Mars Polar Lander Mission Status
7 Jan 1999
(Source: Jet Propulsion Laboratory)
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Diagnostic images taken by Mars Polar Lander's star camera confirmed Wednesday that too much stray light being reflected off the spacecraft's backshell and other surfaces had prevented the spacecraft from identifying the proper star field to set itself in a post-launch cruise configuration.
The flight team at the Jet Propulsion Laboratory and Lockheed Martin Astronautics was able to reorient the spacecraft via a series of ground commands so that surfaces near the star camera's field of view are now in shadow. Following this, the team went to work updating parameters used by the spacecraft's fault protection software, some of which had been disabled during the diagnostic process following launch.
After software parameters were updated and the fault protection system was restarted, the spacecraft automatically performed the sequence of events designed to orient itself after launch. The flight team found the spacecraft performed this sequence of events perfectly, coming very close to the intended orientation with the spacecraft' s medium-gain horn antenna pointed about 40 degrees away from Earth. In this attitude, the star camera is now able to identify star patterns and determine the spacecraft's orientation.
The team was completing minor onboard housekeeping chores Wednesday afternoon to fine-tune all other software and hardware elements of the spacecraft's attitude control system. Tracking of Mars Polar Lander will be reduced on Saturday, January 9, from the current 24-hour-a-day coverage to a schedule of three 4-hour daily passes.
Today Mars Polar Lander is approximately 810,000 kilometers (500,000 miles) from Earth, speeding away at a velocity of 3.35 kilometers per second (7,350 miles per hour) and a velocity of about 33 kilometers per second (73,700 miles per hour) with respect to the Sun.