Galileo Status Report - May 23, 1996
PUBLIC INFORMATION OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
During the last two weeks the Galileo flight team loaded most of the new flight software into the Jupiter-orbiting spacecraft computers, which are in the attitude and articulation control and command and data subsystems. About half the scientific instruments have also been reprogrammed.
In the next few days, the team will finish the process, reprogramming several remaining instruments and completing the inevitable clean-up commanding. The process of specifying, writing and testing the new software and preparing it for installation in the spacecraft now orbiting Jupiter took more than three years and involved more than 100 members of the Galileo project team.
This is the second time Galileo has been massively reprogrammed with new flight software. In February 1995 new software was installed for the approach and initial encounter at Jupiter and for the support of Galileo's atmospheric probe mission. The new software goes a long way further, providing for data compression and other new facilities to maximize the science return from the orbital tour, using the tape recorder and the low-gain antenna.
Galileo is now about five weeks from its first encounter with the Jovian moon Ganymede. The largest of the Galilean satellites, Ganymede orbits at roughly one million kilometers (620,000 miles) from Jupiter and has a diameter of almost 5,300 kilometers (about 3300 miles), larger than the planet Mercury.
The spacecraft is 13.3 million kilometers (8.29 million miles) from Jupiter today, and 668 million kilometers (415 million miles) from Earth. One-way communication time is now 37 minutes. Galileo's speed in orbit around Jupiter is 2.5 kilometers per second, almost 5700 miles per hour.