It's simply amazing anytime astronauts perform an EVA (Extravehicular Activity) because they're only protected by
inches of material in a pressure-suit. So far, Space Shuttle Discovery's STS-114 crew have performed three spacewalks.
In space, the suit has to protect them from various conditions, such as:
--Temperature
--Radiation Exposure (UV Light, Solar Flares, etc.)
--Micrometeoroids and Debris (including sand and dust)
--Chemical Contamination
--Potential Hazards (that could cause entrapment, snagging, tearing, or puncturing the suit)
--Radiation (being emitted from high-power electromagnetic transmitters--microwave, radar, laser, radio, UV/IR visible lamps--on the space module with exterior antennas)
--Electrical Voltage (from inadvertent grounding of electric circuits and from electrical discharge resulting from static charge buildup)
--Positive Pressure (Rupture by overpressurization of the crewmember's suit)
The design of the space suit is also intricate and true "rocket science," as these simplified diagrams show:
