pointing for over 91 hours, carrying out system scans of Saturn's magnetosphere to image hydrogen and oxygen.
 

Wednesday, Aug. 1 (DOY 214)

One of the 34 meter Deep Space Network (DSN) stations in Canberra, Australia, participated in an Operations Readiness Test for next Sunday's Radio Science rings and atmosphere occultation experiment.
 

Thursday, Aug. 2 (DOY 215)

The Attitude and Articulation Control Subsystem team performed a Reaction Wheel Assembly (RWA) bias maneuver while Cassini was being tracked by the DSN. On other missions, maneuvers similar to these are known as a momentum wheel desaturation or "desat" maneuvers. However, on Cassini, the objective is somewhat different, and the process is often referred to as momentum management.

During the same DSN tracking pass, the flight team uplinked two command files to support Sunday's Radio Science experiment. One was a "Live Moveable Block" to refine the timing of spacecraft activities; the other performed an update of the Inertial Vector Propagator for pointing to Saturn.

Cassini passed through apoapsis today at more than twice the "height" of Titan's orbit, going 6,634 kilometers per hour relative to the planet. This marked the start of orbit #170, which has a period of 21.2 days and an inclination of 32.2 degrees.
 

Friday, Aug. 3 (DOY 216)

Since Approach Science began on January 10, 2004, there have been 274,009 images received from the Imaging Science Subsystem, and 143,498 data cubes from the Visible and Infrared Mapping Spectrometer (VIMS). The latter are called "cubes" because each picture element in VIMS's 256 X 512 pixel array has a depth of 352 spectral channels.
 

Saturday, Aug. 4 (DOY 217)

The flight team sent commands today for Orbit Trim Maneuver (OTM) 330, which will execute on Monday night.
 

Sunday, Aug. 5 (DOY 218)

Today's DSN tracking pass was one of three this week that were shortened to about three hours each, compared with the usual nine hours each, in order to free up DSN antenna resources to support Mars Science Laboratory, which landed successfully tonight.

 
Monday, Aug. 6 (DOY 219)

The Radio Science Subsystem team carried out a periodic instrument maintenance activity.
 

Tuesday, Aug. 7 (DOY 220)

Orbit Trim Maneuver (OTM) 330, the apoapsis maneuver targeting to the Titan 86 encounter, was performed early this morning using the main engine. The 25 second burn provided a delta-V of about 4.4 meters per second.

The S77 Sequence Implementation Process (SIP) kickoff meeting was held today. The 10-week sequence will go active on the spacecraft next January.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/13/2012 02:36 PM
Atlas in the Distance

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4606
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/17/2012 08:14 PM
Quote
Cassini Significant Events 08/08/2012 - 08/14/2012

The most recent spacecraft tracking and telemetry data were collected on Aug.4 by the Deep Space Network's 70 meter Station 63 at Madrid, Spain. Except for the Cassini Plasma Spectrometer, which is off, and the inoperative Ultrastable Oscillator, the Cassini spacecraft is in an excellent state of health with all of its subsystems functioning normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

This week included a busy period around Saturn periapsis with close-in remote-sensing observations and a direct-sensing Radio Science Saturn atmosphere and ring occultation experiment.


Wednesday, Aug. 8 (DOY 221)

The Ultraviolet Imaging Spectrograph (UVIS) performed an 18 hour system scan, the last in a series to image hydrogen and oxygen.
 

Thursday, Aug. 9 (DOY 222)

The Navigation Team took five images for optical navigation purposes. The Imaging Science Subsystem (ISS) then made a 16 hour low-resolution movie of the F ring.
 

Friday, Aug. 10 (DOY 223)

RADAR performed a distant Titan Radiometry calibration.

The flight team uplinked two files of commands that will adjust telemetry playback rates to accommodate late changes in the Deep Space Network (DSN) tracking schedule.


Saturday, Aug. 11 (DOY 224)

The Visible and Infrared Mapping Spectrometer (VIMS) observed an occultation of the star Beta Pegasi by the rings.
 

Sunday, Aug. 12 (DOY 225)

To execute a Radio Science (RS) occultation experiment without a functioning Ultrastable Oscillator (USO) on board, the DSN uplinked a reference frequency through Saturn's atmosphere. The Radio Science team had adjusted this uplink frequency so that the spacecraft could receive and lock onto it behind the planet's limb, given the Doppler shift that would be induced by refraction in Saturn's atmosphere. The experiment measured vertical profiles of electron density in the ionosphere, and density, pressure, and temperature in the neutral atmosphere.

The RS occultation experiment continued through the full ring system to make high resolution radial profiles of ring structure, shedding more light on variability of dynamical ring features such as waves, wakes, edges, gaps, and narrow ringlets. In addition, the experiment made measurements of ring particle sizes, wake orientation, packing fraction, and ring thickness.

Following the RS experiment, the Cosmic Dust Analyzer (CDA) measured particle count rates during the ring-plane crossing to extend knowledge of E ring dust configuration.

UVIS made a two-hour "exosphere" observation by watching a star in Orion pass close to Saturn's moon Dione to search for volatiles.

The Composite Infrared Spectrometer (CIRS), ISS, and VIMS made an observation of the F ring with resolution about five times better than most F ring observations.


Monday, Aug. 13 (DOY 226)

Cassini passed through Saturn periapsis today, just inside the orbit of Dione, going 50,000 kilometers per hour relative to Saturn.

ISS performed a nine-hour search for moonlets in the C ring. Then for 4.5 hours, CIRS made radial scans on the morning and afternoon sides of the lit rings for temperature characterization. UVIS then made a 1.5 hour observation of Mimas to map the ultraviolet albedo as a function of longitude and phase angle.
 

Tuesday, Aug. 14 (DOY 227)

ISS, CIRS, and VIMS created an 11 hour medium resolution F ring movie, monitoring time variable structure in the ring.

The first three files of Instrument Expanded Block commands were uplinked today that will be used by the S75 background sequence, which begins execution on August 25. The spacecraft confirmed receiving all 6033 commands.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/21/2012 04:01 PM
Northern Odysseus

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4622
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/24/2012 09:19 AM
Quote
Cassini Significant Events 08/15/2012 - 08/21/2012

The most recent spacecraft tracking and telemetry data were collected on Aug. 22 by the Deep Space Network's70 meter Station 14 in the California desert at Goldstone. Except for the Cassini Plasma Spectrometer, which is off, and the inoperative Ultrastable Oscillator, the Cassini spacecraft is in an excellent state of health with all its subsystems functioning normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.

Fast-paced activities during the periapsis portion of Cassini's orbit last week gave way to some longer and slower, but still important science observations for this week.


Wednesday, Aug. 15 (DOY 228)

While Saturn was just over one million kilometers from Cassini's telescopes and receding, the Ultraviolet Imaging Spectrograph (UVIS) completed a 16-hour map of the planet's visible hemisphere in the extreme-ultraviolet and far-ultraviolet parts of the spectrum. The Composite Infrared Spectrometer (CIRS) then made an 11-hour observation to map Saturn's atmosphere in the far-infrared.
 

Thursday, Aug. 16 (DOY 229)

Today the spacecraft turned its high-gain antenna to Earth and downlinked telemetry data to the Deep Space Network (DSN), while receiving commands and navigation signals across interplanetary space. This was one of only three opportunities this week to connect with the DSN. The Magnetospheric and Plasma Science (MAPS) instruments also undertook survey activities today.

The Attitude and Articulation Control Subsystem team performed a Reaction Wheel Assembly (RWA) bias maneuver. While off Earth-point and not being tracked, thrusters stabilized the spacecraft so the RWA speeds could be adjusted. The Cassini Navigation team relies on telemetry data, which is played back later, to estimate the trajectory effects of the small delta-V resulting from the use of thrusters.

An approval meeting was held for the next ten-week command sequence, S75. Representatives from each science instrument team, the Spacecraft Operations team, and other teams involved, gave their concurrence. The S75 command file was given its final check and authorization for uplink.

Seven remaining files of instrument-expanded block commands, which will support S75 execution, were uplinked today. The distant spacecraft confirmed receipt of all 5481 commands.

New versions of maps for Rhea and Mimas were published on the gallery under Cassini Latest Images: http://saturn.jpl.nasa.gov/photos/

 
Friday, Aug. 17 (DOY 230)

CIRS turned the spacecraft back to Saturn to map its atmosphere in the mid-infrared for 22 contiguous hours.
 

Saturday, Aug. 18 (DOY 231)

The MAPS instruments took survey data again today. During a DSN communications session using the 70 meter dish at Goldstone, California, a heavy rainstorm interfered with capture of telemetry data for 21 minutes. Since excessive presence of water vapor in the troposphere degrades the quality of microwave links propagating throughout it, the heavy precipitation decreased the signal-to-noise ratio enough to drown out the data.
 

Sunday, Aug. 19 (DOY 232)

Optical remote-sensing (ORS) instruments participated today in the campaign to monitor Titan's atmosphere at brief yet frequent intervals; Titan was 3.4 million kilometers away. CIRS and the Imaging Science Subsystem (ISS) then traded opportunities to observe Saturn's atmosphere in a joint campaign to measure winds and atmospheric composition.
 

Monday, Aug. 20 (DOY 233)

The Realtime Operations team uplinked the S75 background sequence today. After a round-trip light time of 2 hours 50 minutes, the spacecraft confirmed successful receipt and storage of all 10,147 individually timed commands. Cassini will begin executing the S75 sequence on Friday.

CIRS and ISS completed a second set of coordinated wind and composition observations.

The image featured today, "Northern Odysseus," examines the huge crater on Saturn's moon Tethys: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4622
 

Tuesday, Aug. 21 (DOY 234)

Still under the control of the S74 sequence, ISS had the spacecraft turn its ORS instruments back towards Titan again, which was now 3.5 million kilometers away. UVIS then executed another set of slow scans of Saturn's atmosphere.

The Sequence Implementation Process teams are working on S76 and S77, which will go active in November and January respectively.
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/27/2012 01:34 PM
Night Side Rings

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4623
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/28/2012 12:14 PM
Rev171: Aug 23 - Sep 13 '12

http://www.ciclops.org/view/7329/Rev171
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/30/2012 11:07 AM
Polar Vortex in Color

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4634
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/30/2012 11:08 AM
Colorful Colossuses and Changing Hues

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4631
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/30/2012 11:08 AM
Obscured by Rings

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4632
Title: Re: NASA - Cassini updates
Post by: racshot65 on 08/30/2012 11:09 AM
A Ring of Color

http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4633
Title: Re: NASA - Cassini updates
Post by: hyper_snyper on 09/04/2012 12:33 PM
Wow!  Those pictures!  Of all the NASA missions Cassini has the best views.  The Saturn system is second only to Earth in beauty. 
Title: Re: NASA - Cassini updates
Post by: bolun on 09/10/2012 03:31 PM
http://www.esa.int/esaSC/SEMQ87AYT6H_index_0.html

Scrambling Saturn’s B-ring
Title: Re: NASA - Cassini updates
Post by: jacqmans on 10/15/2012 05:03 PM
LIFTOFF!
 
Today marks the 15th anniversary of Cassini's launch!
 
The Cassini spacecraft and Huygens probe began their multi-year journey to the ringed planet 15 years ago today where Cassini has been in orbit since 2004. The successful launch of Cassini aboard a Titan IVB/Centaur occurred at 4:43 a.m. PDT, Oct. 15, 1997.
 
Credit: NASA/JPL/KSC
Title: Re: NASA - Cassini updates
Post by: catdlr on 10/16/2012 07:09 PM
News feature: 2012-326                                                                     Oct. 16, 2012

What's Baking on Titan?

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2012-326&cid=release_2012-326

Radar images from NASA's Cassini spacecraft reveal some new curiosities on the surface of Saturn's mysterious moon Titan, including a nearly circular feature that resembles a giant hot cross bun and shorelines of ancient seas. The results were presented today at the American Astronomical Society's Division of Planetary Sciences conference in Reno, Nev.

Steam from baking often causes the top of bread to lift and crack. Scientists think some similar process involving heat may be at play on Titan. The image showing the bun-like mound was obtained on May 22, 2012, by Cassini's radar instrument. Scientists have seen similar terrain on Venus, where a dome-shaped region about 20 miles (30 kilometers) across has been seen at the summit of a large volcano called Kunapipi Mons. They theorize that the Titan cross, which is about 40 miles (70 kilometers) long, is also the result of fractures caused by uplift from below, possibly the result of rising magma.

"The 'hot cross bun' is a type of feature we have not seen before on Titan, showing that Titan keeps surprising us even after eight years of observations from Cassini," said Rosaly Lopes, a Cassini radar team scientist based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "The 'bun' may be the result of what is known on Earth as a laccolith, an intrusion formed by magma pushing up from below. The Henry Mountains of Utah are well-known examples of this geologic phenomenon."

Another group of Cassini scientists, led by Ellen Stofan, who is based at Proxemy Research, Rectortown, Va., has been scrutinizing radar images of Titan's southern hemisphere. Titan is the only place other than Earth that has stable liquid on its surface, though the liquids on Titan are hydrocarbon rather than water. So far, vast seas have only been seen in Titan's northern hemisphere.

A new analysis of Cassini images collected from 2008 to 2011 suggests there were once vast, shallow seas at Titan's south pole as well. Stofan and colleagues have found two good candidates for dry or mostly dry seas. One of these dry seas appears to be about 300 by 170 miles (475 by 280 kilometers) across, and perhaps a few hundred feet (meters) deep. Ontario Lacus, the largest current lake in the south, sits inside of the dry shorelines, like a shrunken version of a once-mighty sea.

Scientists led by Oded Aharonson, another radar team member based at the California Institute of Technology in Pasadena, think that cycles analogous to Earth's Croll-Milankovich cycles, which explain climate changes in terms of the way Earth orbits around the sun, are at play on Titan, too. Such cycles on Titan would cause long-term transfer of liquid hydrocarbons from pole to pole. By this model, the south pole could have been covered with extensive seas less than 50,000 years ago.

"The seas on Titan are temporary hosts for experiments in prebiotic chemistry, and we know they are cycling from one hemisphere to the other over 100,000 years," said Stofan. "I'd love to get a closer look at the seas of the north or these dry seabeds to examine the extent to which this prebiotic chemistry has developed."

The Cassini team has confirmed some of the stability of Titan's northern seas by looking at radar images from Cassini taken about one Titan season (in this case, six Earth years) apart. The newer images, from May 22, 2012, on the same flyby as the hot cross bun images, show the shorelines stayed about the same, indicating the northern lakes are not transient weather events, in contrast to the temporary darkening of parts of the equator after a rainstorm in 2010.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL. The RADAR instrument was built by JPL and the Italian Space Agency, working with team members from the US and several European countries. JPL is a division of the California Institute of Technology in Pasadena.

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov
- end -
Title: Re: NASA - Cassini updates
Post by: jacqmans on 10/25/2012 02:15 PM
RELEASE: 12-375

NASA SPACECRAFT SEES HUGE BURP AT SATURN AFTER LARGE STORM



WASHINGTON -- NASA's Cassini spacecraft has tracked the aftermath of a
rare massive storm on Saturn. Data reveal record-setting disturbances
in the planet's upper atmosphere long after the visible signs of the
storm abated, in addition to an indication the storm was more
forceful than scientists previously thought.

Data from Cassini's composite infrared spectrometer (CIRS) instrument
revealed the storm's powerful discharge sent the temperature in
Saturn's stratosphere soaring 150 degrees Fahrenheit (83 kelvins)
above normal. At the same time, researchers at NASA's Goddard
Spaceflight Center in Greenbelt, Md., detected a huge increase in the
amount of ethylene gas, the origin of which is a mystery. Ethylene,
an odorless, colorless gas, isn't typically observed on Saturn. On
Earth, it is created by natural and man-made sources.

