(From west to east)

• Vesta is in the constellation of Pisces.
• Metis is in the constellation of Cetus.
• Harmonia is in the constellation of Gemini.
• Euterpe is in the constellation of Leo.
• Information about the Minor Planets can be found at the Minor Planet Observer website.

"Scientists continue to search for the cause of the geysers on Saturn's moon Enceladus. The geysers are visible as a large plume of water vapor and ice particles escaping the moon. Inside the plume are jets of dust and gas. What causes and controls the jets is a mystery. The Cassini spacecraft continues to collect new data to look for clues.

At the heart of the search is the question of whether the jets originate from an underground source of liquid water. Some theories offer models where the jets could be caused by mechanisms that do not require liquid water. Painstaking detective work by Cassini scientists is testing the possibilities to get closer to an answer.

What generates Enceladus' jets is a burning question in planetary science, because if liquid water is involved, Enceladus would be shown to have everything it needs, in theory, to provide a habitable environment."

Cassini Imaging Team

"The New Horizons spacecraft has a new 'audience' for the electronic signals it beams back to Earth.

In a successful September demonstration of its growing capabilities, the Allen Telescope Array (ATA) detected transmissions from New Horizons while the spacecraft was more than a billion miles from home. The ATA is a radio interferometer used for astronomical research and searches for signals of intelligent, extraterrestrial origin. A joint effort of the SETI Institute and the Radio Astronomy Laboratory at the University of California, Berkeley, it's being constructed at the Hat Creek Radio Observatory in Northern California.

The SETI Institute routinely observes spacecraft such as New Horizons, which serve as an excellent test signal for confirming the correct functioning and effectiveness of the SETI signal-detection systems."

New Horizons gallery."

"NASA's Dawn spacecraft shut down its ion propulsion system today as scheduled. The spacecraft is now gliding toward a Mars flyby in February of next year.

"Dawn has completed the thrusting it needs to use Mars for a gravity assist to help get us to Vesta," said Marc Rayman, Dawn's chief engineer, of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Dawn will now coast in its orbit around the sun for the next half a year before we again fire up the ion propulsion system to continue our journey to the asteroid belt."

Dawn's ion engines may get a short workout next January to provide any final orbital adjustments prior to its encounter with the Red Planet. Ions are also scheduled to fly out of the propulsion system during some systems testing in spring. But mostly, Dawn's three ion engines will remain silent until June, when they will again speed Dawn toward its first appointment, with asteroid Vesta."

"The International Astronomical Union (IAU) recently approved a proposal from the MESSENGER Science Team to name 15 craters on Mercury. All of the newly named craters were imaged during the missionÕs first flyby of the solar systemÕs innermost planet in January 2008.

The IAU has been the arbiter of planetary and satellite nomenclature since its inception in 1919. In keeping with the established naming theme for craters on Mercury, all of the craters are named after famous deceased artists, musicians, or authors.

'We're pleased that the IAU has again acted promptly to approve this new set of names for prominent craters on Mercury,' says MESSENGER Principal Investigator Sean Solomon of the Carnegie Institution of Washington. 'These latest names honor a diverse suite of some of the most accomplished contributors to mankindÕs higher aspirations. They also make it much easier for planetary scientists to refer to major features on Mercury in talks and publications.'"

"An international team of scientists who analyzed data from the Gamma Ray Spectrometer onboard NASA's Mars Odyssey reports new evidence for the controversial idea that oceans once covered about a third of ancient Mars.

"We compared Gamma Ray Spectrometer data on potassium, thorium and iron above and below a shoreline believed to mark an ancient ocean that covered a third of Mars' surface, and an inner shoreline believed to mark a younger, smaller ocean," said University of Arizona planetary geologist James M. Dohm, who led the international investigation.

"Our investigation posed the question, Might we see a greater concentration of these elements within the ancient shorelines because water and rock containing the elements moved from the highlands to the lowlands, where they eventually ponded as large water bodies?" Dohm said."

"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."

Mars Odyssey THEMIS Images
Thermal Emission Imaging System (THEMIS) website: http://themis.asu.edu/

November 3-7, 2008

The following new images from the Mars Odyssey spacecraft are now available:

• Dunes and Channel (Released 03 November 2008)
  
• Crater Dunes (Released 04 November 2008)
  
• Crater Dunes (Released 05 November 2008)
  
• Delta (Released 06 November 2008)
  
• Dust Devil Tracks (Released 07 November 2008)
  
• All of the THEMIS images are archived here.

