Exciting Times for Cassini

by Amanda Hendrix

It’s an exciting time in Cassini-land these days! We are well into the Equinox Mission, an extension to Cassini’s mission that includes seven flybys of the Saturnian moon Enceladus, discovered in July 2005 to be geologically active. Prior to the prime mission, we knew that Enceladus was interesting and unique, and thus planned and executed three targeted flybys for the prime mission. With the tremendous discovery of water plumes at the south pole of this small icy moon (which happened on the second targeted flyby), we planned a more in-depth investigation for the Equinox Mission. And we are well into it! Our first Enceladus flyby of the Equinox Mission was in August, and we had two in October.

My job on Cassini is two-fold: I am on the science planning team, helping to plan out the science activities that occur during each icy moon encounter, and I am on the team for the ultraviolet imaging spectrograph instrument, studying ultraviolet data of the surfaces of these icy moons. So it’s really fantastic to be involved in planning each encounter, and then analyzing data to understand the moons.

Close-up view of Enceladus, taken on the Oct. 31 flyby. Image credit: NASA/JPL

In order to learn as much as we can about crazy Enceladus (it’s so small and icy — yet it’s got these geysers!), we want to let all of the instruments make measurements, and it isn’t possible to simultaneously get measurements from all instruments. (That’s just the way the spacecraft is built.) We know that the cameras will tell us a lot about the current and historical geology of the surface, the ultraviolet and infrared imagers will tell us about the surface composition, and the long-wavelength infrared instrument will reveal surface temperatures. These four “remote-sensing” instruments can take data simultaneously. But if we want to get the best data from the “in situ” instruments (like the ion and neutral mass spectrometer and cosmic dust analyzer), we need to orient the spacecraft such that it’s nearly impossible to get remote sensing data. So we divide up the flybys and allow many instruments the opportunity to get data. The period around the closest approach during the August flyby (called “E4″) was allocated to the remote-sensing instruments — and this resulted in the highest-resolution images of the active “tiger stripes” ever! (See one of these images here: http://photojournal.jpl.nasa.gov/catalog/PIA11113) The closest approach of the next Enceladus flyby - called “E5,” on October 9 — took the spacecraft deeper into the south polar plume than ever before. Here the priority was given to the in situ instruments, which obtained great, high-signal data of the plume, telling us about the composition of both the gaseous and particle components. And the October 31 flyby - called “E6″ — was again dedicated to remote-sensing, for a last look at the south pole before it heads mostly into seasonal darkness.

It’s so fortunate that Cassini has multiple opportunities to execute close encounters of an object as dynamic as Enceladus. The Voyager spacecraft had just one shot as they flew through the Saturn system, but Cassini, as an orbiter, gives us the chance to analyze our data, figure out what we’ve learned, and make thoughtful decisions on what experiments we need to make to follow up on those discoveries.

Things aren’t completely within our control, however! For instance, southern summer in the Saturn system is coming to a close, limiting the amount of sunlight illuminating the fascinating south polar region of Enceladus. But there’s plenty of important science to do in the dark with the in situ instruments, as well as the composite infrared spectrometer and radar, which is great. Who knows — we’ll see what the equinox season (and hopefully the following solstice) has in store for us! We may get some surprises!

    8 Responses to “Exciting Times for Cassini”

  1. Derek Says:
    November 6th, 2008 at 12:00 am

    I know you guys may not have heard if you are getting approval for an Extended-Extended Mission (Saturn Solstice Mission I think), but I sincerely hope you do! The science provided is outstanding! Space exploration usually requires a lot of patience, but with the Mars Exploration Rovers, Phoenix, Mars Reconnaissance Orbiter, Cassini-Huygens, MESSENGER, Venus Express, Spitzer, GALEX and other spacecraft returning so much data, I can usually find myself entertained on a daily basis. So overall I’d like to thank you and others like you. Unfortunately my collegiate aspirations were dashed by reasons out of my control and so my dreams of working for JPL are probably over–at least for now. But hey, I am only twenty so that gives me time to perhaps return to university in the future. But in the mean time I can feel a part of the team–sort of–just by reading these blogs. You guys really provide a great amount of information that helps me feel like I have a special backstage pass to space exploration. How wonderful is that?

  2. Cesare Guaita Says:
    January 23rd, 2009 at 4:13 am

    As an organic chemist (Milano University) I should be very interested in some
    anticipations about the results of October 9th Enceladus flyby. I don’t find anything on this subiect.
    Some new kind of carbon molecules are found? Have you discovered the nature of
    carbon molecule with a single carbon atom and the nature of molecule with more
    carbon atom?

  3. Alex Tsukernik Says:
    January 28th, 2009 at 1:03 pm

    This is my first comment on the Cassini-Huygens exploration mission or reconnaissance of the planets and moons of our solar system; and eventually beyond.
    The current mission status appears to be going at an extraordinary rate of continuing discoveries. the mission to explore Saturn and its moons, particularly Titan is quintessential. keep up the good work. And eventually JPL, Caltech, and the other organizations devoted to Earth, space and cosmological exploration will be in a unique position to open space travel, tourism and colonizing other worlds, as was recently done only in fantasy, and science fiction. Good luck.

  4. Chris Robert Says:
    August 21st, 2009 at 9:52 am

    Plumes and Fissures and other what not types of pressurized gases are enriched with a substance we know to be called water. Hydrogen-Hydroxide, or water, is evidently in the cooler atmospheres of some of the moons. Their possibly life-sustaining biomes have also been detected to have traces of ammonia in the mix. The shapes of the moons are quite variant in texture and viscosity, but this is irrelevant when looking at the moons from afar and noticing their aura and electro-magnetic qualities, as Herschel did. They were also classified by their sizes, distances and spatial relationship with the rings, long before the surfaces were later examined by later scientists. Plus, the patterns of Saturn’s weather-system is a direct match of our weather-system here on Earth. About every 23 years, our climate transforms, which is the time it takes for the rings to re-position. But, it take 52 years for saturn to return. And, what about the water found on the comets. Were they once moons? Do they carry life. If so, what kind? With all these little tidbits, it’s no wonder that this planet has received so much attention; especially for its preciseness in shape and vastness in singularity.

    Amanda Hendrix says:

    Certainly many bodies in the solar system, both satellites of the outer solar system and comets, are rich in water ice – both on their surfaces and in their interiors. Water on the surface exists as ice due to the extreme cold temperatures, while it is possible for water to be present in a liquid state in the interiors of these bodies, for instance at Europa and perhaps at Enceladus as well. Enceladus’ activity is particularly remarkable and somewhat surprising because it is such a small body, orbiting so far from the Sun. The location of the geologic activity at the south pole was also unexpected.

  5. Paris Ronvenda Says:
    November 30th, 2009 at 12:47 pm

    Looking over the information i have recently found i feel that asteriods has currently effected people thinking on howt the world may end i find nothing quite interesting on this subject but the research if people keep thinkin this way it will be nithing for the human mind to live for

  6. jose riera Says:
    June 21st, 2011 at 1:33 am

    I want know information about elenin comet, may be you can refer other expert.

    thank you

  7. Pablo de Argentina Says:
    July 12th, 2011 at 11:45 am

    I want to see actual pictures of Elenin. Where can I find pictures in NASA? Thank you!

  8. some dude Says:
    July 17th, 2011 at 4:55 pm

    Good luck getting a response on this… people have been retiring from NASA and heading for the hills or silos in Kansas…

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