Home / Glossary
Glossary
The terms used across these pages, one plain sentence each.
- Boil-off
Liquid propellant that slowly warms and turns into gas. A tank must vent it, capture it or spend power keeping the liquid cold.
Related: Building for 94 K and 1.5 bar
- Cryogenic separation
Separating liquids by cooling them until their different boiling points let them evaporate and condense at different temperatures.
Related: Sorting the sea
- Delta-v
The change in velocity a vehicle can make. It is the motion budget for a trip, not a speed it must hold the whole way.
Related: Getting around the Saturn system · Shared spaceflight terms at Concordia glossary
- Electrolysis
Using electric current to split a compound. On Titan, the oxygen plant splits water ice into oxygen and hydrogen.
Related: Water, oxygen and electrolysis
- Exhaust velocity
The speed at which a rocket throws propellant backward. Higher exhaust velocity means more momentum per kilogram of propellant.
Related: Electric propulsion · Shared spaceflight terms at Concordia glossary
- Hall thruster
An electric engine that uses electric and magnetic fields to accelerate ionised propellant. It produces little thrust but can run for a long time.
Related: Electric propulsion · Shared spaceflight terms at Concordia glossary
- Habitat drum
A rotating living module. Rotation gives its floor an outward apparent gravity, much as a spinning wheel presses its rim outward.
Related: Spin gravity and counter-rotation · Shared spaceflight terms at Concordia glossary
- Kraken Mare
The largest known lake or sea on Titan, filled mainly with liquid methane and ethane. The settlement's barge route follows its northern shore.
Related: Kraken Mare and Titan's seas
- Magnetic nozzle
A shaped magnetic field that guides charged hot gas out of an engine without requiring the plasma to touch a solid nozzle wall.
Related: Fusion propulsion and helium-3
- Mass defect
The small difference between the mass of a bound nucleus and the masses of its separate particles. The missing mass corresponds to binding energy.
Related: Energy per kilogram
- Mass ratio
A rocket's mass before a burn divided by its mass after the propellant is spent. The ratio links exhaust speed and propellant demand to delta-v.
Related: Fusion propulsion and helium-3 · Shared spaceflight terms at Concordia glossary
- Methalox
A rocket propellant combination of methane and liquid oxygen. Titan can supply methane from its seas and oxygen from water ice.
Related: Methalox from Titan
- Nuclear-thermal rocket
A rocket in which a reactor heats propellant and the hot gas expands through a nozzle. The propellant is heated, not burned.
Related: Nuclear-thermal rockets · Shared spaceflight terms at Concordia glossary
- Propellant
Material a vehicle expels to change its motion. A chemical rocket's propellant reacts; an electric or thermal engine accelerates it by other means.
Related: Methalox from Titan · Shared spaceflight terms at Concordia glossary
- Radiator
A surface that releases waste heat as infrared light. In space, a radiator is the main way a vehicle gets rid of heat it cannot use.
Related: Radiators: throwing heat away · Shared spaceflight terms at Concordia glossary
- Specific impulse
A measure of how efficiently an engine uses propellant, expressed as the impulse delivered per unit weight flow. Higher values mean less propellant for the same impulse.
Related: Electric propulsion · Shared spaceflight terms at Concordia glossary
- Tholin
A family of complex, reddish-brown organic solids made when sunlight and energetic particles drive reactions in nitrogen- and methane-rich atmospheres.
Related: The orange sky
- Ring-plane crossing
A season when the Sun appears to cross Saturn's ring plane. The rings receive sunlight nearly edge-on and their shadows and brightness change.
Related: Saturn's rings