Asteroid Bennu is one of some 10,000 known near-Earth asteroids. There’s a minuscule chance it’ll strike Earth late in the 22nd century, depending on how its orbit evolves. That’s one of the many reasons NASA chose this asteroid for its OSIRIS-REx sample return mission, which launched from Cape Canaveral Air Force Station on September 8, 2016. If all goes according to plan, the craft will rendezvous with Bennu in August 2018. It’ll survey the asteroid for two years before collecting dirt and pebbles from Bennu’s surface. The craft will then return to Earth and deliver its precious asteroid sample in September 2023. Since scientists can’t ride along with the craft, they’ll be, essentially, blindfolded when the sample return actually takes place. That’s why a trio of cameras has been designed to help guide and capture the scene.
The OSIRIS-REx Camera Suite, or OCAMS, consists of three cameras. PolyCam is a high-resolution camera that will acquire the first images of Bennu and perform an initial mapping of the asteroid. MapCam is a medium-resolution camera that will map the asteroid in color and search for satellites and dust plumes. SamCam will document the sampling process.
Scientists designed the camera suite to be functionally redundant, meaning that if one of the cameras fails during the mission, the other two cameras can stand in. Christian d’Aubigny, OCAMS deputy instrument scientist at the University of Arizona, Tucson, said:
When you have a critical mission like this, you want redundancy. The cameras have some amount of overlap in their capabilities. They’re not exact copies of each other, but if one fails, they can still get the job done.
The spacecraft will store the images captured by OCAMS and send them to the OSIRIS-REx team every few days.
Want more about the OSIRIS-REx cameras? Watch the video at the top of this page.
Want more about asteroid Bennu and the mission itself? Check the video below:
Bottom line: A spacecraft now traveling to asteroid Bennu will retrieve an asteroid sample. Videos and images on this page describe the mission’s cameras, the size of Bennu, and some basic features of the mission itself.
Deborah Byrd created the EarthSky radio series in 1991 and EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.