Galileo Status Report - October 18, 1996

PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
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GALILEO MISSION STATUS

October 18, 1996

Observations of Io and Jupiter's atmosphere were among the data received from NASA's Galileo spacecraft this week. Included were data from the imaging camera and near infrared mapping spectrometer, which looked at Io "face-on" for new volcanic deposits from a distance of 441,000 kilometers (about 274,000 miles).

Galileo's ultraviolet spectrometer also returned data from observations made of Jupiter. The measurements specifically map several gases -- ammonia, acetylene and phosphine among them -- in the atmosphere along a strip from north to south.

On October 14, two optical navigation images of the moon Callisto were taken, but neither was successful. Analysis of the failed images is ongoing, but preliminary results indicate the problem may be attributed to the expected brightness of Callisto; brightness dictates the exposure settings that were selected on the camera. Callisto data returned to date suggest that the models used over-estimated the brightness of Callisto and that the exposure settings were inappropriate.

Galileo's ground data system team this week conducted three more tests of the new array of four different antennas that are electronically linked together and will be used in concert to enhance the data return from Galileo's upcoming November encounter with Callisto and each of the subsequent encounters for the balance of the mission. The telecommunications array links the receiving power of the three largest antennas (one 70-meter and two 34-meter antennas) at the Australian Deep Space Network communications complex in Tidbinbilla, near Canberra, along with the large Parkes radio telescope located about 100 miles from the Tidbinbilla site. It also links the 70-meter antenna at Goldstone during periods when both Goldstone and Canberra are able to "see" the Galileo spacecraft at the same time.

On Wednesday night (October 16), the team was successful in demonstrating recovery from simulated equipment outages. Of the 19 ground data system tests conducted so far, 11 have been successful, five partially successful and three unsuccessful in real time. Post-test analysis of problems have identified explanations and/or simple workaround solutions for most anomalies. No problems are anticipated in completing testing in time for the start of operations support on November 1.

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