bacterial: microscopic living things; certain bacteria can cause disease
satellites: an object that is gravitationally bound to orbit another, larger object; the moon is a satellite of the Earth; human-made satellites are launched into orbit for communications and observation of the planet and outer space
rehydrated: to add water or liquid back into a substance that previously had all of its moisture taken out of it
valves: a movable device that opens and closes to control the flow of liquid or gas through a pipe or other hollow passageway
Vernier engines: a small rocket engine that is used to make very fine adjustments in speed, direction, and position
Avionics: the electronic systems used to fly a vehicle
