Author Topic: NASA - Cassini updates  (Read 190876 times)

Offline litton4

  • Member
  • Full Member
  • **
  • Posts: 207
  • Liked: 41
  • Likes Given: 6
Re: NASA - Cassini updates
« Reply #560 on: 04/27/2017 07:08 AM »
According to the web site, they have detected the carrier signal from Cassini!
Dave Condliffe

Offline litton4

  • Member
  • Full Member
  • **
  • Posts: 207
  • Liked: 41
  • Likes Given: 6
Re: NASA - Cassini updates
« Reply #561 on: 04/27/2017 07:09 AM »
I remember following the orbit insertion live. This is almost as exciting........
Dave Condliffe

Offline Flying Beaver

Re: NASA - Cassini updates
« Reply #562 on: 04/27/2017 07:37 AM »
DSN Live showing both up and down data. Looking good  ;D

https://eyes.nasa.gov/dsn/dsn.html
Saw OG-2 Booster Land in person 21/12/2015.

Offline catdlr

  • Member
  • Senior Member
  • *****
  • Posts: 4304
  • Marina del Rey, California, USA
  • Liked: 1289
  • Likes Given: 736
Re: NASA - Cassini updates
« Reply #563 on: 04/27/2017 07:47 AM »
NASA Spacecraft Dives Between Saturn and Its Rings

https://www.jpl.nasa.gov/news/news.php?feature=6831
Tony De La Rosa

Online Svetoslav

  • Veteran
  • Full Member
  • ****
  • Posts: 864
  • Bulgaria
  • Liked: 266
  • Likes Given: 35
Re: NASA - Cassini updates
« Reply #564 on: 04/27/2017 08:15 AM »
I can see the first photos coming out in the raw section

https://saturn.jpl.nasa.gov/galleries/raw-images/

Online Svetoslav

  • Veteran
  • Full Member
  • ****
  • Posts: 864
  • Bulgaria
  • Liked: 266
  • Likes Given: 35
Re: NASA - Cassini updates
« Reply #565 on: 04/27/2017 08:24 AM »
More raw images coming

Offline Bubbinski

Re: NASA - Cassini updates
« Reply #566 on: 04/27/2017 10:33 AM »
That top image....is that the polar hurricane in the middle of the hexagon?
I'll even excitedly look forward to "flags and footprints" and suborbital missions. Just fly...somewhere.

Offline Star One

  • Senior Member
  • *****
  • Posts: 7499
  • UK
  • Liked: 1204
  • Likes Given: 168
Re: NASA - Cassini updates
« Reply #567 on: 04/27/2017 11:20 AM »
That top image....is that the polar hurricane in the middle of the hexagon?

It looks like it.

Offline FutureSpaceTourist

  • Senior Member
  • *****
  • Posts: 3314
  • UK
    • Plan 28
  • Liked: 2187
  • Likes Given: 736
Re: NASA - Cassini updates
« Reply #568 on: 04/30/2017 06:35 AM »
Quote
A hauntingly beautiful crescent #Saturn with a sliver of its rings. Taken by #Cassini Apr 29 2017.

https://twitter.com/pharaoness/status/858553392033038336

Offline catdlr

  • Member
  • Senior Member
  • *****
  • Posts: 4304
  • Marina del Rey, California, USA
  • Liked: 1289
  • Likes Given: 736
Re: NASA - Cassini updates
« Reply #569 on: 05/02/2017 03:30 AM »
Cassini Finds 'The Big Empty' Close to Saturn

https://www.jpl.nasa.gov/news/news.php?feature=6832

Quote
As NASA's Cassini spacecraft prepares to shoot the narrow gap between Saturn and its rings for the second time in its Grand Finale, Cassini engineers are delighted, while ring scientists are puzzled, that the region appears to be relatively dust-free. This assessment is based on data Cassini collected during its first dive through the region on April 26.
Tony De La Rosa

Offline Ben the Space Brit

  • Senior Member
  • *****
  • Posts: 6872
  • A spaceflight fan
  • London, UK
  • Liked: 489
  • Likes Given: 560
Re: NASA - Cassini updates
« Reply #570 on: 05/02/2017 10:31 AM »
Hmm... Might be worth checking Cassini's velocity. If Saturn has a tenuous atmosphere up higher than previously predicted, that might 'sweep out' ring dust particulates at that altitude.
"Oops! I left the silly thing in reverse!" - Duck Dodgers

~*~*~*~

The Space Shuttle Program - 1981-2011

The time for words has passed; The time has come to put up or shut up!
DON'T PROPAGANDISE, FLY!!!

