Mars Global Surveyor continues to perform excellently as it continues on a path that will reach the red planet just under five weeks from now. The spacecraft is currently 8.43 million kilometers from Mars and is closing that gap at rate of 240,000 km per day.

Flight team members are busily preparing for arrival at Mars. Over the past two weeks, engineers on the team continued their testing of the T1 command sequence. This set of commands will be used to control Surveyor during a 22-minute burn on September 11th that will slow the spacecraft and allow it to enter Martian orbit.

Other major activities that occurred over the last two weeks focused on preparing several of the science instruments for operations at Mars. On Thursday, July 31st, the onboard flight computer activated the Mars Orbiter Laser Altimeter for a several-hour checkout period. During this time, the laser team assessed the operational state of their instrument and transmitted a minor software modification. This change will improve the laser's ability to measure the altitude of surface features on Mars.

On Monday, the flight computer activated the Thermal Emission Spectrometer science instrument. Over the course of several days, the spectrometer team used this opportunity to transmit flight software modifications to their instrument. The modification will allow the spectrometer to achieve a higher data transmission efficiency by increasing the amount of compression in the science data gathered by the instrument. During aerobraking operations, the additional data transmitted by the spectrometer will assist the flight team in gauging the state of the Martian atmosphere.

Today, the flight team transmitted the C10 command sequence to Surveyor. This command set will go active on Monday, August 11th at 7:00 a.m. PDT and will control the spacecraft for the next two weeks. Major activities in this sequence include more long-range imaging of Mars by the camera and Thermal Emission Spectrometer.

After a mission elapsed time of 274 days from launch, Surveyor is 218.68 million kilometers from the Earth and is moving in an orbit around the Sun with a velocity of 21.76 kilometers per second. This orbit will intercept Mars 34 days from now, slightly after 6:00 p.m. PDT on September 11th (01:00 UTC, September 12th). The spacecraft is currently executing the C9 command sequence, and all systems continue to be in excellent condition.

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Status report prepared by:

Office of the Flight Operations Manager
Mars Surveyor Operations Project
NASA Jet Propulsion Laboratory
California Institute of Technology
Pasadena, CA 91109
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