Mars Climate Orbiter/Mars Polar Lander Mission Status September 15, 1999 Mars Climate Orbiter (MCO) The flight team completed its preparations for Mars Climate Orbiter's fourth and final course correction, TCM-4, on Tuesday (September 14), transmitting the TCM-4 command sequence to the spacecraft that evening. MCO successfully executed TCM-4 this morning, with a 15 second burn starting at 09:40 PDT, adjusting its velocity by 1.37 meters/second. Spacecraft performance was excellent; the updated gimble angle trajectory for the stow/unstow movements of the solar array worked just as expected, following last week's in-flight verification tests. Preparation of the MCO spacecraft for Mars Orbit Insertion (MOI) on September 23 has begun. A complete audit of the flight processor's file system was conducted during the past week, verifying both file names and contents versus the equivalent file system in the MCO ground-based simulator, which has been operating 24 hours/day, seven days per week in preparation for Mars arrival. On Friday (September 17), a serlies of new files will be transmitted to the spacecraft, placing it into the correct pre-MOI configuration. The baseline MOI command sequence will also be loaded at the same time; there is one scheduled updated to the main engine burn parameters, which will take place on Monday of next week (September 20). On the evening of September 21, the flight team will transition to a round-the-clock schedule of on-console spacecraft monitoring prior to MOI and post-MOI operations commencing on September 23. MARS CLIMATE ORBITER IS 8 DAYS FROM MOI. Mars Polar Lander (MPL) Mars Polar Lander experienced a quiescent week of nominal cruise operations. Playback of telemetry data collected onboard from the spacecraft's science instruments during instrument checkout #2 on September 9 has been completed. One more repeat playback is scheduled in the coming week to ensure any gaps identified in the data set are filled. Lander activity is intentionally kept low during the next three weeks while the flight team maintains its focus on the critical MCO events leading up to and following orbit insertion.

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