This Week on Galileo March 20-26, 2000
Data playback on Galileo is interrupted once this week as the spacecraft flies the outbound leg of its
orbit around Jupiter. On Tuesday, the spacecraft performs standard maintenance on its onboard
tape recorder. This week’s playback schedule includes observations performed by the Solid-State
Imaging camera (SSI), Near-Infrared Mapping Spectrometer (NIMS), and suite of Fields and Particles
instruments. The observations were made during the spacecraft’s close flyby of Io last month. The
Fields and Particles instruments are comprised of the Dust Detector, Energetic Particle Detector,
Heavy Ion Counter, Magnetometer, Plasma Detector, and Plasma Wave instrument.
Throughout the week, the Fields and Particles instruments continue to return parts of a high resolution
recording of the plasma, dust, and electromagnetic fields surrounding Io. The recording was
performed during the spacecraft’s closest 82 minutes to Io. Fields and Particles data are also
interleaved with data from any remote sensing instrument observation made during the same
82-minute period. A regular occurrence, this is done so high-priority surface targets are not missed
by the remote sensing instruments (NIMS, SSI, Photopolarimeter Radiometer, and Ultraviolet
Spectrometer).
NIMS starts its share of this week’s playback with the return of three observations. The first contains
spectral scans of the Chaac Patera region, complementing data returned last week by SSI. The Chaac
region is known to be home to Io’s “golf courses”, so-called because of their greenish color and similar
shape. The second observation is a mosaic of several volcanic regions on Io, and the third captures
the Prometheus volcanic vent.
SSI then returns part of a four-image mosaic of the Tohil Mons region. These images will be combined
with an observation of Tohil Mons taken in October 1999 in order to produce stereo views of the
region. Tohil Mons is of interest to scientists as it is one of the mountains on Io whose geological
structure, origin and history are not well known. SSI also returns part of a color observation of the
Prometheus region.
SSI and NIMS then return two joint observations. In the first observation, they return data from the
Camaxtli Patera hot spot. The SSI portion of this observation will be combined with one of SSI’s
earlier observations to produce stereo coverage of the Chaac Patera region. The next observation is
the last one on this week’s playback schedule and contains data covering Io’s Amirani volcanic region.
For more information on the Galileo spacecraft and its mission to Jupiter, please visit the Galileo home
page at one of the following URL’s:
