How much does a spacesuit weigh?

The spacesuit weighs approximately 280 pounds (on the ground) without the astronaut in the suit, but including the backpack. Of course, it weighs nothing in space (even if its mass remains unchanged). (See also the answer to Question 12).

How come the astronauts have to wear such heavy equipment?

As long as the crew is inside the pressurized living modules, they wear what people on the ground wear on a warm spring day, usually shorts, a short-sleeve shirt, and socks (since their feet need some bump protection and may get cool, but do not need shoes since they do not walk). They only have to wear special suits during launch and return and when they go outside the pressurized modules to perform an extravehicular activity, or EVA. The launch/landing suits are to give them fire protection and to keep pressure around their bodies if the Shuttle pressurization system failed.

The spacesuits used for EVA must provide breathing gases and pressure for the body so that the crewmember can survive. It must provide protection to the crewmember from sharp objects and fast traveling space debris, so that the suit will hold its pressure. It must provide warmth when the crew is out of the Sun''s heat and cooling when directly exposed to the sun. The suit must provide radio control to the ground, the Shuttle, and the other EVA crewmembers. It must provide lighting for space excursions and for dark workstations, and protection to the crewmember's eyes when in direct sunlight. It must carry space tools attached to it for working on external hardware. It must provide for the crewmember's physiological needs, such as food and water intake and excrement deposit. The suit must continue to function for up to six hours without failures. And it must be adjustable to fit several crew sizes. As you can see, it has to be a little spacecraft in itself. Hence, it has grown to weigh about 280 pounds on Earth, though it weighs nothing in space. (See also the answers to Questions 2 and 16).

Editor:Yang Jie