[sci.space.shuttle] Engine Problem on Shuttle

rcpilz@ablnc.ATT.COM (Robert C. Pilz) (05/02/89)

The shuttle was shut down with 31 seconds left in the countdown.
It was determined that engine #1 had a problem with the pump
that cools the engine. Also, a leak in the hose to the pump
was detected.
I would like to know:
How serious was that problem? What would happen if that problem
was not detected? Abort to Orbit as in a previous mission?
Which engine is engine #1? Was the pump one of those new turbo
pumps that were redesigned since Challenger? Could Magellan
have been launched from a diminished orbit?
Although I was disappointed, I have the feeling that people out
at KSC are being more careful. Am I being naive?

R.C. Pilz
AT&T IMS
Orlando FL

phil@titan.rice.edu (William LeFebvre) (05/04/89)

In article <2282@ablnc.ATT.COM> rcpilz@ablnc.ATT.COM (Robert C. Pilz) writes:
>It was determined that engine #1 had a problem with the pump
>that cools the engine.

Sort of.  It was a recirculation pump.  It is activated within the last
few minutes to bring the engine down closer to the temperature of the
fuel.  I don't believe that it is used after liftoff.

>I would like to know:  How serious was that problem?

Very.

>What would happen if that problem was not detected?

There would have been unexpeted stresses in the engine as very cold liquid
hit metal that was about ambient temperature.  Sudden contraction of the
metal, I suspect.

>Abort to Orbit as in a previous mission?

What probably would have happened is that the on-board computers would
have detected something wrong with the engines between T-6 seconds and T-0
(the main engines are started at T-6s) and would have halted the countdown
before it reached T-0.  If that didn't happen, then the engine would have
been shut down within the first 2 minutes of flight (assuming it didn't
fly apart, that is) and they would have done an RTLS (return to launch
site) abort after the SRBs separated.

>Was the pump one of those new turbo
>pumps that were redesigned since Challenger?

No, I believe that the turbo pumps are something entirely different.

>Although I was disappointed, I have the feeling that people out
>at KSC are being more careful. Am I being naive?

I think that in this particular case, KSC did the appropriate thing.  But
can you really blame them for being overly cautious?  They cannot afford
another catastrophe from a political and PR standpoint.  You and I know
that this is a risky business, the astronauts know it, the launch and
flight controllers know it, most of the people reading this message know
it.  But Joe Average Taxpayer and John Average Congressperson don't know
it.  And you can't convince them of the risks, either.  Public support
would fall to almost nothing, whether NASA deserved such treatment or not.

Oh well.....off my soapbox and back to work.

			William LeFebvre
			Department of Computer Science
			Rice University
			<phil@Rice.edu>