Offline redliox

  • Full Member
  • ****
  • Posts: 1649
  • Arizona USA
  • Liked: 309
  • Likes Given: 54
Re: NASA - Cassini updates
« Reply #571 on: 05/02/2017 10:49 AM »
Another question would be how to interpret 'the big empty' between Saturn and its rings.  Does the lack of material mean it was cleared out eons ago?  Or could it inversely mean the rings are so young nothing's fallen into Saturn just yet?
"Let the trails lead where they may, I will follow."
-Tigatron

Offline jgoldader

  • Full Member
  • ****
  • Posts: 641
  • Liked: 204
  • Likes Given: 124
Re: NASA - Cassini updates
« Reply #572 on: 05/02/2017 03:23 PM »
Another question would be how to interpret 'the big empty' between Saturn and its rings.  Does the lack of material mean it was cleared out eons ago?  Or could it inversely mean the rings are so young nothing's fallen into Saturn just yet?

The issue is that the orbits so close to Saturn, well inside the Roche limit, simply aren't stable over very long timescales, due to perturbations from the planet and the satellites.  Any dust particles that get too low are cleared out quickly; ice particles that result from collisions in the rings might be small enough to sublime over relatively short timescales.  *Very* close to the planet, you'd get drag from the upper atmosphere, and since the atmosphere density drops exponentially, there's a "tail" even at fairly high altitudes still inside the innermost rings, so drag might be significant even at those greater distances (again, over long enough timescales).
Recovering astronomer

Offline FutureSpaceTourist

  • Senior Member
  • *****
  • Posts: 3314
  • UK
    • Plan 28
  • Liked: 2187
  • Likes Given: 736
Re: NASA - Cassini updates
« Reply #573 on: 05/02/2017 08:32 PM »
Quote
Cassini Finds 'The Big Empty' Close to Saturn

As NASA's Cassini spacecraft prepares to shoot the narrow gap between Saturn and its rings for the second time in its Grand Finale, Cassini engineers are delighted, while ring scientists are puzzled, that the region appears to be relatively dust-free. This assessment is based on data Cassini collected during its first dive through the region on April 26.

With this information in hand, the Cassini team will now move forward with its preferred plan of science observations.

"The region between the rings and Saturn is 'the big empty,' apparently," said Cassini Project Manager Earl Maize of NASA's Jet Propulsion Laboratory in Pasadena, California. "Cassini will stay the course, while the scientists work on the mystery of why the dust level is much lower than expected."

A dustier environment in the gap might have meant the spacecraft's saucer-shaped main antenna would be needed as a shield during most future dives through the ring plane. This would have forced changes to how and when Cassini's instruments would be able to make observations. Fortunately, it appears that the "plan B" option is no longer needed. (There are 21 dives remaining. Four of them pass through the innermost fringes of Saturn's rings, necessitating that the antenna be used as a shield on those orbits.)

Based on images from Cassini, models of the ring particle environment in the approximately 1,200-mile-wide (2,000-kilometer-wide) region between Saturn and its rings suggested the area would not have large particles that would pose a danger to the spacecraft.

But because no spacecraft had ever passed through the region before, Cassini engineers oriented the spacecraft so that its 13-foot-wide (4-meter-wide) antenna pointed in the direction of oncoming ring particles, shielding its delicate instruments as a protective measure during its April 26 dive.

Cassini's Radio and Plasma Wave Science (RPWS) instrument was one of two science instruments with sensors that poke out from the protective shield of the antenna (the other being Cassini's magnetometer). RPWS detected the hits of hundreds of ring particles per second when it crossed the ring plane just outside of Saturn's main rings, but only detected a few pings on April 26.

When RPWS data are converted to an audio format, dust particles hitting the instrument's antennas sound like pops and cracks, covering up the usual whistles and squeaks of waves in the charged particle environment that the instrument is designed to detect. The RPWS team expected to hear a lot of pops and cracks on crossing the ring plane inside the gap, but instead, the whistles and squeaks came through surprisingly clearly on April 26.

"It was a bit disorienting -- we weren't hearing what we expected to hear," said William Kurth, RPWS team lead at the University of Iowa, Iowa City. "I've listened to our data from the first dive several times and I can probably count on my hands the number of dust particle impacts I hear."

The team's analysis suggests Cassini only encountered a few particles as it crossed the gap -- none larger than those in smoke (about 1 micron across).

