Asteroid Bennu is a Carbon-rich asteroid, with an age of billions of years. It holds secrets of the Solar System and its becoming. Also, on how Earth became what it is today. It was chosen among over 7000 other asteroids close to our planet to reveal those secrets.
Bennu passed three tests before becoming the target of NASA’s primary interest. It has a proper orbit to return, it has a diameter bigger than 200 meters, and it is Carbon abundant. Only five other asteroids matched the needed profile.
Bennu was discovered in 1999, and it took NASA 19 years to reach it. Today they are very close to collect samples from Bennu. OSIRIS-REx is the spacecraft that will fulfill the complicated mission, as Bennu doesn’t give in easy. It is rocky and has very few places with fine-grained materials for sampling. NASA identified four possible sampling sites and gave them avian names: Kingfisher, Osprey, Sandpiper, and Nightingale. Nightingale is the primary choice, and Osprey the back-up.
The mission of OSIRIS-REx on Asteroid Bennu
Space isn’t used to our speeding time on Earth, so it challenges every little step we make towards it. We are perverted by the fast and easy way things happen in Science-Fiction movies, where spaceships land faster than a car race. But maneuvers in space can take a lot of time. Like 11 hours to cover only 580 meters, if the match-point is to narrow.
It will take months for OSIRIS-REx until it will get the 60 grams sample needed. It takes lots of rehearsals, and gradual closeness before it actually touches the asteroid’s surface. And that before it gets to the 5 seconds required for collecting the sample. Between one rehearsal and the other, it takes weeks to analyze data and to estimate the next best possible approach.
If everything goes as planned, NASA estimates that the sample will be collected after the last rehearsal, programmed on March 26. Then, Asteroid Bennu will continue his mission on Bennu for another year, studying it from a distance. The sample will get back on Earth in 2023.