No Word Yet From Phoenix; Spirit’s Days May be Numbered

by Nancy Atkinson on January 21, 2010

A look at the nearly buried wheels on the Spirit rover on Mars. Credit: NASA/JPL

Not a peep yet from the Phoenix lander. The Mars Odyssey orbiter has completed all 30 relay overflights of the Phoenix landing site that were scheduled for Jan. 18 to 21, and heard nothing from the lander. Additional listening campaigns will be conducted in February and March. NASA has said repeatedly that hearing from the lander would be highly unlikely, as Phoenix was never designed to withstand the Martian arctic winters.

Meanwhile, the outlook isn’t brilliant for the Spirit rover, either.

Efforts to free the rover have barely budged it, and as the Martian autumn approaches, precious sunlight which provides power to the rover is declining each day. As of now, Spirit is tilted the wrong way to generate enough heat to make it through the winter, although the Free Spirit team is working to change the angle of her solar panels.

The rover team has now begun driving Spirit backward as the next technique for attempting to extricate the rover from the sand trap where it is embedded. The first two backward drives produced about 6.5 centimeters (2.6 inches) of horizontal motion and lifted the rover slightly.

However, the right-rear wheel is still non-functional, along with the right-front wheel (even though that wheel came back to life, briefly), and during a recent extrication drive attempt, the left middle wheel stalled. The team is working to get more diagnostic information about that wheel stall. Even with four working wheels, Spirit would have a very difficult path to get out of her predicament.

And rover fans must be continuing to suggest using the rover’s robotic arm to help push Spirit out, because the latest press release about Spirit included some back-of-the-envelope calculations about using the arm for just such an action. They figured out that by pushing with the arm, only about 30 newtons of lateral force could be achieved, while a minimum of several hundreds of newtons would be needed to move the rover. Further, such a technique risks damaging the arm and preventing its use for high-priority science from a stationary rover. The other technique of re-sculpting the terrain and perhaps pushing a rock in front of or behind the left-front wheel was also assessed to be of little to no help and, again, risks the arm. There is also a large risk of accidentally pushing the rock into the open wheel and jamming it.

When asked if he was discouraged about Spirit’s current situation, NASA’s lead scientist for the Mars exploration program, Michael Meyer said, “You gotta be joyful when something that was only supposed to operate for three months lasts over 6 years.”

A 3-D view of Opportunity's view as she leaves Marquette Island, created by Stu Atkinson. Image credit: NASA/JPL/ U of Arizona

The Opportunity rover, on the other side of Mars, continues her approximately 7 mile trek to Endeavour Crater. The rover left the rock called Marquette Island on Sol 2122 (Jan. 12, 2010), and has now crossed the 19-kilometer (11.8-mile) odometer mark. Amazing!

There is a relatively fresh impact crater that has been named “Conception,” and Oppy will stop to investigate, having to detour about 250 meters (820 feet) to the south.

Sources: JPL, NASA TV

About 

Nancy Atkinson is Universe Today's Senior Editor. She also works with Astronomy Cast, and is a NASA/JPL Solar System Ambassador.

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