The Odyssey data are available through a new online access system established by the Planetary Data System at: http://starbrite.jpl.nasa.gov/pds/"

Spirit Status: Spirit Status: Serious but Stable - sol 1730-1736, November 14 - November 20, 2008

"Spirit's condition has improved during the past week, though skies remain fairly dusty after the recent Martian dust storm. Since sol 1730 (Nov. 14, 2008), solar-array energy has averaged 169 watt-hours (100 watt-hours is the amount of energy needed to light a 100-watt bulb for 1 hour). The latest measurement of atmospheric darkness caused by dust, known as Tau, is 0.858. The dust factor, representing the portion of sunlight penetrating the coating of dust on the solar panels, is 0.2912.

Spirit performed a cursory check of the health of the miniature thermal emission spectrometer. After three nights with the spectrometer's heaters disabled, the instrument appeared to be undamaged as of sol 1730. Power is not yet sufficient to re-enable those heaters, though Spirit will continue to monitor the spectrometer while waiting for power to improve. For the most part, Spirit is limiting activities to those necessary for maintaining engineering health and safety.

Spirit endured another challenge when new commands from Earth for sol 1734 (Nov. 18, 2008) did not arrive. At that point, Spirit began to execute a backup set of activities known as a runout plan. On Earth, engineers created a new sequence of commands for sol 1736 (Nov. 20, 2008) to manage communications and preserve power. Meanwhile, they are investigating why Spirit did not receive their previous commands.

According to the latest Martian weather report for Nov. 15 (sol 1731), skies are expected to continue to clear during the next couple of weeks. No other storms have been identified within a couple of thousand kilometers of Spirit's location.

Spirit is preparing for solar conjunction, where the Sun is between Earth and Mars, preventing communications. This period begins Nov. 29th. Before and during solar conjunction, Spirit's activities will remain conservative as the rover waits for the skies to clear and for the power situation to improve."

Opportunity Status: Opportunity Prepares for Two Weeks of Independent Study - sol 1709-1715, November 13-19, 2008

"Opportunity is getting ready for solar conjunction, the time when the Sun is in the line of sight between Earth and Mars. During this two-week period, from Nov. 30, 2008 to Dec. 13, 2008, the mission team will not send new commands to the rover. The science team plans to position Opportunity on a rock outcrop, possibly near a cobble the rover can study with the Moessbauer spectrometer, during this time interval.

Opportunity began the week with a 93-meter (310-foot) drive on Sol 1709 (Nov. 13, 2008). The drive allowed the rover to reach a large expanse of bare outcrop. Another drive on Sol 1710 (Nov. 14, 2008), covering 17 meters (56 feet), placed the rover near potential targets of scientific interest. A candidate target, a cobble about 8 meters (30 feet) away, became the objective of the drive on Sol 1713 (Nov. 17, 2008). The 8-meter drive positioned the cobble, now nicknamed "Santorini", within the work volume of the science instruments on Opportunity's robotic arm.

The challenge for the team was the placement of the science instruments on Santorini using only 4 degrees of freedom of the robotic arm instead of the usual 6. The rover is not able to change the azimuth of the shoulder joint, that is, move it from side to side, because the shoulder azimuth joint (Joint 1) is disabled due to degraded performance.

On Sol 1714 (Nov. 18, 2008), Opportunity successfully placed the Moessbauer spectrometer on a faceted surface of the cobble. The contact switches on the instrument confirmed that the spectrometer had touched the surface. An analysis by the spectrometer is now under way. Rover operators plan to have Opportunity integrate Moessbauer measurements of Santorini for the two-week period of solar conjunction.

Opportunity is acquiring a panorama of images using multiple filters of the panoramic camera and making daily observations of atmospheric dust as well as measuring atmospheric argon using the alpha-particle X-ray spectrometer APXS. The rover is creating occasional, time-lapse movies of clouds with the navigation camera.

This coming weekend, engineers plan another attempt to remove dust from the miniature thermal emission spectrometer mirror by shaking it.

As of Sol 1715 (Nov. 19, 2008), the solar array energy was 565 watt-hours (100 watt-hours is the amount of energy needed to light a 100-watt bulb for one hour). The atmospheric opacity (tau) was 0.747 and the dust factor (a measure of sunlight-blocking dust on the solar arrays) was 0.694."

Landing sites