PDA

View Full Version : Apollo 13 question



Kelfazin
2006-Apr-07, 11:45 PM
One question I've always had is, during the Trans-Earth Coast when the LM got so cold, couldn't the astronauts have put on their space suits to keep them warmer? I'm fairly well versed on the Apollo program so I know there were interior space issues, and that the suits weren't that comfortable, but wouldn't it have been better than freezing? What do I not understand here?

01101001
2006-Apr-08, 12:12 AM
I haven't investiaged whether the site has credibility, but http://www.vibrationdata.com/space/Apollo13.htm says:


The temperature inside the lunar module was very cold. Here is an excerpt from James Lovell: "Fred and I even put on our heavy lunar boots. Jack didn't have any, so he put on extra longjohns. When you were moving around, the cold wasn't so bad, but when you were sitting still, it was unbearable."

Fred Haise said that the temperature inside the lunar module dipped to 32 degrees F. He also said that the body heat of the three astronauts "helped keep you warm."

Note that the lunar module was designed for two astronauts. Inside, it was not much larger than a telephone booth. Yet it served as a lifeboat for all three men. Lovell and Haise were unable to wear their full lunar suits due to limited room.

Kelfazin
2006-Apr-08, 12:24 AM
They could have worn the suits though, because they were going to wear them while on the actual Lunar Mission. If they chose not to wear them due to comfort and felt they were basically warm enough than I guess it makes. I just feel like, had I been there, i would have chosen the warmth. But I also live in the desert and hate being cold so who knows for sure. :)

01101001
2006-Apr-08, 02:01 AM
They could have worn the suits though, because they were going to wear them while on the actual Lunar Mission. If they chose not to wear them due to comfort and felt they were basically warm enough than I guess it makes. I just feel like, had I been there, i would have chosen the warmth. But I also live in the desert and hate being cold so who knows for sure. :)
It was cold. They were cold, especially when not moving. The quoted material says it was a volume issue, that there wasn't room for 3 men in the 2-man LEM if they wore their suits. They probably tossed the suits and anything else movable into the Command Module so they'd have enough room in the "lifeboat".

You might be interested in the discussion in the NASASpaceflight.com forum: Apollo 13 spacesuits to keep warm (http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=1805&start=1)

Bob B.
2006-Apr-08, 12:08 PM
There was concern that wearing the suits would cause the astronauts to perspire, and the perspiration would then cause a worse situation than if they hadn't wore the suits at all.

Cugel
2006-Apr-08, 12:45 PM
What I have read about this issue is basically the same as what Bob said. You cannot wear these suits without running their internal airconditioning units as well. Otherwise the perspiration becomes unbearable very quickly. Unfortunately, there wasn't enough electrical power to run the airco of the suits, so it was never an option. (Except for the boots)

Kelfazin
2006-Apr-08, 03:17 PM
Ah, now the sweating issue makes a lot more sense. Sweating would bring on hypothermia very quickly with no medical help available. As far as the volume issue 01101001 mentioned, could the crew members have spent time inside the CM during the coast?

Bob B.
2006-Apr-08, 09:38 PM
As far as the volume issue 01101001 mentioned, could the crew members have spent time inside the CM during the coast?
The astronauts did occupy both the LM and CM. I believe they move into the CM for their sleep periods. I recall hearing that when they put shades over the windows to darken the cabin the temperature plummeted. In retrospect, using the shades was a bad mistake because the spacecraft never warmed up again. I believe the CM got colder than the LM, but I'm not sure about that. It's possible they spent more time in the LM because it was slightly warmer.

I also recall reading that when the astronauts stayed very still their body heat would cause a layer of warm air to form around them. The warm air would hang around their bodies because of the zero-g condition. As long as they didn't move they could get somewhat comfortable, but as soon as they moved the air got stirred up and the warm layer would dissipate.

JohnD
2006-Apr-08, 10:46 PM
Agree with that last, but you don't need zero-g. I've fallen asleep in normal clothing on trains or road vehicles, and woken up warm, only to suddenly be cold as I start to move again. I'm not a frequent flyer, so can't say if it works in the air too!

Warm still air, as in air trapped in clothing, is the best insulator due to a large coefficient of heat and low conductivity. Most thermal insulation that isn't a vacuum (as in flask) or a metallic coating is gas that cannot convect, as in polystyrene foam or a string vest! For the same reason, air that can move is a good cooling agent - wind chill or blast freezing.



John