Goddard scientists describe the unprecedented belch of energy in a
paper to be published in the Nov. 20 issue of the Astrophysical
Journal.
"This temperature spike is so extreme it's almost unbelievable,
especially in this part of Saturn's atmosphere, which typically is
very stable," said Brigette Hesman, the study's lead author and a
University of Maryland scientist who works at Goddard. "To get a
temperature change of the same scale on Earth, you'd be going from
the depths of winter in Fairbanks, Alaska, to the height of summer in
the Mojave Desert."

First detected by Cassini in Saturn's northern hemisphere on Dec. 5,
2010, the storm grew so large that an equivalent storm on Earth would
blanket most of North America from north to south and wrap around our
planet many times. This type of giant disturbance on Saturn typically
occurs every 30 Earth years, or once every Saturn year.

Not only was this the first storm of its kind to be studied by a
spacecraft in orbit around the planet, but it was the first to be
observed at thermal infrared wavelengths. Infrared data from CIRS
allowed scientists to take the temperature of Saturn's atmosphere and
to track phenomena that are invisible to the naked eye.

Temperature measurements by CIRS, first published in May 2011,
revealed two unusual beacons of warmer-than-normal air shining
brightly in the stratosphere. These indicated a massive release of
energy into the atmosphere. After the visible signs of the storm
started to fade, CIRS data revealed the two beacons had merged. The
temperature of this combined air mass shot up to more than minus 64
degrees Fahrenheit (above 220 kelvins).

According to Hesman, the huge spike of ethylene generated at the same
time peaked with 100 times more ethylene than scientists thought
possible for Saturn. Goddard scientists confirmed the release of the
gas using the Celeste spectrometer mounted on the McMath-Pierce Solar
Telescope on Kitt Peak in Arizona.

The team still is exploring the origin of the ethylene, but has ruled
out a large reservoir deep in the atmosphere.
"We've really never been able to see ethylene on Saturn before, so
this was a complete surprise," said Goddard's Michael Flasar, the
CIRS team lead.

A complementary paper led by Cassini team associate Leigh Fletcher of
Oxford University, England, describes how the two stratospheric
beacons merged to become the largest and hottest stratospheric vortex
ever detected in our solar system. Initially, it was larger than
Jupiter's Great Red Spot.

Their paper in the journal Icarus, which combines CIRS data with
additional infrared images from other Earth-based telescopes,
including NASA's Infrared Telescope Facility at Mauna Kea, Hawaii,
also reports a powerful collar of clockwise winds -- encompassing a
bizarre soup of gases -- around the vortex.

"These studies will give us new insight into some of the photochemical
processes at work in the stratospheres of Saturn, other giants in our
solar system, and beyond," said Scott Edgington, Cassini deputy
project scientist at NASA's Jet Propulsion Laboratory (JPL) in
Pasadena, Calif.
The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency, and the Italian Space Agency. The mission is
managed by JPL for NASA's Science Mission Directorate in Washington.
Hesman's work was funded in part by NASA's Planetary Astronomy
Program in Washington. The CIRS instrument and Celeste spectrometer
were built at Goddard.

To read more about the Fletcher paper, visit:

http://www.esa.int/esaSC/SEMLPIMFL8H_index_0.html

For information about Cassini and this observation, visit:

http://www.nasa.gov/cassini

       
-end-
Title: Re: NASA - Cassini updates
Post by: catdlr on 10/26/2012 04:10 AM
...and now the Video to accompanied the article above:

NASA | Saturn's Record-Setting Storm

Published on Oct 25, 2012 by NASAexplorer

Saturn's 2010 Great White Spot storm has set a new record for largest temperature change ever recorded for a storm on Saturn. By studying the monstrous disturbance using NASA's Cassini spacecraft, researchers spotted a massive belch of energy that sent temperatures soaring to an unprecedented 150 degrees Fahrenheit above normal in Saturn's stratosphere, accompanied by an enormous release of ethylene gas.

http://www.youtube.com/watch?v=O7O8Hsuxjyo

Title: Re: NASA - Cassini updates
Post by: catdlr on 10/31/2012 07:48 PM
Saturn Up Close and Personal - Cassini's 15th Anniversary Video

Published on Oct 31, 2012 by VideoFromSpace

The NASA spacecraft had delivered spectacular imagery of Saturn and its moons. It launched in 1997 and has been exploring the system since 2004.

http://www.youtube.com/watch?v=DPGugequcvA
Title: Re: NASA - Cassini updates
Post by: catdlr on 11/01/2012 01:40 AM

News feature: 2012-344                                                                       Oct. 31, 2012

Cassini Halloween Treat: Titan Glows in the Dark

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2012-344&cid=release_2012-344

A literal shot in the dark by imaging cameras on NASA's Cassini spacecraft has yielded an image of a visible glow from Titan, emanating not just from the top of Titan's atmosphere, but also - surprisingly - from deep in the atmosphere through the moon's haze. A person in a balloon in Titan's haze layer wouldn't see the glow because it's too faint - something like a millionth of a watt. Scientists were able to detect it with Cassini because the spacecraft's cameras are able to take long-exposure images.

"It turns out that Titan glows in the dark - though very dimly," said Robert West, the lead author of a recent study in the journal Geophysical Research Letters and a Cassini imaging team scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It's a little like a neon sign, where electrons generated by electrical power bang into neon atoms and cause them to glow. Here we're looking at light emitted when charged particles bang into nitrogen molecules in Titan's atmosphere."

Scientists are interested in studying the input of energy from the sun and charged particles into Titan's atmosphere because it is at the heart of the natural organic chemistry factory that exists in Titan's atmosphere.

"Scientists want to know what galvanizes the chemical reactions forming the heavy molecules that develop into Titan's thick haze of organic chemicals," said Linda Spilker, Cassini project scientist, also at JPL. "This kind of work helps us understand what kind of organic chemistry could have existed on an early Earth."

The light, known as airglow, is produced when atoms and molecules are excited by ultraviolet sunlight or electrically charged particles. Cassini scientists have already seen an airglow from Titan's nitrogen molecules caused by X-rays and ultraviolet radiation from the sun when Titan was illuminated by the sun. During 2009, Titan passed through Saturn's shadow, offering a unique opportunity for Cassini instruments to observe any luminescence from Titan while in darkness. Cassini's imaging cameras could see in very dim light by using exposure times of 560 seconds.

Scientists expected to see a glow in the high atmosphere (above 400 miles, or 700 kilometers in altitude) where charged particles from the magnetic bubble around Saturn strip electrons off of atmospheric molecules at Titan. Although an extremely weak emission was seen in that region, they were surprised to see Titan's dark face glow in visible wavelengths of light from deeper in the atmosphere (at about 190 miles or 300 kilometers above the surface), as though illuminated by moonshine from nearby satellites.

The scientists took into account sunlight reflected off Saturn. There was still a glow from the part of Titan that was dark. The luminescence was diffusing up from too deep for charged particles from the sun to be exciting atmospheric particles. The area was also not affected by the shooting of charged particles into the magnetic fields, which is what causes auroras.

Scientists' best guess is that the glow is being caused by deeper-penetrating cosmic rays or by light emitted due to some kind of chemical reaction deep in the atmosphere.

"This is exciting because we've never seen this at Titan before," West said. "It tells us that we don't know all there is to know about Titan and makes it even more mysterious."

Scientists have previously reported that the nightside Venus atmosphere also produces a glow, called the Ashen light. Some have suggested that lightning on Venus is responsible, although that explanation is not universally accepted. While Cassini's radio wave instrument has detected lightning at Saturn, it has not detected lightning at Titan. Scientists plan to keep looking for clues as Cassini continues to make its way around the Saturn system for another season.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute in Boulder, Colo.

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

Steve Mullins 720-974-5859
Space Science Institute, Boulder, Colo.
media@ciclops.org
- end -
Title: Re: NASA - Cassini updates
Post by: jacqmans on 11/26/2012 06:29 PM
News release: 2012-367                                                                     Nov. 26, 2012

Cassini Finds a Video Gamers' Paradise at Saturn

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2012-367&cid=release_2012-367

You could call this "Pac-Man, the Sequel." Scientists with NASA's Cassini mission have spotted a second feature shaped like the 1980s video game icon in the Saturn system, this time on the moon Tethys. (The first was found on Mimas in 2010). The pattern appears in thermal data obtained by Cassini's composite infrared spectrometer, with warmer areas making up the Pac-Man shape.

"Finding a second Pac-Man in the Saturn system tells us that the processes creating these Pac-Men are more widespread than previously thought," said Carly Howett, the lead author of a paper recently released online in the journal Icarus. "The Saturn system - and even the Jupiter system - could turn out to be a veritable arcade of these characters."

Scientists theorize that the Pac-Man thermal shape on the Saturnian moons occurs because of the way high-energy electrons bombard low latitudes on the side of the moon that faces forward as it orbits around Saturn. The bombardment turns that part of the fluffy surface into hard-packed ice. As a result, the altered surface does not heat as rapidly in the sunshine or cool down as quickly at night as the rest of the surface, similar to how a boardwalk at the beach feels cooler during the day but warmer at night than the nearby sand. Finding another Pac-Man on Tethys confirms that high-energy electrons can dramatically alter the surface of an icy moon. Also, because the altered region on Tethys, unlike on Mimas, is also bombarded by icy particles from Enceladus' plumes, it implies the surface alteration is occurring more quickly than its recoating by plume particles.

"Studies at infrared wavelengths give us a tremendous amount of information about the processes that shape planets and moons," said Mike Flasar, the spectrometer's principal investigator at NASA's Goddard Space Flight Center in Greenbelt, Md. "A result like this underscores just how powerful these observations are."

Scientists saw the new Pac-Man on Tethys in data obtained on Sept. 14, 2011, where daytime temperatures inside the mouth of Pac-Man were seen to be cooler than their surroundings by 29 degrees Fahrenheit (15 kelvins). The warmest temperature recorded was a chilly minus 300 degrees Fahrenheit (90 kelvins), which is actually slightly cooler than the warmest temperature at Mimas (about minus 290 degrees Fahrenheit, or 95 kelvins). At Tethys, unlike Mimas, the Pac-Man pattern can also be seen subtly in visible-light images of the surface, as a dark lens-shaped region. This brightness variation was first noticed by NASA's Voyager spacecraft in 1980.

"Finding a new Pac-Man demonstrates the diversity of processes at work in the Saturn system," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Future Cassini observations may reveal other new phenomena that will surprise us and help us better understand the evolution of moons in the Saturn system and beyond."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center in Greenbelt, Md., where the instrument was built.

More information about the Cassini-Huygens mission is at: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .
Title: Re: NASA - Cassini updates
Post by: jacqmans on 11/28/2012 08:20 PM
News release: 2012-374                                                                     Nov. 28, 2012

NASA's Cassini Sees Abrupt Turn in Titan's Atmosphere


The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2012-374&cid=release_2012-374

PASADENA, Calif. -Data from NASA's Cassini spacecraft tie a shift in seasonal sunlight to a wholesale reversal, at unexpected altitudes, in the circulation of the atmosphere of Saturn's moon Titan. At the south pole, the data show definitive evidence for sinking air where it was upwelling earlier in the mission. So the key to circulation in the atmosphere of Saturn's moon Titan turned out to be a certain slant of light. The paper was published today in the journal Nature.

"Cassini's up-close observations are likely the only ones we'll have in our lifetime of a transition like this in action," said Nick Teanby, the study's lead author who is based at the University of Bristol, England, and is a Cassini team associate. "It's extremely exciting to see such rapid changes on a body that usually changes so slowly and has a 'year' that is the equivalent of nearly 30 Earth years."

In our solar system, only Earth, Venus, Mars and Titan have both a solid surface and a substantial atmosphere - providing natural laboratories for exploring climate processes. "Understanding Titan's atmosphere gives us clues for understanding our own complex atmosphere," said Scott Edgington, Cassini deputy project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Some of the complexity in both places arises from the interplay of atmospheric circulation and chemistry."

The pole on Titan that is experiencing winter is typically pointed away from Earth due to orbital geometry. Because Cassini has been in orbit around Saturn since 2004, it has been able to study the moon from angles impossible from Earth and watch changes develop over time. Models have predicted circulation changes for nearly 20 years, but Cassini has finally directly observed them happening - marking a major milestone in the mission.

Other Cassini instruments recently obtained images of the formation of haze and a vortex over Titan's south pole, but the data from the composite infrared spectrometer (CIRS) is sensitive to much higher altitudes, provides more quantitative information and more directly probes the circulation and chemistry. The CIRS data, which enable scientists to track changes in atmospheric temperature and the distribution of gases like benzene and hydrogen cyanide, also revealed changes in hard-to-detect vertical winds and global circulation.

Besides the evidence for sinking air, Cassini also detected complex chemical production in the atmosphere at up to 400 miles (600 kilometers) above the surface, revealing the atmospheric circulation extends about 60 miles (100 kilometers) higher than previously expected. Compression of this sinking air as it moved to lower altitudes produced a hot spot hovering high above the south pole, the first indication of big changes to come. The scientists were also able to see very rapid changes in the atmosphere and pinpoint the circulation reversal to about six months around the August 2009 equinox, when the sun shone directly over Titan's equator. The circulation change meant that within two years of equinox, some gases had increased in abundance 100-fold - much more extreme than anything seen so far on Titan.

The results also suggest that a detached layer of haze (first detected by NASA's Voyager spacecraft) may not be so detached after all, since complex chemistry and vertical atmospheric movement is occurring above this layer. This layer may instead be the region where small haze particles combine into larger, but more transparent, clumped aggregates that eventually descend deeper into the atmosphere and give Titan its characteristic orange appearance.

"Next, we would expect to see the vortex over the south pole build up," said Mike Flasar, the CIRS principal investigator at NASA's Goddard Space Flight Center in Greenbelt, Md. "As that happens, one question is whether the south winter pole will be the identical twin of the north winter pole, or will it have a distinct personality? The most important thing is to be able to keep watching as these changes happen."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory manages the mission for NASA's Science Mission Directorate, Washington, D.C. The visual and infrared mapping spectrometer team is based at the University of Arizona, Tucson. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center in Greenbelt, Md., where the instrument was built. JPL is a division of Caltech.

For more information on Cassini, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .
Title: Re: NASA - Cassini updates
Post by: catdlr on 11/28/2012 11:49 PM
Enormous Vortex On Saturn Snapped By Spacecraft | Video

Published on Nov 28, 2012 by VideoFromSpace/Space.com

NASA's Cassini mission beamed back stunning imagery of a swirling storm on the ringed planet on November 27th, 2012.

http://www.youtube.com/watch?v=84MsvY3f6zU
Title: Re: NASA - Cassini updates
Post by: Borklund on 11/29/2012 11:51 AM
(https://planetary.s3.amazonaws.com/assets/images/6-saturn/2012/saturn_cassini_npole_stormFreeMovement.gif?__utma=113505944.1068390105.1338445915.1354176880.1354193220.19&__utmb=113505944.8.9.1354193243817&__utmc=113505944&__utmx=-&__utmz=113505944.1347011653.3.3.utmcsr=militaryphotos.net|utmccn=(referral)|utmcmd=referral|utmcct=/forums/showthread.php&__utmv=-&__utmk=230797663)

in .gif format, centered on the eye of the storm, courtesy of The Planetary Society (http://www.planetary.org/blogs/emily-lakdawalla/2012/saturn-north-pole-animation.html).
Title: Re: NASA - Cassini updates
Post by: jacqmans on 11/30/2012 08:42 AM
Titan’s seasons make sharp turn

 
28 November 2012
Scientists using the international Cassini spacecraft have studied the rapid change in seasons on Saturn’s moon Titan, following equinox in August 2009, which saw the formation of a swirling vortex and a build up of exotic gases at unexpectedly high altitudes.
 
