(astronomy) The real or apparent motion of a star etc. through space.

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

(mathematics) A measurable space having a unit measure

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

Any assemblage of equipment used to generate, store and distribute electrical power on board a satellite or spacecraft

The utilization of low gravity and/or high vacuum to carry out various processes in space

(physics) The ratio of magnetic induction to magnetizing force in a vacuum

The reconnaissance of the surface of a planet from an orbiting spacecraft.

Any of a system of coordinates by which a point is located in space by its distance from a pole, the angle between the polar axis and its radius vector, and its longitude

(astronomy) The reddening of the light from distant stars because of selective absorption and scattering by interstellar dust