Mars Pathfinder Mission Status

31 December 1996


The spacecraft is currently 7.2 million kilometers from Earth and traveling at 32.6 kilometers per second. All spacecraft subsystems continue to operate as expected.

On 30 December 1996 we performed another successful ASI/MET science instrument health check. These are intended to monitor the performance of the pressure transducer that will measure Martian air pressure.

Last Friday, 27 December 1996, we successfully performed our first celestial mode attitude turn. In this turn, the spin axis was turned about 43 degrees, mostly out of the plane of the ecliptic. The spacecraft used the sun sensors and the star scanner to precisely orient the spacecraft's spin axis to the new direction, which is about 35 degrees off the Sun and the Earth. This direction was picked because it is the direction we want the spacecraft's thrusters to be in when we perform our first and largest Trajectory Correction Maneuver.

This maneuver is now scheduled for the evening of 3 January 1997 (Important: see update of 2 January 1997). It has been fully designed and tested using the Flight System Testbed spacecraft simulation at JPL. Because of the superb performance of the Delta II rocket in getting Mars Pathfinder into a Martian trajectory, this maneuver is expected to use less than 25% of the 93 kilograms of hydrazine on-board the spacecraft. It will change the velocity of the spacecraft by about 30 m/s over a burn time of about two hours.


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