What's up in the solar system in December 2010
Posted by Emily Lakdawalla
2010/11/30 05:11 CST
Topics: mission status
The year is racing to a close -- I can't believe December is here already! This month will see Japan's Akatsuki join Venus Express at Venus; that happens on December 6 at 23:49 UT (December 7, Japan time). Cassini will perform a second of a pair of 50-kilometer Enceladus flybys (the first happened early today). Opportunity should, if she keeps up her current pace, arrive within spitting distance of Santa Maria crater. And, closer to home, there'll be a total lunar eclipse over the night of December 20-21.
Here's Olaf Frohn's map of where everybody is on December 1. Compare it to last month's diagram to see how things have moved.Moving on to more detailed accounts of the active planetary exploration missions:In the inner solar system:NASA's MESSENGER spacecraft is cruising along, with only 107 days remaining until Mercury orbit insertion (which is planned for March 18, 2011). Check their gallery for their latest image releases. Last month, they released an 18-Megabyte image of the Caloris basin, a mosaic of many individual images from the first flyby.
ESA's Venus Express, like ten other ESA missions, won a three-year life extension from ESA last month, meaning it gets to carry on its work at Venus through 2014. A press release just posted today discusses a new article in Nature Geoscience about the origin of an odd sulfur dioxide layer in Venus' atmosphere, and what that might mean for Earth's climate.
JAXA's Akatsuki will arrive at Venus next week! Its orbit insertion burn begins at 8:49 a.m. Japan Standard Time on December 7 (23:49 December 6 UT), and will last 12 minutes. I'll post more extensively about the mission later this week.
JAXA's IKAROS, too, is flying toward Venus, and according to this kawaii animation, it will pass Venus (without entering orbit) on December 18. If I understand the Google translation of the IKAROS blog correctly, there will be a communications blackout for IKAROS as Akatsuki passes through its critical orbit insertion phase, so they are preparing for IKAROS to operate autonomously for a few days.
Apart from the posting of those cool deployment and rocket-firing self-portrait videos, China's Chang'E 2 lunar orbiter has been extremely quiet this month.
NASA's Lunar Reconnaissance Orbiter is busily mapping the Moon from its science orbit. They continue to select terrific photos to publish in their gallery, but their site has been down for me all afternoon so I can't point you to a specific one.
On to Mars:Out at Mars, the seasons have shifted; the equinox has passed and it's early spring in the southern hemisphere, so days are now longer than nights. (It's currently Ls 190.4°.) Today it is Mars Exploration Rover Spirit sol 2456 and Opportunity sol 2436. Spirit has still not been heard from since sol 2210 (March 22). It's now getting less likely that we'll ever hear from Spirit again. But there is still reason to hope -- and more than hope, to keep commanding Odyssey to listen for that elusive signal. But Opportunity has rolled on. She pulled off another 800-meter (or more!) month. She's now just a kilometer from the crater named Santa Maria, and a little more than 7 kilometers separates her from the nearest bit of Endeavour crater's rim. Here is Eduardo Tesheiner's latest route map and Google Earth kml file for Opportunity.
ESA's Mars Express mission posted a really fine view of Phoenix Lacus (a very big part of the Valles Marineris canyon system) last month. In this month's Mars Webcam photos, Mars is growing from crescent to quarter phase again (the phase of Mars Webcam images results from the current location of Mars Express' orbital apoapsis). One recent set had some neat high-altitude clouds that cast shadows on the surface below them.
NASA's Mars Reconnaissance Orbiter The latest MARCI weather report speaks of widespread dust activity, but clear skies over both rovers. As always, check in on the latest captioned image releases from HiRISE for your dose of spectacular photos from Mars. Here's a really funky landscape of polygonal terrain with superimposed (or "sub"imposed? it's hard to tell) pits.
NASA's Mars Odyssey remains the longest-lived spacecraft in orbit at Mars. You can see the latest from its THEMIS instrument here. I always love images of streamlined islands, because they clearly tell a story of a Mars that just doesn't exist anymore.