Titan is the only other body in the Solar System with a thick nitrogen-rich atmosphere like Earth’s. Titan’s atmosphere also contains methane and hydrogen, with trace amounts of other gases including hydrocarbons that form at high altitudes as a result of reactions with sunlight.

http://www.esa.int/esaCP/SEMLA6EQZ9H_index_0.html
Title: Re: NASA - Cassini updates
Post by: catdlr on 12/12/2012 07:41 PM
Image advisory: 2012-394                                                                     Dec. 12, 2012

Cassini Spots Mini Nile River on Saturn Moon



The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2012-394&cid=release_2012-394

PASADENA, Calif. - Scientists with NASA's Cassini mission have spotted what appears to be a miniature, extraterrestrial likeness of Earth's Nile River: a river valley on Saturn's moon Titan that stretches more than 200 miles (400 kilometers) from its "headwaters" to a large sea. It is the first time images have revealed a river system this vast and in such high resolution anywhere other than Earth.

Scientists deduce that the river, which is in Titan's north polar region, is filled with liquid hydrocarbons because it appears dark along its entire length in the high-resolution radar image, indicating a smooth surface.

"Though there are some short, local meanders, the relative straightness of the river valley suggests it follows the trace of at least one fault, similar to other large rivers running into the southern margin of this same Titan sea," said Jani Radebaugh, a Cassini radar team associate at Brigham Young University, Provo, Utah. "Such faults - fractures in Titan's bedrock -- may not imply plate tectonics, like on Earth, but still lead to the opening of basins and perhaps to the formation of the giant seas themselves."

The new image is available online at: http://www.nasa.gov/mission_pages/cassini/multimedia/pia16197.html .

Titan is the only other world we know of that has stable liquid on its surface. While Earth's hydrologic cycle relies on water, Titan's equivalent cycle involves hydrocarbons such as ethane and methane. In Titan's equatorial regions, images from Cassini's visible-light cameras in late 2010 revealed regions that darkened due to recent rainfall. Cassini's visual and infrared mapping spectrometer confirmed liquid ethane at a lake in Titan's southern hemisphere known as Ontario Lacus in 2008.

"Titan is the only place we've found besides Earth that has a liquid in continuous movement on its surface," said Steve Wall, the radar deputy team lead, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "This picture gives us a snapshot of a world in motion. Rain falls, and rivers move that rain to lakes and seas, where evaporation starts the cycle all over again. On Earth, the liquid is water; on Titan, it's methane; but on both it affects most everything that happens."

The radar image here was taken on Sept. 26, 2012. It shows Titan's north polar region, where the river valley flows into Kraken Mare, a sea that is, in terms of size, between the Caspian Sea and the Mediterranean Sea on Earth. The real Nile River stretches about 4,100 miles (6,700 kilometers). The processes that led to the formation of Earth's Nile are complex, but involve faulting in some regions.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the US and several European countries. JPL is a division of the California Institute of Technology in Pasadena.

Jia-Rui Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

- end -
Title: Re: NASA - Cassini updates
Post by: jacqmans on 12/18/2012 06:31 PM
From Cassini for the Holidays: A Splendor Seldom Seen

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2012-402&cid=release_2012-402

PASADENA, Calif -- Just in time for the holidays, NASA's Cassini spacecraft, in orbit around Saturn for more than eight years now, has delivered another glorious, backlit view of the planet Saturn and its rings.

On Oct. 17, 2012, during its 174th orbit around the gas giant, Cassini was deliberately positioned within Saturn's shadow, a perfect location from which to look in the direction of the sun and take a backlit view of the rings and the dark side of the planet. Looking back towards the sun is a geometry referred to by planetary scientists as "high solar phase;" near the center of your target's shadow is the highest phase possible. This is a very scientifically advantageous and coveted viewing position, as it can reveal details about both the rings and atmosphere that cannot be seen in lower solar phase.

The last time Cassini had such an unusual perspective on Saturn and its rings, at sufficient distance and with sufficient time to make a full system mosaic, occurred in September 2006, when it captured a mosaic, processed to look like natural color, entitled "In Saturn's Shadow" (http://photojournal.jpl.nasa.gov/catalog/?IDNumber=PIA08329 ). In that mosaic, planet Earth put in a special appearance, making "In Saturn's Shadow" one of the most popular Cassini images to date.

The mosaic being released today by the mission and the imaging team, in celebration of the 2012 holiday season, does not contain Earth; along with the sun, our planet is hidden behind Saturn. However, it was taken when Cassini was closer to Saturn and therefore shows more detail in the rings than the one taken in 2006.

The new processed mosaic, composed of 60 images taken in the violet, visible and near infrared part of the spectrum, can be found at http://www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://ciclops.org .

"Of all the many glorious images we have received from Saturn, none are more strikingly unusual than those taken from Saturn's shadow," said Carolyn Porco, Cassini's imaging team lead based at the Space Science Institute in Boulder, Colo.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team consists of scientists from the U.S., England, France and Germany. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
Title: Re: NASA - Cassini updates
Post by: robertross on 12/18/2012 09:50 PM
stunning image:
Title: Re: NASA - Cassini updates
Post by: Ben the Space Brit on 12/19/2012 10:19 AM
stunning image:

Wow to the reflection of the rings on the planet's night-side.  Saturn really is the most visually amazing of the major planets!
Title: Re: NASA - Cassini updates
Post by: jacqmans on 01/08/2013 05:05 PM
Jan. 8, 2013

Cassini Suggests Icing on a Lake


The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-010&cid=release_2013-010

It's not exactly icing on a cake, but it could be icing on a lake. A new paper by scientists on NASA's Cassini mission finds that blocks of hydrocarbon ice might decorate the surface of existing lakes and seas of liquid hydrocarbon on Saturn's moon Titan. The presence of ice floes might explain some of the mixed readings Cassini has seen in the reflectivity of the surfaces of lakes on Titan.

"One of the most intriguing questions about these lakes and seas is whether they might host an exotic form of life," said Jonathan Lunine, a paper co-author and Cassini interdisciplinary Titan scientist at Cornell University, Ithaca, N.Y. "And the formation of floating hydrocarbon ice will provide an opportunity for interesting chemistry along the boundary between liquid and solid, a boundary that may have been important in the origin of terrestrial life."

Titan is the only other body besides Earth in our solar system with stable bodies of liquid on its surface. But while our planet's cycle of precipitation and evaporation involves water, Titan's cycle involves hydrocarbons like ethane and methane. Ethane and methane are organic molecules, which scientists think can be building blocks for the more complex chemistry from which life arose. Cassini has seen a vast network of these hydrocarbon seas cover Titan's northern hemisphere, while a more sporadic set of lakes bejewels the southern hemisphere.

Up to this point, Cassini scientists assumed that Titan lakes would not have floating ice, because solid methane is denser than liquid methane and would sink. But the new model considers the interaction between the lakes and the atmosphere, resulting in different mixtures of compositions, pockets of nitrogen gas, and changes in temperature. The result, scientists found, is that winter ice will float in Titan's methane-and-ethane-rich lakes and seas if the temperature is below the freezing point of methane -- minus 297 degrees Fahrenheit (90.4 kelvins). The scientists realized all the varieties of ice they considered would float if they were composed of at least 5 percent "air," which is an average composition for young sea ice on Earth. ("Air" on Titan has significantly more nitrogen than Earth air and almost no oxygen.)

If the temperature drops by just a few degrees, the ice will sink because of the relative proportions of nitrogen gas in the liquid versus the solid. Temperatures close to the freezing point of methane could lead to both floating and sinking ice - that is, a hydrocarbon ice crust above the liquid and blocks of hydrocarbon ice on the bottom of the lake bed. Scientists haven't entirely figured out what color the ice would be, though they suspect it would be colorless, as it is on Earth, perhaps tinted reddish-brown from Titan's atmosphere.

"We now know it's possible to get methane-and-ethane-rich ice freezing over on Titan in thin blocks that congeal together as it gets colder -- similar to what we see with Arctic sea ice at the onset of winter," said Jason Hofgartner, first author on the paper and a Natural Sciences and Engineering Research Council of Canada scholar at Cornell. "We'll want to take these conditions into consideration if we ever decide to explore the Titan surface some day."

Cassini's radar instrument will be able to test this model by watching what happens to the reflectivity of the surface of these lakes and seas. A hydrocarbon lake warming in the early spring thaw, as the northern lakes of Titan have begun to do, may become more reflective as ice rises to the surface. This would provide a rougher surface quality that reflects more radio energy back to Cassini, making it look brighter. As the weather turns warmer and the ice melts, the lake surface will be pure liquid, and will appear to the Cassini radar to darken.

"Cassini's extended stay in the Saturn system gives us an unprecedented opportunity to watch the effects of seasonal change at Titan," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We'll have an opportunity to see if the theories are right." The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 01/17/2013 05:21 PM
Titan Gets a Dune 'Makeover'

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-024&cid=release_2013-024

Titan's siblings must be jealous. While most of Saturn's moons display their ancient faces pockmarked by thousands of craters, Titan - Saturn's largest moon - may look much younger than it really is because its craters are getting erased. Dunes of exotic, hydrocarbon sand are slowly but steadily filling in its craters, according to new research using observations from NASA's Cassini spacecraft.

"Most of the Saturnian satellites - Titan's siblings - have thousands and thousands of craters on their surface. So far on Titan, of the 50 percent of the surface that we've seen in high resolution, we've only found about 60 craters," said Catherine Neish, a Cassini radar team associate based at NASA's Goddard Space Flight Center, Greenbelt, Md. "It's possible that there are many more craters on Titan, but they are not visible from space because they are so eroded. We typically estimate the age of a planet's surface by counting the number of craters on it (more craters means an older surface). But if processes like stream erosion or drifting sand dunes are filling them in, it's possible that the surface is much older that it appears.

"This research is the first quantitative estimate of how much the weather on Titan has modified its surface," adds Neish.

Titan is the only moon in the solar system with a thick atmosphere, and the only world besides Earth known to have lakes and seas on its surface. However, Titan has a frigid surface temperature of around minus 290 degrees Fahrenheit (94 kelvins). The rain that falls from Titan's skies is not water, but contains liquid methane and ethane, compounds that are gases at Earth's temperatures.

Neish and her team compared craters on Titan to craters on Jupiter's moon Ganymede. Ganymede is a giant moon with a water ice crust, similar to Titan, so craters on the two moons should have similar shapes. However, Ganymede has almost no atmosphere and thus no wind or rain to erode its surface.

"We found that craters on Titan were on average hundreds of yards [meters] shallower than similarly sized craters on Ganymede, suggesting that some process on Titan is filling its craters," says Neish, who is lead author of a paper about this research published online in the journal Icarus on Dec. 3, 2012.

The team used the average depth-versus-diameter trend for craters on Ganymede derived from stereo images from NASA's Galileo spacecraft. The same trend for craters on Titan was calculated using estimates of the crater depth from images made by Cassini's radar instrument.

Titan's atmosphere is mostly nitrogen with a trace of methane and other, more complex molecules made of hydrogen and carbon (hydrocarbons). The source of Titan's methane remains a mystery because methane in the atmosphere is broken down over relatively short time scales by sunlight. Fragments of methane molecules then recombine into more complex hydrocarbons in the upper atmosphere, forming a thick, orange smog that hides the surface from view. Some of the larger particles eventually rain out onto the surface, where they appear to get bound together to form the sand.

"Since the sand appears to be produced from the atmospheric methane, Titan must have had methane in its atmosphere for at least several hundred million years in order to fill craters to the levels we are seeing," says Neish. However, researchers estimate Titan's current supply of methane should be broken down by sunlight within tens of millions of years, so Titan either had a lot more methane in the past, or it is being replenished somehow.

Team members say it's possible that other processes could be filling the craters on Titan: erosion from the flow of liquid methane and ethane, for example. However, this type of weathering tends to fill a crater quickly at first, then more slowly as the crater rim gets worn down and less steep. If liquid erosion were primarily responsible for the infill, then the team would expect to see a lot of partially filled craters on Titan. "However, this is not the case," says Neish. "Instead we see craters at all stages; some just beginning to be filled in, some halfway, and some that are almost completely full. This suggests a process like windblown sand, which fills craters and other features at a steady rate."

Solid materials under stress flow very slowly over time. This is called viscous flow, and it is like what happens when someone takes a scoop out of a fresh tub of whipped cream -- the material slowly flows in to fill the hole and flatten the surface. Craters on icy satellites tend to get shallower over time as the ice flows viscously, so it's possible that some of the shallow craters on Titan are simply much older or experienced a higher heat flow than the similarly sized, fresh craters on Ganymede studied in this work.

However, Titan's crust is mostly water ice, and at the extremely low temperatures on Titan, ice shouldn't flow enough to account for such a large difference in depth compared to the Ganymede craters, according to the team. Also, just like stream erosion, deformation from viscous flow tends to happen rapidly at first, then more slowly as the material adjusts, so one would expect to see a lot of partially filled craters on Titan if its surface were deforming easily through viscous flow.

As Cassini flies past Titan on its multi-year tour of Saturn and its moons, its radar instrument gradually builds up a map of the surface. To date, the instrument has provided data in strips covering approximately 50 percent of Titan's surface. The craters measured by the team are all within about 30 degrees of the equator, a relatively dry region on Titan.

"However, the presence of liquids on the surface and in the near subsurface can also cause extensive modification to crater shape, as is observed on Earth," says Neish. "In the case of Titan, liquids consist of hydrocarbons, either as wet sediments (such as those observed at the Huygens landing site) or shallow marine environments (such as the lakes observed at the north and south poles). Craters formed in similar environments on Earth lack any significant surface topography, including the absence of a raised rim, as wet sediments slump into the crater. It is possible that the lack of topography associated with marine-target impacts may help to explain the relative scarcity of impact craters observed near the poles of Titan. If Titan's polar regions are saturated by liquid hydrocarbons, craters formed in those regions may lack any recognizable topographic expression."

The team thinks these considerations are good areas for more research. Based on the data so far, the difference in depth between craters on Titan and Ganymede is best explained by filling from windblown sand. However, erosion from liquids and viscous flow might contribute to the modification of Titan's craters.

NASA's Cassini mission, managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the NASA Postdoctoral Program, administered by Oak Ridge Associated Universities, funded the research.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the US and several European countries.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 01/31/2013 05:50 PM
Jan. 31, 2013

NASA's Cassini Watches Storm Choke on Its Own Tail

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-040&cid=release_2013-040

Call it a Saturnian version of the Ouroboros, the mythical serpent that bites its own tail. In a new paper that provides the most detail yet about the life and death of a monstrous thunder-and-lightning storm on Saturn, scientists from NASA's Cassini mission describe how the massive storm churned around the planet until it encountered its own tail and sputtered out. It is the first time scientists have observed a storm consume itself in this way anywhere in the solar system.

"This Saturn storm behaved like a terrestrial hurricane - but with a twist unique to Saturn," said Andrew Ingersoll, a Cassini imaging team member based at the California Institute of Technology, Pasadena, who is a co-author on the new paper in the journal Icarus. "Even the giant storms at Jupiter don't consume themselves like this, which goes to show that nature can play many awe-inspiring variations on a theme and surprise us again and again."

Earth's hurricanes feed off the energy of warm water and leave a cold-water wake. This storm in Saturn's northern hemisphere also feasted off warm "air" in the gas giant's atmosphere. The storm, first detected on Dec. 5, 2010, and tracked by Cassini's radio and plasma wave subsystem and imaging cameras, erupted around 33 degrees north latitude. Shortly after the bright, turbulent head of the storm emerged and started moving west, it spawned a clockwise-spinning vortex that drifted much more slowly. Within months, the storm wrapped around the planet at that latitude, stretching about 190,000 miles (300,000 kilometers) in circumference, thundering and throwing lightning along the way.

Terrestrial storms have never run into their own wakes - they encounter topographic features like mountains first and expend themselves. But Saturn has no land to stop its hurricanes. The bright, turbulent storm head was able to chomp all the way around the planet. It was only when the head of the storm ran into the vortex in June 2011 that the massive, convective storm faded away. Why the encounter would shut down the storm is still a mystery.

