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 ...
No, without operational refrigeration units to force radiant heat loss, there's not enough surface area to radiate the excess heat into space. The spacecraft had a cooling system that needed power, and was shut down. Therefore the heat would have built up. Maybe not enough to kill anyone, but they would have gotten hotter, not colder.
You’re confusing thermal energy and temperature.
Your body doesn’t “pump out 99 degree heat”.
And radiative heat transfer still works just fine in space. You said so yourself. The capsule and everything in it will come to thermal equilibrium, all the while radiating heat out into space.
You’re right, physics is harder for some than for others. Take, for example, the first rule of holes: when you’re in one, stop digging.
I believe that’s the interstellar temperature of big bang cosmic radiation.
The funny thing is your are arguing that what NASA recorded did not happen.
We are in agreement then.
“...and that change - for whatever reason - wasn’t passed on to the people who designed the heater systems...”
A lot, maybe most of the problems I come across is due to a lack of communication. And communicating BEFORE the first nail is driven, hole is dug, or... well I won’t go there.
It is a REALLY big issue for any endeavor.
>> The funny thing is your are arguing that what NASA recorded did not happen.
“Often wrong, never in doubt.”
Here’s something interesting:
“Command Module Cabin Temperature History (°F)”
http://history.nasa.gov/SP-4029/Apollo_18-39_CModule_Cabin_Temperature_History.htm
Read the asterisked footnote for Apollo 13.
But of course NASA must have been mistaken, because Talisker. :-)
Well said. You have more patience than I do.
I think we are in agreement.
>> You have more patience than I do.
Don’t bet on it. :-)
YOU need to study thermodynamics a bit more.
The movie remained very true to Jim Lovell’s book Lost Moon
Typically the average is 100 watts per human adult of heat dissipation. The spacecraft has an enormous differential of surface area relative to the astronauts, to radiate heat from.
As to the movement of heat, have to consider that the radiant transfer of heat goes as the fourth power of absolute temperature difference between surfaces measured on the the Kelvin temperature scale. Outside of the sun and earth/ moon bodies taking up a small portion of the surrounding emptiness and radiating some energy to the ship, the ship being warmer than the vast majority of the backdrop, makes 2.7 K is an almost perfect heat sink.
The radiators spoken of were in the command module to remove any excess heat generated by the multiple fuel cells and the other electronic gear housed there, when they were in operation. No oxygen for operation meant no heat from power production.
Even the lunar lander was rigged to jumper minor amounts of power to the capsule landing systems just prior to re-entry, as the capsule batteries were critically low.
Capricorn One anyone?
Crewcuts and neckties for the win.
Vacuum is not an insulator. Heat transfer occurs by conduction, convection, and radiation. In a vacuum, conduction and convection do not occur. But radiation is maximized when there’s nothing to block it. Spacecraft don’t lose heat by conduction (because there’s nothing to conduct it), or by convection (which requires moving material in a gravity). Spacecraft experience maximum heat loss (or gain, if in sunlight) from radiant heat. Even on earth, deserts experience large heat swings from day to night, because a dry atmosphere doesn’t block radiation very well, so a desert is exchanging increased radiant heat with the sky. At night, the sky is at close to absolute zero, so the desert loses heat quickly.
Um, it’s thermodynamics and physics.
Go sit in a 38DegF fridge with the door closed and see what happens!
Hypothermia is when you lost more body heat than you can make.
I actually met Jim Lovell once at his restaurant in Lake Forest, IL.
He said it was the most surreal experience of his life. (I found his lost credit card)
Thank you for sharing your insights.
North American Aviation in Downey, CA designed the Mercury, Gemini, Apollo and Shuttle rockets. Santa Susana near Chatsworth, CA is a hilly spot with scaffolding to test all the engines. When I asked my father why Apollo 13 was a miracle, he told me that the three astronauts were the best pilots in the country and the Commander, Jim Lovell, was given a most difficult assignment: to pass through the atmosphere at the right angle in order to not get burned up. How tight was the angle? A few degrees. How did Lovell hit it? Perfectly with pure courage, excellent piloting skills and probably a little grace from God.
