This Week on Galileo July 23-29, 2001

With two weeks to go before the next flyby, activities on the spacecraft
are relatively quiet, while activities on the ground are heating up. The
flight team of scientists and engineers are busy putting the final touches
on the series of commands that will govern Galileo as it skims past Io on
August 5. On Friday, the spacecraft performs routine maintenance on the
propulsion system.

The Extreme Ultraviolet Spectrometer (EUV) is continuing its two-month-long
study of interplanetary hydrogen gas. This activity will conclude just
before the start of encounter operations.

During the past two weeks, the Dust Detector instrument (DDS) has seen a
dramatic increase in the number of dust impacts that it measures. During
this cruise period the normal interval between data read-outs from the DDS
instrument is 20 days. The spacecraft team has sent commands to read out
DDS data approximately once every three days during this period of high
activity, which is expected to last one more week.

Playback of the data recorded during Galileo’s May flyby of Callisto is
nearly 60% complete. This week, playback data are expected from the Solid
State Imaging camera (SSI), the Near Infrared Mapping spectrometer (NIMS),
and the suite of Fields and Particles instruments that measure the magnetic
field environment of Jupiter. These instruments are the Energetic Particle
Detector (EPD), Heavy Ion Counter (HIC), Magnetometer (MAG), Plasma
instrument (PLS), and Plasma Wave Subsystem (PWS).

The SSI data are from Callisto global color images and stereo images taken
near closest approach. For the most part, these are samples of the frames,
and the imaging team will use these samples to determine the best choice of
processing and compression parameters to use on the next pass through the data.

NIMS data return includes global color observations of Io, observations of
a hot spot in Jupiter’s atmosphere and of an area in the wake of the Great
Red Spot, and an observation of the Asgard impact basin region on Callisto.
In addition, earlier data sampled from the NIMS Io eclipse observation
revealed new, high-temperature volcanic activity at a location in high
southern latitudes where no volcanic activity had been detected before.
NIMS is replaying about 1 minute of data from this observation with a
greater data density (larger number of spectral samples) in order to better
resolve both the location and the temperature of the new eruption.