By Aug. 28, after 267 days, the Saturn storm stopped thundering for good. While Cassini's infrared detectors continue to track some lingering effects in higher layers of Saturn's atmosphere, the troposphere -- which is the weather-producing layer, lower in the atmosphere - has been quiet at that latitude.

"This thunder-and-lightning storm on Saturn was a beast," said Kunio Sayanagi, the paper's lead author and a Cassini imaging team associate at Hampton University in Virginia. "The storm maintained its intensity for an unusually long time. The storm head itself thrashed for 201 days, and its updraft erupted with an intensity that would have sucked out the entire volume of Earth's atmosphere in 150 days. And it also created the largest vortex ever observed in the troposphere of Saturn, expanding up to 7,500 miles [12,000 kilometers] across."

The vortex grew to be as large as the giant storm known as Oval BA on Jupiter. But Oval BA and Jupiter's more famous storm - the Great Red Spot - are not thunder-and-lightning storms. Jupiter's storms also have a quiet center, unlike the violence at the center of Saturn's storms.

"Cassini's stay in the Saturn system has enabled us to marvel at the power of this storm," said Scott Edgington, Cassini's deputy project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We had front-row seats to a wonderful adventure movie and got to watch the whole plot from start to finish. These kinds of data help scientists compare weather patterns around our solar system and learn what sustains and extinguishes them."

This storm was the longest running of the massive storms that appear to break out in Saturn's northern hemisphere once every Saturn year (30 Earth years). The longest storm of any size ever detected on Saturn actually unfolded over 334 days in 2009 in an area known as "Storm Alley" in the southern hemisphere, but it was about 100 times smaller in area than the latest northern storm.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team consists of scientists from the U.S., England, France and Germany. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .
Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/04/2013 04:21 PM
Cassini spies Venus from Saturn orbit
 
4 March 2013

 A distant world gleaming in sunlight, Venus shines like a bright beacon through Saturn’s rings in this image taken by the international Cassini spacecraft.
 
The image was taken last November when Cassini was placed in the shadow of Saturn. This allowed Cassini to look in the direction of the Sun and take a backlit image of the planet and its rings.
 
http://www.esa.int/Our_Activities/Space_Science/Cassini_spies_Venus_from_Saturn_orbit
Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/05/2013 04:58 AM
Cassini Spies Bright Venus From Saturn Orbit

 

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-079&cid=release_2013-079

PASADENA, Calif. - A distant world gleaming in sunlight, Earth's twin planet, Venus, shines like a bright beacon in images taken by NASA's Cassini spacecraft in orbit around Saturn.

One special image of Venus and Saturn was taken last November when Cassini was placed in the shadow of Saturn. This allowed Cassini to look in the direction of the sun and Venus, and take a backlit image of Saturn and its rings in a particular viewing geometry called "high solar phase." This observing position reveals details about the rings and Saturn's atmosphere that cannot be seen in lower solar phase.

One of the Venus and Saturn images being released today is a combination of separate red, green and blue images covering the planet and main rings and processed to produce true color. Last December, a false-color version of the mosaic was released.

Another image, taken in January, captures Venus just beyond the limb of Saturn and in close proximity to Saturn's G ring, a thin ring just beyond the main Saturnian rings. The diffuse E ring, which is outside the G ring and created by the spray of the moon Enceladus, also is visible.

These images can be found at http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA14935 and http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA14936.

Venus is, along with Mercury, Earth and Mars, one of the rocky "terrestrial" planets in the solar system that orbit relatively close to the sun. Though Venus has an atmosphere of carbon dioxide that reaches nearly 900 degrees Fahrenheit (500 degrees Celsius) and a surface pressure 100 times that of Earth's, it is considered a twin to our planet because of their similar sizes, masses, rocky compositions and close orbits. It is covered in thick sulfuric acid clouds, making it very bright.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team consists of scientists from the U.S., England, France and Germany. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .
Title: Re: NASA - Cassini updates
Post by: catdlr on 04/25/2013 08:47 PM
April 25, 2013
 
RELEASE : 13-120
 
 
NASA Probe Observes Meteors Colliding With Saturn's Rings
 
 
WASHINGTON -- NASA's Cassini spacecraft has provided the first direct evidence of small meteoroids breaking into streams of rubble and crashing into Saturn's rings.

These observations make Saturn's rings the only location besides Earth, the moon, and Jupiter where scientists and amateur astronomers have been able to observe impacts as they occur. Studying the impact rate of meteoroids from outside the Saturn system helps scientists understand how different planet systems in the solar system formed.

Our solar system is full of small, speeding objects. Planetary bodies frequently are pummeled by them. The meteoroids at Saturn range from about one-half inch to several yards (1 centimeter to several meters) in size. It took scientists years to distinguish tracks left by nine meteoroids in 2005, 2009 and 2012.

Details of the observations appear in a paper in the Thursday edition of Science.

Results from Cassini already have shown Saturn's rings act as very effective detectors of many kinds of surrounding phenomena, including the interior structure of the planet and the orbits of its moons. For example, a subtle but extensive corrugation that ripples 12,000 miles (19,000 kilometers) across the innermost rings tells of a very large meteoroid impact in 1983.

"These new results imply the current-day impact rates for small particles at Saturn are about the same as those at Earth-- two very different neighborhoods in our solar system, and this is exciting to see," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "It took Saturn's rings acting like a giant meteoroid detector -- 100 times the surface area of the Earth -- and Cassini's long-term tour of the Saturn system to address this question."

The Saturnian equinox in summer 2009 was an especially good time to see the debris left by meteoroid impacts. The very shallow sun angle on the rings caused the clouds of debris to look bright against the darkened rings in pictures from Cassini's imaging science subsystem.

"We knew these little impacts were constantly occurring, but we didn't know how big or how frequent they might be, and we didn't necessarily expect them to take the form of spectacular shearing clouds," said Matt Tiscareno, lead author of the paper and a Cassini participating scientist at Cornell University in Ithaca, N.Y. "The sunlight shining edge-on to the rings at the Saturnian equinox acted like an anti-cloaking device, so these usually invisible features became plain to see."

Tiscareno and his colleagues now think meteoroids of this size probably break up on a first encounter with the rings, creating smaller, slower pieces that then enter into orbit around Saturn. The impact into the rings of these secondary meteoroid bits kicks up the clouds. The tiny particles forming these clouds have a range of orbital speeds around Saturn. The clouds they form soon are pulled into diagonal, extended bright streaks.

"Saturn's rings are unusually bright and clean, leading some to suggest that the rings are actually much younger than Saturn," said Jeff Cuzzi, a co-author of the paper and a Cassini interdisciplinary scientist specializing in planetary rings and dust at NASA's Ames Research Center in Moffett Field, Calif. "To assess this dramatic claim, we must know more about the rate at which outside material is bombarding the rings. This latest analysis helps fill in that story with detection of impactors of a size that we weren't previously able to detect directly."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter and its two onboard cameras. The imaging team consists of scientists from the United States, England, France and Germany. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For images of the impacts and information about Cassini, visit:

http://www.nasa.gov/cassini

 
- end -
Title: Re: NASA - Cassini updates
Post by: catdlr on 04/29/2013 05:02 PM
News release: 2013-149                                                                    April 29, 2013

NASA Probe Gets Close-Up Views of Large Hurricane on Saturn



The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-149&cid=release_2013-149

PASADENA, Calif. - NASA's Cassini spacecraft has provided scientists the first close-up, visible-light views of a behemoth hurricane swirling around Saturn's north pole.

In high-resolution pictures and video, scientists see the hurricane's eye is about 1,250 miles (2,000 kilometers) wide, 20 times larger than the average hurricane eye on Earth. Thin, bright clouds at the outer edge of the hurricane are traveling 330 mph(150 meters per second). The hurricane swirls inside a large, mysterious, six-sided weather pattern known as the hexagon.

"We did a double take when we saw this vortex because it looks so much like a hurricane on Earth," said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena. "But there it is at Saturn, on a much larger scale, and it is somehow getting by on the small amounts of water vapor in Saturn's hydrogen atmosphere."

Scientists will be studying the hurricane to gain insight into hurricanes on Earth, which feed off warm ocean water. Although there is no body of water close to these clouds high in Saturn's atmosphere, learning how these Saturnian storms use water vapor could tell scientists more about how terrestrial hurricanes are generated and sustained.

Both a terrestrial hurricane and Saturn's north polar vortex have a central eye with no clouds or very low clouds. Other similar features include high clouds forming an eye wall, other high clouds spiraling around the eye, and a counter-clockwise spin in the northern hemisphere.

A major difference between the hurricanes is that the one on Saturn is much bigger than its counterparts on Earth and spins surprisingly fast. At Saturn, the wind in the eye wall blows more than four times faster than hurricane-force winds on Earth. Unlike terrestrial hurricanes, which tend to move, the Saturnian hurricane is locked onto the planet's north pole. On Earth, hurricanes tend to drift northward because of the forces acting on the fast swirls of wind as the planet rotates. The one on Saturn does not drift and is already as far north as it can be.

"The polar hurricane has nowhere else to go, and that's likely why it's stuck at the pole," said Kunio Sayanagi, a Cassini imaging team associate at Hampton University in Hampton, Va.

Scientists believe the massive storm has been churning for years. When Cassini arrived in the Saturn system in 2004, Saturn's north pole was dark because the planet was in the middle of its north polar winter. During that time, the Cassini spacecraft's composite infrared spectrometer and visual and infrared mapping spectrometer detected a great vortex, but a visible-light view had to wait for the passing of the equinox in August 2009. Only then did sunlight begin flooding Saturn's northern hemisphere. The view required a change in the angle of Cassini's orbits around Saturn so the spacecraft could see the poles.

"Such a stunning and mesmerizing view of the hurricane-like storm at the north pole is only possible because Cassini is on a sportier course, with orbits tilted to loop the spacecraft above and below Saturn's equatorial plane," said Scott Edgington, Cassini deputy project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "You cannot see the polar regions very well from an equatorial orbit. Observing the planet from different vantage points reveals more about the cloud layers that cover the entirety of the planet."

Cassini changes its orbital inclination for such an observing campaign only once every few years. Because the spacecraft uses flybys of Saturn's moon Titan to change the angle of its orbit, the inclined trajectories require attentive oversight from navigators. The path requires careful planning years in advance and sticking very precisely to the planned itinerary to ensure enough propellant is available for the spacecraft to reach future planned orbits and encounters.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team consists of scientists from the United States, the United Kingdom, France and Germany. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

Images and two versions of a movie of the hurricane can be viewed online at: http://go.usa.gov/TQSB .

For more information about Cassini and its mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov

- end -
Title: Re: NASA - Cassini updates
Post by: catdlr on 04/29/2013 06:03 PM
Now with Two Videos:

Saturn Hurricane Movie

Published on Apr 29, 2013
This movie, made from images obtained by NASA's Cassini spacecraft, shows the clouds of a hurricane-like storm, which circulate around the north pole of Saturn out to 88.5 degrees north latitude.

http://www.youtube.com/watch?v=71AFyQBLhyc

http://www.youtube.com/watch?v=75RnmfKNiP8
Title: Re: NASA - Cassini updates
Post by: jacqmans on 05/15/2013 06:34 PM
Cassini Shapes First Global Topographic Map of Titan

 

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-161&cid=release_2013-161

Scientists have created the first global topographic map of Saturn's moon Titan, giving researchers a valuable tool for learning more about one of the most Earth-like and interesting worlds in the solar system. The map was just published as part of a paper in the journal Icarus.

Titan is Saturn's largest moon - at 1,600 miles (2,574 kilometers) across it's bigger than planet Mercury - and is the second-largest moon in the solar system. Scientists care about Titan because it's the only moon in the solar system known to have clouds, surface liquids and a mysterious, thick atmosphere. The cold atmosphere is mostly nitrogen, like Earth's, but the organic compound methane on Titan acts the way water vapor does on Earth, forming clouds and falling as rain and carving the surface with rivers. Organic chemicals, derived from methane, are present in Titan's atmosphere, lakes and rivers and may offer clues about the origins of life.

"Titan has so much interesting activity - like flowing liquids and moving sand dunes - but to understand these processes it's useful to know how the terrain slopes," said Ralph Lorenz, a member of the Cassini radar team based at the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., who led the map-design team. "It's especially helpful to those studying hydrology and modeling Titan's climate and weather, who need to know whether there is high ground or low ground driving their models."

Titan's thick haze scatters light in ways that make it very hard for remote cameras to "see" landscape shapes and shadows, the usual approach to measuring topography on planetary bodies. Virtually all the data we have on Titan comes from NASA's Saturn-orbiting Cassini spacecraft, which has flown past the moon nearly 100 times over the past decade. On many of those flybys, Cassini has used a radar imager, which can peer through the haze, and the radar data can be used to estimate the surface height.

"With this new topographic map, one of the most fascinating and dynamic worlds in our solar system now pops out in 3-D," said Steve Wall, the deputy team lead of Cassini's radar team, based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "On Earth, rivers, volcanoes and even weather are closely related to heights of surfaces - we're now eager to see what we can learn from them on Titan."

There are challenges, however. "Cassini isn't orbiting Titan," Lorenz said. "We have only imaged about half of Titan's surface, and multiple 'looks' or special observations are needed to estimate the surface heights. If you divided Titan into 1-degree by 1-degree [latitude and longitude] squares, only 11 percent of those squares have topography data in them."

Lorenz's team used a mathematical process called splining - effectively using smooth, curved surfaces to "join" the areas between grids of existing data. "You can take a spot where there is no data, look how close it is to the nearest data, and use various approaches of averaging and estimating to calculate your best guess," he said. "If you pick a point, and all the nearby points are high altitude, you'd need a special reason for thinking that point would be lower. We're mathematically papering over the gaps in our coverage."

The estimations fit with current knowledge of the moon - that its polar regions are "lower" than areas around the equator, for example - but connecting those points allows scientists to add new layers to their studies of Titan's surface, especially those modeling how and where Titan's rivers flow, and the seasonal distribution of its methane rainfall. "The movement of sands and the flow of liquids are influenced by slopes, and mountains can trigger cloud formation and therefore rainfall. This global product now gives modelers a convenient description of this key factor in Titan's dynamic climate system," Lorenz said.

The most recent data used to compile the map is from 2012; Lorenz says it could be worth revising when the Cassini mission ends in 2017, when more data will have accumulated, filling some of the gaps in present coverage. "We felt we couldn't wait and should release an interim product," he says. "The community has been hoping to get this for a while. I think it will stimulate a lot of interesting work."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.
Title: Re: NASA - Cassini updates
Post by: catdlr on 05/22/2013 07:47 PM
News feature: 2013-170                                                                    May 22, 2013

Forecast for Titan: Wild Weather Could be Ahead



The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-170&cid=release_2013-170

Saturn's moon Titan might be in for some wild weather as it heads into its spring and summer, if two new models are correct. Scientists think that as the seasons change in Titan's northern hemisphere, waves could ripple across the moon's hydrocarbon seas, and hurricanes could begin to swirl over these areas, too. The model predicting waves tries to explain data from the moon obtained so far by NASA's Cassini spacecraft. Both models help mission team members plan when and where to look for unusual atmospheric disturbances as Titan summer approaches.

"If you think being a weather forecaster on Earth is difficult, it can be even more challenging at Titan," said Scott Edgington, Cassini's deputy project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We know there are weather processes similar to Earth's at work on this strange world, but differences arise due to the presence of unfamiliar liquids like methane. We can't wait for Cassini to tell us whether our forecasts are right as it continues its tour through Titan spring into the start of northern summer."

Titan's north polar region, which is bejeweled with sprawling hydrocarbon seas and lakes, was dark when Cassini first arrived at the Saturn system in 2004. But sunlight has been creeping up Titan's northern hemisphere since August 2009, when the sun's light crossed the equatorial plane at equinox. Titan's seasons take about seven Earth years to change. By 2017, the end of Cassini's mission, Titan will be approaching northern solstice, the height of summer.