My father was an engineer for the Navaho. Insiders will know how that rocket triggered the Kennedy speech and NASA. He told me that the basic mathematics for orbiting was taken from Rene Descartes (1596-1650). Shows us the brilliance of French mathematicians.
By the way, the average age of the engineers for the sixteen Apollo missions was 25. The astronauts were always the oldest members of the team at 35. Very humbling.
A good book on the American space industry is William Mellberg, Moon Missions (1997).
http://amzn.com/1882663128
Nervous Tick: But of course NASA must have been mistaken, because Talisker. :-)
It was pretty much a given that my questioning of Muslim-outreach DOD-owned-and-operated NASA would result in mindless insults and mockery from the peanut gallery. So it's not like I'm surprised, although I constantly expect better on FR. Oh well.
My point for those reading this thread, however, is extremely simple - and worthy of consideration. Simply put, it's hard to get rid of excess heat in space, because for all intents and purposes, space is a vacuum. It's not impossible, however. Mainly, excess heat is channeled into radiators, which simply "radiate" the heat into space through the infrared spectrum. In other words, they glow with heat. The problem is that this isn't very efficient, so to be useful, it needs the help of refrigeration-type machinery. Heat exchangers based on conduction and convection, making use of the "atmosphere" inside the spacecraft consisting mainly of the breathable gas environment keeping the astronauts alive.
From there, the heat is channeled into some sort of liquid, that passes through the radiators. Very much like your home refrigerator, but you have to imagine being inside the refrigerator, an that's what people have a hard time understanding. Space is NOT "cold." Space has energy passing through it, and because it's almost a vacuum, measuring "temperature" give low values simply because there aren't a whole lot of molecules of anything to vibrate - and vibrating molecules are what we measure as heat.
As a vacuum, however, space prevents heat loss naturally, in the same way that a vacuum bottle prevents heat loss naturally - because radiatin is a slow and inefficient process. So, since the CSM module used what NASA calls an "environmental control system" (ECS) to moderate temperature, and since that system was complex and ran on refrigeration mechanics principles, and was powered by energy, what happened to the temperature inside the capsule when the power was turned off - and thus, the ECS refrigeration unit was turned off?
The two sources of heat were electronics and bodies. With loss of power, electronics heat stopped. But that heat didn't heat the capsule - it was radiated into space by it's own radiator system anyway, or it would overheat the astronauts. But the ECS also ran on power, and it stopped. So it wasn't available to remove the heat generated by the bodies of the three men. So, my simple question is, why didn't they then heat up the capsule environment, since their heat was no longer being removed by the ECS?
This is a legitimate question, based on sound thermodynamics. Insults, therefore, are merely efforts to run away from the question. I found a NASA publication on the CSM ECS from 1972 at: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720012252.pdf
The Abstract of the paper states: This paper presents a comprehensive review of the design philosophy of the Apollo environmental control system, and the development history of the total system and of selected com- ponents within the system. In particular, discussions are presented relative to the development history and to the problems associatedwith the equipment cooling coldplates, the evaporator and its electronic control system, and the space radiator system used for rejection of the spacecraft thermal loads. Apollo flight experience and operational difficulties associated with the spacecraft water system and the waste management system are discussed in detail to provide definition of the problem and the corrective action taken when applicable.
Notice that the efforts of the ECS are toward COOLING, not heating (or in some cases moderating the cooling to keep things at operational temperatures). That is my point - what happens to the astronauts when that COOLING system is turned off? Obviously, they'd heat up! But the Apollo 13 movie, the Apollo 13 summary report, and all the FReeper geniuses snorting down through their noses at me claim the opposite. So if that's the case, why include a cooling system at all? Seems like a big waste of money and equipment if there was no need for it. Also, take a look at Figure 12 on page 18, that shows the whole CSM ECS system, and remember, on Apollo 13, that entire cooling system STOPPED.
But the astronauts then got cold?
Believe what you want, I won't stop you. After all, Hollywood says they got cold. So you gonna argue with Tom Hanks?
Thank you for playing. Goodbye.
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