Halbert.PA@PARC-MAXC.ARPA (07/19/83)
>From a message from Phil Karn sent to the Ham-Radio list, about the new
amateur radio satellite, OSCAR-10 (it's doing OK now):
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...
Telemetry from the launcher showed that all events up to and INCLUDING
separation of OSCAR-10 from the third stage of the Ariane were perfectly
nominal. This explains why the "event frame" stored away by the
Oscar-10 computer 1 second after separation showed proper sun angles, etc.
At separation time, two pyrotechnic bolt cutters fired to release our
spacecraft, and three separation springs mounted on the attach fitting
propelled us out from the lower SYLDA half-shell and away from the top
of the Ariane at about .5 meter/second.
At 53 seconds after separation and again about 1 second later, the
accelerometers on the launcher registered "bumps". This was the third
stage slamming back into our payload. It turns out that the onboard
sequencer had been programmed to vent extra liquid oxygen, probably
through the engine bell, and the resulting impulse slowly accelerated
the stage to the point where it "caught up" with us. The impact
velocity was estimated to be 1.5 meters/sec. If the stage had been
reoriented to point in a different direction before venting, the
collision would have been avoided.
...
----------------------------------------------------------------REM@MIT-MC@sri-unix.UUCP (07/22/83)
From: Robert Elton Maas <REM @ MIT-MC> How dumb can they be!!!! Didn't they simulate the whole launch and orbital sequence on a computer and notice that the booster was drifting uncomfortably close to the Oscar-10 satellite and decide to make sure they were far apart? Or didn't anyone on their staff randomly do an armchair calculation and notice the booster wasn't far away and wonder if it could possibly be within collision distance? (Gee, monday-morning quarterbacking is fun and accurate isn't it!)