Given the wind-sculpted dunes Cassini has seen on Titan, scientists were baffled about why they hadn't yet seen wind-driven waves on the lakes and seas. A team led by Alex Hayes, a member of Cassini's radar team who is based at Cornell University, Ithaca, N.Y., set out to look for how much wind would be required to generate waves. Their new model, just published in the journal Icarus, improves upon previous ones by simultaneously accounting for Titan's gravity; the viscosity and surface tension of the hydrocarbon liquid in the lakes; and the air-to-liquid density ratio.

"We now know that the wind speeds predicted during the times Cassini has observed Titan have been below the threshold necessary to generate waves," Hayes said. "What is exciting, however, is that the wind speeds predicted during northern spring and summer approach those necessary to generate wind waves in liquid ethane and/or methane. It may soon be possible to catch a wave in one of the solar system's most exotic locations."

The new model found that winds of 1 to 2 mph (2 to 3 kilometers per hour) are needed to generate waves on Titan lakes, a speed that has not yet been reached during Titan's currently calm period. But as Titan's northern hemisphere approaches spring and summer, other models predict the winds may increase to 2 mph (3 kilometers per hour) or faster. Depending on the composition of the lakes, winds of that speed could be enough to produce waves 0.5 foot (0.15 meter) high.

The other model about hurricanes, recently published in Icarus, predicts that the warming of the northern hemisphere could also bring hurricanes, also known as tropical cyclones. Tropical cyclones on Earth gain their energy from the build-up of heat from seawater evaporation and miniature versions have been seen over big lakes such as Lake Huron. The new modeling work, led by Tetsuya Tokano of the University of Cologne, Germany, shows that the same processes could be at work on Titan as well, except that it is methane rather than water that evaporates from the seas. The most likely season for these hurricanes would be Titan's northern summer solstice, when the sea surface gets warmer and the flow of the air near the surface becomes more turbulent. The humid air would swirl in a counterclockwise direction over the surface of one of the northern seas and increase the surface wind over the seas to possibly 45 mph (about 70 kilometers per hour).

"For these hurricanes to develop at Titan, there needs to be the right mix of hydrocarbons in these seas, and we still don't know their exact composition," Tokano said. "If we see hurricanes, that would be one good indicator that there is enough methane in these lakes to support this kind of activity. So far, scientists haven't yet been able to detect methane directly."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. The mission is managed by JPL for NASA's Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology in Pasadena, Calif.

For more information about Cassini and its mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

2013-170

- end -
Title: Re: NASA - Cassini updates
Post by: catdlr on 05/29/2013 11:49 PM
News feature: 2013-178                                                                    May 29, 2013

Cassini Finds Hints of Activity at Saturn Moon Dione



The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-178&cid=release_2013-178

From a distance, most of the Saturnian moon Dione resembles a bland cueball. Thanks to close-up images of a 500-mile-long (800-kilometer-long) mountain on the moon from NASA's Cassini spacecraft, scientists have found more evidence for the idea that Dione was likely active in the past. It could still be active now.

"A picture is emerging that suggests Dione could be a fossil of the wondrous activity Cassini discovered spraying from Saturn's geyser moon Enceladus or perhaps a weaker copycat Enceladus," said Bonnie Buratti of NASA's Jet Propulsion Laboratory in Pasadena, Calif., who leads the Cassini science team that studies icy satellites. "There may turn out to be many more active worlds with water out there than we previously thought."

Other bodies in the solar system thought to have a subsurface ocean - including Saturn's moons Enceladus and Titan and Jupiter's moon Europa - are among the most geologically active worlds in our solar system. They have been intriguing targets for geologists and scientists looking for the building blocks of life elsewhere in the solar system. The presence of a subsurface ocean at Dione would boost the astrobiological potential of this once-boring iceball.

Hints of Dione's activity have recently come from Cassini, which has been exploring the Saturn system since 2004. The spacecraft's magnetometer has detected a faint particle stream coming from the moon, and images showed evidence for a possible liquid or slushy layer under its rock-hard ice crust. Other Cassini images have also revealed ancient, inactive fractures at Dione similar to those seen at Enceladus that currently spray water ice and organic particles.

The mountain examined in the latest paper -- published in March in the journal Icarus -- is called Janiculum Dorsa and ranges in height from about 0.6 to 1.2 miles (1 to 2 kilometers). The moon's crust appears to pucker under this mountain as much as about 0.3 mile (0.5 kilometer).

"The bending of the crust under Janiculum Dorsa suggests the icy crust was warm, and the best way to get that heat is if Dione had a subsurface ocean when the ridge formed," said Noah Hammond, the paper's lead author, who is based at Brown University, Providence, R.I.

Dione gets heated up by being stretched and squeezed as it gets closer to and farther from Saturn in its orbit. With an icy crust that can slide around independently of the moon's core, the gravitational pulls of Saturn get exaggerated and create 10 times more heat, Hammond explained. Other possible explanations, such as a local hotspot or a wild orbit, seemed unlikely.

Scientists are still trying to figure out why Enceladus became so active while Dione just seems to have sputtered along. Perhaps the tidal forces were stronger on Enceladus, or maybe the larger fraction of rock in the core of Enceladus provided more radioactive heating from heavy elements. In any case, liquid subsurface oceans seem to be common on these once-boring icy satellites, fueling the hope that other icy worlds soon to be explored - like the dwarf planets Ceres and Pluto - could have oceans underneath their crusts. NASA's Dawn and New Horizons missions reach those dwarf planets in 2015.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter and its two onboard cameras. The imaging team consists of scientists from the United States, England, France and Germany. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

Hammond's work was funded through a NASA Outer Planets Research grant.

For more information about Cassini, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Jia-Rui Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

- end -
Title: Re: NASA - Cassini updates
Post by: catdlr on 06/05/2013 10:53 PM
News feature: 2013-188                                                                    June 5, 2013

Cassini Sees Precursors to Aerosol Haze on Titan



The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-188&cid=release_2013-188

Scientists working with data from NASA's Cassini mission have confirmed the presence of a population of complex hydrocarbons in the upper atmosphere of Saturn's largest moon, Titan, that later evolve into the components that give the moon a distinctive orange-brown haze. The presence of these complex, ringed hydrocarbons, known as polycyclic aromatic hydrocarbons (PAHs), explains the origin of the aerosol particles found in the lowest haze layer that blankets Titan's surface. Scientists think these PAH compounds aggregate into larger particles as they drift downward.

"With the huge amount of methane in its atmosphere, Titan smog is like L.A. smog on steroids," said Scott Edgington, Cassini deputy project scientist based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "These new papers using Cassini data shed light on how the heavy, complex hydrocarbon molecules that make up Titan's smog came to form out of the simpler molecules in the atmosphere. Now that they have been identified, the longevity of Cassini's mission will make it possible to study their variation with Titan seasons."

Of all the bodies in the solar system, Saturn's largest moon, Titan, has the atmosphere most resembling that of Earth. Like that of our planet, Titan's atmosphere is largely composed of molecular nitrogen. Unlike Earth's atmosphere, however, Titan's contains only small traces of oxygen and water. Another molecule, methane, plays a similar role to that of water in Earth's atmosphere, and makes up about 2 percent of Titan's atmosphere. Scientists have speculated that the atmosphere of this moon may resemble that of our planet in its early days, before primitive living organisms enriched it with oxygen via photosynthesis.

When sunlight or highly energetic particles from Saturn's magnetic bubble hit the layers of Titan's atmosphere above about 600 miles (1,000 kilometers), the nitrogen and methane molecules there are broken up. This results in the formation of massive positive ions and electrons, which trigger a chain of chemical reactions, producing a variety of hydrocarbons -- a wide range of which have been detected in Titan's atmosphere. These reactions eventually lead to the production of carbon-based aerosols, large aggregates of atoms and molecules that are found in the lower layers of the haze that enshrouds Titan, well below 300 miles (500 kilometers). The process is similar to Earth, where smog starts with sunlight breaking up hydrocarbons that are emitted into the air. The resulting pieces recombine to form more complex molecules.

Aerosols in Titan's lower haze have been studied using data from the descent of the European Space Agency's Huygens probe, which reached the surface in 2005, but their origin remained unclear. New studies analyzing data from Cassini's visual and infrared mapping spectrometer (VIMS) gathered in July and August 2007 might solve the problem. One new study of Titan's upper atmosphere in the Astrophysical Journal describes the detection of the PAHs, which are large carbon-based molecules that form from the aggregation of smaller hydrocarbons.

"We can finally confirm that PAHs play a major role in the production of Titan's lower haze, and that the chemical reactions leading to the formation of the haze start high up in the atmosphere," said this paper's lead author Manuel López-Puertas from the Astrophysics Institute of Andalucia in Granada, Spain. "This finding is surprising: we had long suspected that PAHs and aerosols were linked in Titan's atmosphere, but didn't expect we could prove this with current instruments."

The team of scientists had been studying the emission from various molecules in Titan's atmosphere when they stumbled upon a peculiar feature in the data. One of the characteristic lines in the spectrum -- from methane emissions -- had a slightly anomalous shape, and the scientists suspected it was hiding something.

Bianca Maria Dinelli from the Institute of Atmospheric Sciences and Climate (part of the National Research Council) in Bologna, Italy, was the lead author of a related paper in the journal Geophysical Research Letters. She and her colleagues conducted a painstaking investigation to identify the chemical species responsible for the anomaly. The additional signal was found only during daytime, so it clearly had something to do with solar irradiation.

"The central wavelength of this signal, about 3.28 microns, is typical for aromatic compounds -- hydrocarbon molecules in which the carbon atoms are bound in ring-like structures," said Dinelli.

The scientists tested whether the unidentified emission could be produced by benzene, the simplest aromatic compound consisting of one ring only, which had been detected earlier in Titan's atmosphere. However, the relatively low abundances of benzene are not sufficient to explain the emission that had been observed.

After they ruled out benzene, the scientists tried to reproduce the observed emission with the more complex PAHs. They checked their data against the NASA Ames PAH Infrared Spectral Data Base. And they were successful: the data can be explained as emission by a mixture of many different PAHs, which contain an average of 34 carbon atoms and about 10 rings each.

"PAHs are very efficient in absorbing ultraviolet radiation from the sun, redistributing the energy within the molecule and finally emitting it at infrared wavelengths," said co-author Alberto Adriani from the Institute for Space Astrophysics and Planetology at Italy's National Institute for Astrophysics (INAF) in Rome. He is part of the Cassini-VIMS co-investigators team and started this investigation. He manages the team that collected and processed VIMS data.

These hydrocarbons also are peculiarly capable of sending out profuse amounts of infrared radiation even in the rarefied environment of Titan's upper atmosphere, where the collisions between molecules are not very frequent. The molecules are themselves an intermediate product, generated when radiation from the sun ionizes smaller molecules in the upper atmosphere of Titan that then coagulate and sink.

The Cassini-Huygens mission is a cooperative project of NASA, ESA and Italy's ASI space agency. The Jet Propulsion Laboratory manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington DC, USA. The visual and infrared mapping spectrometer team is based at the University of Arizona, Tucson. The California Institute of Technology in Pasadena manages JPL for NASA.

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

Markus Bauer 011-31-71-565-6799
European Space Agency, Noordwijk, the Netherlands
markus.bauer@esa.int

- end -
Title: Re: NASA - Cassini updates
Post by: catdlr on 06/18/2013 09:31 PM
News release: 2013-204                                                                    June 18, 2013

Cassini Probe to Take Photo of Earth From Deep Space



The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-204&cid=release_2013-204

PASADENA, Calif. - NASA's Cassini spacecraft, now exploring Saturn, will take a picture of our home planet from a distance of hundreds of millions of miles on July 19. NASA is inviting the public to help acknowledge the historic interplanetary portrait as it is being taken.

Earth will appear as a small, pale blue dot between the rings of Saturn in the image, which will be part of a mosaic, or multi-image portrait, of the Saturn system Cassini is composing.

"While Earth will be only about a pixel in size from Cassini's vantage point 898 million [1.44 billion kilometers] away, the team is looking forward to giving the world a chance to see what their home looks like from Saturn," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We hope you'll join us in waving at Saturn from Earth, so we can commemorate this special opportunity."

Cassini will start obtaining the Earth part of the mosaic at 2:27 p.m. PDT (5:27 p.m. EDT or 21:27 UTC) and end about 15 minutes later, all while Saturn is eclipsing the sun from Cassini's point of view. The spacecraft's unique vantage point in Saturn's shadow will provide a special scientific opportunity to look at the planet's rings. At the time of the photo, North America and part of the Atlantic Ocean will be in sunlight.

Unlike two previous Cassini eclipse mosaics of the Saturn system in 2006, which captured Earth, and another in 2012, the July 19 image will be the first to capture the Saturn system with Earth in natural color, as human eyes would see it. It also will be the first to capture Earth and its moon with Cassini's highest-resolution camera. The probe's position will allow it to turn its cameras in the direction of the sun, where Earth will be, without damaging the spacecraft's sensitive detectors.

"Ever since we caught sight of the Earth among the rings of Saturn in September 2006 in a mosaic that has become one of Cassini's most beloved images, I have wanted to do it all over again, only better," said Carolyn Porco, Cassini imaging team lead at the Space Science Institute in Boulder, Colo. "This time, I wanted to turn the entire event into an opportunity for everyone around the globe to savor the uniqueness of our planet and the preciousness of the life on it."

Porco and her imaging team associates examined Cassini's planned flight path for the remainder of its Saturn mission in search of a time when Earth would not be obstructed by Saturn or its rings. Working with other Cassini team members, they found the July 19 opportunity would permit the spacecraft to spend time in Saturn's shadow to duplicate the views from earlier in the mission to collect both visible and infrared imagery of the planet and its ring system.

"Looking back towards the sun through the rings highlights the tiniest of ring particles, whose width is comparable to the thickness of hair and which are difficult to see from ground-based telescopes," said Matt Hedman, a Cassini science team member based at Cornell University in Ithaca, N.Y., and a member of the rings working group. "We're particularly interested in seeing the structures within Saturn's dusty E ring, which is sculpted by the activity of the geysers on the moon Enceladus, Saturn's magnetic field and even solar radiation pressure."

This latest image will continue a NASA legacy of space-based images of our fragile home, including the 1968 "Earthrise" image taken by the Apollo 8 moon mission from about 240,000 miles (380,000 kilometers) away and the 1990 "Pale Blue Dot" image taken by Voyager 1 from about 4 billion miles (6 billion kilometers) away.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington, and designed, developed and assembled the Cassini orbiter and its two onboard cameras. The imaging team consists of scientists from the United States, the United Kingdom, France and Germany. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

To learn more about the public outreach activities associated with the taking of the image, visit: http://saturn.jpl.nasa.gov/waveatsaturn .

For more information about Cassini, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov

- end -
Title: Re: NASA - Cassini updates
Post by: Borklund on 07/23/2013 08:22 AM
July 22, 2013

RELEASE 13-227
NASA Releases Images of Earth Taken By Distant Spacecraft
WASHINGTON -- Color and black-and-white images of Earth taken by two NASA interplanetary spacecraft July 19 show our planet and its moon as bright beacons from millions of miles away in space.
NASA's Cassini spacecraft captured the color images of Earth and the moon from its perch in the Saturn system nearly 900 million miles (1.5 billion kilometers) away. MESSENGER, the first probe to orbit Mercury, took a black-and-white image from a distance of 61 million miles (98 million kilometers) as part of a campaign to search for natural satellites of the planet.

In the Cassini images Earth and the moon appear as mere dots -- Earth a pale blue and the moon a stark white, visible between Saturn's rings. It was the first time Cassini's highest- resolution camera captured Earth and its moon as two distinct objects.

It also marked the first time people on Earth had advance notice  their planet's portrait was being taken from interplanetary distances. NASA invited the public to celebrate by finding Saturn in their part of the sky, waving at the ringed planet and sharing pictures over the Internet. More than 20,000 people around the world participated.

