Galileo Status Report - May 9, 1996
PUBLIC INFORMATION OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
The orbit trim maneuver performed last Friday slightly changed the spacecraft's arrival time and geometry for the Ganymede encounter on June 27, as planned. This was the first trajectory correction using the small 10-newton thrusters since late August 1995. There is an opportunity for another trim maneuver in June if it is needed.
The celestial mechanics radioscience team, which uses perturbations in the spacecraft flight path as it flies by planets and other bodies to analyze their mass properties, published a report Friday, May 3, in Science magazine that they found Jupiter's moon Io to have a large dense iron core. Galileo flew close to Io on Dec. 7, 1995, as it approached Jupiter, gaining a gravity boost from the moon that allowed it to be captured in orbit around Jupiter. Other observations of unexpected magnetic field changes and of interplanetary dust made at about the same time are being analyzed and prepared for future publication.
Tomorrow's issue of Science magazine will carry reports by Galileo probe scientists who are based at NASA's Ames Research Center in Mountain View, Calif., and at other laboratories. The issue also features articles by Earth-based observers on their studies of Jupiter's atmosphere and environment, which are derived from data collected during the probe's descent into Jupiter's atmosphere on Dec. 7, 1995.
Next Monday, May 13, the Galileo team will begin installation of massive new flight software in the spacecraft, transmitting the computer code in installments over a period of 10 days to two weeks. This will almost double the software used by the main spacecraft computers in the command and data subsystem.
Galileo is now 15.7 million kilometers (9.8 million miles) from Jupiter, coming closer at a rate of 1.9 kilometers (1.2 miles) every second. It is currently 701 million kilometers (436 million miles) from Earth, so that each digital bit of the flight software going to the spacecraft next week will take a little less than 39 minutes to reach the spacecraft.