Mars

Mars Odyssey celebrated its 15th launch anniversary in April; its 15th arrival anniversary is coming up on October 24. I wrote a blog post about their new morning imaging with THEMIS last month; you can see the results of those morning images on the THEMIS website.

There was little news from Mars Express this month. The Mars Webcam has been active, with the most recent images dating to April 28.

Mars Reconnaissance Orbiter has been quiet, too. The latest weather report from MARCI includes "local dust storms observed across many regions of the southern hemisphere" and "At low latitudes, diffuse water-ice clouds associated with the aphelion cloud-belt persisted through each afternoon." Don't forget to check the HiRISE website regularly for image updates. I have a lot of favorites this month, including a dramatically lit view of some gullies, and the awesome faulted layers in the walls of some collapse pits.

I just realized that I've been neglecting to include Mars Orbiter Mission in these updates. Unfortunately, I don't have any information on its recent status. A news release from the mission yesterday concerned a paper that was released in March, and the official Twitter and Facebook pages have been quiet since December. I hope someday to see public release of archival data from its color camera!

MAVEN performed an orbital trim maneuver on April 10, the first in 77 days. Its periapsis was raised to 164.5 kilometers -- still much lower than the circular orbits of the other NASA orbiters. At that altitude, Mars' atmopheric density is 70 grams per cubic kilometer, which is pretty sparse, but enough for a spacecraft's orbit to slowly decay. MAVEN's next two deep-dip campaigns are planned for early June and late July of this year.

In the first half of April, Opportunity's science and engineering teams conducted a "mini walkabout" of Marathon valley, looking for sites for in-situ investigation. It's now investigating the first of those sites, "Pierre Pinaut," but has been slowed down a bit by a couple of anomalies with the Microscopic Imager. Things seem to be okay, though, and the power situation is very good, with more than 600 watt-hours being generated all month. The latest atmospheric opacity number is heading upward, though, which I hope is not a warning of dustier skies in May. Check out these and other updates at the Opportunity website.

On the other side of Mars, Curiosity has still not quite crossed the Naukluft Plateau because the team decided to drill into a silica-rich halo in the Stimson rock unit at a site called Lubango before they finished the crossing. Curiosity drilled its 10th hole on Mars last week, and has just driven to a new site named Ovitoto to sample some Stimson rock outside a halo. Once they complete the next drill hole, they should be back on the road.

Beyond Mars

Rosetta's science is getting better all the time as it continues to watch comet Churyumov-Gerasimenko change. Last month, the mission released some maps showing how the color of the comet changed between August and November of 2014. No previous mission has orbited a comet, and no previous comet has been seen by a spacecraft more than twice, so Rosetta's long-term survey is going to be scientifically revolutionary. Meanwhile, the formal release of Navcam images has slowly but steadily been catching up with the present, and the latest Navcam image releases were taken only 6 weeks ago. That's pretty extraordinary. The Rosetta mission will come to an end in only 5 months, at the end of September.

Dawn is now orbiting Ceres at the lowest altitude it'll ever achieve: an average 385 kilometers. Last month, principal investigator Chris Russell told reporter Govert Schilling that the mission was considering targets beyond Ceres for an extended mission, surprising many (by which I mean to say, this was a huge surprise to me). The latest Dawn Journal reports that Dawn's remaining two reaction wheels continue to work fine and that the mission has done a good job husbanding hydrazine, but the remaining fuel is still expected to last only partway through 2017 even if the reaction wheels stay 100% healthy. Check the Photojournal for the latest images! Here's a lovely photo mosaic of Haulani crater: