Re: What if Apollo fire in orbit?


"Heinrich Zinndorf-Linker (zili@home)" <spam-trash@xxxxxxx> wrote in message
news:e8uh37$4a2$01$1@xxxxxxxxxxxxxxxxxxxx
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.

Unfortunately you're apparently overlooking a little detail. The diaphragm.

The astronaut can push air away and suck it in. The candle can't.

Now, obviously they do use fans on spacecraft and this might provide enough
"wind" for a candle.

Studies done on the shuttle in burn boxes tend to show that candles "pulse"
as they heat up air around the wick, it moves out in all directions,
suffocates the flame, goes down, new O2 comes in, etc. But not a continuous
burn like on Earth.


Note, I believe one lesson learned from Mir was in the event of a fire on
orbit the procedure is to shut down all fans.



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...

Definitely.



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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