Author Topic: NASA - Cassini updates  (Read 170174 times)

Offline Star One

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Re: NASA - Cassini updates
« Reply #500 on: 03/14/2017 02:03 PM »
Enceladus' south pole is warm under the frost

https://phys.org/news/2017-03-enceladus-south-pole-frost.html

Offline Ben the Space Brit

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Re: NASA - Cassini updates
« Reply #501 on: 03/14/2017 02:23 PM »
Tidal heating from Saturn and Titan's gravitational fields?
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Offline Star One

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Re: NASA - Cassini updates
« Reply #502 on: 03/14/2017 04:12 PM »
Tidal heating from Saturn and Titan's gravitational fields?

Sounds more than likely. As these hot spots vary in position over geological time by the sound of it, does that indicate there are variations in the moons orbits over the longer term?

Offline CuddlyRocket

Re: NASA - Cassini updates
« Reply #503 on: 03/14/2017 11:26 PM »
Tidal heating from Saturn and Titan's gravitational fields?

Sounds more than likely. As these hot spots vary in position over geological time by the sound of it, does that indicate there are variations in the moons orbits over the longer term?

More likely, perhaps, is that the axis of rotation shifts?

Offline TakeOff

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Re: NASA - Cassini updates
« Reply #504 on: 03/15/2017 11:53 AM »
Tidal heating from Saturn and Titan's gravitational fields?
Isn't it more likely with tidal heating from Saturn's internal gravity concentrations (the effects of which can be seen in the ring structure) and its flatness and it rotating three times faster than Enceladus orbits? Saturn is 5,000 times more massive than Titan and five times closer to Enceladus.

I wonder how the heating occurs on a pole instead of at the equator, where tidal effects are the greatest on earth?

EDIT: Gaah, you wrote Saturn's AND Titan's gravity field, yes, I agree with that, I only saw titan when I posted this.
« Last Edit: 03/15/2017 11:56 AM by TakeOff »

Offline CuddlyRocket

Re: NASA - Cassini updates
« Reply #505 on: 03/16/2017 08:17 PM »
I wonder how the heating occurs on a pole instead of at the equator, where tidal effects are the greatest on earth?

It may depend on the inclination of the axis of rotation to the orbital plane. Tidal effects on Enceladus due to Saturn are greatest along the line connecting the centres of the two bodies.

Offline ugordan

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Re: NASA - Cassini updates
« Reply #506 on: 03/16/2017 09:29 PM »
I wonder how the heating occurs on a pole instead of at the equator, where tidal effects are the greatest on earth?

I believe it might be a case of the region with the thinnest ice reorienting itself to one of the poles due to a tidal gradient on a non-spherical body. IIRC, the active south polar region is actually topographically slightly depressed compared to the rest of the ice shell on account of liquid water underneath having higher density than bulk ice.

It doesn't mean there's necessarily a mechanism that somehow concentrates the heating to the pole, just that the largest liquid pocket ended up there on account of either ice shell (if the ocean is really global, but deepest at the pole) or entire moon rotational drift.

Offline jacqmans

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Re: NASA - Cassini updates
« Reply #507 on: 03/30/2017 08:31 AM »
March 29, 2017
MEDIA ADVISORY M17-037

NASA to Preview ‘Grand Finale’ of Cassini Saturn Mission

NASA's Cassini spacecraft will make 22 orbits of Saturn during its Grand Finale, exploring a totally new region

NASA will hold a news conference at 3 p.m. EDT Tuesday, April 4, at the agency’s Jet Propulsion Laboratory (JPL) in Pasadena, California, to preview the beginning of Cassini's final mission segment, known as the Grand Finale, which begins in late April. The briefing will air live on NASA Television and the agency’s website.

Cassini has been orbiting Saturn since June 2004, studying the planet, its rings and its moons. A final close flyby of Saturn's moon Titan on April 22 will reshape the Cassini spacecraft's orbit so that it begins its final series of 22 weekly dives through the unexplored gap between the planet and its rings. The first of these dives is planned for April 26. Following these closer-than-ever encounters with the giant planet, Cassini will make a mission-ending plunge into Saturn's upper atmosphere on Sept. 15.

The panelists for the briefing are:
•Jim Green, director of NASA’s Planetary Science Division at the agency’s headquarters in Washington
•Earl Maize, Cassini project manager at JPL
•Linda Spilker, Cassini project scientist at JPL
•Joan Stupik, Cassini guidance and control engineer at JPL

Media who would like to attend the event at JPL must arrange access in advance by contacting Gina Fontes in the JPL Media Relations Office at 818-354-9380 or georgina.d.fontes@jpl.nasa.gov. Media who arrange access must bring to the event valid media credentials, and for non-U.S. citizens, valid passports.

