Vostok, Russian for “east,” was a small, relatively simple spacecraft, consisting of a cabin and an instrument module. The spherical, 7.5-foot-diameter cabin was large enough to accommodate only one person. The outside of the cabin was coated with a protective heat shield. Communication antennae extended from the top of the cabin, and nitrogen and oxygen tanks for life support were stored beneath it. The instrument module, containing a small rocket and thrusters, was strapped to the cabin with steel bands.