Why do astronauts wear pressurized suits?

Answer 1

There is no atmospheric pressure and no oxygen in outer space to sustain life. Inside the spacecraft, the atmosphere can be controlled so that special clothing isn't needed, but when outside, humans need the protection of a space suit. Besides providing protection from bombardment by micrometeoroids, the space suit insulates the wearer from the temperature extremes of space. As well as provides other "creature comforts".
ie: air conditioning, urine collection, oxygen, etc.

Edit Hey :bostonianinmo, once again you have NO idea what you are talking about.
According to NASA's own Astrophysicist Team:



"The Question
(Submitted June 03, 1997)

How would the unprotected human body react to the vacuum of outer space? Would it inflate to bursting? or would it not? or would just the interior gases hyperinflate? We are also relating this to short-term exposure only. This question primarily relates to the pressure differential problems. Temperature or radiation considerations would be interesting as well.

The question arose out of a discussion of the movie 2001. When Dave "blew" himself into the airlock from the pod without a helmet, should he have "blown up" or is there "no difference" as shown in the movie correct?

The Answer

From the now extinct page http://medlib/jsc.nasa.gov/intro/vacuum.html:

How long can a human live unprotected in space?

If you don't try to hold your breath, exposure to space for half a minute or so is unlikely to produce permanent injury. Holding your breath is likely to damage your lungs, something scuba divers have to watch out for when ascending, and you'll have eardrum trouble if your Eustachian tubes are badly plugged up, but theory predicts -- and animal experiments confirm -- that otherwise, exposure to vacuum causes no immediate injury. You do not explode. Your blood does not boil. You do not freeze. You do not instantly lose consciousness.

Various minor problems (sunburn, possibly "the bends", certainly some [mild, reversible, painless] swelling of skin and underlying tissue) start after ten seconds or so. At some point you lose consciousness from lack of oxygen. Injuries accumulate. After perhaps one or two minutes, you're dying. The limits are not really known.

You do not explode and your blood does not boil because of the containing effect of your skin and circulatory system. You do not instantly freeze because, although the space environment is typically very cold, heat does not transfer away from a body quickly. Loss of consciousness occurs only after the body has depleted the supply of oxygen in the blood. If your skin is exposed to direct sunlight without any protection from its intense ultraviolet radiation, you can get a very bad sunburn.

At NASA's Manned Spacecraft Center (now renamed Johnson Space Center) we had a test subject accidentally exposed to a near vacuum (less than 1 psi) in an incident involving a leaking space suit in a vacuum chamber back in '65. He remained conscious for about 14 seconds, which is about the time it takes for O2 deprived blood to go from the lungs to the brain. The suit probably did not reach a hard vacuum, and we began repressurizing the chamber within 15 seconds. The subject regained consciousness at around 15,000 feet equivalent altitude. The subject later reported that he could feel and hear the air leaking out, and his last conscious memory was of the water on his tongue beginning to boil.

Aviation Week and Space Technology (02/13/95) printed a letter by Leonard Gordon which reported another vacuum-packed anecdote:

"The experiment of exposing an unpressurized hand to near vacuum for a significant time while the pilot went about his business occurred in real life on Aug. 16, 1960. Joe Kittinger, during his ascent to 102,800 ft (19.5 miles) in an open gondola, lost pressurization of his right hand. He decided to continue the mission, and the hand became painful and useless as you would expect. However, once back to lower altitudes following his record-breaking parachute jump, the hand returned to normal."

References:

Frequently Asked Questions on sci.space.*/sci.astro

The Effect on the Chimpanzee of Rapid Decompression to a Near Vacuum, Alfred G. Koestler ed., NASA CR-329 (Nov 1965).

Experimental Animal Decompression to a Near Vacuum Environment, R.W. Bancroft, J.E. Dunn, eds, Report SAM-TR-65-48 (June 1965), USAF School of Aerospace Medicine, Brooks AFB, Texas.

Survival Under Near-Vacuum Conditions in the article "Barometric Pressure," by C.E. Billings, Chapter 1 of Bioastronautics Data Book, Second edition, NASA SP-3006, edited by James F. Parker Jr. and Vita R. West, 1973.

Personal communication, James Skipper, NASA/JSC Crew Systems Division, December 14, 1994.

Henry Spencer wrote the following for the sci.space FAQ:

How Long Can a Human Live Unprotected in Space?