"We can't see individual continents or people in this portrait of Earth, but this pale blue dot is a succinct summary of who we were on July 19," said Linda Spilker, Cassini project scientist, at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "Cassini's picture reminds us how tiny our home planet is in the vastness of space, and also testifies to the ingenuity of the citizens of this tiny planet to send a robotic spacecraft so far away from home to study Saturn and take a look-back photo of Earth."

Pictures of Earth from the outer solar system are rare because from that distance, Earth appears very close to our sun. A camera's sensitive detectors can be damaged by looking directly at the sun, just as a human being can damage his or her retina by doing the same. Cassini was able to take this image because the sun had temporarily moved behind Saturn from the spacecraft's point of view and most of the light was blocked.
A wide-angle image of Earth will become part of a multi-image picture, or mosaic, of Saturn's rings, which scientists are assembling. This image is not expect to be available for several weeks because of the time-consuming challenges involved in blending images taken in changing geometry and at vastly different light levels, with faint and extraordinarily bright targets side by side.

"It thrills me to no end that people all over the world took a break from their normal activities to go outside and celebrate the interplanetary salute between robot and maker that these images represent," said Carolyn Porco, Cassini imaging team lead at the Space Science Institute in Boulder, Colo. "The whole event underscores for me our 'coming of age' as planetary explorers."

In the MESSENGER image, Earth and the moon are less than a pixel, but appear very large because they are overexposed. Long exposures are required to capture as much light as possible from potentially dim objects. Consequently, bright objects in the field of view become saturated and appear artificially large.

"That images of our planet have been acquired on a single day from two distant solar system outposts reminds us of this nation's stunning technical accomplishments in planetary exploration," said MESSENGER principal investigator Sean Solomon of Columbia University's Lamont-Doherty Earth Observatory in Palisades, N.Y. "And because Mercury and Saturn are such different outcomes of planetary formation and evolution, these two images also highlight what is special about Earth. There's no place like home."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL designed, developed and assembled the Cassini orbiter and its two onboard cameras. The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., designed and built MESSENGER, a spacecraft developed under NASA's Discovery Program. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the program for the agency's Science Mission Directorate in Washington. JPL and APL manage their respective missions for NASA.

To view the Earth images visit:
http://go.nasa.gov/1383AHq
More information about the picture and the Wave at Saturn campaign is available at:
http://saturn.jpl.nasa.gov/waveatsaturn
To view the MESSENGER image, visit:
http://go.nasa.gov/16Vnt5G
-end-
Title: Re: NASA - Cassini updates
Post by: Borklund on 07/23/2013 08:24 AM
See last page for the press release

Below you'll find the full size annotated and unannotated pictures. They are stunning  :o I can't wait for the full-size mosaic!

You can read more about the pictures here:
http://www.nasa.gov/mission_pages/cassini/multimedia/pia17171.html

NASA also released a close-up of the Earth Moon system which you can find here:
http://www.nasa.gov/mission_pages/cassini/multimedia/pia17170.html
Title: Re: NASA - Cassini updates
Post by: Borklund on 07/23/2013 02:22 PM
Removed the arrow from the desktop sized picture, enjoy.
Title: Re: NASA - Cassini updates
Post by: robertross on 07/23/2013 03:11 PM
Removed the arrow from the desktop sized picture, enjoy.

That IS stunning!
Title: Re: NASA - Cassini updates
Post by: morphium on 07/23/2013 09:31 PM
Sorry, but I am not sure where to find the earth on these pictures. Maybe the NASA isn't sure as well?

It seems that different things were identified as earth. I marked it in red on the attached image.


Wide angle pictures:
http://photojournal.jpl.nasa.gov/catalog/PIA17171 (http://photojournal.jpl.nasa.gov/catalog/PIA17171)

Detail Pictures:
http://photojournal.jpl.nasa.gov/catalog/PIA17170 (http://photojournal.jpl.nasa.gov/catalog/PIA17170)
http://photojournal.jpl.nasa.gov/catalog/PIA14949 (http://photojournal.jpl.nasa.gov/catalog/PIA14949)

Am I wrong? What do you think about this?
Title: Re: NASA - Cassini updates
Post by: Borklund on 07/23/2013 10:10 PM
I believe you are wrong, but thanks for bringing it up; something else is wrong. I superimposed the wide angle picture released today on top of the simulated view from the June 18th announcement post. Circled in red is Earth's location in the wide angle picture, the big blue orb next to it is from the simulated view. It matches up pretty well with what's in the wide angle picture. Either the detail (narrow angle) pictures are able to produce a picture where the Earth and the Moon are both distinctly visible, or they've messed up the identification in the narrow angle pictures.
Title: Re: NASA - Cassini updates
Post by: saturnapollo on 07/23/2013 10:31 PM
If you zoom in far enough you can just see the Moon to the right of Earth.

Keith
Title: Re: NASA - Cassini updates
Post by: ugordan on 07/23/2013 10:34 PM
Either the detail (narrow angle) pictures are able to produce a picture where the Earth and the Moon are both distinctly visible, or they've messed up the identification in the narrow angle pictures.

They haven't messed up anything. The narrow-angle camera has 10x the spatial resolution of the wide-angle. The Moon is barely detectable in the WAC view.
Title: Re: NASA - Cassini updates
Post by: morphium on 07/23/2013 11:40 PM
Thanks for your answers but I am not entirely convinced.

As in the description of picture PIA17170 (http://photojournal.jpl.nasa.gov/catalog/PIA17170) it was taken with the WAC and simply cut out from the original. It could be just pure coincidence, but if you superimpose it with PIA17171 (http://photojournal.jpl.nasa.gov/catalog/PIA17171) the dots fit together exactly with those on the bottom part of this image.

The pictures from the NAC are completely different: http://saturn.jpl.nasa.gov/photos/raw/rawimagedetails/index.cfm?imageID=294984
Title: Re: NASA - Cassini updates
Post by: saturnapollo on 07/24/2013 01:27 AM
I see what you mean. It does appear that the two objects are identical to the other photo - and no that isn't a coincidence I don't think. They overlap far too accurately.

Would the Moon and Earth appear to be so far apart from each other as seen from around a billion miles away?

Keith

PS Thought I'd fill in a feedback form at the Cassini website to see if they can throw any light on the matter. If I hear anything, I'll post the answer.
Title: Re: NASA - Cassini updates
Post by: ugordan on 07/24/2013 08:43 AM
It could be just pure coincidence, but if you superimpose it with PIA17171 (http://photojournal.jpl.nasa.gov/catalog/PIA17171) the dots fit together exactly with those on the bottom part of this image.

NAC has 10x the resolution of the WAC. Did you take that into account while superimposing non-magnified versions of both images?


Quote
The pictures from the NAC are completely different: http://saturn.jpl.nasa.gov/photos/raw/rawimagedetails/index.cfm?imageID=294984
Yes, because as they said in PIA14949 :

"Earth was brighter than the estimated brightness used to calculate the narrow-angle camera exposure times. Hence, information derived from the wide-angle camera images was used to process this color composite."

In other words, they cheated and cleaned up the CCD charge bleed due to overexposure. You should also not directly compare raw images posted on the web to calibrated versions because the raw images are uncorrected for lookup table encoding and are also contrast-stretched before posting on the web.

In addition "Both Earth and the moon have been increased in brightness for easy visibility; in addition, brightness of the moon has been increased relative to the Earth, and the brightness of the E ring has been increased as well."
Title: Re: NASA - Cassini updates
Post by: saturnapollo on 07/24/2013 10:07 AM
Quote
NAC has 10x the resolution of the WAC. Did you take that into account while superimposing non-magnified versions of both images?

Yes, I tried that and allowing for the vagaries of Photoshop reduction software, a X10 reduction of 17170 fits perfectly over 17171. I've put the overlay slightly below the original image so you can judge the positioning of both objects.

And for ease of actually seeing it I've blown the resulting image up by 200%.

Keith

Title: Re: NASA - Cassini updates
Post by: ugordan on 07/24/2013 04:02 PM
Yes, I tried that and allowing for the vagaries of Photoshop reduction software, a X10 reduction of 17170 fits perfectly over 17171.

Except that PIA17170 is itself a 5x magnification of the original NAC composite, i.e. of PIA14949. Even says so in the description.

However, I now see where (part of) the confusion about which image is which may have arisen from - PIA17170 has "Instrument" incorrectly labeled as the wide-angle camera.
Title: Re: NASA - Cassini updates
Post by: saturnapollo on 07/24/2013 08:08 PM
OK, thank goodness that has been solved.

Good of Morphium to bring it up, but must just be a co-incidence that these two objects line up so perfectly with the closeup of the Earth/Moon system.

Keith
Title: Re: NASA - Cassini updates
Post by: apace on 07/30/2013 09:23 AM
Around Saturn, Video compilation of the Cassini photos by fabio di donato:
http://vimeo.com/70532693

Title: Re: NASA - Cassini updates
Post by: jacqmans on 07/31/2013 07:44 PM
RELEASE 13-241


NASA's Cassini Spacecraft Reveals Forces Controlling Saturn Moon Jets


The intensity of jets of water ice and organic particles that shoot out from Saturn's moon Enceladus depends on the moon's proximity to the ringed planet, according to data obtained by NASA's Cassini spacecraft.

The finding adds to evidence that a liquid water reservoir or ocean lurks under the icy surface of the moon. This is the first clear observation the bright plume emanating from Enceladus' south pole varies predictably. The findings are detailed in a scientific paper in this week's edition of Nature.

"The jets of Enceladus apparently work like adjustable garden hose nozzles," said Matt Hedman, the paper's lead author and a Cassini team scientist based at Cornell University in Ithaca, N.Y. "The nozzles are almost closed when Enceladus is closer to Saturn and are most open when the moon is farthest away. We think this has to do with how Saturn squeezes and releases the moon with its gravity."

Cassini, which has been orbiting Saturn since 2004, discovered the jets that form the plume in 2005. The water ice and organic particles spray out from several narrow fissures nicknamed "tiger stripes."

"The way the jets react so responsively to changing stresses on Enceladus suggests they have their origins in a large body of liquid water," said Christophe Sotin, a co-author and Cassini team member at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "Liquid water was key to the development of life on Earth, so these discoveries whet the appetite to know whether life exists everywhere water is present."

For years scientists hypothesized the intensity of the jets likely varied over time, but no one had been able to show they changed in a recognizable pattern. Hedman and colleagues were able to see the changes by examining infrared data of the plume as a whole, obtained by Cassini's visual and infrared mapping spectrometer (VIMS), and looking at data gathered over a long period of time.

The VIMS instrument, which analyzed a wide range of data including the hydrocarbon composition of the surface of another Saturnian moon, Titan, and the seismological signs of Saturn's vibrations in its rings, collected more than 200 images of the Enceladus plume from 2005 to 2012.

These data show the plume was dimmest when the moon was at the closest point in its orbit to Saturn. The plume gradually brightened until Enceladus was at the most distant point, where it was three to four times brighter than the dimmest detection. This is comparable to moving from a dim hallway into a brightly lit office.

Adding the brightness data to previous models of how Saturn squeezes Enceladus, the scientists deduced the stronger gravitational squeeze near the planet reduces the opening of the tiger stripes and the amount of material spraying out. They think the relaxing of Saturn's gravity farther away from planet allows the tiger stripes to be more open and for the spray to escape in larger quantities..

"Cassini's time at Saturn has shown us how active and kaleidoscopic this planet, its rings and its moons are," said Linda Spilker, Cassini project scientist at JPL. "We've come a long way from the placid-looking Saturn that Galileo first spied through his telescope. We hope to learn more about the forces at work here as a microcosm for how our solar system formed."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate in Washington. The VIMS team is based at the University of Arizona in Tucson.

For more information about the Cassini mission, visit:

http://www.nasa.gov/cassini

Title: Re: NASA - Cassini updates
Post by: catdlr on 08/21/2013 05:40 PM
News advisory: 2013-256                                                                   Aug. 21, 2013

Cassini Releases Image of Earth Waving at Saturn



The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-256&cid=release_2013-256

PASADENA, Calif. - People around the world shared more than 1,400 images of themselves as part of the Wave at Saturn event organized by NASA's Cassini mission on July 19 -- the day the Cassini spacecraft turned back toward Earth to take our picture. The mission has assembled a collage from those images. The collage is online at: http://www.nasa.gov/mission_pages/cassini/multimedia/collage2013.html .

"Thanks to all of you, near and far, old and young, who joined the Cassini mission in marking the first time inhabitants of Earth had advance notice that our picture was being taken from interplanetary distances," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "While Earth is too small in the images Cassini obtained to distinguish any individual human beings, the mission has put together this collage so that we can celebrate all your waving hands, uplifted paws, smiling faces and artwork."

The images came from 40 countries and 30 U.S. states via Twitter, Facebook, Flickr, Instagram, Google+ and email.

From its perch in the Saturn system, Cassini took a picture of Earth as part of a larger set of images it was collecting of the Saturn system. Scientists are busy putting together the color mosaic of the Saturn system, which they expect will take at least several more weeks to complete. The scientists who study Saturn's rings are poring over visible-light and infrared data obtained during that campaign.

For more information on the Wave at Saturn campaign, visit: http://saturn.jpl.nasa.gov/waveatsaturn .

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA's Science Mission Directorate in Washington.

For more information about the Cassini mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Jia-Rui Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

- end -
Title: Re: NASA - Cassini updates
Post by: Borklund on 08/21/2013 08:08 PM
When will we get the actual real mosaic we are all craving, does anybody know?
Title: Re: NASA - Cassini updates
Post by: Artyom. on 09/04/2013 10:28 AM
Cassini Sees Saturn Storm's Explosive Power


A monster storm that erupted on Saturn in late 2010 – as large as any storm ever observed on the ringed planet -- has already impressed researchers with its intensity and long-lived turbulence. A new paper in the journal Icarus reveals another facet of the storm's explosive power: its ability to churn up water ice from great depths. This finding, derived from near-infrared measurements by NASA's Cassini spacecraft, is the first detection at Saturn of water ice. The water originates from deep in Saturn's atmosphere.

"The new finding from Cassini shows that Saturn can dredge up material from more than 100 miles [160 kilometers]," said Kevin Baines, a co-author of the paper who works at the University of Wisconsin-Madison and NASA's Jet Propulsion Laboratory, Pasadena, Calif. "It demonstrates in a very real sense that typically demure-looking Saturn can be just as explosive or even more so than typically stormy Jupiter." Water ice, which originates from deep in the atmosphere of gas giants, doesn't appear to be lofted as high at Jupiter.

Monster storms rip across the northern hemisphere of Saturn once every 30 years or so, or roughly once per Saturn year. The first hint of the most recent storm first appeared in data from Cassini's radio and plasma wave subsystem on Dec. 5, 2010. Soon after that, it could be seen in images from amateur astronomers and from Cassini's imaging science subsystem. The storm quickly grew to superstorm proportions, encircling the planet at about 30 degrees north latitude for an expanse of nearly 190,000 miles (300,000 kilometers).

The new paper focuses on data gathered by Cassini's visual and infrared mapping spectrometer on Feb. 24, 2011. The team, led by Lawrence Sromovsky, also of the University of Wisconsin, found that cloud particles at the top of the great storm are composed of a mix of three substances: water ice, ammonia ice, and an uncertain third constituent that is possibly ammonium hydrosulfide. The observations are consistent with clouds of different chemical compositions existing side-by-side, though it is more likely that the individual cloud particles are composed of two or all three of the materials.

The classic model of Saturn’s atmosphere portrays it as a layered sandwich of sorts, with a deck of water clouds at the bottom, ammonia hydrosulfide clouds in the middle, and ammonia clouds near the top. Those layers are just below an upper tropospheric haze of unknown composition that obscures almost everything.

But this storm appears to have disrupted those neat layers, lofting up water vapor from a lower layer that condensed and froze as it rose. The water ice crystals then appeared to become coated with more volatile materials like ammonium hydrosulfide and ammonia as the temperature decreased with their ascent, the authors said.

