Gravity shield

From Tardis Wiki, the free Doctor Who reference

A gravity shield was used to stop objects in space from succumbing to the gravitational pull of celestial bodies when in orbit around them.

One such gravity shield kept the Le Verrier space station in orbit around Neptune. The Twelfth Doctor turned off the gravity shield, making the space station fall out of orbit, and, he assumed, destroying the Sandmen. (TV: Sleep No More)