On Monday, Wednesday, and Friday of the week that began on February 24th, the Surveyor spacecraft rotated to a position that allowed the Mars Orbiter Camera to obtain images within a cluster of stars called the Pleiades. Images were gathered over the course of one hour on each day's opportunity. These images, combined with the images obtained on February 21st, will allow the camera team to determine settings to control the instrument's focus.
Late in the afternoon on Friday, the spacecraft experienced a minor glitch with the star scanner. Normally, this device constantly scans a set of reference stars in deep space. These distant stars serve as fixed reference points that allow the spacecraft to determine its proper pointing orientation relative to the Earth and Sun. This process is called attitude control and is not related to the camera's star imaging for focus determination purposes.
This glitch occurred during Friday's playback of Mars Orbiter Camera data from Surveyor's recorders. At that time, the star scanner began misidentifying stars. As a consequence, the flight team transmitted a command to the flight software to reset the portion of the attitude control software that controls the star scanner. After several hours, all conditions returned to normal.
Although the cause of the glitch has not yet been determined, the flight team suspects that the star scanner was fooled by sunlight reflecting off of dust particles in the vicinity of the spacecraft. In order to further investigate this event, a playback of spacecraft engineering data recorded during the glitch will occur later this week.
After a mission elapsed time of 113 days from launch, Surveyor is 31.76 million kilometers from the Earth, 83.40 million kilometers from Mars, and is moving in an orbit around the Sun with a velocity of 27.74 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.
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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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