On Monday, the on-board command sequence controlling Surveyor executed a test called the "Solar Array Feather." During the several-hour test, the solar arrays were rotated back and forth several times in a similar fashion to the motion that a person makes when rotating the wrist joint.
This activity was performed for the benefit of the Magnetometer science team. The test simulated the rotation of the solar arrays that will occur as the arrays automatically track the Sun during Mars mapping operations. Because the Magnetometer sensors sit at the end of the solar arrays, the data collected from the test will allow the science team to determine the effect of the solar array rotation on the quality of their data.
On Tuesday, the flight team loaded new parameters to Surveyor's attitude control software. These parameters deal with the performance of the star scanner that controls the spacecraft's ability to point at targets in space. With this parameter update, the spacecraft will be able to point its science instruments at objects with better accuracy than previously possible.
Later on Tuesday, the Ka-band communications team accomplished a major milestone in their experiment. Over a several hour time period, an antenna at the Goldstone tracking station recorded data transmitted simultaneously from Surveyor's X-band and Ka-band transmitters. Normally, the spacecraft utilizes the 25-Watt, X-band transmitter for communicating with the Earth. The main difference between the two signals is that the 1-Watt, Ka-band transmitter operates at a frequency near 32 gigaHertz versus 8 gigaHertz for X-band.
An analysis of the experiment indicated that no disagreements existed between the X-band and Ka-band data for all 12 million data bits observed on Tuesday. This positive result marks the first verified data transmission by an interplanetary spacecraft using a Ka-band signal. The result affirms a long-held belief that the use of Ka-band signals can allow a spacecraft to transmit information at faster data rates with transmitters that consume much less power.
After a mission elapsed time of 120 days from launch, Surveyor is 36.46 million kilometers from the Earth, 76.39 million kilometers from Mars, and is moving in an orbit around the Sun with a velocity of 27.23 kilometers per second. This orbit will intercept Mars on September 12th, 1997. The spacecraft is currently executing the C5 command sequence, and all systems continue to be in excellent condition.
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