NASA has admitted that in October 2014 the Lunar Reconnaissance Orbiter (LRO) was hit by a small object and survived the colision.
NASA believes that "a small natural meteorite" was to blame for the collision.
Mark Robinson, a professor at Arizona State University's school of earth and space exploration, said: "LRO was struck and survived to keep exploring the moon."
Mr Robinson suggested that a tiny meteorite hit the probe, knocking its cameras so they produced a "wild and jittery" image of the moon's surface.
"The meteoroid was travelling much faster than a speeding bullet," Robinson added.
NASA also revealed why it took so long to release details of the collision.
"Since the impact presented no technical problems for the health and safety of the instrument, the team is only now announcing this event as a fascinating example of how engineering data can be used, in ways not previously anticipated, to understand what is happening to the spacecraft over 236,000 miles from the Earth," said John Keller, LRO project scientist at NASA's Goddard Space Flight Center.