April 14, 2009, 1:25 PM — Less than three months after dealing with a glitch that stalled one of its two Mars rovers, NASA is reporting yet another problem with the same machine.
The Mars rover Spirit appeared to reboot its computer, unprompted from the ground, twice over the past weekend, NASA's Jet Propulsion Laboratory (JPL) reported late Monday. While the rover, which has been working on the Red Planet for more than five years, communicated with its NASA controllers on Friday, Saturday and Sunday, the JPL said that some of the communications were "irregular".
"While we don't have an explanation yet, we do know that Spirit's batteries are charged, the solar arrays are producing energy and temperatures are well within allowable ranges. We have time to respond carefully and investigate this thoroughly," said John Callas, NASA's project manager for Spirit and its Mars rover companion, Opportunity, in a statement. "The rover is in a stable operations state called automode and taking care of itself. It could stay in this stable mode for some time if necessary while we diagnose the problem."
Late in January, scientists at the JPL reported that Spirit had begun failing to respond to instruction from its controllers. NASA engineers fixed that problem within days. However, after running a series of diagnostic tests, the NASA engineers reported that they still were unclear about what caused the problem.
The January problems with the Spirit Mars rover came about a month after testing and hardware problems delayed the launch of a new SUV-size Mars rover, the $2.3 billion NASA Mars Science Laboratory from next fall to 2011.
In the past five weeks, though, Spirit has made good progress moving across the Martian terrain. In a statement, NASA noted that the rover has travelled 390 feet, moving around a low plateau to get closer to "destinations of scientific interest".
Spirit and Opportunity, which are both working on the Mars equator but on different sides of the planet, have been on Mars for five years, far outlasting the three month projection set by engineers at its launch. "We are aware of the reality that we have an aging rover, and there may be age-related effects here," Callas said.
The robotic rovers have been sending and receiving information to and from Earth every day, with a team of about two-dozen programmers and engineers uploading code to guide the movements of the rovers and aim their cameras. All of that information travels about 200 million miles one way, and takes between five to 21 minutes to travel from one planet to the other.