NASA Reveals The Four Best Sample Sites On Asteroid Bennu

As we recently reported, NASA is busy determining the best possible location for its OSIRIS-REx mission to pluck a sample from the rocky asteroid Bennu. After quite a bit of work, the team behind the mission has narrowed down the list of candidates to four favorable locations, two of which will eventually be declared the primary and backup locations for collecting the sample.

Bennu is a large rocky asteroid currently being observed by NASA's OSIRIS-REx spacecraft, which will soon accomplish an incredible mission: collecting a physical sample from the space rock. Getting the sample will require OSIRIS-REx to get very close to the asteroid, which means researchers must be careful to pick the safest location.

NASA has detailed the four sites it is considering for the mission: Sandpiper, Osprey, Kingfisher, and Nightingale. Each site has its own benefits and potential downsides, including things like the high likelihood of fine-grain materials, but also the potential for poor lighting conditions or large nearby rocks.

In addition to making sure that OSIRIS-REx can reach the materials and isn't at risk of smacking into boulders or outcroppings, NASA must ensure that the chosen site contains materials that are smaller than 2.5cm in diameter, which is the upper limit for how large the samples can be.

Ultimately, NASA says it will not be easy to decide which of the four sites should be the primary target and which should be the backup. As well as considering the safety of the sample site and the size of its materials, experts must also consider the scientific value of the materials that will be collected.

Osprey, for example, is likely to contain carbon-rich materials, but it's also possible that the same area contains materials that are too big to pick up. Despite the struggle, the space agency says that a final decision will be made soon, paving the way for the remainder of the mission.