(From west to east)

• Iris is in the constellation of Sagittarius.
• Psyche is in the constellation of Capricornus.
• Isis is at opposition on the 8th in the constellation of Aquarius.
• Juno is at opposition on the 21st in the constellation of Pisces.
• Massalia is at opposition on the 24th in the constellation of Pisces.
• Julia is in the constellation of Andromeda.
• Melpomene is in the constellation of Pisces.
• Vesta is in the constellation of Cancer.

• Information about the Minor Planets can be found at the Minor Planet Observer website.

"Astronomers have identified a storm cell on Titan the size of the country of India. The storm system appeared in April 2008 in the moon's tropical region, an area not known for its cloudiness. Using the Gemini North Telescope and NASA Infrared Telescope Facility on Hawaii's Mauna Kea volcano, a team of astronomers from the University of Hawaii, the Lowell Observatory, and the California Institute of Technology found a significant mass of methane clouds in a cold desert area where no clouds were expected. Large cloud outbursts such as these are thought to be associated with significant amounts of precipitation and probably play a major part in shaping the geological features on the surface of Titan..

The paper, "Storms in the tropics of Titan," appears in the Aug. 13 issue of Nature."

Cassini Imaging Team

"The New Horizons mission team has closed out a successful summer workout, putting its Pluto-bound spacecraft back into hibernation Aug. 27 after seven weeks of functional tests and system checks.

The mission's third annual checkout (ACO-3), which started July 7, "went very well," says Mission System Engineer Chris Hersman, of the Johns Hopkins University Applied Physics Laboratory. "New Horizons is in good shape."

Principal Investigator Alan Stern, of the Southwest Research Institute, says ACO-3 was less "cluttered and complex" than previous ACOs, kept simple to let mission engineers and scientists focus on Pluto-encounter planning. But it was still productive: the team performed functional checkouts of all seven science instruments and every spacecraft subsystem, including the primary and backup hardware in each system; carefully tracked the spacecraft to refine its knowledge of New Horizons trajectory; and uploaded the instructions that will guide New Horizons through hibernation."

New Horizons gallery

"Mission controllers at NASA's Jet Propulsion Laboratory in Pasadena, Calif., have received a transmission from the Dawn spacecraft confirming it has re-ignited its ion propulsion system. For those of you scoring at home, Thruster # 1 received the honors. Over the course of its eight-year mission, first to asteroid Vesta and then off to dwarf planet Ceres, Dawn's three ion engines will accumulate 2,000 days of operation."

"On September 29, the MESSENGER spacecraft will pass by Mercury for the third time, flying 141.7 miles above the planet's rocky surface for a final gravity assist that will enable it to enter orbit about Mercury in 2011. This encounter will also provide new observational opportunities for MESSENGER's Magnetometer, designed to determine the structure and origin of Mercury's intrinsic magnetic field.

The comparison of magnetosphere observations from MESSENGER's first flyby in January 2008 with data from the probe's second pass in October 2008 provided key new insight into the nature of the planet's internal magnetic field and revealed new features of Mercury's magnetosphere, explains Brian Anderson, of the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md.

"MESSENGER's first flyby of Mercury and Mariner 10's encounters with the planet provided data only from Mercury's eastern hemisphere," says Anderson, MESSENGER's Deputy Project Scientist. "The October 2008 flyby provided the first measurements from Mercury's western hemisphere, and scientists learned that the planet's magnetic field is highly symmetric. This finding is significant for the planet's internal field because it implies that the dipole is even more closely aligned with the planet's rotation axis than we could conclude before the second flyby."

The probe's third flyby of Mercury next month will take it again over the planet's western hemisphere, and the observations will be used to refine the estimate of the planetary magnetic field, Anderson explains."

"PASADENA, Calif. - NASA's long-lived Mars Odyssey spacecraft has completed an eight-month adjustment of its orbit, positioning itself to look down at the day side of the planet in mid-afternoon instead of late afternoon.

This change gains sensitivity for infrared mapping of Martian minerals by the orbiter's Thermal Emission Imaging System camera. Orbit design for Odyssey's first seven years of observing Mars used a compromise between what worked best for the infrared mapping and for another onboard instrument.

"The orbiter is now overhead at about 3:45 in the afternoon instead of 5 p.m., so the ground is warmer and there is more thermal energy for the camera's infrared sensors to detect," said Jeffrey Plaut of NASA's Jet Propulsion Laboratory, Pasadena, Calif., project scientist for Mars Odyssey."

"A simulated fly-through using the newly assembled imagery is available online.

