A spacecraft has been launched from a US space base in California on a NASA mission to test its ability to alter an asteroid's trajectory.
The US space agency's Double Asteroid Redirection Test spacecraft lifted off from the Vandenberg Space Force Base at 10:21 p.m. on Tuesday local time, carried aboard a Space X Falcon 9 rocket.
NASA is looking into ways to deflect an asteroid from a potential collision with Earth by altering its trajectory.
The DART mission is aimed at investigating and demonstrating a method of asteroid deflection by changing an asteroid's motion through kinetic impact.
The DART spacecraft will begin a 10-month journey to the 160-meter-diameter asteroid moonlet Dimorphos, located 11 million kilometers from Earth.
The spacecraft, which weighs about 500 kilograms, is designed to direct itself to impact an asteroid while traveling at a speed of roughly 24,000 kilometers per hour.
Scientists plan to measure the change in Demorphos' orbit from the ground as well as from another spacecraft to be launched later.
NASA says the asteroid poses no threat of actual impact to Earth, and the mission is just aimed at demonstrating the DART's technological ability.
NASA says it is highly unlikely that any asteroid of a size large enough to bring huge damage to Earth will collide with the planet for the next 100 years.
But more than 20 asteroids that are said to have potential risk of crashing into Earth have been identified, and there are smaller asteroids whose orbits are not known in detail.
In 2016, NASA established the Planetary Defense Coordination Office to detect and monitor potentially hazardous objects in space.