Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!philabs!seismo!hao!hplabs!sri-unix!Halbert.PA@PARC-MAXC.ARPA From: Halbert.PA@PARC-MAXC.ARPA Newsgroups: net.space Subject: Fender benders in space! Message-ID: <3241@sri-arpa.UUCP> Date: Tue, 19-Jul-83 12:48:39 EDT Article-I.D.: sri-arpa.3241 Posted: Tue Jul 19 12:48:39 1983 Date-Received: Thu, 21-Jul-83 17:07:31 EDT Lines: 27 >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): ----- ... 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. ... ----------------------------------------------------------------