Gravity assist
/ˈɡɹævɪti əˈsɪst/
"Gravity assist" in a Sentence (3 examples)
After going into orbit around Jupiter with a gravity assist from the volcanic moon Io, Galileo will spend 22 months studying the planet.
Cassini is supposed to swing by Earth in 1999 for a gravity assist that would sling it out toward Saturn.
MESSENGER successfully flew by Mercury yesterday, gaining a critical gravity assist that will enable it to enter orbit about Mercury in 2011.