On Saturday, March 29th, the flight team performed a several-hour communications test to measure low-level interference between Surveyor's ultra-stable-oscillator-generated X-band signal and the Ka-band signal. Normally, the spacecraft utilizes the 25-Watt, X-band transmitter for communicating with the Earth. The main differences between the two are that the 1-Watt, Ka-band transmitter is experimental and operates at a frequency near 32 gigaHertz versus 8 gigaHertz for X-band.
During last Saturday's test, the spacecraft simultaneously activated both the X- and Ka-band signal sources. The test was designed to determine the effect of the Ka-band signal on the purity of the X-band signal as generated by the ultra-stable oscillator. Understanding the performance of the oscillator under potential interference conditions is important because this device functions as an electronic clock that precisely controls the tone of Surveyor's radio signal. Precision control of the signal's tone is important for gathering data regarding the Martian atmosphere.
On Monday, March 31st, the spacecraft passed through a major milestone on its way to Mars. For the first time in the mission, Surveyor was closer to Mars than to Earth. This equi-distant point was approximately 57 million kilometers between the two planets. The half-way point measured in terms of days to reach Mars will occur on April 10th.
After a mission elapsed time of 148 days from launch, Surveyor is 61.05 million kilometers from the Earth, 53.20 million kilometers from Mars, and is moving in an orbit around the Sun with a velocity of 25.36 kilometers per second. This orbit will intercept Mars on September 12th, 1997. The spacecraft is currently executing the C6 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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