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Cassini's Closest Visit of Iapetus

Friday, September 7, 2007

Cassini image
On New Year's Eve 2004, Cassini flew past Saturn's intriguing moon Iapetus, capturing the four visible light images that were put together to form this global view.
Credit: NASA/JPL/Space Science Institute
On Sept. 10, the Cassini spacecraft performs its closest flyby during the entire mission of the odd moon Iapetus, passing by about 1,640 kilometers (1,000 miles). Iapetus is a world of sharp contrasts. The leading hemisphere is as dark as a freshly-tarred street, and the white, trailing hemisphere resembles freshly-fallen snow. Scientists want to know more about the composition of the dark material that coats Iapetus. They also want to learn more about Iapetus' distinctive walnut shape and the chain of mountains along its equator.

More: NASA Cassini-Huygens Iapetus Flyby

More: NASA - Encountering Iapetus (image right)

HiRISE Camera Returns New View of Dark Pit on Mars

Friday, September 7, 2007

dark  pit on mars
HiRISE image of a dark pit seen on Mars. The pit is a vertical shaft that cuts through lava flow on the flank of the Arsia Mons volcano.
Credit: NASA/JPL-Caltech/University of Arizona

The High Resolution Imaging Experiment (HiRISE) has confirmed that a dark pit seen on Mars in an earlier HiRISE image really is a vertical shaft that cuts through lava flow on the flank of the Arsia Mons volcano. Such pits form on similar volcanoes in Hawaii and are called "pit craters."

More: NASA - Dark Pit on Mars' Arsia Mons, with Sunlit Wall

More: UA News - HiRISE Camera Returns New View of Dark Pit on Mars

More: LPL - HiRISE access images, news, and and instrument information

Mars Rovers Survive Dust Storms, Ready for Next Objectives

Friday, September 7, 2007

Two months after sky-darkening dust from severe storms nearly killed NASA's Mars exploration rovers, the solar powered robots are awake and ready to continue their mission. Opportunity's planned descent into the giant Victoria Crater was delayed, but now the rover is preparing to drive into the 800-meter-diameter crater (half-mile-diameter) as early as Sept. 11. Victoria Crater contains an exposed layer of bright rocks that may preserve evidence of interaction between the Martian atmosphere and surface from millions of years ago, when the atmosphere might have been different from today's. Victoria is the biggest crater Opportunity has visited.

Spirit, Opportunity's rover twin, also survived the global dust storms. The rovers are 43 months into missions originally planned to last three months. On Sept. 5, Spirit climbed onto its long-term destination called Home Plate, a plateau of layered bedrock bearing clues to an explosive mixture of lava and water.

More: NASA - Mars Rovers Survive Dust Storms, Ready for Next Objectives

More: NASA Podcast - Opportunity knocks -- on a Martian crater