NASA is preparing to bring an asteroid back to Earth. But not quite as big as you might expect if you imagined a spaceship towing a giant space rock. Next Tuesday, the OSIRIS REx robotic spaceship (origin, spectral interpretation, resource identification, security, regolith discoverer) will take a sample of an asteroid named 101955 Bennu and then bring it home – or at least over 60 grams.
"OSIRIS-REx (will touch the surface) with a long, three-meter arm with the collecting head on the end," Jason Dworkin, OSIRIS-REx project scientist at NASA's Goddard Space Flight Center, told Digital Trends. “With this long arm, we can image and weigh the sample in order to assess the success of the collection. OSIRIS-REx uses an annular jet of nitrogen gas to loosen and move a large amount of the sample from the topmost inches of the surface and capture it in the collector with a design that collects at least 60 grams and up to 2,000 grams of stones and Dust. "
This is a different approach than a year ago when the Japanese spacecraft Hayabusa2 collected two samples from the near-Earth asteroid Ryugu. In this approach, a metal ball was fired at close range into the surface of an asteroid, causing a cloud of dust to collect. However, the amount that can be collected in this case is much less, Dworkin said, noting that it could be anything from "milligrams to maybe a gram".
In comparison, the sample planned for OSIRIS-REx at Bennu is anything but tiny. "Sixty grams is a tremendous amount for the techniques to use, (although) more samples are always better," continued Dworkin. "The Stardust mission rewrote part of the history of the solar system by examining (only) a few milligrams of dust from comet Wild 2."
The OSIRIS-REx has been in development for a long time. The spacecraft launched in 2016 and arrived in Bennu more than two years later in December 2018. Once the sample has been collected (if the uptake was unsuccessful the first time, there is enough nitrogen for two more attempts), it will arrive back on our planet on September 24, 2023. Examining the sample's organic compounds could help provide information about the origin of life on earth.