sentence: Specific impulse is a useful value to compare rocket or jet engines.
sentences_after: It is used much like 'miles per gallon' or 'litres per 100 kilometres' is used to compare cars. An engine with a higher specific impulse uses fuel better. This means that the same amount of fuel lets the rocket go faster after all fuel is depleted.
concept_name: specific impulse
headings: Specific impulse
categories: Spaceflight Mechanics