Exploring Saturn:The NASA-ESA-ASI Cassini mission spent nearly all of November (from November 2 to 24) in safe mode, due to a flipped bit in a really bad spot in one of its computers. But it's back in action now and, in fact, had a very close targeted flyby of Enceladus just two hours after its periapsis today, right after a really nice set of views of Hyperion on Sunday (the 28th). These activities are described in the rev 141 Looking Ahead article. At present Cassini is on the outbound leg of 20-day-long Rev 141; it'll reach apoapsis, beginning rev 142, on December 10, and do a repeat close flyby of Enceladus on December 21. The orbital inclination is now nearly zero, so I expect to see lots of fine pictures of moons showing up on the raw images website over the coming weeks; the Looking Ahead article mentions Daphnis, Pan, Pandora, Dione, Tethys, and Rhea. There were a couple of big press releases this month that I haven't had time to investigate: today they wrote of the hottest temperatures yet measured in Enceladus' tiger stripes in data from an August flyby, and the detection of an oxygen-containing exosphere at Rhea. As I mentioned last month, Exploring a Comet:NASA's Deep Impact has now completed its lookback observations of comet Hartley 2. The encounter science is not quite over; it's now doing some star observations to provide calibration information for the cameras. After that's done, and all the data has been sent back to Earth, Deep Impact will hibernate. But it won't be mothballed, contrary to what I've said in previous updates; NASA is now soliciting proposals for another mission extension. Sadly, there's not enough fuel remaining to target a third comet, but it could conceivably be used for more exoplanet observations from its current orbit.
Cruising from here to there:All systems on NASA's Stardust are "nominal" as only 76 days remain until its flyby of comet Tempel 1. It successfully completed a trajectory correction maneuver on November 20, refining its approach to the comet. Stardust's trajectory correction manuevers are not only to make sure it passes the right distance from the comet; they are also trying to time it so that Tempel 1 will show the face containing the Deep Impact crater. But there's enough uncertainty in Tempel 1's rotation rate that it can't be 100% guaranteed that the crater will actually be in view when Stardust passes by. Closest approach will happen at 8:42 p.m. PST on February 14, 2011, or 04:42 February 15 UTC.
NASA's Dawn has now been in space for three years. It continues patiently propelling itself toward a rendezvous with Vesta in July 2011, only 228 days away.
NASA's New Horizons has 13.58 AU to go to reach Pluto. It's still on course for a January to July 2015 encounter with the Pluto and Charon system. There are 1686 days left until Pluto closest approach.
ESA's Rosetta mission is preparing to hibernate from July 2011 to January 2014. The next object it'll encounter will be its goal, comet 67/P Churyumov-Gerasimenko; rendezvous is set for May 2014.
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.
And beyond:Finally, NASA's Voyager 1 and 2 spacecraft are still going strong. Follow the current position of both using the Twitter feed of Voyager 2, which also mentions the position of Voyager 1 once a day.
Some other milestones to take note of this month, taken from JPL's Space Calendar:
- Mercury will be at its greatest eastern elongation tomorrow (December 1), meaning it's visible in the evening.
- The Fall Meeting of the American Geophysical Union takes place from December 13-17 in San Francisco. There'll be a ton of press releases, probably.
- There'll be a total lunar eclipse on December 21, all of it visible throughout north America! The instant of greatest eclipse is at 08:17 UT on December 21 (which will be in the middle of the night after December 20 for us in North America). It'll be visible from South America, Europe, and western Africa, too, but for you the Moon will set before it comes back out of Earth's shadow. Observers in east Asia and Australia will see the Moon rise as it comes out of eclipse. Details here.
- Winter solstice is at 23:38 UT on December 21. I can't wait for the days to stop getting shorter and start getting longer again. It's only 4:30 p.m. here in Los Angeles and the Sun is already setting behind the house across the street.
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