Re: What if Apollo fire in orbit?

Am Mon, 10 Jul 2006 20:57:57 GMT schrieb "EricT":

It's enough for a fire, but not for the sort of sudden massive
conflagration that swept through the Apollo 1 CM. Enough to be trouble,
but probably not enough to be lethal.

I had read somewhere that another reason the 'sudden massive conflagration'
could not occur in orbit is because in a weightless state there would not
have been a draft to feed the flame, as you have on the ground. On the
ground hot gasses rise upward, pulling fresh air (or oxygen in this case) to
the base of the flame, thus giving the fuel an oxidizer (oxygen). In
weightlessness the flame would have burned the fuel and oxygen around the
flame and then would have died out, just smoldered, or perhaps spread but at
a far slower rate then it did on ground at the pad. I do not know what the
atmosphere was on Mir, but if it were pure oxygen it is far better that the
fire occurred in space then in sealed up capsule on the ground.

The same question is discussed at this moment in the German parallel
newsgoup news:de.sci.raumfahrt and MY personal conclusion is, that an
open flame (like e.g. that of a candle) CAN burn sustained in the real
environment of a spacecraft, simply because the Astronauts have to be
able to breathe too, what is ensured by sustained ventilation of the
whole spacecraft. So a stationary mounted candle will burn even in
weightlessness, like any other combustible object will do, if held in
a fixed position.

Other circumstances were, if a candle or other burning object would
float free in midair, and had enough time and air resistance to 'sail'
within the air stream. Then the candle would burn with a spherical
flame, and caused by missing sustained oxygen support within this
special environment would extinguish itself soon with its own exhaust
gases. And caused by that self-extinguishing effect even the
propagation of "stationary" fires should be somewhat restrained.

So the risk assessment concerning fire in a spacecraft should show a
somewhat diminished risk if the spacecraft is on-orbit, but some fire
risk remains everytime, everywhere, nevertheless...
cu, ZiLi aka HKZL

--
Gib mir die Zahlen die Du hast,
und gib mir die Zahlen die Du brauchst -
Und ich suche dann die richtigen Tests raus,
um aus den einen die anderen Zahlen zu machen.
.

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