What's up in the Solar System in August 2012

Welcome to the monthly roundup of our Solar System's envoy of electronic explorers!

All human eyes are focused on the Mars Science Laboratory Curiosity as it completes its eight-month journey to Mars this Monday. In a span of ten minutes, the rover will discard its cruise stage, plunge through the planet's atmosphere, deploy a supersonic parachute, discard its heat shield, separate from its backshell, and be lowered by a rocket-powered Sky Crane onto the Martian soil.

If all goes well, landing at Gale crater should occur August 6th at 5:31 UTC; that's August 6th 1:31AM EDT / August 5th 10:31PM PDT here in the United States. To read dozens of past articles on the subject, you can browse the Curiosity-MSL keyword on The Planetary Society's website. If you're near Pasadena, we hope you'll come out to Planetfest and watch the drama unfold with us!

Good luck, Curiosity! On to the rest of the Solar System.

The inner planets:

NASA's MESSENGER spacecraft has been in orbit around Mercury more than 500 days, circling our innermost planet over 1,000 times. On July 23, the MESSENGER team released an awesome collection of images featuring some of the most exciting pictures taken by the spacecraft to date. The image gallery also continues to be updated regularly with lots of great pictures.

ESA's Venus Express orbiter continues to circle Venus, Earth's cloudy neighbor. No new mission status updates have been recently posted.

Ebb and Flow, the twin spacecraft of NASA's GRAIL mission, are temporarily powered off before they begin their extended science operations on August 30. Make sure you check out some of the MoonKAM's greatest hits, including a neat picture of the Earth rising over the far side of the lunar surface.

NASA's ARTEMIS spacecraft are presumably still orbiting the Moon. They were sent into lunar orbit in 2011 to study the Moon's magnetic field, and should last for at least seven years.

China's Chang'E 2 spacecraft left the Sun-Earth L2 point sometime in April for asteroid 4176 Toutatis. China also recently announced that Chang'E 3 will launch in 2013, and include a rover.

NASA's Lunar Reconnaissance Orbiter continues to collect high-resolution imagery of the lunar surface. At the LRO Camera website, there is a new 'featured images' section with collections of Apollo landing site images. The LROC team also posted a brief article confirming that the American flag at the Apollo 11 landing site seems to be missing, validating Buzz Aldrin's observation that it was blown over by exhaust from the lunar lander's ascent engine.

Out at Mars:

NASA's Mars Exploration Rover Opportunity worked right through her 3000th Sol on Mars prior to roving on to new targets near the rim of Endeavour Crater. She's now sitting tight at a spot called Whim Creek, performing some light science while her Deep Space Network time is temporarily donated to her approaching sibling, Curiosity. Check out the latest MER Update by Salley Rayl for more information on the intrepid rover.

ESA's Mars Express will assist with the tracking of Curiosity on August 6. The orbiter will listen for the UHF carrier signal from Curiosity, extrapolating the position of the descending spacecraft from apparent changes in the frequency. Mars Express also played an important role in helping to refine the landing ellipse for Curiosity. Check out this 3D image of Gale Crater created with data from the High Resolution Stereo Camera.

Also lending support to Curiosity will be NASA's Mars Reconnaissance Orbiter, which will attempt to use its HiRISE camera to capture imagery of the rover descending toward the surface. During a recent presentation, the University of Arizona's Shane Byrne estimated a 66% chance that HiRISE would successfully snap a picture of Curiosity before it makes it to the surface. In non-Curiosity news, the HiRISE camera continues to deliver daily jaw-dropping imagery of Mars' surface.

The most critical member of Curiosity's orbital support group will be NASA's Mars Odyssey spacecraft. After suffering a breakdown in one of its three main reaction wheels on June 8, engineers switched to a spare. Then, on July 11, the aging spacecraft entered 'safe mode' after making a minor orbital adjustment. Subsequent analysis determined the orbiter could resume normal operation, and on July 24, a six-second thruster burn put the spacecraft in position to relay information about Curiosity's descent in near real-time.

In the Asteroid Belt:

NASA's Dawn spacecraft is beginning its long, slow goodbye with asteroid Vesta. The spacecraft fired its ion thrusters on July 25 to begin raising its orbit, and it will overcome Vesta's gravitational pull on August 26, beginning its journey to dwarf planet Ceres. Dawn collected over 4,700 images of Vesta during High-Altitude Mapping Orbit 2. A recent set released in July explain how Dawn's framing camera is able to illuminate shadowed areas of Vesta’s surface.

Mighty Saturn:

The NASA-ESA-ASI Cassini Saturn orbiter is currently on Rev 170, which lasts through August 23. This mission phase will provide some great polar views of Saturn and Titan, as well as more rings shots. The month will have a meteorological theme, as Cassini looks for Saturnian storms with its wide-angle camera early in the month and tracks clouds with its Composite Infrared Spectrometer (CIRS) later in August. It also looks like we'll be treated to some color photos of Mimas; look for those to pop up in the raw images section with everything else.

Cruising along:

NASA's New Horizons spacecraft has moved 0.26 AU closer to Pluto since the last Solar System update, with 8.59 AU to go. Closest approach to the Pluto system occurs in 2015, and the Hubble Space Telescope recently discovered that New Horizons will have a fifth moon to observe when it arrives! If you'd like to help in the selection of New Horizons' Kuiper belt target, head over to Cosmoquest's Ice Investigators website.

NASA's Juno spacecraft continues to head outbound from the Sun, crossing far beyond Mars' orbit before heading sunward again. An Earth flyby in August 2013 will send it on to its July 2016 Jupiter arrival.

NASA's Deep Impact is in solar orbit, awaiting further instructions for a possible second mission extension. The spacecraft may attempt a flyby of near-Earth object 163249 (2002 GT) in January 2020.

JAXA's Akatsuki is now in solar orbit, on its long cruise to attempt a second Venusian orbital insertion in November 2015.

JAXA's IKAROS has still not been heard from since December 24, 2011. A July 26 IKAROS blog entry says the most recent communication attempt failed, but the space agency intends to keep trying.

ESA's Rosetta is now on the final, long leg of its cruise to its target comet. It's been placed into hibernation and will not communicate with Earth again until 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 comes home, ICE can be returned to a Sun-Earth L1 halo orbit, or can use multiple Earth swing-bys to encounter Comet Wirtanen during its near-Earth apparition in December 2018.

Finally, NASA's Voyager 1 and 2 spacecraft are still going strong. Follow the current position of both using the NASAVoyager2 twitter feed (this is not an official NASA account, but it's the one with the most information). Voyager 1 saw a five-percent jump in cosmic rays originating from outside the Solar System on July 28, but levels have since returned to normal. Scientists are now analyzing magnetic field data to look for additional signs that the spacecraft is approaching interstellar space.