To participate by phone, media must email their name and affiliation to georgina.d.fontes@jpl.nasa.gov by 8 a.m. April 4.

Media and the public also may ask questions during the briefing on Twitter using the hashtag #askNASA.

Supporting graphics, video and background information about Cassini's Grand Finale will be posted before the briefing at:

http://saturn.jpl.nasa.gov/grandfinale

The Cassini mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. JPL, a division of Caltech in Pasadena, California, manages the mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter.

For more information about Cassini, go to:

http://www.nasa.gov/cassini

and

http://saturn.jpl.nasa.gov

Offline jacqmans

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Re: NASA - Cassini updates
« Reply #508 on: 04/05/2017 06:51 AM »
April 04, 2017
RELEASE 17-037

NASA’s Cassini Mission Prepares for 'Grand Finale' at Saturn

NASA's Cassini spacecraft, in orbit around Saturn since 2004, is about to begin the final chapter of its remarkable story. On Wednesday, April 26, the spacecraft will make the first in a series of dives through the 1,500-mile-wide (2,400-kilometer) gap between Saturn and its rings as part of the mission’s grand finale.

"No spacecraft has ever gone through the unique region that we'll attempt to boldly cross 22 times," said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. "What we learn from Cassini’s daring final orbits will further our understanding of how giant planets, and planetary systems everywhere, form and evolve. This is truly discovery in action to the very end."

During its time at Saturn, Cassini has made numerous dramatic discoveries, including a global ocean that showed indications of hydrothermal activity within the icy moon Enceladus, and liquid methane seas on its moon Titan.

Now 20 years since launching from Earth, and after 13 years orbiting the ringed planet, Cassini is running low on fuel. In 2010, NASA decided to end the mission with a purposeful plunge into Saturn this year in order to protect and preserve the planet's moons for future exploration – especially the potentially habitable Enceladus.

But the beginning of the end for Cassini is, in many ways, like a whole new mission. Using expertise gained over the mission's many years, Cassini engineers designed a flight plan that will maximize the scientific value of sending the spacecraft toward its fateful plunge into the planet on Sept. 15. As it ticks off its terminal orbits during the next five months, the mission will rack up an impressive list of scientific achievements.

"This planned conclusion for Cassini's journey was far and away the preferred choice for the mission's scientists," said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. "Cassini will make some of its most extraordinary observations at the end of its long life."

The mission team hopes to gain powerful insights into the planet's internal structure and the origins of the rings, obtain the first-ever sampling of Saturn's atmosphere and particles coming from the main rings, and capture the closest-ever views of Saturn's clouds and inner rings. The team currently is making final checks on the list of commands the robotic probe will follow to carry out its science observations, called a sequence, as it begins the finale. That sequence is scheduled to be uploaded to the spacecraft on Tuesday, April 11.

Cassini will transition to its grand finale orbits, with a last close flyby of Saturn's giant moon Titan, on Saturday, April 22. As it has many times over the course of the mission, Titan's gravity will bend Cassini's flight path. Cassini's orbit then will shrink so that instead of making its closest approach to Saturn just outside the rings, it will begin passing between the planet and the inner edge of its rings.

"Based on our best models, we expect the gap to be clear of particles large enough to damage the spacecraft. But we're also being cautious by using our large antenna as a shield on the first pass, as we determine whether it's safe to expose the science instruments to that environment on future passes," said Earl Maize, Cassini project manager at JPL. "Certainly there are some unknowns, but that's one of the reasons we're doing this kind of daring exploration at the end of the mission."

In mid-September, following a distant encounter with Titan, the spacecraft's path will be bent so that it dives into the planet. When Cassini makes its final plunge into Saturn's atmosphere on Sept. 15, it will send data from several instruments – most notably, data on the atmosphere's composition – until its signal is lost.

"Cassini's grand finale is so much more than a final plunge," said Spilker. "It's a thrilling final chapter for our intrepid spacecraft, and so scientifically rich that it was the clear and obvious choice for how to end the mission."

Resources on Cassini's grand finale, including images and video, are available at:

https://saturn.jpl.nasa.gov/mission/grand-finale/grand-finale-resources

An animated video about Cassini's Grand Finale is available at:



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

More information about Cassini is at:

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov

Offline eeergo

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Re: NASA - Cassini updates
« Reply #509 on: 04/05/2017 10:10 AM »




What a nicely done video, thanks! Especially worth praising is the re-entry sequence, with the thruster pods frantically firing to illustrate the attempt to keep comms lock on Earth, and the visuals of Saturn's skies from up close.
-DaviD-

Offline Ben the Space Brit

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Re: NASA - Cassini updates
« Reply #510 on: 04/05/2017 11:20 AM »
I'm going to miss the old girl.
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Offline ChrisGebhardt

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Re: NASA - Cassini updates
« Reply #511 on: 04/10/2017 05:52 PM »
NASA to Reveal New Discoveries in News Conference on Oceans Beyond Earth

NASA will discuss new results about ocean worlds in our solar system from the agency’s Cassini spacecraft and the Hubble Space Telescope during a news briefing 2 p.m. EDT on Thursday, April 13. The event, to be held at the James Webb Auditorium at NASA Headquarters in Washington, will include remote participation from experts across the country.

The briefing will be broadcast live on NASA Television and the agency's website.

These new discoveries will help inform future ocean world exploration -- including NASA’s upcoming Europa Clipper mission planned for launch in the 2020s -- and the broader search for life beyond Earth.

The news briefing participants will be:
Thomas Zurbuchen, associate administrator, Science Mission Directorate at NASA Headquarters in Washington
Jim Green, director, Planetary Science Division at NASA Headquarters

Mary Voytek, astrobiology senior scientist at NASA Headquarters

Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California
Hunter Waite, Cassini Ion and Neutral Mass Spectrometer team lead at the Southwest Research Institute (SwRI) in San Antonio

Chris Glein, Cassini INMS team associate at SwRI
William Sparks, astronomer with the Space Telescope Science Institute in Baltimore
A question-and-answer session will take place during the event with reporters on site and by phone. Members of the public also can ask questions during the briefing using #AskNASA.

To participate by phone, reporters must contact Dwayne Brown at 202-358-1726 or dwayne.c.brown@nasa.gov and provide their media affiliation no later than noon April 13.

Offline Bubbinski

Re: NASA - Cassini updates
« Reply #512 on: 04/12/2017 04:50 PM »
Tomorrow April 13th, NASA will announce new results from Cassini and Hubble about the outer solar system:

http://www.spaceref.com/calendar/calendar.html?pid=9444

Supposed to be big.
I'll even excitedly look forward to "flags and footprints" and suborbital missions. Just fly...somewhere.

Offline meekGee

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Re: NASA - Cassini updates
« Reply #513 on: 04/13/2017 02:29 AM »
ABCD - Always Be Counting Down

Offline Star One

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Re: NASA - Cassini updates
« Reply #514 on: 04/13/2017 06:43 AM »
In relation to the above.

Hydrothermal Activity in The Seas of Enceladus: Implications For Habitable Zones

Quote
On Thursday NASA will announce evidence that hydrothermal activity on the floor of an ice-covered ocean on Saturn's moon Enceladus is most likely creating methane from carbon dioxide. The process is indicative of possible habitable zones within the ocean of Enceladus.

But before we go any further, "habitable" does not mean "inhabited".

NASA bases this determination on the amount of hydrogen in plumes emanating from the moon's south pole. The large amount of hydrogen is strongly suggestive of a constant hydrothermal process wherein the ocean under the surface of Enceladus is interacting with rock and organic compounds. The amount of hydrogen present is in disequilibrium i.e. if there was not a process that was constantly generating hydrogen the observed hydrogen levels would likely be lower than what is seen. Something is pumping it out.

http://astrobiology.com/2017/04/hydrothermal-activity-in-the-seas-of-enceladus-implications-for-habitable-zones.html

Offline Crispy

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Re: NASA - Cassini updates
« Reply #515 on: 04/13/2017 11:04 AM »




What a nicely done video, thanks! Especially worth praising is the re-entry sequence, with the thruster pods frantically firing to illustrate the attempt to keep comms lock on Earth, and the visuals of Saturn's skies from up close.

It's by Erik Wernquist. He also did a preview video for New Horizons (I wish he'd update it with what we know now!) and the fantastic short film Wanderers, which reduces me to floods of space tears every time.

https://vimeo.com/erikwernquist

Fun fact, he also animated Crazy Frog, a ringtone craze and novelty pop act from 2004 https://en.wikipedia.org/wiki/Crazy_Frog


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Re: NASA - Cassini updates
« Reply #516 on: 04/13/2017 11:25 AM »
His space stuff only just makes up for that cultural plague that was that bloody frog!! ;)
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Offline Star One

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Offline Alpha_Centauri

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Re: NASA - Cassini updates
« Reply #518 on: 04/13/2017 06:27 PM »
***
« Last Edit: 04/13/2017 06:30 PM by Alpha_Centauri »

Offline Star One

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Re: NASA - Cassini updates
« Reply #519 on: 04/13/2017 06:37 PM »
Couldn't they use a stripped down version of Europa Clipper, as Saturn has a less fearsome radiation environment, as an Enceladus Clipper?

I can't help feeling maybe we should be going to Enceladus first not Europa?

Some reporting of what I assume is the Q & A session.

https://mobile.twitter.com/EBotkinKowacki/status/852585362362949633
« Last Edit: 04/13/2017 06:45 PM by Star One »

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