Emily Lakdawalla • Nov 30, 2009
What's up in the solar system in December 2009
The two big things happening this month are the launch of the Wide-field Infrared Survey Explorer (WISE), from Vandenberg Air Force Base no earlier than December 9 at 06:09 PST (15:09 UTC), and the December meeting of the American Geophysical Union (AGU) from the 14th through the 18th.
AGU should generate lots of press releases from points across the solar system. Last year's AGU meeting was the last major conference I was able to attend in person, due to the arrival of the second kid. Hopefully I'll be able to start traveling a bit more next year! I'll do my best to cover the news from AGU from home. You can read the schedule and abstracts for yourself here. If you will be attending AGU and want to guest blog, plan to Tweet about it, or would like Tweet updates through me without having to set up and promote your own Twitter account, please send me an email!
As for WISE, I will attempt to watch and Tweet its launch live. I won't be giving regular updates on WISE here, since it's primarily an astronomy mission, but I'm sure I'll have cause to mention it in the context of the discovery of nearby brown dwarfs and maybe, hopefully, previously undiscovered planet-sized bodies in the distant reaches of the solar system.
Oh, and this month has a blue Moon! There are two full Moons, on the 2nd and 31st of December.
Now to round up what's going on with all our unmanned emissaries to our astronomical backyard.
In the inner solar system:
The MESSENGER spacecraft performed its last big deep-space maneuver on November 24, positioning itself for Mercury orbit insertion with a 3.3-minute engine firing. I wonder if they'll make it to orbit insertion without another thruster firing? In the past they've managed to do trajectory correction using solar sailing, conserving fuel. Mercury orbit insertion is planned for March 18, 2011.
Venus Express remains healthy (as of November 14) in orbit at Venus. Its current mission extension runs through 2012.
Lunar Reconnaissance Orbiter is busily mapping the Moon from its science orbit. Last month they released a neato image from the Mini-RF radar instrument. Meanwhile eye candy from LROC continues to be spectacular. My favorite recent one was this, a highly oblique shot on the Cabeus crater area. This page is better for browsing the images but doesn't get you to the "featured image" captions.
At the Sun:
The ESA/NASA SOHO mission has been looking at a very quiet Sun lately -- no sunspots. As always, SOHO's near-real-time data and images are available here.
The twin STEREO spacecraft are currently 64 degrees ahead (STEREO A) and 65 degrees behind (STEREO B) Earth. They're far enough apart now that the mission homepage now features a neat rotating view of the two spacecraft's images that covers nearly the entire Sun. The daily STEREO image viewer includes the latest SOHO image, which gives you three slightly different viewpoints on the current, quiet appearance of the Sun.
On to Mars:
Out at Mars, it's early southern hemisphere autumn (Ls 17°). Today it is Spirit sol 2101 and Opportunity sol 2081. As you're all no doubt aware, the Mars Exploration Rover Spirit finally started rolling in the effort to climb out of Troy last month; I'll have a more detailed update on that effort later this week or net week (it's a slow process, so I see no point in too-frequent updates). Opportunity is finishing its third week at Marquette Island, a rock that proved, upon closer examination, to be yet another meteorite. A. J. S. Rayl's latest update on what the rovers have been doing for the past month should be posted soon; I'll put in a link here when it's live.
Mars Reconnaissance Orbiter is still in safe mode. According to a press release from the mission, they're finally ready to proceed with uploading some changes to onboard software that will hopefully prevent future spontaneous reboots; that process begins this week. It'll be tricky, because they have to safeguard against the possibility of another spontaneous reboot happening during the software update. The release includes no promises about when the orbiter may be prepared to resume science activities. Meanwhile, the HiRISE team continues to release gorgeous images. I can't seem to make enough time to browse the latest releases in the HiRISE catalog, so if some readers want to take it upon yourselves to send me a heads up about particularly noteworthy images, I'll be glad for the help!
ESA's Mars Express is still diligently mapping Mars. The Mars Webcam is currently returning high-phase shots of Mars. For the next few months, VMC images will be downlinked more rapidly than normal, meaning that in some cases, VMC images appear on the Web within hours of their capture on the spacecraft! Such rapid routine release of images is a first for ESA -- well done, guys! I'll have much more to say about VMC later this week.
NASA's Mars Odyssey remains the longest-lived spacecraft in orbit at Mars. You can see the latest from its THEMIS instrument here I like this one of Nirgal Vallis, a Mars feature that says "water was here" but also that the biggest channels on Mars are really, really different from Earth rivers.
Cassini has just completed two spectacularly close flybys of Enceladus, so this month will hopefully be a bit easier on the team. We do get one nontargeted flyby of Tethys on December 26. This month contains revs 122 (19 days long) and 123 (back to 16 days, same as Titan's orbital period); both revs include a targeted flyby of Titan. Cassini's orbit apoapsis remains at a fairly high phase of 104°, which means that the global shots of Saturn will show it as a pretty, fat crescent.
Rosetta successfully accomplished its third Earth flyby last month. It's hard to believe, but this is the last gravity assist, and therefore last major change in its trajectory, before its May 2014 rendezvous with comet Churyumov-Gerasimenko. There will be one deep-space maneuver in January 2011. The next big science event for Rosetta will be a flyby of asteroid Lutetia in July of 2010.
The International Cometary Explorer remains on course for a return visit to Earth in 2014. When it does, ICE can be returned to a Sun-Earth L1 halo orbit, or can use multiple Earth swingbys to encounter Comet Wirtanen during its near-Earth apparition in December 2018.
In the asteroid belt, NASA's Dawn is now in the asteroid belt for good, and is steadily thrusting with its ion engines, patiently propelling itself toward a rendezvous with Vesta in July 2011. The latest Dawn Journal will be posted tomorrow.
NASA's Deep Impact is cruising toward its October 2010 flyby of comet 103P/Hartley 2.
NASA's Stardust is cruising ever onward toward a February 14, 2011 encounter with comet Tempel 1. The October status reports indicate the spacecraft is in good health.
As I reported recently, Hayabusa is down one more ion engine but, through yet another feat of engineering ingenuity, is still on track to return to Earth in June 2010. On November 26 they posted a neat image taken by Hayabusa's star tracker taken on November 12, showing Mars (as a bright dot) in Leo.
NASA's New Horizons has 16.65 AU to go to reach Pluto. It's still on course for a January to July 2015 encounter with the Pluto and Charon system. On December 29, New Horizons will reach a significant milestone: it'll then be closer to Pluto than Earth.
Finally, NASA's Voyager 1 and 2 spacecraft were still responding to commands from Earth as of September 25. Both have now crossed the "termination shock," where the solar wind slows down as it impinges upon the interstellar medium.
Some other milestones to take note of this month, taken mostly from JPL's Space Calendar:
- From December 5 to 15 there'll be a workshop in Sudan on asteroid-turned-meteorite 2008 TC3.
- December 21: Happy solstice!
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