Time again for my monthly look at what's going on with the robots exploring the solar system! It'll be a busy month for Cassini, with lots of cool icy moon observations: it'll spend several days looking at Iapetus, and will pass very close to Helene mid-month before doing some RADAR work on a Titan flyby. Opportunity just seems to get faster every month -- if she keeps up her pace, she'll be at the rim of Endeavour crater by the end of the summer. And Dawn is still getting closer to Vesta, though I have to say that my enthusiasm for its approach to this new world has cooled a bit since they haven't released any images since their first view of Vesta early last month.
Before I go into mission-by-mission detail, here's Olaf Frohn's marvelous map of where all of our explorers are on June 1. There are two major changes to this map since last month's: Spirit is now "grayed out," and it'll be the last time her name appears; and OSIRIS-REx has been added to the list of future launches.
Solar system exploration missions in June 2011
Solar system exploration missions in June 2011, by Olaf Frohn
Exploring the inner solar system:
NASA's MESSENGER spacecraft is well into its primary science phase. Watch their gallery for regular image releases. They're also doing weekly Web articles detailing the spacecraft's plans. The most recent one is the first I've seen that has an update on what's been accomplished so far in the science mission; there's a map showing the current state of coverage of Mercury's surface with laser altimeter tracks..
ESA's Venus Express remains in orbit on a mission that has been extended through 2014.
Out at Mars, it's high summer in the southern hemisphere; we're in the period of the longest sunlit days of the year, with the welcome boost to solar power that that brings. (It's currently Ls 302.6°.) This is, sadly, the last time I will mention Mars Exploration Rover Spirit in this "What's up" update; she was last heard from well over a year ago, on sol 2210 or March 22, 2010, and NASA has now given up on her phoning home again. Today it is Opportunity sol 2613. Opportunity started the month exploring a small cluster of craters (Sigma 7, Friendship 7, Faith 7, and Freedom 7) and has been making incredibly fast progress toward Endeavour crater, probably a kilometer and a half in the last month alone. Her odometer is just about to turn past the 30-kilometer mark. Here is Eduardo Tesheiner's latest route map and Google Earth kml file for Opportunity.
NASA's Mars Odyssey is now the longest-lived spacecraft ever to operate at Mars. You can see the latest from its THEMIS instrument here. Here's a cool one of a layering within Terby crater.
In the Asteroid Belt:
NASA's Dawn spacecraft is steadily approaching Vesta and will be captured into orbit on July 16. It's now fewer than 600,000 kilometers from Vesta and closing fast. According to the weekly mission status updates, they've been taking images regularly, but they've only released one image so far -- I would sure love to see a few more. Come on, Dawn team, show us Vesta!.
The NASA-ESA-ASI Cassini mission is just wrapping up Rev 148 and will spend most of June in its Rev 149. It'll be yet another orbit within the ring plane, but unlike the last several such, this one will feature lots of observations of moons other than Titan, as explained in the Rev 149 Looking Ahead article. On June 7 and 8 Cassini will approach to within 900,000 kilometers of Iapetus, which doesn't sound very close, but since Iapetus is among the largest of Saturn's moons it'll result in some of the best images of that moon that we've seen in a while. On June 16, there'll be a nice mutual event of Rhea crossing Titan. Just before periapsis on June 18, Cassini will pass within 7,000 kilometers of Helene, gathering observations that should "finish off" Cassini's global map of the co-orbital moon. On June 20 there's a targeted Titan flyby, which belongs mostly to the RADAR team for scatterometry, altimetry, and SAR imaging. Over the last few months the apoapsis of Cassini's orbit has been shifted so that it is closer to the Saturn-Sun line, so Cassini's views of Saturn have lower and lower phase (Saturn looks fuller and fuller). To see what Cassini's doing when, check out my long and detailed page on Cassini's tour of the Saturn sytem.
Cruising from here to there:
NASA's New Horizons has 12.08 AU to go to reach Pluto. It's on course for a January to July 2015 encounter with the Pluto and Charon system. There are 1504 days left until Pluto closest approach.
Deep Impact is in solar orbit, awaiting further instructions for a possible second mission extension.
JAXA's Akatsuki is now in solar orbit, on its long cruise to a second encounter with Venus in December 2016.
JAXA's IKAROS flew past Venus in December and has been operating successfully since May 21, 2010, really an amazing accomplishment for such a small, experimental craft. Follow the IKAROS blog to keep up with its relatively infrequent contacts with Earth; the last one was today.
ESA's Rosetta is now on the final, long leg of its cruise to its target comet. After going through solar conjunction in May and June, it will 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.