The Best Present From Space Won't Arrive for Another Three Years
OSIRIS-REx is cruising home with a sample from asteroid Bennu so large it jammed its own collector — but Earth won't see it until 2023.
While everyone else is unwrapping gifts today, NASA’s OSIRIS-REx spacecraft is quietly settling into the long haul home with the best present of the year already sealed in its cargo hold. Back on October 20, the spacecraft reached down and touched asteroid Bennu, firing a burst of nitrogen gas to kick up loose material and catch it in a collector head called TAGSAM. The maneuver worked almost too well — so much regolith and gravel got scooped up that some of it wedged the collector’s flap open, and mission engineers spent days worrying about material drifting back out into space before they stowed the sample away for good.
That’s the part of this story I keep coming back to: an asteroid sample-return mission whose biggest problem was collecting too much material. Most of NASA’s sample-return efforts have had to fight for every milligram. OSIRIS-REx apparently just needed to tap the brakes.
By this point in December, the spacecraft has left Bennu’s vicinity behind and is deep into checkout for its return cruise. It won’t actually depart for Earth until spring 2021, and even then, the trip back is not quick — current projections put touchdown in the Utah desert in September 2023. That’s nearly three years from now. In an era where everything from phone releases to console launches to vaccine timelines feels compressed into weeks, there’s something almost calming about a mission that just says: this is going to take a while, and that’s fine.
Why wait three years for dirt
The reason is worth remembering the next time someone asks why any of this matters. Bennu is a carbonaceous asteroid, meaning it’s rich in carbon compounds and likely holds organic molecules and hydrated minerals that have barely changed since the early solar system formed some 4.5 billion years ago. Unlike meteorites that survive atmospheric entry and sit around picking up terrestrial contamination, this sample has been handled in vacuum from the moment it left Bennu’s surface. Scientists want to know what the raw ingredients of planets — and maybe the chemical precursors to life — actually looked like before Earth had a chance to cook them.
It also matters as a hedge. Bennu has a small but real chance of passing uncomfortably close to Earth in the late 2100s, and characterizing exactly what it’s made of feeds directly into planetary-defense modeling. Knowing whether an asteroid is basically a loose rubble pile or a solid rock changes everything about how you’d deflect one.
For now, though, there’s no dramatic footage to watch, no landing to refresh a livestream for. Just a spacecraft, a jar of 4.5-billion-year-old gravel, and a very long, very quiet drive home.