(From west to east)

• Iris is in the constellation of Corvus.
• Daphne is in the constellation of Virgo.
• Information about the Minor Planets can be found at the Minor Planet Observer website.

"PASADENA, Calif. -- NASA is extending the international Cassini-Huygens mission by two years. The historic spacecraft's stunning discoveries and images have revolutionized our knowledge of Saturn and its moons.

Cassini's mission originally had been scheduled to end in July 2008. The newly-announced two-year extension will include 60 additional orbits of Saturn and more flybys of its exotic moons. These will include 26 flybys of Titan, seven of Enceladus, and one each of Dione, Rhea and Helene. The extension also includes studies of Saturn's rings, its complex magnetosphere, and the planet itself."

Cassini Imaging Team

"A year ago, New Horizons was flying through the heart of the Jupiter system, gradually picking up speed and systematically gathering spectacular data on the solar systemÕs largest planet and its closest moons. The results of that spectacular flyby have since been featured on thousands of electronic and printed pages, including a special issue of the journal Science in October 2007.

New Horizons scientists recently took a new look at one of the more memorable images from the Jupiter collection: that of the erupting volcano Tvashtar on the moon Io. Taken through two of the four filters in the sensitive Multispectral Visible Imaging Camera, the picture shows the reddish colors of the plume deposits surrounding the base of the volcano - a view we hadnÕt seen in earlier pictures. Check it out in the New Horizons gallery."

"NASA's Dawn spacecraft has successfully completed the initial checkout phase of the mission and begun its interplanetary cruise phase, which is highlighted by nearly continuous thrusting of its ion propulsion system. Dawn is on a 8-year, 3-billion mile journey to asteroid Vesta and dwarf planet Ceres."

"The International Astronomical Union (IAU) has approved new names for features on Mercury and agreed on a new theme for fossae on the planet. These newly christened features were discovered from images taken by the MESSENGER spacecraft during its first flyby of Mercury in January.

The IAU is the internationally recognized authority for assigning designations to surface features on celestial bodies. "We are very pleased with how quickly the IAU has responded to the need to name many of the prominent landforms on Mercury first seen in MESSENGER images," says MESSENGER Principal Investigator Sean Solomon of the Carnegie Institution of Washington. 'The Science Team has just submitted our first scientific papers on the flyby observations, and this prompt action by the IAU has meant that we are able to refer to these features by their formal names.'"

"PASADENA, Calif. - NASA's Mars Odyssey orbiter has found evidence of salt deposits. These deposits point to places where water once was abundant and where evidence might exist of possible Martian life from the Red Planet's past.

A team led by Mikki Osterloo of the University of Hawaii, Honolulu, found approximately 200 places on southern Mars that show spectral characteristics consistent with chloride minerals. Chloride is part of many types of salt, such as sodium chloride or table salt. The sites range from about a square kilometer (0.4 square mile) to 25 times that size."

"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 http://themis.asu.edu."

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

April 21-25, 2008

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

• Coprates Chasma (Released 21 April 2008)
  
• Elysium Fossae (Released 22 April 2008)
  
• Aeolis Landslides (Released 23 April 2008)
  
• Rim Channels (Released 24 April 2008)
  
• Montevallo Crater (Released 25 April 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 Still "Sitting Pretty" for This Time of Year - sol 1517-1524, April 09-16, 2008

"Despite a slight increase in atmospheric opacity caused by dust, Spirit is still enjoying higher-than-expected energy levels for this time of year. Solar array input has been approximately 240 watt-hours per Martian day, or sol (100 watt-hours is the amount of energy needed to light a 100-watt bulb for one hour).

Clear skies have had the unfavorable effect, however, of causing a drop in temperatures at the surface of Mars, increasing the bitter cold experienced by Spirit's rover electronics module. Nighttime temperatures are creeping closer to the point where they will trigger the survival heaters, which draw a large amount of power. A much more desirable strategy is to keep Spirit awake long enough each day to keep the electronics module sufficiently warm with heat from normal operations, providing more time for science observations. "Awake time" vs. heating time is just one of the many trade-offs the team makes each day to keep Spirit going through the Martian winter."

Opportunity Status: Opportunity Reverses Path - sol 1498-1504, April 10-17, 2008

"During the past week, Opportunity celebrated another major milestone by reaching 1,500 sols (Martian days) of continuous exploration of the red planet!

Meanwhile, Opportunity continued to execute a "toe dip" stategy of driving forward a short distance and backing up again to characterize the sandy terrain beneath the rover's wheels. While driving toward the promontory known as "Cape Verde" in the rim of "Victoria Crater," Opportunity experienced wheel slippage of more than 90 percent. The rover also experienced high tilt during the backward part of the drive. Following a series of adjustments to both slippage and tilt limits, Opportunity's front wheels had begun to dig into the terrain. At that point, the rover's handlers decided to concentrate on driving backward to extract the rover's front wheels and prevent them from digging further into the sand. Making slow and steady progress, as of sol 1502 (April 15, 2008), Opportunity had driven backward 24 centimeters (9.5 inches) with no errors, giving rover drivers hope that the rover would soon be out of the sand.

Opportunity's handlers implemented a "Stow/Go/Unstow" strategy of unstowing the robotic arm after each day's drive to avoid having the arm in the stow position during thermal cycling (overnight temperature changes). This freed the arm for full use of its scientific tools in the event of a cold-induced motor failure. On sol 1502 (April 15, 2008), while attempting to unstow the arm, Opportunity experienced a stall in the joint that controls shoulder position. The nature of the stall appeared to be different from previous stalls in the same joint (known as Joint 1). On sol 1504 (April 17, 2008), the rover's handlers directed Opportunity to run a diagnostic test of movement in the robotic arm. While moving the joint, Opportunity experienced another stall. Investigation of this anomaly is expected to continue for the remainder of this week.

Opportunity is healthy and all subsystems are performing as expected, with the exception of the investigation of the robotic arm. Immediate plans call for continued focus on getting out of the sand and resolving the robotic-arm anomaly."

Landing sites