High Winds Aloft

December 2, 1996

How frustrating!!! First, the launch of Mars Pathfinder was delayed on Sunday due to "high winds aloft"--meaning the winds near the ground weren't too bad, but that at several hundred feet up the winds would have posed a danger to the spacecraft or pushed it further out of its planned path than we would have been able to recover from. Now today, a software glitch in the ground system (computers on the ground used to command the spacecraft, as opposed to the computer on board the spacecraft) caused an abort or scrub of the launch when there was only 30 seconds to go before launch. I couldn't believe we'd gotten so close and not been able to launch. It reminded me of the Hubble Space Telescope launch: the time we got down to 13 seconds and then the launch was delayed for a week.

It's currently about 3 a.m. at the Cape, and the last I heard (they still weren't sure what the problem was!) we should be able to launch tomorrow night. Because of the orientation of the Earth with respect to Mars, we have to launch exactly on time, or postpone it for almost 24 hours (minus a few minutes). We're so used to space shuttle launches where they can delayed for minutes or hours, the exact time for Pathfinder may seem a bit odd, but it has to do with the fact that the shuttle only goes to Earth orbit, whereas Pathfinder is going waaaaaaay further than that. I spent the several hours before launch with some friends of mine (who don't work in the space program, but who find it fascinating) who came to the Jet Propulsion Laboratory (where I work) to watch the launch. We saw videos about the mission and a tape of some of the spacecraft and hardware testing that has gone on over the last few years. Pathfinder is using many things that no one else has ever used before so there was more of this sort of testing (as well as more "going back and fixing" of things) than on other projects. The test that most people remember is that airbags (similar to those used in cars but much larger and of tougher materials) will be used to cushion Pathfinder's landing, after a parachute deploys to slow the craft down to about 60 mph. It took quite a long time to find material that was strong enough not to burst on impact, (Pathfinder will bounce several times before it comes to rest) particularly when that impact will almost certainly be on sharp volcanic rocks.

My mind is wandering a bit, as it's late and I'm still very keyed up. One of my brothers and his son showed up about half an hour before the scheduled launch time, and then my mother got there just a few minutes before we were to go, having rushed to get to the train from San Diego (where she lives) to LA, then rushed over from the train station. We were all so disappointed when they said they had to scrub! All that anticipation! In some ways, it's funny: all that build up, and then nothing happens. But it's also scary: the Russian mission, Mars 96, was unable to escape Earth's gravity just a few weeks ago. Somehow, that makes us worry more about our launch, even though neither their spacecraft, nor their launch vehicle are similar to ours. Guess scientists and engineers can be a little superstitious, and believe in good and bad omens, just like anyone else. As I said, it's quite late now, even here on the West Coast, and my cats are trying to crawl in my lap, saying it's time for sleeping. I'm to call in the morning to find out if they've fixed the problem and if we'll try again to launch tonight. Wish us luck!