Scientists Turn Rover’s Gaze to Martian Dusk, Moons’ Eclipses

The Mars rover Opportunity shifted its gaze from the microscopic to the celestial -- moving from an examination of grains of soil to a dramatic Martian sunset.

Scientists on Thursday unveiled time-lapse images of the setting sun in a murky Martian dusk. These first sunset images of the mission were captured about two weeks ago by the rover’s panoramic camera.

Calling it an “inspirational moment,” Jim Bell, a Cornell University scientist and leader of the panoramic camera team, said the sky appeared deep blue because of the high concentration of atmospheric dust. The sun appeared as a small, pale sphere in the haze.

Next week, scientists at the Jet Propulsion Laboratory in Pasadena will attempt a Martian first -- recording an eclipse of the Martian moons Phobos and Deimos.

Opportunity and its twin, Spirit, located on the opposite side of the Martian surface, are trying to determine if the planet ever had enough water to give rise to life.

Ray Arvidson, the mission’s deputy principal investigator, expressed cautious optimism that by the end of the rovers’ projected 90-day missions, they will find the answer.

“We will have a lot to say about the role of water -- or not -- at these two sites,” he said.

The rovers have so far collected more than 11,000 images. The panoramic, infrared and microscopic views form a rich data stream -- much of it waiting in the rovers’ memory banks to be downloaded to Earth.

Over the next two or three weeks, Spirit will head to a promising shallow crater dubbed “Bonneville” -- about 50 feet deep and 500 feet across. Scientists expect to examine rocks tossed from the crater when it was formed by an asteroid impact. Such rocks could show signs of ancient water not visible in other surface features.

Spirit, which landed on Mars Jan. 4, will take detailed images from the lip of the crater to help assess the risk and rewards of entering the site. If the trip is deemed too risky, the rover “may turn to the southeast and head for the hills,” Arvidson said, referring to a set of hills about two miles away.

From its position on Meridiani Planum, Opportunity this week has been examining a finely layered rock outcropping named “El Capitan” in an effort to determine how it was formed -- by volcanic activity, water flow or other geological processes. It will soon move out of the small crater where it landed Jan. 24.

Jennifer Trosper, a mission project manager, described the health of both craft as “fantastic.”

A heater switch stuck in the “on” position has been draining Opportunity’s batteries, but not seriously, Trosper said. In about a month engineers plan to upload a software fix for the problem.