NASA’s OSIRIS-REx asteroid mission will return rock samples to Earth on Sunday. : NPR

This mosaic of images of asteroid Bennu taken by the OSIRIS-REx spacecraft shows its surprisingly clumsy surface.

NASA/Goddard/University of Arizona

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NASA/Goddard/University of Arizona

This mosaic of images of asteroid Bennu taken by the OSIRIS-REx spacecraft shows its surprisingly clumsy surface.

NASA/Goddard/University of Arizona

If all goes as planned, on Sunday morning, a bell-shaped space capsule the size of a small refrigerator will blast through the atmosphere toward the Utah desert.

Inside would be some precious cargo: a cup’s worth of rocks and dust collected by a NASA spacecraft from an asteroid called Bennu that was, at the time, more than 200 million miles away.

This will be the largest amount of extraterrestrial material returned to Earth by any nation since Apollo astronauts ferried moon rocks home, and is the culmination of NASA’s first mission to bring home samples from an asteroid.

The 4.5 billion-year-old pebbles inside the return capsule are believed to be primitive remains from the early days of the solar system, when planets were first forming.

Scientists want to study these rocks to learn more about the chemistry that eventually gave rise to life on Earth, assuming the capsule parachuted out unscathed and its contents were not destroyed in a landing accident.

Last month, team members practiced recovering a sample return capsule, using a replica, at the Department of Defense Test and Training Range in Utah.

NASA/Keegan Barber

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Last month, team members practiced recovering a sample return capsule, using a replica, at the Department of Defense Test and Training Range in Utah.

NASA/Keegan Barber

“That would be heartbreaking, wouldn’t it?” He says Dante Lauretta from the University of Arizona, the principal investigator for NASA’s OSIRIS-REx mission, who compared this scenario to fumbling a football in the end zone while trying to make what could be a winning touchdown in the final seconds of a game.

Lauretta, who has devoted nearly two decades of his life to asteroid sampling efforts, says he and his colleagues have already experienced a number of traumatic and surprising events along the way. Now they wait for the final.

“For me, the minute the parachute opens, I’ll know we’re there. We’re home,” Loretta says.

The anxiety caused by mission critical moments often gives him strange, vivid dreams. In one dream, for example, he found himself in a gift shop on a rocky asteroid.

“I thought, ‘How did I get this job? I’m not supposed to be selling Beano memorabilia,'” Loretta recalls, saying his self-dream then thought, “If we can build a gift shop, why would I do it?” Am I stressing too much about getting all this sample? I can just catch some now.”

In a more recent dream, as the day of the sample’s return approached, he opened the capsule and saw a bright green gem sitting on top of the black asteroid dust. “I grabbed it and put it in my mouth,” he says with a laugh.

In real life, no one would taste asteroid rocks, although Loretta says they might get a whiff of them at some point. Expect a smell like rotten eggs or ammonia.

“I never want to touch it or eat it, because we did everything we could to get it,” Loretta says.

“Naughty” encounter

Launched in 2016, the tiny OSIRIS-REx spacecraft took about two years to reach Bennu, which is roughly the size of the Empire State Building.

Researchers consider Bennu a potentially dangerous asteroid, as it appears to have a one in 1,750 chance of hitting Earth between now and the year 2300.

When the probe arrived at Bennu in 2018, researchers were surprised that instead of the smooth surface they expected, the asteroid was studded with huge boulders.

The team had to figure out how to maneuver the spacecraft around obstacles with nicknames like “Mount Doom” so it could get into a space the size of a few parking spaces.

In October 2020, the spacecraft touched down briefly, and connected to the surface with an arm equipped with a special collection device at the end.

Shockingly, the arm basically fell off, with the asteroid behaving more like a liquid than a solid, suggesting that it was made up of pieces of rock barely held together by gravity.

At first, the researchers were thrilled that they were able to recover a much larger amount of asteroid material than their original goal of about two ounces, or 60 grams.

Once the spacecraft backed away from the asteroid and stopped to assess its treasure, its jubilation turned to alarm.

They grabbed so much that the Mylar flap that was supposed to close the collecting device got jammed by a rock that appeared to be about an inch wide. This created a gap that allowed gravel and dust to escape. Images taken by the plane’s onboard camera showed it floating away.

That moment, he says, “was painful.” Jason Durkin from NASA’s Goddard Space Flight Center, and is a project scientist for the mission. “Seeing those particles drifting away…. Every particle is an unfulfilled discovery. It’s been difficult.”

Mission managers scrambled to insert this assembly device into their return case so that the case could be sealed, trapping everything inside.

