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OFJ Field Journal from Jim Erickson - 11/27/95

THINKING ABOUT CONTINGENCY PLANS

Thanksgiving was a good break from the pressure. Not only did we get the holiday itself, but we had planned on working Saturday and Sunday on TCM-28 and a tweak of it (a TCM is a trajectory correction maneuver, and to tweak it means to change it after it was sent to the spacecraft to refine it). The project decided that the spacecraft was close enough to the target not to try and correct it, and canceled the maneuver.

But, there is more than enough work to keep us busy, thank you. We gave a final approval for the three background science sequences which will operate during the arrival time period. These sequences are responsible for the recording of the Fields and Particles information as we pass through the Io torus. We begin uplinking them (sending them to the spacecraft) on Thursday.

We've also been doing more work on "contingency plans." These are plans that are prepared to solve specific problems that might happen. It's always better to have foreseen a difficulty, and figured out what steps might be taken to solve it *before* you get hit with the problem. That way, you can fix the problem quickly, and not waste time trying to find a solution right when the spacecraft is about to do something critical. The difficulty with this process is that there isn't a defined stopping point; you can put an infinite amount of work into thinking of possible problems and what should be done in each case. So, judgments have to be continually made about whether a possible problem is likely enough to justify the work. Some of the contingencies we've been thinking about involve the tape recorder that we've been having trouble with. Others involve what to do in the case that our main engine doesn't perform exactly as designed.

With only a week to go, I'm really excited. It's hard to sleep at night. Frequently I get stuck thinking about a possible problem, and I have to just give up, go downstairs and write out what I'm thinking about so I know I won't forget it in the morning. Even doing that I can't always get back to sleep, but sometimes it works. I know what will work, and that is a successful Probe Relay and Jupiter Orbit Insertion.