Vandenberg Air Force Base, California - NASA has launched a satellite on Wednesday that will deliberately crash into an asteroid, aiming to alter its course in the first mission of its kind.

The planetary defense probe, powered by a Falcon 9 rocket made by Elon Musk's SpaceX, is set to took off at 1:20 AM local time from Vandenberg Space Force Base in California.

"Asteroid Dimorphos: we're coming for you!" the space agency tweeted.

The satellite – which NASA says is the size of a vending machine – is due to smash into the Dimorphos asteroid in October next year, in what has been dubbed the Double Asteroid Redirection Test (DART).

Dimorphos, a moonlet whose diameter measures some 175 yards, does not pose a danger to Earth, according to NASA's calculations, and the mission is designed to ensure that even after the impact, there would be no risk to the planet.

The European Space Agency mission Hera is scheduled to launch a mission in 2024 to study the impact in greater detail.

NASA hopes the mission, costing some $330 million, will deliver insights about how to protect Earth from any approaching asteroids.

Scientists are not aware of any asteroids currently threatening Earth but have identified some 27,000 asteroids in our planet's proximity, with some 10,000 of them measuring more than 150 yards in diameter.