Gravity bubble
From Tardis Wiki, the free Doctor Who reference
A Gravity Bubble was a form of Dalek technology that allowed an object to beat the boundaries of gravity and travel in space.
Edwin Bracewell applied this technology to Spitfires, allowing the pilots to travel around the orbit of planet Earth and attack the Dalek Saucer. (DW: Victory of the Daleks)
Silurians used this technology to transport themselves from their civilization to the surface of Earth. (DW: Cold Blood)
