By Alexandra Witze
NASA is about to grab its first-ever taste of an asteroid. On 20 October, some 334 million kilometres from Earth, the agency’s OSIRIS-REx spacecraft will approach a dark-coloured, diamond-shaped asteroid named Bennu, with the aim of touching its surface for a few seconds — long enough to hoover up a collection of dust and pebbles. If successful, the spacecraft will then fly this carbon-rich rubble back to Earth, where scientists can probe it for clues to the history of the Solar System.
The journey to Bennu’s surface won’t be easy. The spacecraft will have to navigate its way past a towering boulder nicknamed Mount Doom, then onto a sampling area no larger than a few car-parking spaces. “We may not be successful on our first attempt,” says Dante Lauretta, the mission’s principal investigator and a planetary scientist at the University of Arizona in Tucson. But if it does work, he says, “I hope the world looks at this as a piece of good news — something we can be proud of with all the insanity that’s going on this year.”
There and back again
Launched in 2016, the US$800-million OSIRIS-REx is NASA’s first asteroid-sampling mission. It follows two missions from the Japan Aerospace Exploration Agency (JAXA) that have scooped dust off the surface of asteroids — including some retrieved last year that is currently on its way back to Earth for analysis. Before JAXA’s missions, scientists learnt about asteroids’ contents mainly by studying meteorites that had fallen to Earth — and those can be contaminated as they travel through the atmosphere and hit the planet.
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