Re: Questions about Apollo 13
- From: "Stuf4" <tdadamemd-spamblock-@xxxxxxxxxx>
- Date: 1 Nov 2006 20:08:28 -0800
From PP@xxxxxx:
And one for Sy: I just got to see the show from the History Channel
last week. You mentioned that you requested the cryo stir, either an
extra one or maybe just at an unscheduled time, don't remember which.
Do you think the timing of the stir had anything to do with the
explosion, or was it likely to happen whenever the next stir took
place?
There has been a lot of feedback presented to this forum that the word
'explosion' is a term that was not used in the many descriptions of the
incident that were published in the official NASA report:
===============
And here are some pertinent quotes from NASA's official "REPORT OF
APOLLO 13 REVIEW BOARD" (http://history.nasa.gov/ap13rb/ch1.pdf) that
have been posted:
"It is now clear that oxygen tank no. 2 or its associated tubing
lost pressure integrity because of combustion within the tank,
and that effects of oxygen escaping from the tank caused the
removal of the panel covering bay 4 and a relatively slow leak
in oxygen tank no. 1 or its lines or valves."
"After the relatively slow propagation process ... took
place, there was a relatively abrupt loss of oxygen tank no. 2
integrity. About 69 seconds after the pressure began to rise, it
reached the peak recorded, 1008 psia, the pressure at which the
cryogenic oxygen tank relief valve is designed to be fully open.
Pressure began a decrease for 8 seconds, dropping to 996 psia
before readings were lost."
"27. Findings
a. The pressure relief valve was designed to be fully open at
about 1000 psi.
b. Oxygen tank no. 2 telemetry showed a pressure drop from
1008 psia at 55:54:45 to 996 psia at 55:54:53, at which time
telemetry data were lost.
Determination
This drop resulted from the normal operation of the pressure
relief valve as verified in subsequent tests."
===============From p5-22, http://history.nasa.gov/ap13rb/ch5.pdf
....and this is from an old post with a reference to a diagram in the
official report that clearly shows how the tank was designed not to
explode catastrophically:
===============
It is part of EECOM's job to know the possible failure modes for
systems they are responsible for. They are thoroughly trained in the
design of, and use of, the O2 tank's overpressure "Relief valve". See
page 4-3, figure 4-1 titled "Oxygen tank no. 2 internal components":
http://history.nasa.gov/ap13rb/ch4pt.1.pdf
This diagram shows how the tank was designed with a "Blowout disc" (at
top). The tank was engineered to not explode. The Relief valve was
the safety. The Blowout disc was the safety to the safety, to protect
for a case of operators not catching the overpressure condition in
time.
An O2 tank actually exploding would easily have catastrophic results.
Designers knew this so they redundantly protected against it.
The reason to protect against it is so that your other critical systems
will still be useable in the case of a blowout disc expulsion. I would
expect this information to be known by the systems experts, and if not
then I would expect this info to have been volunteered in a simple
phone call from Downey (North American).
===============
~ CT
.
- Follow-Ups:
- Re: Questions about Apollo 13
- From: Stuf4
- Re: Questions about Apollo 13
- Prev by Date: Re: Whatever happened to MCS?
- Next by Date: Re: Questions about Apollo 13
- Previous by thread: Missile Design Bureau and Soviet Manned Space Policy 1953-1970
- Next by thread: Re: Questions about Apollo 13
- Index(es):
Relevant Pages
|