The fly-through plus tools for wandering across and zooming into the large image are at THEMIS."

Daily Mars Odyssey THEMIS Images
Can be found at the Thermal Emission Imaging System (THEMIS) website.

The Odyssey data are available through a new online access system established by the Planetary Data System.

SPIRIT UPDATE: Regional Dust Storm - sols 2002-2008, August 20-26, 2009:

"Spirit continues to profile the geology at her embedded location, called "Troy," on the west side of Home Plate. However, the rover is currently affected by a large regional dust storm.

Although orbital observations indicate the storm is abating, the skies over Gusev crater are expected to remaining dusty for several sols. As a result, the rover team has been conservative with Spirit's planning, keeping energy consumption low and maintaining high states of charge in the batteries until the skies clear.

Spirit began the week continuing a long Mössbauer (MB) integration of the surface target "Polyphemus Eye." On Sol 2006 (Aug. 24, 2009), Sprit initiated a set of penetrometer experiments to directly measure physical properties of the embedding soil. The rock abrasion tool (RAT) was pressed into the soil at three different pre-load levels of force. The resulting indentation (soil penetration) after each pre-load was then documented with a set of images. Also on the same sol an atmospheric argon measurement was collected with the alpha particle X-ray spectrometer (APXS), and the MB was placed for another multi-sol integration.

On Earth, testing is being done with two different-weight rovers, the full-weight surface system testbed (SSTB) rover and the near Mars-weight SSTB Lite rover, in two different soil simulants. Testing with both rovers will help determine the effects of different gravity on Earth-based test results, all in preparation for the first extraction moves on Mars.

Atmospheric conditions have deteriorated owing to the large regional dust storm. As of Sol 2007 (Aug. 25, 2009), Spirit's solar-array energy production was precipitously down to 322 watt-hours, with a large increase in the atmospheric opacity (tau) to 2.61. The dust factor declined to 0.658, meaning that about 65.8 percent of the sunlight hitting the solar array penetrates through the dust on the array. Spirit's total odometry remains at 7,729.93 meters (4.80 miles)."

OPPORTUNITY UPDATE: Meteorite Examination Continues - sols 1981-1987, August 20-26, 2009:

"Opportunity is continuing its contact investigation of the 70-centimeter (28-inch) meteorite called "Block Island."

On Sol 1981 (Aug. 20, 2009), the rover performed a very small rotation that moved the robotic arm (instrument deployment device, or IDD) in azimuth to reach new targets on the meteorite. On the next sol, the IDD collected a stack of microscopic imager (MI) images of new targets and then placed the alpha particle X-ray spectrometer (APXS) onto a target.

The IDD changed tools the following sol from the APXS to the Mössbauer (MB) spectrometer and placed it on the target "Siahs Swamp2" for a multi-sol integration. On Sol 1986 (Aug. 25, 2009), the MB was retracted and an ambitious MI imaging campaign, including stereo imaging, was performed on the surface of the meteorite. At the end of that, the MB was replaced for continued integration.

The shroud of the miniature thermal emission spectrometer (Mini-TES) continues to be left open on scheduled sols to allow the environment to clean putative dust contamination from the elevation mirror. No improvement in Mini-TES performance has been observed so far, but the rover has seen no wind events.

As of Sol 1986 (Aug. 25, 2009), Opportunity's solar-array energy production was 453 watt-hours with an atmospheric opacity (tau) of 0.526 and a dust factor of 0.550. The rover's total odometry was 17,229.16 meters (10.71 miles)."

Landing sites

Mars Reconnaissance Orbiter Mission Status Report

"PASADENA, Calif. -- Engineers for NASA's Mars Reconnaissance Orbiter project have stepped up the communication rate being received from the orbiter as an early step in the process of determining why the spacecraft spontaneously rebooted its computer on Aug. 26.

The latest reboot occurred at 5:42 a.m. Pacific Daylight Time (12:42 Universal Time) on Wednesday, Aug. 26.

Data received from the orbiter indicate that this reboot had a different signature from reboots in February and June of this year.

Three new pieces of information are available to guide the investigation. This latest reboot affected some memory locations that had not been affected by the earlier ones. Also, unlike those earlier reboots, this event occurred while the spacecraft was using its backup, "B Side," main computer. In early August, the orbiter unexpectedly switched itself from the "A Side" main computer to the "B Side" computer. And finally, the decreasing intervals between the four safe-mode events this year are also providing clues to the problem."

MARS RECONNAISSANCE ORBITER HIRISE IMAGES
All of the HiRISE images are archived here.