A "gravity tractor" is a spacecraft that uses its own gravity to attract and move asteroids or other objects away from their original paths, reducing the risk of collision with Earth. Full definition
The mission could even help to validate a concept known as enhanced gravity tractor. (sciencedaily.com)
I know about gravity tractors and mirror arrays, but not spray paint; it goes to show that sometimes seemingly simple solutions can be used to tackle complex problems. (treehugger.com)
Once retrieved the tug would use the boulder's extra mass to act as a «gravity tractor,» orbiting the asteroid in such a way as to subtly change the asteroid's trajectory. (scientificamerican.com)