Emily Lakdawalla • Oct 27, 2010
What's up in the solar system in November 2010
I'm getting to this update early this month, as I anticipate a busy few days. The major event of the month will be, of course, Deep Impact's flyby of small comet Hartley 2, which happens at 13:50 UTC on November 4. But there's some other things to take note of: Cassini has a very, very close flyby of Enceladus' north pole (not the pole with the plumes, the other one) on November 30. Also China's Chang'E 2 is, as I write, orbiting even closer to the Moon than that, passing just 15 kilometers over Sinus Iridum. November is also the most likely month for the reestablishment of contact with the long-silent Mars Exploration Rover Spirit -- keep your fingers crossed. Here's Olaf Frohn's map of where everybody is on November 1. Compare it to last month's diagram to see how things have moved.
In the inner solar system:
NASA's MESSENGER spacecraft is cruising along, with only 141 days remaining until Mercury orbit insertion (which is planned for March 18, 2011). Check their gallery for their latest image releases; my favorite recent one shows Derain, a crater with an odd dark splash of ejecta.
ESA's Venus Express is still orbiting our sister planet, under an extended mission proposed to last through 2012. They posted a story about the results of their atmospheric drag experiments last month.
JAXA's Akatsuki is en route to join Venus Express at the second planet. It is planned to arrive at Venus on December 7 -- in 41 days! They recently posted some deep-space calibration images taken on October 8 by two of their cameras of the constellation Sagittarius. They actually commanded all four cameras to take photos, but no details were expected to show up in the longer wavelengths, and indeed there were no stars in the longwave camera images.
JAXA's IKAROS, too, is flying toward Venus, and according to this kawaii animation, it will pass Venus (without entering orbit) on December 18. I am not sure what, if anything, the spacecraft will be able to do to mark this event. The IKAROS Blog is still updated almost daily, and talks about changing the spin rate, experimenting with acceleration, and the communications bit rate dropping as the sail travels farther and farther from Earth.
China's Chang'E 2 lunar orbiter has been extremely busy this month, of course; it successfully entered orbit on October 1. On October 9, it achieved its target orbit 100 kilometers above the surface. Just this morning, I got an email from Yong-Chun Zheng of the NAOC stating that Chang'E 2 has successfully lowered its perilune to an incredible 15 kilometers above the lunar surface. Just imagine!! That's not much higher than aircraft cruising altitude on Earth. The closest approach is above Sinus Iridum, the "Bay of Rainbows," which is the location that they have chosen for their Chang'E 3 soft lander; Chang'E 2 is taking high-resolution photos of the site for reconnaissance. I know Chang'E 2 carries some kind of hard lander or probe -- I wonder if they will try to drop it off from this orbit? (That's just my speculation.) Zheng's message said that once Chang'E 2 has completed the photo reconnaissance of Sinus Iridum, it will return to its 100-by-100-kilometer science orbit and will have a science mission lasting six months.
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; one recent feature is, in fact, on Sinus Iridum, Chang'E 2's current photographic target. At the bottom of that feature, Mark Robinson promises that "this winter a global 100 meter digital elevation model will be released," based on DLR's processing of the wide-angle camera data set.
On to Mars:
Out at Mars, it's late winter in the southern hemisphere, (it's currently Ls 171.1°), which means that the rovers' nights, though long, are getting shorter every sol. Today it is Mars Exploration Rover Spirit sol 2423 and Opportunity sol 2403. Spirit has still not been heard from since sol 2210 (March 22). This month is, as far as I understand it, the one with the most hope for reestablishing contact. Opportunity is, as usual, driving for two; she's really been burning rubber this month, driving something like 800 meters in October alone, averaging about 100 meters per driving sol. That's got to be a speed record. She's now 2 kilometers from the crater called Santa Maria, and a little more than 8 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 nice HRSC view of Melas Chasma (a very big part of the Valles Marineris canyon system) last month. As with last month, Mars Webcam has not been given a lot of data volume recently but the few postings that there have been are really fine high-phase (crescent) views of Mars covering the northern polar cap.
NASA's Mars Reconnaissance Orbiter The latest MARCI weather report speaks of widespread dust activity, including, worryingly, over Spirit's site. Opportunity's location remains relatively clear. As always, check in on the latest captioned image releases from HiRISE for your dose of spectacular photos from Mars. Here's some nifty dark dunes on brighter soils.
NASA's Mars Odyssey remains the longest-lived spacecraft in orbit at Mars. You can see the latest from its THEMIS instrument here. I liked this view of a crater's central peak.
The NASA-ESA-ASI Cassini mission will reach apoapsis on October 428 to begin Rev 140, a low-inclination (3°) orbit with a 24-day period. There's no Looking Ahead article covering this period yet. My Cassini tour page indicates that Cassini doesn't have very many close encounters with moons this month, and even the targeted Titan flyby on November 11 is a relatively distant one at about 8,000 kilometers. That flyby will tighten Cassini's orbit and raise its inclination to coincide with the ring plane. The month will end with Cassini passing through periapsis on Rev 141 just before a ridiculously close encounter with Enceladus (at an altitude of 48 kilometers). Unlike most recent flybys of Enceladus, the closest approach on this one -- and a nearly identical one that will happen on the next orbit, in December -- are very near the north pole instead of the south pole. As I mentioned in my previous post, Space Calendar:
- The Space Shuttle Discovery's last launch is scheduled for November 1, and Mat Kaplan is going to be there to watch!
- In the U.S., Daylight Saving Time ends on Sunday, November 7 at 02:00 local time. I will be in a bad mood for the ensuing several months because it will be getting dark so early in the day. Stupid Los Angeles thinks it's too cool to be in the Mountain time zone, which is where it should be, longitudinally speaking.
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