(physics) The localized excess electric charge in a specific volume; especially such a negative charge

(biology) Any of various biological sciences that deal with living things in a space environment

The loss of energy of a signal (due to absorption, dispersion etc) as it travels through a medium; measured in decibels

The environment encountered by living creatures (and vehicles) in space; especially a lack of atmosphere and gravity

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

Alternative spelling of space defense

(mathematics) A vector space having n vectors as its basis

(in an electromagnetic coil) The ratio of the volume occupied by the wire in the winding, or the iron in the core, to the total volume of the winding or the core

Any defensive measure against an attack by missiles etc while in space

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