“We think this huge thunderstorm is driving these cloud particles upward, sort of like a volcano bringing up material from the depths and making it visible from outside the atmosphere,” said Sromovsky. “The upper haze is so optically thick that it is only in the stormy regions where the haze is penetrated by powerful updrafts that you can see evidence for the ammonia ice and the water ice. Those storm particles have an infrared color signature that is very different from the haze particles in the surrounding atmosphere.”

In understanding the dynamics of this Saturn storm, researchers realized that it worked like the much smaller convective storms on Earth, where air and water vapor are pushed high into the atmosphere, resulting in the towering, billowing clouds of a thunderstorm. The towering clouds in Saturn storms of this type, however, were 10 to 20 times taller and covered a much bigger area. They are also far more violent than an Earth storm, with models predicting vertical winds of more than about 300 mph (500 kilometers per hour) for these rare giant storms.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate, Washington. The California Institute of Technology in Pasadena manages JPL for NASA. The VIMS team is based at the University of Arizona in Tucson.

http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20130903.html
Title: Re: NASA - Cassini updates
Post by: jacqmans on 09/30/2013 04:16 PM

RELEASE 13-301

NASA's Cassini Spacecraft Finds Ingredient of Household Plastic in Space

NASA's Cassini spacecraft has detected propylene, a chemical used to make food-storage containers, car bumpers and other consumer products, on Saturn's moon Titan.

This is the first definitive detection of the plastic ingredient on any moon or planet, other than Earth.

A small amount of propylene was identified in Titan's lower atmosphere by Cassini's Composite Infrared Spectrometer (CIRS). This instrument measures the infrared light, or heat radiation, emitted from Saturn and its moons in much the same way our hands feel the warmth of a fire.

Propylene is the first molecule to be discovered on Titan using CIRS. By isolating the same signal at various altitudes within the lower atmosphere, researchers identified the chemical with a high degree of confidence. Details are presented in a paper in the Sept. 30 edition of the Astrophysical Journal Letters.

"This chemical is all around us in everyday life, strung together in long chains to form a plastic called polypropylene," said Conor Nixon, a planetary scientist at NASA's Goddard Space Flight Center in Greenbelt, Md., and lead author of the paper. "That plastic container at the grocery store with the recycling code 5 on the bottom -- that's polypropylene."

CIRS can identify a particular gas glowing in the lower layers of the atmosphere from its unique thermal fingerprint. The challenge is to isolate this one signature from the signals of all other gases around it.

The detection of the chemical fills in a mysterious gap in Titan observations that dates back to NASA's Voyager 1 spacecraft and the first-ever close flyby of this moon in 1980.

Voyager identified many of the gases in Titan's hazy brownish atmosphere as hydrocarbons, the chemicals that primarily make up petroleum and other fossil fuels on Earth.

On Titan, hydrocarbons form after sunlight breaks apart methane, the second-most plentiful gas in that atmosphere. The newly freed fragments can link up to form chains with two, three or more carbons. The family of chemicals with two carbons includes the flammable gas ethane. Propane, a common fuel for portable stoves, belongs to the three-carbon family.

Voyager detected all members of the one- and two-carbon families in Titan's atmosphere. From the three-carbon family, the spacecraft found propane, the heaviest member, and propyne, one of the lightest members. But the middle chemicals, one of which is propylene, were missing.

As researchers continued to discover more and more chemicals in Titan's atmosphere using ground- and space-based instruments, propylene was one that remained elusive. It was finally found as a result of more detailed analysis of the CIRS data.

"This measurement was very difficult to make because propylene's weak signature is crowded by related chemicals with much stronger signals," said Michael Flasar, Goddard scientist and principal investigator for CIRS. "This success boosts our confidence that we will find still more chemicals long hidden in Titan's atmosphere."

Cassini's mass spectrometer, a device that looks at the composition of Titan's atmosphere, had hinted earlier that propylene might be present in the upper atmosphere. However, a positive identification had not been made.

"I am always excited when scientists discover a molecule that has never been observed before in an atmosphere," said Scott Edgington, Cassini's deputy project scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "This new piece of the puzzle will provide an additional test of how well we understand the chemical zoo that makes up Titan's atmosphere."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate in Washington. The CIRS team is based at Goddard.

For more information about the Cassini mission, visit:

http://www.nasa.gov/cassini
Title: Re: NASA - Cassini updates
Post by: catdlr on 10/18/2013 01:05 AM
Image Advisory: 2013-297                                                             Oct. 17, 2013

Rings, Dark Side of Saturn Glow in New Cassini Image



The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-297&cid=release_2013-297

Story Highlights:
• The Cassini spacecraft scanned across Saturn and its rings when the sun was behind the planet and faint rings were easier to detect.
• This latest infrared image shows a strip about 340,000 miles (540,000 kilometers) across that includes the planet and its rings out to Saturn's second most distant ring.

PASADENA, Calif. -- The gauzy rings of Saturn and the dark side of the planet glow in newly released infrared images obtained by NASA's Cassini spacecraft.

"Looking at the Saturn system when it is backlit by the sun gives scientists a kind of inside-out view of Saturn that we don't normally see," said Matt Hedman, a participating scientist based at the University of Idaho, Moscow, Idaho. "The parts of Saturn's rings that are bright when you look at them from backyard telescopes on Earth are dark, and other parts that are typically dark glow brightly in this view."

The images are available at: http://www.nasa.gov/mission_pages/cassini/multimedia/pia17468.html and http://www.nasa.gov/mission_pages/cassini/multimedia/pia17469.html .

It can be difficult for scientists to get a good look at the faint outer F, E and G rings, or the tenuous inner ring known as the D ring when light is shining directly on them. That's because they are almost transparent and composed of small particles that do not reflect light well. What's different about this viewing geometry?

• When these small particles are lit from behind, they show up like fog in the headlights of an oncoming vehicle.
• The C ring also appears relatively bright here; not because it is made of dust, but because the material in it -- mostly dirty water ice -- is translucent. In fact, in the 18th and 19th centuries, it was known as the "crepe ring" because of its supposed similarity to crepe paper.
• The wide, middle ring known as the B ring -- one of the easiest to see from Earth through telescopes because it is densely packed with chunks of bright water ice -- looks dark in these images because it is so thick that it blocks almost all of the sunlight shining behind it.

Infrared images also show thermal, or heat, radiation. While a visible-light image from this vantage point would simply show the face of the planet as dimly lit by sunlight reflected off the rings, Saturn glows brightly in this view because of heat from Saturn's interior.

In a second version of the image, scientists "stretched" or exaggerated the contrast of the data, which brings out subtleties not initially visible.

• Structures in the wispy E ring -- made from the icy breath of the moon Enceladus -- reveal themselves in this exaggerated view.

"We're busy working on analyzing the infrared data from this special view of the Saturn system," said Phil Nicholson, a visual and infrared mapping spectrometer team member from Cornell University, Ithaca, N.Y. "The infrared data should tell us more about the sizes of the particles which make up the D, E, F and G rings, and how these sizes vary with location in the rings, as well as providing clues as to their chemical composition."

Launched in 1997, Cassini has been exploring the Saturn system for more than nine years with a suite of instruments that also includes visible-light cameras, ultraviolet and infrared spectrometers, as well as magnetic field and charged particle sensors. Scientists working with the visible light cameras are still busy putting together and analyzing their mosaic -- or multi-image picture -- of the Saturn system.

"Cassini's long-term residency at the ringed planet means we've been able to observe change over nearly half a Saturn-year (one Saturn-year is equal to almost 30 Earth-years) with a host of different tools," said Linda Spilker, Cassini project scientist, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Earth looks different from season to season and Saturn does, too. We can't wait to see how those seasonal changes affect the dance of icy particles as we continue to observe in Saturn's rings with all of Cassini's different 'eyes.'"

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate, Washington. The California Institute of Technology in Pasadena manages JPL for NASA. The VIMS team is based at the University of Arizona in Tucson.

For more information about the Cassini mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

- end -
Title: Re: NASA - Cassini updates
Post by: veblen on 10/19/2013 12:22 AM
NASA Image of the Day courtesy of Gordan Ugarkovic and Cassini.

http://www.nasa.gov/mission_pages/cassini/multimedia/saturn20131017.html#.UmHNjnCsg6Y

So beautiful.
Title: Re: NASA - Cassini updates
Post by: apollolanding on 10/19/2013 12:46 PM
And a nice writeup on NBC about ordan's mosaic: http://www.nbcnews.com/science/fantastic-full-frontal-picture-saturn-created-amateur-8C11422981 (http://www.nbcnews.com/science/fantastic-full-frontal-picture-saturn-created-amateur-8C11422981)
 
Beautiful job!!!  Another affirmation that the membership of NSF are some of the most passionate, enthusiastic and knowledgeable members of the spaceflight and exploration community.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 10/24/2013 08:27 AM
Cassini Gets New Views of Titan's Land of Lakes

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-304

 PASADENA, Calif.-- With the sun now shining down over the north pole of Saturn's moon Titan, a little luck with the weather, and trajectories that put the spacecraft into optimal viewing positions, NASA's Cassini spacecraft has obtained new pictures of the liquid methane and ethane seas and lakes that reside near Titan's north pole. The images reveal new clues about how the lakes formed and about Titan's Earth-like "hydrologic" cycle, which involves hydrocarbons rather than water.

 The new images are available online at: http://www.nasa.gov/mission_pages/cassini/multimedia/index.html.

 While there is one large lake and a few smaller ones near Titan's south pole, almost all of Titan's lakes appear near the moon's north pole. Cassini scientists have been able to study much of the terrain with radar, which can penetrate beneath Titan's clouds and thick haze. And until now, Cassini's visual and infrared mapping spectrometer and imaging science subsystem had only been able to capture distant, oblique or partial views of this area.

 Several factors combined recently to give these instruments great observing opportunities. Two recent flybys provided better viewing geometry. Sunlight has begun to pierce the winter darkness that shrouded Titan's north pole at Cassini's arrival in the Saturn system nine years ago. A thick cap of haze that once hung over the north pole has also dissipated as northern summer approaches. And Titan's beautiful, nearly cloudless, rain-free weather continued during Cassini's flybys this past summer.

 The images are mosaics in infrared light based on data obtained during flybys of Titan on July 10, July 26, and Sept. 12, 2013. The colorized mosaic from the visual and infrared mapping spectrometer, which maps infrared colors onto the visible-color spectrum, reveals differences in the composition of material around the lakes. The data suggest parts of Titan's lakes and seas may have evaporated and left behind the Titan equivalent of Earth's salt flats. Only at Titan, the evaporated material is thought to be organic chemicals originally from Titan's haze particles that once dissolved in liquid methane. They appear orange in this image against the greenish backdrop of Titan's typical bedrock of water ice.

 "The view from Cassini's visual and infrared mapping spectrometer gives us a holistic view of an area that we'd only seen in bits and pieces before and at a lower resolution," said Jason Barnes, a participating scientist for the instrument at the University of Idaho, Moscow. "It turns out that Titan's north pole is even more interesting than we thought, with a complex interplay of liquids in lakes and seas and deposits left from the evaporation of past lakes and seas."

 The near-infrared images from Cassini's imaging cameras show a bright unit of terrain in the northern land of lakes that had not previously been visible in the data. The bright area suggests that the surface here is unique from the rest of Titan, which might explain why almost all of the lakes are found in this region. Titan's lakes have very distinctive shapes -- rounded cookie-cutter silhouettes and steep sides -- and a variety of formation mechanisms have been proposed. The explanations range from the collapse of land after a volcanic eruption to karst terrain, where liquids dissolve soluble bedrock. Karst terrains on Earth can create spectacular topography such as the Carlsbad Caverns in New Mexico.

 "Ever since the lakes and seas were discovered, we've been wondering why they're concentrated at high northern latitudes," said Elizabeth (Zibi) Turtle, a Cassini imaging team associate based at the Johns Hopkins Applied Physics Laboratory, Laurel, Md. "So, seeing that there's something special about the surface in this region is a big clue to help narrow down the possible explanations."

 Launched in 1997, Cassini has been exploring the Saturn system since 2004. A full Saturn year is 30 years, and Cassini has been able to observe nearly a third of a Saturn year. In that time, Saturn and its moons have seen the seasons change from northern winter to northern summer.

 "Titan's northern lakes region is one of the most Earth-like and intriguing in the solar system," said Linda Spilker, Cassini project scientist, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We know lakes here change with the seasons, and Cassini's long mission at Saturn gives us the opportunity to watch the seasons change at Titan, too. Now that the sun is shining in the north and we have these wonderful views, we can begin to compare the different data sets and tease out what Titan's lakes are doing near the north pole."

 The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate, Washington. The California Institute of Technology in Pasadena manages JPL for NASA. The VIMS team is based at the University of Arizona in Tucson. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

 For more information about the Cassini mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .
Title: Re: NASA - Cassini updates
Post by: Borklund on 11/12/2013 08:02 PM
Finally!  ;D

http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20131112/

NASA's Cassini Spacecraft Provides New View of Saturn and Earth
• Natural-color portrait that is first to show Saturn, its moons and rings, plus Earth, Venus and Mars
• Sweeps nearly 405,000 miles (652,000 kilometers) across Saturn and its inner rings
NASA has released a natural color image of Saturn from space, the first in which Saturn, its moons and rings, and Earth, Venus and Mars, all are visible.
The new panoramic mosaic of the majestic Saturn system taken by NASA's Cassini spacecraft, which shows the view as it would be seen by human eyes, was unveiled at the Newseum in Washington on Tuesday.
Cassini's imaging team processed 141 wide-angle images to create the panorama. The image sweeps 404,880 miles (651,591 kilometers) across Saturn and its inner ring system, including all of Saturn's rings out to the E ring, which is Saturn's second outermost ring. For perspective, the distance between Earth and our moon would fit comfortably inside the span of the E ring.

'In this one magnificent view, Cassini has delivered to us a universe of marvels,' said Carolyn Porco, Cassini's imaging team lead at the Space Science Institute in Boulder, Colo. 'And it did so on a day people all over the world, in unison, smiled in celebration at the sheer joy of being alive on a pale blue dot.'
The mosaic is part of Cassini's 'Wave at Saturn' campaign, where on July 19, people for the first time had advance notice a spacecraft was taking their picture from planetary distances. NASA invited the public to celebrate by finding Saturn in their part of the sky, waving at the ringed planet and sharing pictures over the Internet.

An annotated version of the Saturn system mosaic labels points of interest. Earth is a bright blue dot to the lower right of Saturn. Venus is a bright dot to Saturn’s upper left. Mars also appears, as a faint red dot, above and to the left of Venus. Seven Saturnian moons are visible, including Enceladus on the left side of the image. Zooming into the image reveals the moon and the icy plume emanating from its south pole, supplying fine, powder-sized icy particles that make up the E ring.

The E ring shines like a halo around Saturn and the inner rings. Because it is so tenuous, it is best seen with light shining from behind it, when the tiny particles are outlined with light because of the phenomenon of diffraction. Scientists who focus on Saturn's rings look for patterns in optical bonanzas like these. They use computers to increase dramatically the contrast of the images and change the color balance, for example, to see evidence for material tracing out the full orbits of the tiny moons Anthe and Methone for the first time.
'This mosaic provides a remarkable amount of high-quality data on Saturn’s diffuse rings, revealing all sorts of intriguing structures we are currently trying to understand,' said Matt Hedman, a Cassini participating scientist at the University of Idaho in Moscow. 'The E ring in particular shows patterns that likely reflect disturbances from such diverse sources as sunlight and Enceladus' gravity.'

Cassini does not attempt many images of Earth because the sun is so close to our planet that an unobstructed view would damage the spacecraft's sensitive detectors. Cassini team members looked for an opportunity when the sun would slip behind Saturn from Cassini's point of view. A good opportunity came on July 19, when Cassini was able to capture a picture of Earth and its moon, and this multi-image, backlit panorama of the Saturn system.

