OFJ Field Journal from Glenn Orton - 10/16/95We had an emergency meeting of many people on the Galileo project this afternoon. A malfunction of the Data Management System (DMS), which is a tape recorder on the spacecraft failed to center itself properly at the start of the three SSI images last Wednesday. It subsequently failed to stop its rewind at the end of the tape track and kept on running for 16 hours before controllers could send out a "manual" stop command.
We learned that, while the issue is far from resolved, a hardware error is apparently more likely than a software error. We fear that the tape is entirely wound on one spool and is unusable for the rest of the mission. While we won't have more information until further tests are in on Thursday or Friday, we started to plan what sort of mission we could mount using only the 100-kbyte memory buffer which was to service the original mission - the one with a functioning high-gain antenna.
To mount new software for getting the data from the instruments into a buffer from which it would be transmitted to the ground will take several months into 1996 to create. This means while most of the Probe data are safe, the remote sensing data which will track the Probe entry site in the atmosphere and establish the correspondence between remote sensing and directly measured results is lost.
This, for me, is pretty devastating news, as this has been the central goal of my Interdisciplinary Investigation since 1978 when I was chosen.
Whatever correlation is done, should the DMS really be unusable, will have to be done from ground-based data. These, in turn, are going to be very difficult to get, as Jupiter is only 9 degrees from the Sun on December 7, and most telescopes just won't point that close to the sun in order to avoid damage to the telescope from focused sunlight. The IRTF is one exception where we practiced last year with NSFCAM and MIRAC2, using a thin film of polypropylene (which you last saw lining the inside of a potato chip bag). We stretched this material over the 3-meter IRTF primary mirror and were able to observe wavelengths of 10 microns and longer with no difficulty, 5-10 microns with a little more time needed to get decent signal, and nothing shortward of 5 microns. Time will tell.