NASA’s OSIRIS-REx space probe reached the asteroid Bennu just over a year ago, and now the agency has decided where it will descend to pick up a sample from the space rock. The site, known as Nightingale, is a gravel-strewn pit near the asteroid’s north pole. It’ll be a delicate operation to collect samples from Bennu and return them to Earth, but we could learn a great deal from the pristine material on the asteroid.
NASA spent almost $1 billion getting OSIRIS-REx out to Bennu, which crosses the orbits of Earth and Mars. Upon its arrival, mission managers were surprised to learn that Bennu has a much more rocky surface than expected. That meant more hazards to avoid when the probe makes its way to the surface. The Japanese team operating the Hayabusa2 asteroid sample return mission was met with similar challenges recently.
The team started with a list of 50 potential candidate sites, whittling them down based on the likely surface composition and visible obstacles. NASA now has four possible landing zones called Nightingale, Osprey, Sandpiper, and Kingfisher. Eventually, the team settled on Nightingale with Osprey as a backup.
Next year, OSIRIS-REx will drift down to Nightingale and make contact with the surface as it blasts out a jet of compressed nitrogen. That should disturb material on the surface, allowing the sampling mechanism to scoop it up. NASA hopes to collect as much as 2.1 ounces (60 grams) of material from Bennu. That’s much more than the 100 milligrams collected by Hayabusa2.
Even after carefully selecting a landing zone, the descent will be tricky. OSIRIS-REx has to operate autonomously because of the distances involved, and its solar panels stretch 20 feet (6.2 meters) from tip to tip. The safe area of Nightingale is about 52 feet (16 meters) across. So, OSIRIS-REx can’t drift too much, lest it runs into a boulder. There’s also a 23-foot-high (7-meter) monolith at the edge of Nightingale that the team has jokingly dubbed “Mount Doom” (visible in the lower right above).
Currently, NASA is targeting August 25, 2020 for the probe’s sample collection run. Before that, OSIRIS-REx will make two close passes over Nightingale to collect more scans. NASA will also conduct two dress rehearsals before the final sample run. No one is taking any chances here. Collecting multiple ounces of material from an asteroid could be an incredible boon for scientists. These bits of Bennu could unlock secrets from the early solar system, but we have to collect them first.
- Japan’s Hayabusa2 Spacecraft Drops Off Its Last Robot on Asteroid Ryugu
- OSIRIS-REx Spots Unexplained Particle Ejections from Asteroid Bennu
- NASA Probe Spots Evidence of Water on Asteroid Bennu