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OFJ Field Journal from Dave Atkinson - 9/28/95

Thursday, September 28 - Today I finally got the first of my long awaited data sets. Following the probe release in July, and a detailed study of the radio signal from the orbiter when the probe was released, it was possible for the Galileo Navigation team to put together a rather accurate prediction of the probe entry time, location, and where in the atmosphere of Jupiter the probe would be during its descent. According to the data I have, the probe will enter the atmosphere at about 4 minutes, 5 seconds after 3:00 P.M. (Pacific Standard Time) at a latitude of 6.54 degrees North of the equator. This is actually the time that we will find out, on Earth, that the probe has entered the atmosphere. The probe entry will actually occur about 1 hour earlier, but we won't know about it because Jupiter is so far away (the time for the radio signal to travel from the orbiter at Jupiter to Earth is 52 minutes). The entry location is slightly different from what I was told in July, so I have to start asking some questions to find out if this is a real change, or if my calculations are wrong.

It turns out that there's a problem with reading the data file that I got from the Navigation team. This wasn't totally unexpected: if I write a program to read a data file, and then I actually try to use it to read the data file perfectly, often there are small but nettlesome problems. That's what happened to me. The data file I received happens to have a couple of extra spaces placed here and there, and where there used to be a space there is now the number '1'. So, now it is back to the computer to fix my program so that it can read the new data file. I think that this should be pretty easy to do.