A command sent to the wrong computer address caused a cascade of events that led to the loss of the Mars Global Surveyor spacecraft in November, National Aeronautics and Space Administration investigators reported.
The error by ground controllers in the Denver area caused the spacecraft to think mistakenly that its solar panels were stuck. By trying to free them, one of its onboard batteries overheated, eventually causing a loss of power, according to the report released Friday.
The spacecraft, which had orbited Mars for 10 years, was given up for lost Jan. 28.
The spacecraft was managed by the Jet Propulsion Laboratory in Pasadena, Calif., and Lockheed Martin Space Systems in metro Denver.
Although the command error apparently originated in Denver, a spokesman at JPL said both the credit for the craft’s successes and the blame for its loss were shared by the team.
Fuk Li, Mars Exploration Program manager at JPL, said an “end-to-end” review of all missions will be undertaken to make sure the mistakes made with the probe are not repeated.
Mars Global Surveyor was launched in 1996 on what was expected to be a two-year mapping and science mission. Its mission was extended four times by NASA.
The spacecraft discovered that the martian surface is made up of large amounts of sedimentary rocks, suggesting a more complicated geological history than had been previously thought. It also found that carbon-dioxide ice was disappearing from the planet’s south pole, raising the possibility that a new round of global warming is underway on the planet.
Its most exciting find was announced in December, just weeks after it was lost. Scientists presented evidence that water still flowed on the martian surface from small springs.
According to the preliminary report from the Mars Global Surveyor Operations Review Board, the problems with the spacecraft began in June, when a command that oriented the craft’s main communications antenna was sent to the wrong address. The mistake caused a problem with the positioning of the solar-power panels.
The problems came to a head Nov. 2, when the spacecraft detected the positioning error and tried to go into a safe, or contingency, mode. That, in turn, exposed one of the batteries to direct sunlight, causing it to overheat.
Software on the spacecraft interpreted the overheating as a battery overcharge and shut down the charging system. As a result, the batteries drained within 12 hours, resulting in a loss of communications with Earth.
The review panel found the management team followed existing procedures in dealing with the problem, but those procedures “were inadequate to catch the errors that occurred.” The panel also said the probe’s onboard fault-protection system failed to respond correctly to the errors. Instead of protecting the craft, the programmed response made it worse.
The panel, chaired by Dolly Perkins, deputy director of NASA’s Goddard Spaceflight Center in Greenbelt, Md., also noted that over the years budgets and staff had been cut “in an effort to operate the mission as economically as possible.”
