On 8 September, a NASA spacecraft is set to launch on a seven-year mission to retrieve rocks and dust from a near-Earth asteroid called Bennu. Those samples could help scientists to better understand the origins of the Solar System’s planets — and, perhaps, of life itself.
Called OSIRIS-REx, the mission comes as a handful of companies pursue controversial plans to mine asteroids, in search of rare minerals or even fuel for extended space missions. If the NASA effort succeeds, it will serve as a proof of concept for more ambitious attempts to exploit asteroids for scientific or commercial gain.
“We’re cheering for them for a successful launch and mission,” says Chris Lewicki, president and chief executive of Planetary Resources in Redmond, Washington, a company that is developing technology to mine asteroids. Extracting resources from space rocks, he says, will “unleash the economic potential of exploring the Solar System”.
OSIRIS-REx’s target, Bennu, formed about 4.5 billion years ago at the same time as Earth and the other planets in the Solar System. It is just 500 metres wide and travels at more than 100,000 kilometres per hour. NASA scientists chose Bennu because its nearly circular path brings it within 300,000 kilometres of Earth every six years, making it relatively accessible. And unlike many smaller space rocks, it does not rotate so quickly that it flings off debris that could harm a spacecraft.
But grabbing a sample will not be easy. After OSIRIS-REx enters orbit around Bennu, it will descend close to the surface and deploy a 3.35-metre-long arm equipped with a suction-cup-like device. When the arm makes contact, it will release a jet of nitrogen gas to loosen surface rocks and dust, and push at …