Cassini will next cross through the ring plane Tuesday, May 2, at 12:38 p.m. PDT (3:38 p.m. EDT) in a region very close to where it passed on the previous dive. During this orbit, in advance of the crossing, Cassini's cameras have been looking closely at the rings; in addition, the spacecraft has rotated (or "rolled") faster than engineers have ever allowed it to before, in order to calibrate the magnetometer. As with the first finale dive, Cassini will be out of contact during closest approach to Saturn, and is scheduled to transmit data from this dive on May 3.

Picture caption:

Quote
The Sound of Science: Comparison of Cassini Ring Crossings PIA21446
The sounds and spectrograms in these two videos represent data collected by the Radio and Plasma Wave Science, or RPWS, instrument on NASA's Cassini spacecraft, as it crossed the plane of Saturn's rings on two separate orbits.
Credits: NASA/JPL-Caltech/University of Iowa

https://www.nasa.gov/feature/cassini-finds-the-big-empty-close-to-saturn

Offline catdlr

  • Member
  • Senior Member
  • *****
  • Posts: 4304
  • Marina del Rey, California, USA
  • Liked: 1289
  • Likes Given: 736
Re: NASA - Cassini updates
« Reply #574 on: 05/03/2017 09:43 PM »
NASA: Cassini's First Fantastic Dive Past Saturn

NASA Jet Propulsion Laboratory

Published on May 3, 2017
As NASA's Cassini spacecraft made its first-ever dive through the gap between Saturn and its rings on April 26, 2017, one of its imaging cameras took a series of rapid-fire images that were used to make this movie sequence. The video begins with a view of the vortex at Saturn's north pole, then heads past the outer boundary of the planet's hexagon-shaped jet stream and continues further southward.

https://www.youtube.com/watch?v=9LBLCgCYy0I?t=001


Offline Star One

  • Senior Member
  • *****
  • Posts: 7499
  • UK
  • Liked: 1204
  • Likes Given: 168
Re: NASA - Cassini updates
« Reply #575 on: 05/10/2017 08:27 AM »
Cassini downlinks view of Titan’s methane clouds on third loop inside rings

https://astronomynow.com/2017/05/10/cassini-downlinks-view-of-titans-methane-clouds-on-third-loop-inside-rings/

Offline ugordan

  • Senior Member
  • *****
  • Posts: 7314
    • My mainly Cassini image gallery
  • Liked: 1459
  • Likes Given: 312
Re: NASA - Cassini updates
« Reply #576 on: 05/10/2017 08:41 AM »
JPL release on the clouds: https://saturn.jpl.nasa.gov/resources/7673/

Titan is really trolling us now and just rubbing it in. After so many years Cassini has spent at Saturn, it decides to start cranking out these clouds only after the last ever flyby by Cassini...

Offline eeergo

  • Phystronaut
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 4615
  • Milan, Italy; Spain; Virginia
  • Liked: 376
  • Likes Given: 313
Re: NASA - Cassini updates
« Reply #577 on: 05/29/2017 09:51 PM »
Look at those Daphne-induced ring ripples at the Keeler gap  :o
-DaviD-

Offline eeergo

  • Phystronaut
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 4615
  • Milan, Italy; Spain; Virginia
  • Liked: 376
  • Likes Given: 313
Re: NASA - Cassini updates
« Reply #578 on: 05/29/2017 09:58 PM »
Also, another milestone showing us the Solstice Mission is really over and the Grande Finale is upon us is that... well, solstice has passed for Saturn :)


https://saturn.jpl.nasa.gov/news/3065/cassini-looks-on-as-solstice-arrives-at-saturn/


The sixth inter-ring passage has occurred, 16 more to go!
-DaviD-

Offline Star One

  • Senior Member
  • *****
  • Posts: 7499
  • UK
  • Liked: 1204
  • Likes Given: 168
Re: NASA - Cassini updates
« Reply #579 on: 05/31/2017 09:51 AM »
Cassini finds Saturn's moon Enceladus may have tipped over

Quote
Saturn's icy, ocean-bearing moon Enceladus may have tipped over in the distant past, according to recent research from NASA's Cassini mission. Researchers with the mission found evidence that the moon's spin axis—the line through the north and south poles—has reoriented, possibly due to a collision with a smaller body, such as an asteroid.

Examining the moon's features, the team showed that Enceladus appears to have tipped away from its original axis by about 55 degrees—more than halfway toward rolling completely onto its side. "We found a chain of low areas, or basins, that trace a belt across the moon's surface that we believe are the fossil remnants of an earlier, previous equator and poles," said Radwan Tajeddine, a Cassini imaging team associate at Cornell University, Ithaca, New York, and lead author of the paper.

https://m.phys.org/news/2017-05-cassini-saturn-moon-enceladus.html

Tags: