PSI wrote:
When NASA’s OSIRIS-REx mission spacecraft arrived at the asteroid Bennu, it discovered more rocks and boulders than envisioned. Mapping all these potential hazards was necessary to select a location to collect a sample of the surface for return to Earth. This effort was the work of multiple teams around the globe. One of those teams consisted of more than 3,500 citizen scientists who used CosmoQuest’s Bennu Mappers project to mark rocks, measure boulders, and map craters. Together, they made more than 14 million annotations of features on a global map of Bennu. CosmoQuest is a project that is based at the Planetary Science Institute in Tucson, Ariz. (CosmoQuest.org).

These volunteers had no way of knowing in advance if the sites they studied and mapped would be the one selected as the final sampling site for the OSIRIS-REx spacecraft. Folks who saw images with fewer rocks could hope “This is it!” But first, they had to first mark all the photos with hundreds of rocks and dozens of boulders so mission scientists could choose the images critical to site selection.

“It is amazing that more than 3,500 citizen scientists participated in CosmoQuest’s project to map Bennu and help mission scientists find the best place for OSIRIS-REx to collect a sample,” said Pamela L. Gay, Senior Scientist and Senior Education and Communication Specialist at PSI. “This kind of a volunteer effort makes it easier to find safe places to sample and scientifically interesting places to explore."

While the majority of people marked fewer than 10 images from the global mosaic, 68 volunteers marked 100 to 500 images, and 23 marked more than 500 pictures! Each image took as much as 45 minutes to complete, and these people put in weeks of individual effort during the four months it took to map this world.