A spacecraft that must ultimately crash in order to succeed lifted off late on Tuesday from California on a Nasa mission to demonstrate the world’s first planetary defence system.
Carried aboard a SpaceX-owned Falcon 9 rocket, the Dart (Double Asteroid Redirection Test) spacecraft soared into the sky at 10.21pm Pacific time from the Vandenberg US Space Force Base, about 150 miles (240km) north-west of Los Angeles.
The plan is to crash the robot spacecraft into the moonlet Dimorphos at 15,000mph (24,100km/h) and change its path by a fraction. If the mission is successful, it will mean that Nasa and other space agencies could deflect an asteroid heading towards Earth and avert an Armageddon-style impact.
The Dart payload, about the size of a small car, was released from the booster minutes after launch to begin its 10-month journey into deep space, some 6.8 million miles (11 km) from Earth.
Once there Dart will test its ability to alter an asteroid’s trajectory with sheer kinetic force. Cameras mounted on the impactor and on a briefcase-sized mini-spacecraft to be released from Dart about 10 days beforehand will record the collision and beam images of it back to Earth.
The asteroid being targeted by Dart poses no actual threat and is tiny compared with the cataclysmic Chicxulub asteroid that struck Earth 66m years ago, leading to extinction of the dinosaurs. But scientists say smaller asteroids are far more common and pose a greater theoretical danger in the near term.
The team behind Dart chose the Didymos system because its relative proximity to Earth and dual-asteroid configuration make it ideal for observing the results of the impact.
The blast-off was shown live on Nasa TV and on the SpaceX Twitter account.
It is the latest of several Nasa missions in recent years to explore and interact with asteroids, primordial rocky remnants from the solar system’s formation 4.6bn years ago.
Last month, Nasa launched a probe on a voyage to the Trojan asteroid clusters orbiting near Jupiter, while the grab-and-go spacecraft Osires-Rex is on its way back to Earth with a sample collected in October last year from the asteroid Bennu.
The Dimorphos moonlet is one of the smallest astronomical objects to receive a permanent name and is one of 27,500 known near-Earth asteroids of all sizes tracked by Nasa.
Nasa has put the entire cost of the Dart project at $330m, well below that of many of the space agency’s most ambitious science missions.