'Pure exploration': NASA scientists share excitement as they plan for asteroid samples drop

WATCH: NASA spaceship hits asteroid A NASA spacecraft rammed an asteroid at blistering speed in an unprecedented practice run for a day another rock menaces Earth.

In less than a month, a capsule full of NASA's first asteroid samples will hit our atmosphere and tumble down into the Utah desert, bringing clues to the beginning of our solar system – and maybe even the building blocks of life.

But before we can learn from the samples, they have to be delivered safely by the OSIRIS-REx spacecraft. And if the upcoming window of opportunity to drop the capsule is missed, NASA will have to wait two more years to unravel the secrets that asteroid Bennu might hold.

"I think it wants us to unravel this mystery, to explore these giant questions," Dante Lauretta, principal investigator of the OSIRIS-REx asteroid sample return mission, said in a news conference Wednesday.

"The biggest question … is the origin of life. What is life, how did it originate and why was the Earth the place that it occurred? And because Bennu is so rich in carbonaceous compounds … we believe we're bringing back that kind of material – literally, maybe, representatives of the seeds of life – that these asteroids delivered at the beginning of our planet."

Speaking near the desert site Wednesday where the sample capsule is expected to touch down on Sept. 24, NASA experts ran a test drop with a duplicate of the sample capsule and explained how it will arrive on Earth, as well as the delicate process they will undertake to remove the samples for analysis.

A striped parachute carried the test capsule down to the Utah desert, where it was carefully approached by a team of recovery experts running through the assessments they will need to do when it comes time for the real thing.

"It was great to watch the drop test today. It was just a little sneak preview of that emotional moment," Lauretta said. "As soon as I see that parachute unfurl, I know we've made it."

September's sample drop is the culmination of OSIRIS-Rex's seven-year journey through space, which began in 2016. The spacecraft reached Bennu 200 million miles away from Earth in 2018 and successfully collected the samples in 2020.

Canada, as one of the international partners that contributed to the OSIRIS-REx mission, will receive a portion of the sample for study. The Canadian Space Agency provided the OSIRIS-REx Laser Altimeter, a laser scanning system that allowed the spacecraft to find the best location on Bennu to extract samples.

"We're just a few weeks away from the delivery of those samples to the Utah desert," Melissa Morris, OSIRIS-REx program executive at NASA, said in the press conference. "OSIRIS-REx is a phenomenal mission. It has achieved so much already. It's the first U.S. mission to return samples from an asteroid. And that sample mass collected is the largest from beyond the orbit of the Moon."

The spacecraft's journey is far from over – after OSIRIS-REx drops off the samples, it will rendezvous with the asteroid Apophis in 2029.

So how will the Bennu samples get to the ground on their own? The answer is very carefully.

THE HURTLE TO EARTH

In July, NASA performed the first manoeuvre to shift the path of the OSIRIS-REx spacecraft towards the Utah landing zone. A series of manoeuvres in early September will ensure it is on the correct path.

When the spacecraft is four hours away from Earth, NASA will send the final instructions to OSIRIS-REx to point it in the right direction for capsule release. After it releases the capsule, the spacecraft will perform a divert manoeuvre to peel away from the Earth as the capsule continues on its path through space towards Utah.

When it hits our atmosphere, the capsule will travel at 12.3 kilometres per second. Two parachutes later – one to help guide it and then a main chute to slow it down – and the capsule will slow to a mere 17 kilometres per hour before it touches down.

One thing working in NASA's favour is the Utah desert itself.

"It's enormous. Its expanse is mind-boggling," Rich Burns, project manager for OSIRIS-REx, said at the news conference.

The landing area is around 647 square kilometres. Although it's a big target, the capsule will be released when it is still more than 107,000 kilometres away from the Earth, and there's no steering it after that.

"It's the equivalent of throwing a dart across the length of a basketball court and hitting a bullseye," Burns said.

THE 'GO OR NO GO' MOMENT

The critical moment for NASA engineers will come around 2 a.m. local time in Utah, right before the spacecraft releases the capsule.

That's when NASA will have its last chance to cancel the drop if there are any warning signs – the "go or no go" moment.

If even the smallest detail is off, the capsule could land outside of the landing zone and potentially endanger human lives.

The backup plan, if something goes wrong, is for the capsule to stay on OSIRIS-REx as it performs its divert manoeuvre to avoid the Earth. The spacecraft would then have to wait in orbit around the Earth for two years until the circumstances are right again to attempt another capsule drop.

"There's an opportunity in 2025. It's risky, we have to get close to the sun, beyond what we tested the spacecraft to do, we don't want to do that," Lauretta said. "We want to release that capsule (now)."

