Which NASA mission deliberately created a crater on Comet Tempel 1 in 2005?

NASA’s Deep Impact mission deliberately created a crater on Comet Tempel 1 on July 4, 2005.

The spacecraft released a 370-kilogram impactor that struck the comet at about 10.3 kilometers per second. Deep Impact’s flyby spacecraft photographed the collision and studied the cloud of material ejected from the comet’s interior. Scientists hoped the exposed material would reveal how comets formed and evolved.

The mission was not a planetary-defense test. It was designed primarily as a scientific experiment to examine a comet’s composition beneath its dark surface. The later DART mission also struck a small body, but DART tested asteroid-orbit deflection rather than investigating comet geology.

After completing its primary objective, the spacecraft was given an extended mission called EPOXI. It observed additional targets, including Comet Hartley 2 during a 2010 flyby, demonstrating the value of reusing a functioning spacecraft.