Galileo Status Report - August 1, 1996
PUBLIC INFORMATION OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov
The spacecraft is operating normally in its dual-spin mode. This past weekend, Galileo received a software "patch" for the Near Infrared Mapping Spectrometer (NIMS) instrument. The patch rewrites a small portion of central computer software in order to begin playback of the NIMS Ganymede data today.
Tape recorder conditioning -- now a standardized procedure which is to be done at least every 30 days -- was executed properly by the spacecraft July 25. In addition, a new "beginning-of-track" marker was written onto the tape recorder's track 1 as planned. The marker is the last of several that engineers placed on the recorder as part of a strategy to optimize and preserve operation of the faulty mechanism.
Command procedures are being developed to circumvent a software error that triggers a high voltage alarm on the Energetic Particle Detector. These commands will be radioed in real-time prior to the Ganymede-2 encounter, which occurs on Sept. 6, and written into the spacecraft command sequences thereafter until an Energetic Particle Detector flight software patch can be installed.
The NIMS anomaly that occurred a day after Ganymede-1 closest approach continues under investigation. There is still no clue as to what happened and the NIMS has been operating normally since the software was reloaded. Sequenced reloading at key points during Ganymede-2 is being considered to provide scheduled autonomous recoveries of NIMS to mitigate against a repeat of this anomaly, which prevented NIMS from taking data near the end of the Ganymede-1 encounter.
Galileo is 645.9 million kilometers (about 401.3 million miles) from Earth and about 9.1 million kilometers (about 5.6 million miles) from Jupiter. It is traveling at a speed of about 1.5 kilometers per second (about 3,350 miles an hour) relative to Jupiter.