Dr. Marc Rayman's Mission Log

  November 12, 1998

Mission Update:

Thank you for visiting the Deep Space 1 mission status information site, now in its third week on the list of most frequently visited logged sources in the solar system for information on this technology validation mission. This message was logged in at 8:10 pm Pacific Time on Thursday, November 12.

Software onboard Deep Space 1 designed to protect the spacecraft in case of unusual events detected a possible problem with the spacecraft's star tracker yesterday, prompting the software to put the craft in a predefined safe configuration. The star tracker, cleverly named because it tracks stars, helps determine the spacecraft's orientation; this is not one of the advanced technologies onboard DS1 for evaluation but is a new and sophisticated device. For reasons that are not yet understood, the unit was unable to report its orientation to the spacecraft computer. The spacecraft's protective software took several steps to correct the problem and ultimately placed the spacecraft in the safe configuration. The software worked exactly as designed, and all of the spacecraft's systems are healthy and safe. The star tracker resumed normal operation shortly after the onboard protective system took action. The mission operations team observed the entire event and elected to allow the onboard protective system to proceed through its steps.

Tomorrow the team will send commands to Deep Space 1 to return the spacecraft to normal cruise configuration, and technology validation activities will resume. Early next week, tests of the autonomous navigation system and the combination camera/imaging spectrometer will be conducted.

Analysis of the wealth of data collected during Tuesday's first test of the ion propulsion system continues. This work is supplemented with data from laboratory tests of ion thrusters of the same design and from space-based tests of smaller systems. In the first test, the thruster turned off after about 4 and a half minutes of thrusting. The operations team is proceeding with development of plans for the next experiment with the normal prudence that is appropriate for operating a probe in deep space. The next tests with the thruster probably will be in the second half of next week.

Deep Space 1 is now more than 8 times as far away as the moon. Each day it recedes from Earth by nearly 150,000 kilometers, or more than 90,000 miles.

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