“We planned for a very convenient process for storing them,” Durkin says. “It was out the window. We had to act fast.”

In the end, they estimate they were able to protect about 8 ounces of asteroid rock, but they won’t know for sure until they open the box.

Once they do, they expect to see everything from dust to pebbles to even larger rocks like the one Loretta calls “the troublemaker” — the ones that kept their collecting device from shutting down.

“We’re really excited to see it,” Loretta says. “What was that? It must have been rough and probably different from the bulk of the asteroid.”

Head home

Early Sunday morning, mission operators will ask the OSIRIS-REx spacecraft to jettison its sample return capsule, sending it on a collision course with Earth.

This will happen when the spacecraft is about 67,000 miles away, and the capsule will aim at a target area in the desert of about 250 square miles.

“It’s the equivalent of throwing a dart across the length of a basketball court and hitting the bullseye,” he says. Rich Burnsa project manager based at NASA’s Goddard Space Flight Center.

NASA says the capsule will enter the atmosphere at about 36 times the speed of sound, and will encounter temperatures “weaker than lava.” As it falls toward the high mountain desert in Utah for testing and training, it will deploy parachutes to slow its speed.

At least, that’s the plan.

In 2004, a parachute failure led to the failure of NASA’s Genesis mission, which returned samples of solar wind particles. Lauretta says his team has watched video of this unfortunate incident “too many times.”

No matter what happens on Sunday, the rescue crew will be waiting to pounce once the OSIRIS-REx capsule reaches Earth.

Some researchers will take samples of soil and other materials from the landing site – just in case, despite their best efforts, some kind of contamination occurs, and they will later have to figure out what came from the asteroid and what is an terrestrial intruder.

No one expects any kind of alien life, Loretta says. Bennu has been exposed to radiation for eons, making it highly inhospitable. His team worked with NASA’s Office of Planetary Conservation, which found that returning parts of this asteroid to Earth did not require any special precautions.

“We’re more concerned about terrestrial organisms contaminating the sample than about the sample’s impact on the biosphere,” he says.

If the capsule returns home without a hitch, the asteroid sample will remain completely uncontaminated, making it different from the space rocks that regularly fall to Earth and are collected as meteorites.

The capsule will be whisked away to a nearby clean room, where its heat shield will be removed to expose the canister containing the sample.

The biggest reveal

The next day, Monday, workers plan to transport this canister to NASA’s Johnson Space Center in Houston, Texas, which houses a repository for outer space samples such as moon rocks.

Loretta says that on Tuesday morning, if all goes according to schedule, they will open the case inside a private laboratory.

NASA’s Johnson Space Center has built a new facility to house asteroid rocks, and workers there have trained to open the sample container in a setting that will keep the material uncontaminated.

James Blair – NASA – JSC

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James Blair – NASA – JSC

NASA’s Johnson Space Center has built a new facility to house asteroid rocks, and workers there have trained to open the sample container in a setting that will keep the material uncontaminated.

James Blair – NASA – JSC

“I expect we will see dust sticking to surfaces as soon as we open the box,” he says, adding that this asteroid dust will immediately be put into microscopes and other instruments.

Over the following days, workers will disconnect the assembly device, which is locked in its protective case.

“It will be a very slow and deliberate process,” Durkin says. “There’s a lot of fasteners that have to be removed. Each screw head can have Bennu inside of it that we have to remove to preserve it.”

The biggest reveal is scheduled to come on October 5 or 6, when they open the collection device itself.

The researchers expect to hold a press conference on October 11 to review everything they have collected and their preliminary findings. About a quarter of the asteroid sample will be delivered immediately to researchers, who have set up their own laboratories for analysis.

Some will be preserved for the future, so that researchers can study them using technology that has not yet been invented — just like some Apollo moon rocks that were left in sealed containers for nearly half a century before they were opened and taken out. Lesson.

The asteroid sample’s arrival is the first event in what NASA officials call “asteroid fall.”

The space agency is scheduled to launch in early October spirit A mission to a metal-rich asteroid, an iron-nickel asteroid similar to the building block of planetary cores.

In November, NASA’s Lucy mission will fly by an asteroid called… Dinkenish, the first encounter with an asteroid in a planned 12-year tour that will take it to multiple space rocks orbiting the Sun at the distance of Jupiter. These asteroids are believed to be leftovers from the formation of exoplanets.

OSIRIS-REx has more asteroid adventures waiting for you, too. After delivering its payload, the spacecraft will bypass Earth and continue moving. Its next stop is a near-Earth asteroid called Apophis, which it will reach in 2029.