henry@utzoo.uucp (Henry Spencer) (01/24/88)
[Special advance sneak peek at the Jan 4 issue reveals what happened.]
The Dec 19 test actually was done on Dec 23; the delay was due to some
minor malfunction in control gear. The test was a cold-weather one,
obviously, with heaters on the joints and other key places. The hardware
was intended to be the definitive fixed version. One other major feature
of the test was right-to-the-stops nozzle gimballing, much more severe
than a shuttle flight would use except in the event of serious trouble.
The test superfically went fine, no problems.
Unfortunately, when the booster was inspected a few days later, a problem
surfaced. The joint between the swivelling nozzle and the booster casing
is sealed by a flexible "boot". That boot is held on by composite clamping
rings. One of the clamping rings was seriously damaged, with material
missing over a wide arc. More will be known when the booster is disassembled
for closer inspection. Nobody is sure yet whether it was a manufacturing
defect or a design flaw. The clamping ring was of a new design, put in to
solve some minor problems with the old one; the old design might be used
instead as a fallback measure. Regardless, the next launch will slip from
June to September or thereabouts: assessing this problem and sorting out
what to do about it will take time, and there is no longer any slack in
the schedule.
The head of the NRC oversight team says that the problem is not disastrous
and would not have caused an accident if it had occurred in flight. He
also said that it vindicated the policy of complete design review, rather
than just fixing the problem that destroyed Challenger.
--
Those who do not understand Unix are | Henry Spencer @ U of Toronto Zoology
condemned to reinvent it, poorly. | {allegra,ihnp4,decvax,utai}!utzoo!henry