Calibration and performance of the Galileo solid-state imaging system in Jupiter orbit

Abstract

Abstract. The solid-state imaging subsystem (SSI) on the National Aeronautics and Space Administration's (NASA's) Galileo Jupiter orbiter spacecraft has successfully completed its 2-yr primary mission exploring the Jovian system. The SSI has remained in remarkably stable calibration during the 8-yr flight, and the quality of the returned images is exceptional. Absolute spectral radiometric calibration has been determined to 4 to 6% across its eight spectral filters. Software and calibration files are available to enable radiometric, geometric, modulation transfer function (MTF), and scattered light image calibration. The charge-coupled device (CCD) detector endured the harsh radiation environment at Jupiter without significant damage and exhibited transient image noise effects at about the expected levels. A lossy integer cosine transform (ICT) data compressor proved essential to achieving the SSI science objectives given the low data transmission rate available from Jupiter due to a communication antenna failure. The ICT compressor does introduce certain artifacts in the images that must be controlled to acceptable levels by judicious choice of compression control parameter settings. The SSI team's expertise in using the compressor improved throughout the orbital operations phase and, coupled with a strategy using multiple playback passes of the spacecraft tape recorder, resulted in the successful return of 1645 unique images of Jupiter and its satellites.

Volcanic activity at Tvashtar Catena, Io

“…However, if the energy from a saturated pixel overflows into adjacent pixels (i.e., bleeding occurs), as in the I25 image of Tvashtar (Fig. 2), then the total power over a column of bleeding pixels can be estimated rather precisely by counting the number of pixels into which the charge spilled (Klaasen et al, 1997;Klaasen et al, 1999;Klaasen et al, 2003;McEwen et al, 1998b).…”

“…The Solid State Imaging (SSI) camera on Galileo used an 800 × 800 pixel charge coupled device (CCD) as its detector, with a filter wheel containing eight filters (Klaasen et al, 1997;Klaasen et al, 1999;Klaasen et al, 2003). The filters used for collecting data at Io were the 413 nm (violet), 559 nm (green), 664 nm (red), 756 nm, and 889 nm bandpass filters, a 968 nm cutoff (>968 nm) filter, and a clear filter (380-1100 nm) .…”

Remote Sensing and Data Analyses on Planetary Topography

“…The Galileo mission aimed to conduct high-resolution mapping of the Galileo satellite on Jupiter with far higher resolutions than the Voyager mission [168]. However, the partial failure of the deployment of a high gain antenna reduced the transmitted data set to 10% of the original observations [169]. Especially, Io and Europa mapping outcomes were mostly lost.…”

The search for current geologic activity on Europa

“…First, the Voyager and Galileo images were each calibrated with the appropriate routines (ISIS procedures voycal and ssical), and the spacecraft geometric pointing information was transferred to them (ISIS procedures spicelab and naiflab). See Klaasen et al [1999] for a detailed description of the steps used to calibrate Galileo images. The reseau marks were then cropped out from the Voyager image, and it was ratioed with a noise template to improve image clarity [Eliason and McEwen, 1990].…”