[AR] Re: clustering big rockets
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Sun, 27 Dec 2015 18:42:45 -0500 (EST)
On Sun, 27 Dec 2015, Chris Jones wrote:
Even RCS was the cryo LOX/kero.
True on Buran. The orbital insertion engine on Energiya's first
payload, Polyus, was UDMH/NTO. Due to a Polyus attitude control error,
it was pointing the wrong way when it fired and the payload failed to
achieve orbit, though the Energiya itself had performed correctly.
More precisely, attitude control and propulsion for Polyus were provided
by an FGB tug module -- like some of the Mir add-ons and the Zarya module
which began ISS -- and to give it a launch environment as close as
possible to what it was qualified for, it was at the top end of the Polyus
stack during launch. This meant that the stack had to do a 180deg flip,
to put the FGB aft, before doing the final insertion burn.
The flip was started properly, and then attitude control was turned off
momentarily for FGB solar-panel deployment... and due to a sequencing
error, it was never turned back on. (In hindsight, this could have been
detected in the telemetry records from some of the full-system ground
testing, but the project was way behind schedule by that time, and data
analysis had been sketchy.) So the insertion burn was done with the whole
stack slowly rotating end over end, and net delta-V was nearly zero.
Splash.
Henry
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