4. Glossary

aerobic; airbreathing

System that uses air as a combustion agent, drawing it from the Earth's atmosphere (via one or more air intakes).

propellants

Reagents (oxidizer and fuel) used for propulsion: propellant(s).

dynalpie flow; momentum

Expressed in Newtons, the momentum of the gas flow admitted or ejected.

specific impulse(s)

The ratio between thrust and the weight of the propellant used to generate it, this performance metric for a given time period is the parameter that reflects the mass consumption of a propulsion system. It is useful to know its definition, the orders of magnitude for different engines, and its practical application.

structural index, mass factor, mass ratio