The team has made plans for how to assess damage and still salvage materials in the event of a crash landing due to a parachute not deploying, which happened in 2004 when the Genesis mission's sample return capsule smashed into the ground at 311 kilometres per hour.

AN EXTRATERRESTRIAL UNBOXING

The delicate dance isn't over if the capsule touches down safe and sound in Utah.

After the capsule lands in the Utah desert, four helicopters will deploy a recovery team. Once team members have assessed the surroundings to ensure it is safe to approach the capsule, they will prepare to transport it to a temporary "clean room" that has been built at the test range.

A clean room is a place to receive sensitive materials in order to cut down on the risk of contamination. The capsule will be carried there in a net suspended from a helicopter.

At the clean room, the capsule will be partially disassembled, then placed inside a specially designed shipment container to be flown down to Johnson Space Center in Houston, Texas.

The Johnson Space Center is NASA's hub for material from space. It currently houses Apollo lunar samples, meteorites from Antarctica and solar wind ions brought back by the Genesis mission, among other extraterrestrial treasures.

At the Johnson Space Center, the samples will be housed in a dedicated clean room, made for only Bennu samples.

"(There are) two nitrogen glove boxes that the sample will be handled and processed in and this is to protect the sample from contamination," Kevin Righter, curation deputy lead at Johnson Space Center, said.

A glove box is a sealed chamber that has built in gloves extending into the chamber so that researchers standing outside of the box can manipulate its contents without risking contamination.

Only once the capsule is inside a sealed glove box will researchers open the lid and begin disassembly, which could take several weeks.

"Once that occurs, we will start to characterize the sample, understand better what we have, how much we have, how many different rock types and lithologies there might be within the sample," Righter said. "The characterization will be used to determine material that we allocate to international partners from JAXA (Japan Aerospace Exploration Agency) and the Canadian Space Agency, as well as determining what will be appropriate to allocate to the science team for their studies."

SECRETS FROM THE BEGINNING OF THE SOLAR SYSTEM

The capsule return is only the start for NASA researchers, who are eager to get a glimpse back in time to before the Earth existed.

Part of the excitement is due to Bennu itself, nicknamed the "trickster asteroid" by Lauretta.

"This mission is one of pure exploration, meaning we didn't really know much about Bennu before we launched," Burns said. "So it surprised us in pretty much just about every dimension."

Bennu is 500 metres across, around the size of the Empire State building or a small mountain, Lauretta said, adding that it is shaped like "a droplet made out of rock, gravel and boulder that are barely held together by their own gravity."

When OSIRIS-REx made contact with the asteroid in 2020, NASA was surprised by how much material was disturbed by the careful touch.

"We thought for sure we were going to touch down on a solid surface. This was an asteroid, it was a rock from outer space, but it actually responded more like a fluid, like if you dropped yourself into a ball pit at a children's playground," Lauretta said.

"The good news is because of that really soft surface, we collected an enormous amount of material. We promised the agency we would bring back two ounces, or about 60 grams of material. We believe … that we have at least four times the material in that sample return capsule."

Only one other country has successfully brought asteroid samples back to Earth. JAXA's Hayabusa2 mission successfully dropped its sample capsule, containing material from the asteroid Ryugu, in the Australian outback in 2020.

Morris said they're looking forward to comparing the two sets of asteroid samples.

"It's so exciting to be working with both the Japanese and the Canadians, and we want to be stronger together to investigate these big problems and where we came from," she said.

She added that although Ryugu and Bennu may visually appear similar, that doesn't mean they are the same.

"I think the thing that would make me the happiest is if we have something totally different," she said.

One aspect that may set Bennu apart is its strange consistency. The asteroid appears to be "heavily hydrated," Lauretta said.

Using an instrument that measures wavelengths beyond what the human eye can perceive, researchers noticed "a long wavelength that is very indicative of water molecules."

Liquid water wouldn't have been able to survive on the surface of Bennu, but scientists theorize there could be molecules trapped in clay material on the asteroid.

"My estimate is about 10 per cent, by weight, of the asteroid is water," Lauretta said. "And maybe five to 10 per cent, by weight, is carbon."

Although it could take months or even years to analyze the material within the sample capsule, we may get answers to some of these questions in a matter of weeks. A press conference to discuss the initial findings is set for early October.

There may not be anyone inside OSIRIS-REx piloting it towards the Earth to drop off the samples. But for the scientists on the ground, it's still an emotional moment to see their work come to fruition.

"A little bit of us is on that spacecraft and a little bit of us is coming home with that," Burns said.