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Mars Pathfinder Mission Status

10 January 1997

The Mars Pathfinder spacecraft is currently 10 million km (6.2 million miles) from Earth, traveling at 32 km/s on its trajectory to Mars. All spacecraft subsystems continue to operate as expected.

Earlier in the week we successfully updated attitude control software to further compensate for the apparent obscuration of the sun sensors. Miguel San Martin, lead Attitude Control Subsystem Engineer, stated: "This software update should allow the spacecraft to perform all turns and maneuvers needed to get it to Mars. We are very pleased with the subsystem's performance in spite of the sun sensor obscuration."

At 7:40 PM PST on January 9, we successfully performed our first and largest Trajectory Correction Maneuver (TCM). This maneuver, planned by lead Flight Engineer Rob Manning, used two of the spacecraft's eight 1 pound thrusters. These thrusters were fired continuously for an hour and a half, and changed the velocity of the spacecraft by 31 meters/second. The purpose of this maneuver was to correct small launch vehicle targeting errors and reduce the planetary protection trajectory bias. Later we turned the spacecraft's spin axis 35 degrees back toward Earth so that we can perform radio navigation more effectively. We will leave the spacecraft in this attitude until the next TCM scheduled for early February.

From the Doppler radio signature, it appears that last night's TCM performance was well within our expectations. In the next few days, radio ranging data will allow us to precisely gauge the quality of the maneuver.

Next week we will turn on the backup heat rejection system pump and allow it to operate for a while in parallel with the primary pump. These pumps circulate Freon around the perimeter of the cruise stage and down into the lander to keep the lander and rover electronics cool during the 7 month cruise to Mars.

We will continue to keep you informed of our progress. For more information, please visit our website at

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