fisher@wsgate.DEC (Burns Fisher, MRO3-1/E13, DTN 231-4108.) (08/01/85)
<Bug Abort>
A couple of questions that the abort brings up:
1) Did they use up ~all the fuel in the ET? If not, why not?
2) I thought that the usual abort procedures involved increasing thrust to
109%. Am I wrong, or was this particular abort a special case?
3) At the beginning of the shuttle program, I learned that there were three
primary abort mechanisms: Return to launch site (RTL), Transatlantic Abort
(TAA?) and Abort Once Around (AOA). Is this ATO a relatively new mode?
I initially expected that ATO was just a new name for AOA, and that they would
be landing at the end of the first orbit. Imagine my surprise and pleasure!
What is done differently in an AOA? No (or less) OMS burn?
4) While listening to the ascent, I heard the call "single engine ATO" before
the actual failure. It seems to me that this call used to be called "Press to
MECO". True? Or is ATO different?
5) I understand that for a few seconds before the failure they were discussing
a failure of one of the redundant heat sensors. Unfortunately, the NASA
spokesman was talking over it, so I did not hear until the actual failure.
Did anyone else hear it?
Thanks,
Burns
UUCP: ... {decvax|allegra|ucbvax}!decwrl!rhea!dvinci!fisher
ARPA: fisher%dvinci.dec@decwrl.ARPAalb@alice.UUCP (Adam L. Buchsbaum) (08/02/85)
ATO is a fourth abort option. TAL (transatlantic abort) would have been used, except that Challenger was already 33 seconds past the furthest point from which it could do this. AOA would have been used had Challenger not been able to achieve a stable orbit (note that before the OMS burn, the orbit was 129 by 3 (!!) miles).