OSIRIS-REx Touches Bennu, Grabs NASA's First Asteroid Sample
NASA's OSIRIS-REx briefly touched down on asteroid Bennu and fired nitrogen gas to collect a sample, the first U.S. asteroid retrieval mission.
Today NASA pulled off something that sounds almost too delicate to work: a spacecraft the size of a large van reached down, tapped the surface of an asteroid hurtling through space millions of miles away, and grabbed a handful of rock and dust before backing off again. Mission control confirmed contact at 6:08 p.m. EDT, with OSIRIS-REx touching down within about three feet of its target site on Bennu, a spot the team nicknamed “Nightingale.”
That kind of precision is wild when you think about the numbers involved. Bennu is roughly 200 million miles from Earth right now, which means every command sent to the spacecraft takes several minutes just to arrive, and the confirmation of success takes just as long to come back. There’s no joystick here — the whole touch-and-go maneuver had to be scripted in advance and executed autonomously, with the spacecraft using its own navigation system to find the actual landing spot in real time since Bennu’s surface turned out to be far rockier than mission planners expected when they first picked candidate sites.
How the sample grab actually worked
OSIRIS-REx doesn’t have legs or a scoop in the traditional sense. It uses something called TAGSAM — Touch-And-Go Sample Acquisition Mechanism — a robotic arm tipped with a round collector head. On contact, the arm fired a burst of nitrogen gas into the asteroid’s surface for about six seconds. That gas blast stirs up loose regolith — the layer of rock and dust sitting on top — and the collector head is positioned to catch the material kicked up before the spacecraft thrusts itself away from the surface. The whole encounter lasted only seconds, and then OSIRIS-REx was already backing off, its job on the surface done.
This is the first time a U.S. mission has collected a sample from an asteroid. Japan’s Hayabusa2 has been doing similar work at a different asteroid, Ryugu, and is on its way back to Earth with its own sample right now, so there’s a nice bit of parallel science happening this year with two different space agencies grabbing pieces of two different ancient rocks.
Why bother with any of this? Bennu is considered a time capsule from the early solar system — a carbon-rich asteroid that’s been drifting around largely unchanged for billions of years, unlike rocks on Earth that get resurfaced, weathered, and geologically churned. Scientists want to get their hands on unaltered material to study the chemistry that was present when the planets were forming, including the kinds of organic compounds that might be relevant to questions about the origins of life.
Assuming today’s grab was successful — the team still needs to confirm how much material actually made it into the collector head, and there’s discussion of a possible second attempt if the first didn’t gather enough — OSIRIS-REx will stow the sample and begin its long trip home. Return to Earth isn’t expected until 2023, so this is a story that unfolds over years, not days. But the hard part, reaching out and touching an object we’ve only ever seen through cameras and radar, happened today.