On Monday, May 10th, NASA’s Osiris REx spacecraft fired up its thrusters for its long-anticipated journey back to earth. After successfully collecting the samples from the Bennu asteroid it was sent in reconnaissance for last year; its 2-year trek home has begun. Its flight path will wind around the Sun towards the Earth’s orbit. Scheduled to arrive close enough to the atmosphere in 2023, the minivan-sized spacecraft is expected to drop off a capsule full of asteroid samples in the Utah region.

The Osiris-REx team made easy work of the spacecraft’s Asteroid Departure Maneuver (ADM). Though simple enough, it marks a big step in space study. The spoils of the Osiris REx mission will be the start of the first-ever pristine condition cache of asteroid samples in NASA’s history. So there is much to celebrate for all involved. The thrusters were confirmed to have begun firing at 4 PM ET Monday and the success reported, brought elated cheers.

“All stations, the ADM burn has completed. We had a nominal ADM burn, and we’re bringing our samples home!” stated Navigation Team Chief Pete Antreasian, prompting applause inside the control room.

The Beginning of Osiris-REx story

The Osiris-REx began its mammoth journey of over 100 million miles back in 2016 launching from Florida. The trip to Bennu was a long one. The asteroid in question is acorn-shaped with a mythological Egyptian deity as its namesake. The deity supposedly symbolizes the world’s creation and as the asteroid is a remnant of our ancient solar system it seems fitting. Scientists hope the samples will hold clues as to the origins of life on our planet.

The Osiris-REx was officially the first US spacecraft to circle an asteroid when it entered Bennu’s orbit last year with its gradual approach. The samples were collected via an extendable 11-foot robotic arm. The collection itself took a matter of seconds somewhat anticlimactic for such a long journey but dramatic nonetheless. Emitting pressurized gas from its showerhead-shaped device it blasted hard enough to loosen debris which was then caught in its sampling head container. For a moment it seemed like a touch-and-go situation as the surface of the Bennu asteroid was softer than anticipated. More rocks were disrupted than expected and the sample gathered weighed around 2 ounces. The rocks jammed the door of the sample container open. 

Osiris-REx’s sampling arm plucks
Osiris-REx’s sampling arm plucks a sample from the Bennu asteroid on October 20th, 2020. Image credit: theverge.com

Fortunately, engineers managed to fix the tricky situation and stow the rocks safely within the capsule. After a little while enjoying Bennu’s orbit from within the crater it marked upon the asteroid’s surface the craft is at last on its way home.

Jason Dworkin views the AMD success as the next chapter in the craft’s mission. Working within the Osiris-REx project team to maintain the scientific integrity of the sampling mission, he sees himself as the bridge between the engineering team and the scientists anticipating the asteroid samples. “I’ve been waiting a long time to get this sample to the laboratory,” he tells The Verge. “I started in 2004. My daughter was in diapers, and now she’s graduating from high school.”

NASA will examine crushed asteroids

The team calibrated the timing of the first thruster burn to ensure that Osiris-REx meets the Earth’s orbital path two and a half years from now, at an altitude of 6,000 miles above the surface. The return journey will see it circle the Sun twice whilst it nudges closer to Earth with gentle thruster bursts along the way. By the time it reaches its final destination Osiris-REx will have racked up over 1.4 billion miles. “This is really the finality — we’re done at Bennu, we aren’t going back,” says Sandy Freund, Lockheed Martin’s Osiris-REx Mission Operations Program Manager. “There’s a little bit of sadness, in that we’ve gotten to know this asteroid, we’ve learned so much. But then there’s that excitement of what we’re going to learn when these samples are here on Earth.”

“It is important to anticipate that”

The capsule is described as dishwasher-sized and will enter the atmosphere for delivery at the Utah Test and Training Range on September 24th, 2023. The Osiris-REx is staying put 6,000 miles away but NASA hinted in a blog post on Monday that it may be given new missions if enough fuel remains after its 2-year trek. 

The cargo will be transported by NASA teams from Utah to the Johnson Space Center in Houston to be stored alongside the Moon rocks they currently have there.

The agency plans to use around a quarter of the materials gathered for immediate investigation. This is because researchers hope to prolong their value. The rest will be stored for future scientists that haven’t even been born yet as Joey Roulette at The Verge pointed out which is strange to think about. 

Technologies will undoubtedly come along in the future that may be able to learn more from the samples than we can currently examine. Dworkin says it is important to anticipate that. 

“That means every decision I make has the weight of history on it,” Dworkin says. “So I want to make sure that I arm all future scientists with the best tools I can, so they can use the samples as best as possible. That’s one of the things that a project scientist does — they help enable more science to be done than they can personally do.”

“I look forward to in 50 years, or longer, maybe your readers, or your readers’ children or grandchildren, may be inspired to ask new questions with new techniques on these old samples,” he says. “It would be thrilling.”