This Week on Galileo - December 8-14, 1997
The Galileo Europa Mission (GEM) officially starts today, December 8. The spacecraft spends this week reading, processing and transmitting to Earth pictures and information stored on the onboard tape recorder. This data comes from the last few observations of Galileo's primary mission and includes observations of Jupiter's atmosphere, Io, and the minor moons. Most of these observations are on the tape recorder playback schedule for a second time to allow the science teams to fill in any gaps that may have been caused by transmission problems. The science teams also take advantage of this second transmission opportunity to return new data or re-play particularly interesting data.
Information gathered by the Near Infrared Mapping Spectrometer (NIMS) comprises the bulk of information on Jupiter's atmosphere this week. NIMS returns eight observations of the feature known as a brown barge. This feature was originally seen by the Voyager spacecraft, but scientists though it had disappeared since then. Its unique color suggests the presence of interesting chemical reactions that are yet to be understood. The NIMS team also returns portions of a thermal observation of a north-south strip of Jupiter's atmosphere. The Photopolarimeter Radiometer (PPR) team returns a similar observation of an east- west strip. The Solid-State Imaging (SSI) team contributes this week two observations that were designed to look for lightning in Jupiter's atmosphere and three observations designed to build a time-lapse record of the development of aurora. The Ultraviolet Spectrometer (UVS) team completes the Jupiter set by also returning an auroral observation.
Science data from observations of Io are returned by the SSI and NIMS teams. NIMS returns a standard set of information designed to look for changes in the chemistry, temperature and activity on Io's surface. The SSI team returns an observation of the topography (shape and location of surface objects) on Io, but also returns several observations designed to catch volcanic plumes in action. The volcanic regions covered in this campaign, and transmitted to Earth this week, include Culann, Volund, Marduk, Pillan, Loki and Kanehikili.
The SSI team returns the remaining set of information on this week's recorder playback schedule. This set contains several observations designed to gather more information on the global shape of Jupiter's minor moons, Amalthea, Adrastea, Metis and Thebe.
Toward the end of the week, the spacecraft performs the final orbital path correction, known as an orbit trim maneuver, prior to the mission's next encounter on December 16. This will be the first encounter of the Galileo Europa Mission and will be the closest ever by the Galileo spacecraft. The spacecraft will fly over the surface of the moon Europa at a distance of only 200 km (124 miles).
Catch all the details at this same URL with the return of Today on Galileo, next Monday, 15 Dec.!!!