Print Story 15 years ago tonight...
By ana (Tue Jul 22, 2014 at 11:43:09 AM EST) (all tags)
I was at the Kennedy Space Center, waiting.

The idea was that the Chandra X-ray Observatory (formerly AXAF, the Advanced X-ray Astronomy Facility) was to be launched on the Space Shuttle mission STS-95, in the wee hours of the morning.

It was the third try, what with weather and various technical problems (a million or so parts all have to work, together, at the same time.) A night launch really lights up the whole county. Since it was the third try, my boss had decided she had to go back to work, and I scored her VIP stand pass, so I got to watch from about 3 miles away (across a lagoon, next to a museum housing one of the few extant Saturn V rockets).

There were a couple of anomalies on the way uphill, including a pin ejected from one of the Space Shuttle Main Engines (SSME), which dinged a hole in the inner surface of the engine bell. These nozzles are actually heat exchangers, preheating the liquid hydrogen fuel before it's burned. Detailed looks up the tail pipe during the launch showed a little jet of flame sticking into the engine bell where it should not have been. It didn't change the thrust much, but the engines did shut down a few seconds early, producing a slightly lower orbit than was planned.

Also one of the power buses that runs the SSME computers failed. There are three engines, each with its own controlling computer. There are three redundant power buses, each powering two SSME computers. So we were covered, but if another went offline, we would have lost an engine, and an even lower orbit (or trans-atlantic abort) would have resulted.

But no harm was done. The astronauts deployed the observatory with its solid-fueled Inertial Upper Stage attached, which boosted it to a much higher orbit, reached several days later. After a commissioning phase of a few months, slowly turning stuff on, letting it outgas, opening covers, etc., we had an observatory. It's been a great mission.

There will be a google+ hangout to celebrate the anniversary, of course. More info here.

Fifteen years later, we're still go for another ten or so, pending availability of funding, and continued good luck in the operations side of things. The NASA Senior Review, which every two years looks at all operating missions, seems to like us. Later on in the fall there'll be a science symposium in honor of Fifteen Years of Chandra Science. The astronaut crew have been invited and most of them have confirmed they'll be there.
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15 years ago tonight... | 2 comments (2 topical, 0 hidden) | Trackback
One more year by wiredog (4.00 / 2) #1 Tue Jul 22, 2014 at 12:05:31 PM EST
Chandra can get a driver's license!

Earth First!
(We can strip mine the rest later.)

Happy snotty teenage hood to Chandra! by Scrymarch (4.00 / 1) #2 Tue Jul 22, 2014 at 12:19:26 PM EST

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15 years ago tonight... | 2 comments (2 topical, 0 hidden) | Trackback