Project Mercury Project Mercury is the name that has been given to the initial United States man-into-space program. The capsule designed to carry our first astronaut into space is conical in shape and barely large enough to accommodate one man, one of the seven astronauts who have been selected and trained for flight into space. The capsule weighs about one ton and is 9½ feet high and 6½ feet in diameter. It is equipped with controls to keep it stable and to regulate its position so that the blunt nose end faces forward. When the astronaut has completed his orbital trip, small rockets in the blunt end of the capsule will be fired to slow down his speed. As speed decreases the capsule will lose altitude and be pulled toward the earth by gravity. To protect the capsule from burning up when it re-enters the earth's atmosphere, its nose end is equipped with a fiber-glass shield that vaporizes under the intense heat caused by the friction of the air. When the capsule's speed has been slowed to a certain point, parachutes will open automatically to help ease its descent to the earth.