If you *don't* try to hold your breath, exposure to space for half a minute of so is unlikely to produce permanent injury. Holding your breath is likely to damage your lungs, something scuba divers have to watch out for when ascending, and you'll have eardrum trouble if your Eustachian tubes are badly plugged up, but theory predicts -- and animal experiments confirm -- that otherwise, exposure to vacuum causes no immediate injury. You do not explode. Your blood does not boil. You do not freeze. You do not instantly lose consciousness.

Various minor problems (sunburn, possibly "the bends", certainly some [mild, reversible, painless] swelling of skin and underlying tissue) start after 10 seconds or so. At some point you lose consciousness from lack of oxygen. Injuries accumulate. After perhaps one or two minutes you're dying. The limits are not really known.

References:

The Effect on the Chimpanzee of Rapid Decompression to a Near Vacuum, Alfred G. Koestler ed., NASA CR-329 (Nov. 1965)

Experimental Animal Decompression to a Near Vacuum Environment, R.W. Bancroft, J.E. Dunn, eds, Report SAM-TR-65-48 (June 1965), USAF School of Aerospace Medicine, Brooks AFB, Texas.

You would probably pass out in around 15 seconds because your lungs are now exchanging oxygen out of the blood. The reason that a human does not burst is that our skin has some strength. For instance compressed oxygen in a steel tank may be at several hundreds times the pressure of the air outside and the strength of the steel keeps the cylinder from breaking. Although our skin is not steel, it still is strong enough to keep our bodies from bursting in space.

Also, the vapor pressure of water at 37 C is 47 mm Hg. As long as you keep your blood-pressure above that (which you will unless you go deep into shock) your blood will not boil. My guess is that the body seems to regulate blood pressure as a gauge, rather than absolute pressure (e.g. your blood vessels don't collapse when you dive 10 feet into a pool).

The saliva on your tongue might boil, however.

For more information and references, see http://www.sff.net/people/geoffrey.landis/vacuum.html

Hope this helps!
The Ask an Astrophysicist Team "

Answer 2

While a space craft is pressurized if it sprung a leak the astronauts would have to put on their pressurized suits if they didn't then the oxygen and other gases in the blood would come out of suspension which is what happens to a soda when you open it that same fuzzy foam will form in the body and kill the astronaut. It should also be noted that their is no air in space an d no air pressure.

Answer 3

The maximum pressure altitude that a human can live in is under 20,000 feet. Some people suffer altitude sickness as low as 7,000 feet, one of my friends (a twenty something woman from LA) couldn't get out of the car on the south rim of the grand canyon.

There are a couple of basic issues that the human body can't overcome, one is that oxygen needs to be provided to the lungs in sufficient quantities to support life. The pressence of gas molecules equates to pressure and humans need about 1.2psi partial pressure of oxygen to live.

You could just supply pure oxygen to the lungs, but then you'd have the chest cavity pressurised to 1.2psi and you wouldn't be able to breathe out again.

There's also the issue of temperature and fluid loss, without any pressure around your body you would evaporate off any moisture that didn't get squeezed out by your 15 psi internal pressure. The temperature of space is down near absolute zero in the shaddows and roasting hot in the sun. When the sun is visible in space it is much hotter than the hottest day in death valley, the ultraviolet would also toast you to a crisp. In shaddow you radiate heat like an unlagged water heater.

You need the pressure suit to heat, cool and compress you. Without it you'd be dead in seconds.

Answer 4

You don't think about it, but you are moving around in a fluid we call air. The weight of the air above us is equal to 1 atmosphere, or about 14.7 pounds per square inch. Now, you might say something like, "That can't be, I have hundreds of square inches over my body and it that were true, I would be crushed." That would be true, except that we have the same 14.7 psi on the inside as well.
For an astronaut to function for longer than a few minutes, he must have air, but in space the outside air pressure is zero or close to it. For him to breath air, he gets the 14.7 psi into his lungs. If the counter 14.7 psi were not present on his outside, his blood would likely boil and within a fraction of a second, he would die. He would freeze to death very quickly, if the pressure didn't kill him first.

Answer 5

In a pressurized environment one can control temperature and air availability (not to mention air pressure). All these things are required for living beings to live in space. Since space is, for practical understanding, a vacuum, we couldn't live there without having this ability.

Answer 6

Because there's no air in space. If the suit wasn't pressurized, they'd die in a matter of seconds. In the vacuum of space, blood will boil at room temperature.

Answer 7

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Answer 8

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Answer 9

Astronauts have to wear presurized everything because if they don't, then the person will be crushed by the pressure that outer space holds.

Answer 10

There is no air in space. The astronauts would suffocate without the suits--to say nothing of freezing to death in the cold!

Answer 11

Because the difference in atmospheric pressure would cause them to explode