After a remarkable seven-year journey through the cosmos, one of NASA’s groundbreaking asteroid missions has reached a triumphant conclusion; OSIRIS-REx, which set out in 2016 to explore the asteroid Bennu, has returned to Earth with a record-breaking 8.8 ounces or 250 grams of carbon-rich asteroid material.
The 2022 NASA Goddard video above shares the surprising moment when the asteroid sample was collected.
“When images of the TAG event beamed back to Earth, they were far more dramatic than anticipated. Despite its slow touchdown, OSIRIS-REx had punched through the surface and set off an explosion of loose material. Tons of rocks and pebbles were ejected, radiating outward in a wall of debris.
“The pictures were stunning, but why did Bennu’s surface behave so unexpectedly?”
“The answer involves cohesion, an attractive force that can bind molecules together. Cohesion gives water its surface tension and keeps droplets together even in a microgravity environment, like the International Space Station. Granular materials like wheat flour, cocoa, and dust can also exhibit cohesion, which pulls individual grains into clumps.
“On Bennu, scientists had expected cohesion to act like a bit of glue between the rocks, making its loose surface more solid. But the TAG event showed that Bennu’s uppermost layers are nearly cohesionless, deforming under stress like a fluid. A good analogy is a ball pit. Although the plastic balls are solid, they easily slide past one another (and past boisterous children), behaving en masse like a fluid.”
The OSIRIS-REx sample return capsule, a black saucer resembling a mid-20th century UFO, touched down on September 24, 2023 within the Department of Defense’s Utah Test and Training Range. From Nature:
“The NASA curation team planned to put the Bennu samples into an atmosphere of pure nitrogen soon after the capsule touched down, to reduce the potential for contamination. That will enable scientists to study the asteroid’s geology and chemistry, preserved all the way back to the formation of the Solar System, more than 4.5 billion years ago. The pristine material hasn’t been altered by passing through Earth’s atmosphere, as happens with meteorites. ‘The thing that will really be different about this sample is we’ll have that chain of custody of keeping it protected from Earth’s atmosphere,’ says Nicole Lunning, the mission’s lead sample curator at the Johnson Space Center…
“The bits collected by OSIRIS-REx probably contain organic compounds — carbon-based molecules found in many meteorites that are the building blocks of many exciting types of chemistry, including those conducive to life.”
This August 2023 NASA Goddard video summarizes the mission, the capsule’s return home, and the nine-year-long part two of OSIRIS’ adventure to Apophis:
OSIRIS-REx is short for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer. The asteroid was named for Bennu, the heron-like bird associated with the Sun God Ra in Egyptian mythology.
From 2016: OSIRIS-REx: Chasing Asteroid Bennu.
Watch these related videos next:
• Space Rocks: Comets, asteroids, meteors, and meteorites
• ESA’s Incredible Adventures of the Hera Asteroid Mission
• NASA’s Lucy Mission to the Trojan Asteroids
• Did an asteroid kill the dinosaurs?
• Inside the Meteorite Clean Room at the Smithsonian
• Rosetta spacecraft, Philae lander, & an animated history of comets
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