The first picture from the Stardust spacecraft shows Mars as the bright object in the lower left-hand corner

March 23, 1999
Web posted at: 6:10 p.m. EST (2310 GMT)

(CNN) -- NASA mission controllers were trying to determine what caused the Stardust spacecraft to enter a "safe" mode during testing of the navigation camera and transmission of its images to Earth last week en route toward its rendezvous with Comet Wild-2.

Stardust's main computer had indicated it was carrying out an excessive number of functions, triggering fault protection software that placed the spacecraft in a low-activity state, NASA said.

When the spacecraft is flown in "safe" mode, all non-critical activities are halted and the spacecraft points its antenna toward Earth and awaits new commands.

Controllers waited until the next telecommunications opportunity on Friday evening to resume contact with Stardust, and successfully commanded the spacecraft to resume normal operations, NASA said.

Mission controllers are performing detailed analysis of the data to determine what activities or software could have led the spacecraft computer to trigger fault protection that placed Stardust in its temporary safe state.

Last week, the spacecraft successfully exercised the mirror on the navigation camera for the first time, moving the device outward 90 degrees and back. The mirror will allow the navigation camera to gather close-up images of heart of Comet Wild-2 without being struck by debris that will be flying off the comet's nucleus. Stardust encounters the comet in 2004.

Mission scientists said were surprised and pleased last week with Stardust's exceptionally steady orientation in flight. Data from the navigation camera showed that the spacecraft's "drift," or the balancing adjustments it makes to maintain its orientation in space, was about 10 times less than anticipated.

The spacecraft has also transmitted its first image from space. The image shows Mars shining brightly against the star background as seen from the Stardust's view.

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