Saturday, April 14, 2007

A complex series of events, including a five month-old computer error, was responsible for the battery failure that led to the loss of NASA’s Mars Global Surveyor last year, an internal review board says. Findings from a preliminary report released on Friday say that while NASA controllers followed procedures while operating the craft, the procedures did not cover the types of errors that occurred.

According to NASA, on November 2, 2006, the Global Surveyor was ordered to perform a routine adjustment of its solar panels. However, the Global Surveyor reoriented to an angle that exposed one of its two batteries to direct sunlight. The battery overheated, which led to the depletion of both batteries. An incorrect setting in antenna orientation prevented Global Surveyor from relaying its status to NASA controllers. Its preprogrammed systems did not take into account the need to maintain a thermally safe orientation.

That was the last communication that NASA controllers had with the spacecraft.

The Global Surveyor was the first US mission to Mars in twenty years, For ten years, the craft returned detailed information to NASA scientists providing new insights, including evidence that appeared to show the presence of water on Mars and identification of deposits of water-related minerals, which led to selection of a Mars rover landing site.

“The loss of the spacecraft was the result of a series of events linked to a computer error made five months before the likely battery failure,” said Dolly Perkins, board chairperson and deputy director-technical of NASA’s Goddard Space Flight Center.

The board concluded that NASA controllers had followed procedures, but that the procedures did not adequately cover the type of errors that occurred. In its final report, the board will offer recommendations applicable to future missions.

“We are making an end-to-end review of all our missions to be sure that we apply the lessons learned from Mars Global Surveyor to all our ongoing missions,” said Fuk Li, Mars Exploration Program manager at NASA’s Jet Propulsion Laboratory.

The Global Surveyor was the longest operating spacecraft at Mars and had lasted four times longer than expected.