Softpedia >News >Science >Space
Softpedia Homepage   

Second Test Rover to Begin Test Drives

It is lighter than the Spirit/Opportunity replica

Aug 24, 2009 08:40 GMT  ·  By
Testing at NASA's Jet Propulsion Laboratory in August 2009 is assessing possible maneuvers that the Mars rover Spirit might use for escaping from a patch of soft soil where it is embedded at a Martian site called “Troy”
   Testing at NASA's Jet Propulsion Laboratory in August 2009 is assessing possible maneuvers that the Mars rover Spirit might use for escaping from a patch of soft soil where it is embedded at a Martian site called “Troy”

Experts at the NASA Jet Propulsion Laboratory (JPL), in Pasadena, California, have just added a second rover to their experiments designed to figure out a way to get the Martian rover Spirit out of its sand trap on the Red Planet. The team has added a lighter-weight version of the two MER components, and it will begin drive tests soon, alongside the accurate, full-weight replica, which has been running maneuvers in the JPL sandbox for several weeks now. Up to this point, no real progress has been made.

The reason why the second robot is added has to do with the power of gravity. Here on Earth, the replica is much heavier than Spirit is on Mars, even though the two rovers have the same mass. But the second test machine, which does not carry a science payload and robotic arm, is much lighter than the replica and Spirit. However, its weight nears that Spirit now has on Mars, accounting for the planet's reduced gravitational pull, as compared to the Earth's.

“There is no perfect Earth analog for Spirit's current situation. There's less gravity on Mars, little atmosphere, and no moisture in the soil where Spirit is. It is not anything like being stuck in sand or snow or mud on Earth. Plus, since the rover moves only about as fast as a tortoise, you cannot use momentum to help. No rocking back and forth as you might do on Earth,” JPL expert John Callas, who is the project manager for both Mars Exploration Rovers (MER), explains.

The two rovers will be used in identical setups, and the differences between their behaviors will hopefully provide experts at the laboratory with sufficient data to employ in their future, longer duration test drives. Spirit has been stuck on Mars since May 6th, in a loose patch of sand and soil that mission controllers dubbed Troy. The robot was driving backwards, with one wheel off the ground, when it got stuck, and, to make matters worse, a rock was photographed under its belly, which really makes rescue efforts that much more difficult.

“The team has also made further assessments of the position of a rock underneath Spirit relative to the rover's center of gravity. Part of the strategy for getting Spirit free will be to avoid getting in a position with the center of gravity directly over a rock touching the rover,” a JPL press release says.