" How is the pressure adjusted by the suit?

 

Life without air pressure

Maintaining proper pressure inside a space suit is essential to astronaut survival during a spacewalk. A lack of pressure will cause body fluids to turn into gas, resulting in death in a few seconds.

. While making spacewalks possible, pressure produces its own problems. An inflated space suit can be very difficult to bend. In essence, a space suit is a balloon with an astronaut inside. The rubber of the balloon keeps in oxygen that is delivered to the suit from pressurized oxygen tanks in the backpack. But, as pressure inside the balloon builds, its walls stiffen, making normal bending motions impossible. Lack of flexibility defeats the purpose of the space suit: mobility and the ability to do work in space.

Is there pressure outside the space suit?

 In space, outside of the Earth's atmosphere, there are almost no molecules in the gas that surrounds the International Space Station. The absence of molecules, means that the air pressure is extremely low – in fact it is almost zero, so it is nearly a perfect vacuum 

What did the spacesuit designers learn?

Space suit designers have learned that strategically placed breaking points at appropriate locations outside the pressure bladder (the balloon-like layer inside a space suit) make the suit more bendable. The breaking points help form joints that bend more easily than unjointed materials. In the restraint layer, stitching folds spread apart and contract to aid bendability. Joints are also built into this layer, serving like ribs on a dryer vent hose to make the layer easier to bend.

Benefiting from the Apollo Flight and the NASA Project

We want someone in our suit to have the mobility of a geologist on Earth," says Raul Blanco, deputy manager of the EVA (Extravehicular Activity) systems project for Constellation, NASA's current program aimed at sending humans beyond low Earth orbit. His team is "picking the brains" of former Apollo spacesuit designers and looking at current suits worn by shuttle astronauts to prepare for a preliminary design review in 2010. All spacesuit designs must protect humans from the grim effects of depressurization, which occurs during sudden exposure to a vacuum. Under such conditions trapped air can expand and tear fragile tissues in the lungs' air sacs. And water or other fluids vaporize into gases that cause bodily swelling, interfere with blood circulation, and cool the mouth and airways to dangerously low temperatures as they escape the body.

The importance of the suit and the basics of its design 

Spacesuits provide protection from meteors Minutes, radiation and temperatures Maximum.

It also provides oxygen. Spacesuit designs should protect Humans from the effects of lowering pressure, that occur during sudden exposure in the void. 

Under these conditions, trapped air can stretch and tear the fragile tissue in the vesicles of the lungs and convert water or other liquids into gases that cause material damage. Interfere with circulation, cooling the mouth and airways to dangerously low temperatures as they escape the body.