Posted on 04/15/2016 5:23:58 PM PDT by MtnClimber
While planning the lunar landings, Nasa had a decision to make: What route would they use to reach the Moon? It was one of many that needed to be made, but little did they know then, it would have an important effect of the survival of the ill-fated Apollo 13 crew.
This Sunday, 17 April, marks the safe return of James Lovell, “Jack” Swigert and Fred Haise after almost 88 tense hours on board their critically wounded craft thanks to that stroke of luck. The drama started unfolding at almost 56 hours Ground Elapsed Time (GET), meaning it was the evening of 13 April in Houston. Shortly after a live television broadcast, Mission Control had asked Apollo 13 to run through some standard checks.
"13, we've got one more item for you, when you get a chance. We'd like you to stir up the cryo tanks,” said capsule communicator Jack Lousma at Mission Control. The purpose of stirring the cryogenic tanks containing the hydrogen and oxygen was to give more accurate readings of how much gas was left. But because of an electrical fault, one of the oxygen tanks exploded. Initially the crew thought a meteoroid had hit them, but it soon became apparent they were losing oxygen. “It looks to me… that we are venting something,” replied Jack Swigert. “It’s a gas of some sort.” The clock was ticking. The explosion on board Apollo 13 marked the start of one of the greatest rescue missions in human exploration, but the three crewmembers owed their lives to a decision made years previously.
(Excerpt) Read more at bbc.com ...
I asked a thermodynamics question and that's your answer.
THAT'S bizarre.
So?
You forgot about one method of heat loss. RADIATION. Less than 25 percent of the LEM/Command Module was exposed to sunlight, the remainder was radiating away heat into space.
There was also heat loss due to emergency depressurization.
Radiation is all I've been talking about, if you read my posts. What people don't realize is that the vacuum of space is an insulator. Radiation is very inefficient. Also, human bodies generate heat. Read the posts.
Excellent book reference on the overall subject, thanks. However AFAIK, the depressurization was the explosive rupture of the Service Module bay when the oxygen tank blew up - not in the Command Module where the astronaut were. So I’m not clear on how that lowered the CM temperature.
The atmosphere acts as a blanket slowing radiative cooling.
The common Thermos bottle has a contained vacuum and the glass liner is silvered or aluminized to slow radiative heat transfer.
You just go right on believing what you like,and I’ll just hope you are not in a position to do harm.
The atmosphere enables the convective cooling off the earth, which is orders of magnitude more efficient than radiation. The atmosphere itself then radiates heat into space.
What is really interesting, though, is that you find it necessary to make personal insults over a discussion of thermodynamics. That really is evidence of mental instability.
When they designed the LEM they took the heat generation into account. That's one of the reasons the LEM has all those flat surfaces and angles: To passively radiate the heat from the computer and astronauts.
During Apollo 13 they had to shut down all the fancy tech, so they removed a lot of heat generation. But they couldn't adjust the shape and materials of the spacecraft, so they kept radiating heat at the same rate. This means the ship got colder.
The very low gas density of space would mean the heat loss would be solely due to radiation and not the much faster convection.
Without the astronauts thermal emissions to maintain the low temperature equilibrium the ship would eventually reach background temperature.
No problem, I welcome the discussion. Like you, I’ve been thinking about the LM. Hooked to the CSM, if NASA is telling the truth about the temperature, maybe the entire LM acted as a giant radiator, and that was how the * joined * spacecraft got rid of the astronaut’s body heat. It would also solve the mystery of why the LM didn’t freeze solid. The walls of the LM are thin aluminum. So the body heat kept the LM above freezing, while the LM radiation effect lowered the living temperature to just above freezing. So it all depends on which direction you look at it from, to determine whether the resulting temperature was “hot” or “cold” inside.
They weren't in a vacuum... they were in a pressurized capsule with oxygen (and CO2) in it.
Radiation works very well in space. If you're facing the sun you heat up, in the dark and you cool down.
Gee thanks. So what happens when you face both at the same time on either side of the space craft? Why does the ISS need giant radiator panels? Why does the CSM bother with an active Environmental heat exchange system? What happens when it is turned off? Or are those questions to difficult to consider?
Thanks for sharing your wisdom though - sun hot, dark cold. I'll keep that in mind.
Which, in turn, was surrounded by a vacuum.
Bzzzzt. Next.
http://science.nasa.gov/science-news/science-at-nasa/2001/ast21mar_1/
The Earth's surrounded by a vacuum too... so what's your point?
So cute. Never change!
Well for one thing, scale.
But don't worry about it.
Personal contempt in a science discussion.
Classy.
Do your own research. Own your own opinions. Stop boring me
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