OSIRIS-REx stirs up a rocky blizzard tagging an asteroid in search of samples

After “tagging” the asteroid Bennu on 20 October, NASA’s OSIRIS-REx spacecraft backed away and beamed back a series of images captured before, during and immediately after the encounter, giving scientists a bird’s eye view of the encounter. Pressurized nitrogen gas was released one second after contact, stirring up a rocky blizzard directly below the spacecraft’s Touch-and-Go Sample Acquisition Mechanism, or TAGSAM, collector. The mechanism was designed to blow at least 60 grams of rock and soil into into collection chambers for return to Earth in 2023. Scientists were astonished by the mesmerizing views, stringing the images together to form a stop-action movie. The shots below show highlights from the encounter (images: NASA/Goddard/University of Arizona):

The TAGSAM collector, mounted on the end of a 3.3-metre )11-foot) robot arm, is seen poised just above the surface of Bennu as the spacecraft slowly descended toward contact.


The TAGSAM is pressed into the surface of Bennu, sinking slightly into the loose soil and rock.


One of three nitrogen gas bottles fires through vents inside the TAGSAM collector, stirring up a shower of small rocks and soil for about five seconds.


A relatively large rock, loosened by the jet of pressurized nitrogen, zips past TAGSAM’s robot arm.


OSIRIS-REx backs away from Bennu after a six-second encounter, presumably carrying a priceless cache of rock and soil samples.