An artist's concept of NASA's Galileo spacecraft in orbit around Jupiter. Photo: NASA/JPL

This holiday week sees the Galileo spacecraft continue its normal cruise activities. On Monday, an attitude maintenance turn is performed to keep the spacecraft's communications antenna pointed at the Earth. On Thursday, a standard test of the on-board gyroscopes is performed. Due to repeated dosages of the intense radiation near Jupiter, some of the electronic components used to report data from the gyros have degraded. These periodic tests check the current health of the electronics, and also determine if updates are needed to software parameters used by the spacecraft's computers to correct the measurements from the gyros.

On Sunday, controllers take the final step in a series of reconfigurations of the radio communications parameters during the recent period of solar conjunction, when Galileo appeared to pass behind the Sun as seen from Earth. In this final step, as Galileo and Jupiter continue to move away from the Sun (as seen from Earth), the spacecraft returns to its normal configuration for telemetry.

The Extreme Ultraviolet Spectrometer (EUV) instrument continues its two-month-long study of the interplanetary medium. Playback of data stored on the tape recorder from the May flyby of Callisto also continues. This week will see the conclusion of our first survey pass through the Solid State Imaging (SSI) pictures on the tape, and the beginning of the second pass, including data from the other instruments. Expected SSI data include global color pictures of Callisto and pictures of hot spots in the atmosphere of Jupiter. The Near Infrared Mapping Spectrometer (NIMS) will return measurements of Io taken while that satellite was in Jupiter's shadow, as well as additional global coverage of that volcanic moon. The Photopolarimeter Radiometer instrument (PPR) will return data from global observations of Io and measurements of a white oval in Jupiter's atmosphere.