Wiktionary
n. (alternative form of gravity assist English)
WordNet
n. (spaceflight) a trajectory that passes close to a planetary body in order to gain energy from its gravitational field
Usage examples of "gravity-assist".
They had lost a gravity-assist flight to Venus and Mercury, asteroid and comet encounters, Grand Tour probes to the outer planets.
The conventional wisdom was that the SCOREs were going to perform gravity-assist maneuvers, do slingshot turns around the Moonpoint Singularity and come in for landings on Earth to commence a Breeding Binge.
Sulu found himself responding almost before he was consciously aware of the need to do so, flinging the shuttle across the vector of the blast instead of fighting it, then spiraling its uncontrolled tumble into a gravity-assisted dive that made the metal nacelles scream in protest as he exceeded their strain limit.