On Tuesday morning, the Surveyor spacecraft and flight team participated in a live simulation of telecommunications procedures with one of the Deep Space Network's tracking stations in Madrid, Spain. This readiness test was designed to prepare both the flight team and tracking station personnel for Mars mapping operations that will commence on 15 March 1998.
During mapping operations, Surveyor will circle the red planet once every two hours. On each orbit, the spacecraft will pass behind Mars and will not be able to maintain a communications link with the Earth. Upon entry and exit into this occultation zone, Surveyor's radio signal will pass through the thin Martian atmosphere on its way to Earth. An analysis of the distortion of the signal's strength and tone as it fades and reappears will enable scientists to determine the atmospheric properties at a specific location on Mars.
Tuesday's simulation was performed because tracking the spacecraft as its signal repeatedly passes in and out of the Martian atmosphere requires practice. During the readiness test, the spacecraft turned its radio transmitter on and off over the course of a six-hour period in order to simulate three orbits worth of communications events. Several more of these readiness tests are scheduled over the course of the next two months.
After a mission elapsed time of 246 days from launch, Surveyor is 184.13 million kilometers from the Earth, 15.05 million kilometers from Mars, and is moving in an orbit around the Sun with a velocity of 21.87 kilometers per second. This orbit will intercept Mars 62 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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