|The Department Graduate Students Ground-Based Research|
Mariner 10 |
Pioneer Venus |
Voyagers 1 & 2 |
Mars Observer |
Lunar Prospector | IMAGE
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I started here in July of ’79, and preparations were made for the encounter of Pioneer 11 with Saturn. By September, I was up there at NASA Ames, in the Mountain View, California area, to help run the instrument, the imaging photopolarimeter that Tom Gehrels had developed on the Pioneer spacecraft. Because I was single and unattached, they gave me the graveyard shift, midnight to 8am, because they needed people there 24 hours a day to help run the instrument—send the commands up to the instrument and watch the data coming back.
It was a long roundtrip time. I think it was about three hours roundtrip, a big travel time between the commands and response. That was one of the most exciting things I ever did in my career, actually being in that big control room and watching the data come down on the consoles.
The most exciting moment of that mission was the ring-plane crossing. You have to realize at that time there wasn’t that much knowledge about the Saturn system. Even though the Pioneer spacecraft was passing Saturn at a distance that was beyond the boundaries of the known rings, we didn’t know what sort of particles would still be in those rings that hadn’t been visible from Earth. The issue was whether the spacecraft would be destroyed at that instant, as it passed through the ring plane.
This was not only important for the survival of the spacecraft itself and the continuity of the mission, it was also important for the upcoming Voyager encounters with Saturn, because they wanted to know how close they could get. I think, in fact, it had to do with whether they would be able to deflect the spacecraft off to go to Uranus afterwards and so on.
So there was a lot at stake in this ring-plane crossing. We had this big electronic clock up in front of the room, showing the Earth-received time of the carrier wave signal from the spacecraft, and they were counting down on that to see if the spacecraft would survive. Of course, if the spacecraft had been destroyed there would have been just a complete loss of signal.
During that countdown, we—at least I—forgot that I was sitting at Ames and really felt more like we were there with the spacecraft. We were the ones going through the ring plane and trying to decide if we were going to survive or not. So this countdown, watching for this continuity of the signal, was really a pretty exciting moment.
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