The space in an electron tube in which there is no modulated field

A mental representation of a particular problem, including initial, final and possible intermediate states

The guidance operations needed to launch a spacecraft into orbit or space, navigate in space, and return to Earth or some other body

The determination of the three-dimensional position and velocity of a spacecraft (relative to a frame of reference)

(medicine) The branch of medicine that deals with the effects of space travel on human beings

Communication between space vehicles, or between such vehicles and a base on Earth, the Moon or other planet, especially when using high-frequency radio waves

simple past tense and past participle of space out

(psychology) The awareness of the position, size, form, distance, and direction of an object, or of oneself

(architecture) A three-dimensional truss, often of steel, forming a rigid, stable structure

The competition between nations in the field of space exploration.