'With a long, intricate dance around the Saturn system, Cassini aims to study the Saturn system from as many angles as possible,' said Linda Spilker, Cassini project scientist based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. 'Beyond showing us the beauty of the Ringed Planet, data like these also improve our understanding of the history of the faint rings around Saturn and the way disks around planets form -- clues to how our own solar system formed around the sun.'

Launched in 1997, Cassini has explored the Saturn system for more than nine years. NASA plans to continue the mission through 2017, with the anticipation of many more images of Saturn, its rings and moons, as well as other scientific data.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter and its two onboard cameras. The imaging team is based at the Space Science Institute, Boulder, Colo.
To view the image, visit: http://photojournal.jpl.nasa.gov/catalog/pia17172 .

A new version of the collage of photos shared by the public, with the Saturn system as backdrop, is available at: http://photojournal.jpl.nasa.gov/catalog/pia17679 .

More information about Cassini is available at: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Direct link to the fantastic 9000x3500 pixel mosaic here: http://photojournal.jpl.nasa.gov/jpeg/PIA17172.jpg

I have also attached it to this post.
Title: Re: NASA - Cassini updates
Post by: savuporo on 11/13/2013 12:51 AM
http://www.planetary.org/blogs/guest-blogs/van-kane/20131112_Cassini_extended_mission.html

I think its the copy of the original post here
http://futureplanets.blogspot.com/2013/11/will-we-lose-cassinis-new-mission-at.html
Title: Re: NASA - Cassini updates
Post by: belegor on 11/14/2013 07:50 PM
Emily Lakdawalla posted a very nice explanation for those of us, who where slightly confused by the above image:
http://www.planetary.org/blogs/emily-lakdawalla/2013/11131344-cassini-saturn-photo-explained.html (http://www.planetary.org/blogs/emily-lakdawalla/2013/11131344-cassini-saturn-photo-explained.html)
Title: Re: NASA - Cassini updates
Post by: Artyom. on 12/05/2013 09:29 AM
NASA's Cassini Spacecraft Obtains Best Views of Saturn Hexagon


NASA's Cassini spacecraft has obtained the highest-resolution movie yet of a unique six-sided jet stream, known as the hexagon, around Saturn's north pole.

This is the first hexagon movie of its kind, using color filters, and the first to show a complete view of the top of Saturn down to about 70 degrees latitude. Spanning about 20,000 miles (30,000 kilometers) across, the hexagon is a wavy jet stream of 200-mile-per-hour winds (about 322 kilometers per hour) with a massive, rotating storm at the center. There is no weather feature exactly, consistently like this anywhere else in the solar system.

"The hexagon is just a current of air, and weather features out there that share similarities to this are notoriously turbulent and unstable," said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena. "A hurricane on Earth typically lasts a week, but this has been here for decades -- and who knows -- maybe centuries."

Weather patterns on Earth are interrupted when they encounter friction from landforms or ice caps. Scientists suspect the stability of the hexagon has something to do with the lack of solid landforms on Saturn, which is essentially a giant ball of gas.

Better views of the hexagon are available now because the sun began to illuminate its interior in late 2012. Cassini captured images of the hexagon over a 10-hour time span with high-resolution cameras, giving scientists a good look at the motion of cloud structures within.

They saw the storm around the pole, as well as small vortices rotating in the opposite direction of the hexagon. Some of the vortices are swept along with the jet stream as if on a racetrack. The largest of these vortices spans about 2,200 miles (3,500 kilometers), or about twice the size of the largest hurricane recorded on Earth.

Scientists analyzed these images in false color, a rendering method that makes it easier to distinguish differences among the types of particles suspended in the atmosphere -- relatively small particles that make up haze -- inside and outside the hexagon.

"Inside the hexagon, there are fewer large haze particles and a concentration of small haze particles, while outside the hexagon, the opposite is true," said Kunio Sayanagi, a Cassini imaging team associate at Hampton University in Virginia. "The hexagonal jet stream is acting like a barrier, which results in something like Earth's Antarctic ozone hole."

The Antarctic ozone hole forms within a region enclosed by a jet stream with similarities to the hexagon. Wintertime conditions enable ozone-destroying chemical processes to occur, and the jet stream prevents a resupply of ozone from the outside. At Saturn, large aerosols cannot cross into the hexagonal jet stream from outside, and large aerosol particles are created when sunlight shines on the atmosphere. Only recently, with the start of Saturn's northern spring in August 2009, did sunlight begin bathing the planet's northern hemisphere.

"As we approach Saturn's summer solstice in 2017, lighting conditions over its north pole will improve, and we are excited to track the changes that occur both inside and outside the hexagon boundary," said Scott Edgington, Cassini deputy project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
A black-and-white version of the imaging camera movie and movies obtained by Cassini's visual and infrared mapping spectrometer are also tools Cassini scientists can use to look at wind speeds and the mini-storms inside the jet stream.

Cassini launched in 1997 and arrived at Saturn on July 1, 2004. Its mission is scheduled to end in September 2017. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter and its two onboard cameras. The imaging team is based at the Space Science Institute, Boulder, Colo.

http://www.nasa.gov/jpl/cassini/saturn-north-pole-hexagon-20131204.html
Title: Re: NASA - Cassini updates
Post by: go4mars on 12/31/2013 03:18 PM
Emily Lakdawalla posted a very nice explanation for those of us, who where slightly confused by the above image:
http://www.planetary.org/blogs/emily-lakdawalla/2013/11131344-cassini-saturn-photo-explained.html (http://www.planetary.org/blogs/emily-lakdawalla/2013/11131344-cassini-saturn-photo-explained.html)
As usual, Emily gave a very efficient and useful treatment of the photo. 

Now I just need someone to sell this as high-res wallpaper!
Title: Re: NASA - Cassini updates
Post by: catdlr on 03/14/2014 05:41 PM
Cassini: Coming Attractions at Saturn

Published on Mar 14, 2014
What incredible things will the Cassini spacecraft at Saturn see and do over the next few years? Here's a preview.

http://www.youtube.com/watch?v=fAQM9rfZq7w
Title: Re: NASA - Cassini updates
Post by: corrodedNut on 03/19/2014 09:36 AM
Surf's up!

http://www.bbc.com/news/science-environment-26622586
Title: Re: NASA - Cassini updates
Post by: Star One on 04/03/2014 09:49 PM
Saturn's Enceladus moon hides 'great lake' of water.

http://www.bbc.co.uk/news/science-environment-26872184
Title: Re: NASA - Cassini updates
Post by: jacqmans on 04/15/2014 06:06 AM
April 14, 2014
NASA Cassini Images May Reveal Birth of New Saturn Moon


NASA's Cassini spacecraft has documented the formation of a small icy object within the rings of Saturn that may be a new moon, and may also provide clues to the formation of the planet's known moons.

Images taken with Cassini's narrow angle camera on April 15, 2013 show disturbances at the very edge of Saturn's A ring -- the outermost of the planet's large, bright rings. One of these disturbances is an arc about 20 percent brighter than its surroundings, 750 miles (1,200 kilometers) long and 6 miles (10 kilometers) wide. Scientists also found unusual protuberances in the usually smooth profile at the ring's edge. Scientists believe the arc and protuberances are caused by the gravitational effects of a nearby object. Details of the observations were published online today (April 14, 2014) by the journal Icarus.

The object is not expected to grow any larger, and may even be falling apart. But the process of its formation and outward movement aids in our understanding of how Saturn's icy moons, including the cloud-wrapped Titan and ocean-holding Enceladus, may have formed in more massive rings long ago. It also provides insight into how Earth and other planets in our solar system may have formed and migrated away from our star, the sun.

"We have not seen anything like this before," said Carl Murray of Queen Mary University of London, and the report's lead author. "We may be looking at the act of birth, where this object is just leaving the rings and heading off to be a moon in its own right."

The object, informally named Peggy, is too small to see in images so far. Scientists estimate it is probably no more than about a half mile in diameter. Saturn's icy moons range in size depending on their proximity to the planet -- the farther from the planet, the larger. And many of Saturn's moons are comprised primarily of ice, as are the particles that form Saturn's rings. Based on these facts, and other indicators, researchers recently proposed that the icy moons formed from ring particles and then moved outward, away from the planet, merging with other moons on the way.

"Witnessing the possible birth of a tiny moon is an exciting, unexpected event," said Cassini Project Scientist Linda Spilker, of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. According to Spilker, Cassini's orbit will move closer to the outer edge of the A ring in late 2016 and provide an opportunity to study Peggy in more detail and perhaps even image it.

It is possible the process of moon formation in Saturn's rings has ended with Peggy, as Saturn's rings now are, in all likelihood, too depleted to make more moons. Because they may not observe this process again, Murray and his colleagues are wringing from the observations all they can learn.

"The theory holds that Saturn long ago had a much more massive ring system capable of giving birth to larger moons," Murray said. "As the moons formed near the edge, they depleted the rings and evolved, so the ones that formed earliest are the largest and the farthest out."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, manages the mission for NASA's Science Mission Directorate in Washington.

To view an image of the Saturn ring disturbance attributed to the new moon, visit:

http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA18078

For more information about Cassini, visit:

http://www.nasa.gov/cassini

Title: Re: NASA - Cassini updates
Post by: bolun on 04/30/2014 03:29 PM
EGU 2014 press conference

Cassini and Saturn: the 10th anniversary and new results

http://client.cntv.at/EGU2014/?play=30
Title: Re: NASA - Cassini updates
Post by: Star One on 06/23/2014 06:56 AM
Waves discovered on Titan? Shame they cannot keep Cassini going beyond 2017 as Titan will be in full summer by then.

Quote
Now, the most recent flyby of the hazy moon has revealed a distinct bright spot in the second-largest sea  near the moon’s north pole. The spot  appears to suddenly disappear almost as soon as it appears in the maps.

Dubbed the “magic island,” this geologic mystery may be best explained by waves or bubbles floating on the surface of these methane lakes, according to the new study published in Nature Geoscience this week.

“This discovery tells us that the liquids in Titan’s northern hemisphere are not simply stagnant and unchanging, but rather that changes do occur,” said the lead author of the study,  Jason Hofgartner, a Cornell University graduate student.

“We don’t know precisely what caused this ‘magic island’ to appear, but we’d like to study it further.”

This suggests to planetary scientists that what we may be witnessing are the first hints of Titan’s seas reacting to the changing seasons from spring to summer, just like what happens on Earth.

Windy weather may very well be kicking up waves on Titan. To Cassini’s radar,  the results look like ghostly islands. Alternately, gas bubbles may be breaching the lake surface.

http://newswatch.nationalgeographic.com/2014/06/22/waves-discovered-on-saturns-moon-titan/
Title: Re: NASA - Cassini updates
Post by: Targeteer on 08/08/2014 03:45 AM
http://solarsystem.nasa.gov/news/display.cfm?News_ID=47981

NASA's Cassini spacecraft will execute the largest planned maneuver of the spacecraft's remaining mission on Saturday, Aug. 9. The maneuver will target Cassini toward an Aug. 21 encounter with Saturn's largest moon, Titan.

The main engine firing will last about a minute and will provide a change in velocity of 41 feet per second (12.5 meters per second). This is the largest maneuver by Cassini in five years. No other remaining maneuver comes close, in the amount of propellant it will consume and the amount by which it will change the spacecraft's velocity. By contrast, the smallest maneuvers Cassini routinely executes are about 0.4 inches (10 millimeters) per second.

The large size of the Aug. 9 burn is needed to begin the process of "cranking down" Cassini's orbit, so that the spacecraft circles Saturn nearer to the plane of the rings and moons. Previously, with each Titan flyby, mission controllers adjusted the spacecraft's orbit to be increasingly inclined, carrying Cassini high above Saturn's polar regions. The upcoming maneuver starts reversing that trend, making the orbit increasingly close to the equator.

Although Cassini has occasionally performed similar large propulsive maneuvers during its decade in the Saturn system, Titan itself has proven to be the workhorse for steering Cassini around Saturn. It is not uncommon for the spacecraft to receive a gravitational assist, or boost, from Titan that rivals or exceeds the 96-minute engine burn Cassini performed in 2004 to insert itself into Saturn orbit.

The Cassini mission recently celebrated a decade studying Saturn, its rings, moons and magnetosphere.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, California, manages the mission for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology.

For more information about Cassini, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov
Title: Re: NASA - Cassini updates
Post by: Star One on 09/30/2014 11:58 AM
Titan's mystery island has reappeared again.

http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20140929/

NASA's Cassini spacecraft is monitoring the evolution of a mysterious feature in a large hydrocarbon sea on Saturn's moon Titan. The feature covers an area of about 100 square miles (260 square kilometers) in Ligeia Mare, one of the largest seas on Titan. It has now been observed twice by Cassini's radar experiment, but its appearance changed between the two apparitions.
Images of the feature taken during the Cassini flybys are available at:
http://photojournal.jpl.nasa.gov/catalog/PIA18430
The mysterious feature, which appears bright in radar images against the dark background of the liquid sea, was first spotted during Cassini's July 2013 Titan flyby. Previous observations showed no sign of bright features in that part of Ligeia Mare. Scientists were perplexed to find the feature had vanished when they looked again, over several months, with low-resolution radar and Cassini's infrared imager. This led some team members to suggest it might have been a transient feature. But during Cassini's flyby on August 21, 2014, the feature was again visible, and its appearance had changed during the 11 months since it was last seen.
Scientists on the radar team are confident that the feature is not an artifact, or flaw, in their data, which would have been one of the simplest explanations. They also do not see evidence that its appearance results from evaporation in the sea, as the overall shoreline of Ligeia Mare has not changed noticeably.
The team has suggested the feature could be surface waves, rising bubbles, floating solids, solids suspended just below the surface, or perhaps something more exotic.
The researchers suspect that the appearance of this feature could be related to changing seasons on Titan, as summer draws near in the moon's northern hemisphere. Monitoring such changes is a major goal for Cassini's current extended mission.
“Science loves a mystery, and with this enigmatic feature, we have a thrilling example of ongoing change on Titan," said Stephen Wall, the deputy team lead of Cassini's radar team, based at NASA's Jet Propulsion Laboratory in Pasadena, California. "We’re hopeful that we’ll be able to continue watching the changes unfold and gain insights about what’s going on in that alien sea.”
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.
For more information about Cassini and its mission, visit:
http://www.nasa.gov/cassini
http://saturn.jpl.nasa.gov
Title: Re: NASA - Cassini updates
Post by: Scylla on 10/31/2014 03:16 PM
This near-infrared, color mosaic from NASA's Cassini spacecraft shows the sun glinting off of Titan's north polar seas. While Cassini has captured, separately, views of the polar seas (see PIA17470) and the sun glinting off of them (see PIA12481 and PIA18433) in the past, this is the first time both have been seen together in the same view.
http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA18432
Title: Re: NASA - Cassini updates
Post by: catdlr on 12/14/2014 06:06 PM
Titan's 300-foot-high sand dunes were formed by westerly wind

http://www.latimes.com/science/sciencenow/la-sci-sn-titan-saturn-sand-dunes-20141209-story.html

Quote
Sand dunes have been found in just a few places throughout the solar system - on Venus, Mars, Earth and Titan - but Titan is the only moon where dunes have been discovered.

The sand that makes up Titan's dunes is not made of silicates like the sands we find on Earth, however. Instead, scientists believe it is made of hydrocarbons, and may include particles of water ice.
Title: Re: NASA - Cassini updates
Post by: jacqmans on 03/11/2015 07:39 PM
March 11, 2015

Spacecraft Data Suggest Saturn Moon's Ocean May Harbor Hydrothermal Activity

NASA's Cassini spacecraft has provided scientists the first clear evidence that Saturn’s moon Enceladus exhibits signs of present-day hydrothermal activity which may resemble that seen in the deep oceans on Earth. The implications of such activity on a world other than our planet open up unprecedented scientific possibilities.

“These finding