This Week on Galileo
January 1-7, 2001
Happy New Year!
Galileo's first day of 2001 sees the completion of the few remaining remote sensing observations planned for this encounter. The remainder of the week is spent primarily in completing week 10 of a 14-week-long survey of the Jovian magnetosphere. The survey is being performed by Galileo's Fields and Particles instruments. The spacecraft performs one navigation activity this week, and one engineering activity. On Tuesday, Galileo makes a small flight path adjustment. On Wednesday, the spacecraft executes a small turn to keep its radio antenna pointed toward Earth.
Monday's remaining remote sensing observations are performed by the Solid-State Imaging camera (SSI). The first two observations focus on a turbulent region just northwest of Jupiter's Great Red Spot. In observations performed in previous orbits, this particular region of Jupiter's atmosphere has been the site of very active thunderstorms. The observations performed today are the last of a series taken over four Jupiter rotations, which will enable scientists to study the evolution of these storms over long time scales. Jupiter rotates once every 10 hours. Observations during the previous three rotations were made yesterday.
SSI also performs three observations of Jupiter's main ring. These images will allow scientists to determine the vertical structure of the ring and also shed light on some unexpected patchiness seen in the ring in previous observations.
The Fields and Particles instruments on Galileo are the Dust Detector, Energetic Particle Detector, Heavy Ion Counter, Magnetometer, Plasma Detector, and Plasma Wave instrument. One of the themes of this encounter has been their 14-week survey of the Jovian magnetosphere, performed in conjunction with instruments on the Cassini spacecraft. The survey data obtained by the Galileo instruments are being occasionally stored on Galileo's onboard tape recorder in order to keep the survey continuous.
Typically, magnetospheric data are collected in real time, which means they are almost immediately packaged and transmitted to Earth. However, when radio antennas of the Deep Space Network (DSN) are being used by other spacecraft, Galileo has a data buffer (a section of computer memory) which can store up to seven hours of survey data at one time. The tape recorder is necessary because some gaps in DSN tracking are longer than seven hours. In these cases, the contents of the data buffer are dumped to the tape recorder. These data are planned for playback, along with other recorded data, in a few weeks, at the completion of the 14-week survey. This week, Galileo will use its tape recorder five times.