Planet Earth is about to receive a special delivery: the largest sample of an asteroid yet.
A US Space Agency (NASA) spacecraft will fly by Earth on Sunday, expected to leave behind at least a cup of debris it picked up from the asteroid Bennu, concluding a seven-year search.
The monster capsule will parachute into the Utah desert as the mothership, the OSIRIS-REx spacecraft, lifts off for a rendezvous with another asteroid.
Scientists expect to ingest about 250 grams of pebbles and dust, much more than the teaspoon Japan brought back from two other asteroids.
No other country has collected pieces of asteroids and time capsules from the beginning of our solar system that could help explain how Earth – and life – came to be.
Sunday’s landing concludes a 6.4 billion km (four billion mile) journey, culminating in an encounter with carbon-rich Bennu, a unique touchdown and pogo-stick style monster grabber, a jammed lid that leaves part of the stockpile went into space, and now the return of NASA’s first asteroid samples.
“I ask myself how many heartbreaking moments you can have in one lifetime, because I feel like I’m reaching my limit,” said Dante Lauretta of the University of Arizona, the mission’s lead scientist.
Here’s everything you need to know about the spacecraft and its payload:
When was OSIRIS-REx fired?
Asteroid hunter OSIRIS-REx took off in 2016 on a $1 billion mission. He arrived at Bennu in 2018 and spent the next two years flying around the small spinning space rock and scouting out the best spot to take samples.
Three years ago, the spacecraft – whose full name is Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) – swooped in and reached out with its 3.35-meter-long stem vacuum, briefly destroying the asteroid hit. surface and sucks up dust and stones.
The device pressed down with such force and gripped so much that stones became stuck around the edge of the lid. As samples floated into space, Lauretta and his team tried to get the remaining material into the capsule.
The exact amount contained will not be known until the container is opened.
What do we know about the asteroid Bennu?
Discovered in 1999, Bennu is believed to be a remnant of a much larger asteroid that collided with another space rock.
It is barely half a kilometer wide, about the height of the Empire State Building in New York City, and its black, rugged surface is littered with boulders.
Bennu has a round shape, resembling a spinning top, and orbits the sun every fourteen months, while it rotates every four hours. Scientists believe Bennu preserves remnants of the formation of the solar system 4.5 billion years ago.
It could come dangerously close and hit Earth on September 24, 2182 – exactly 159 years after the first pieces of the asteroid arrived. OSIRIS-REx’s close-up study could help humanity figure out how to avert Bennu if necessary, Lauretta said.
When will the sample be released?
OSIRIS-REx will release the sample capsule from a distance of 102,000 km (63,000 miles) four hours before it lands at the U.S. Department of Defense’s Utah Test and Training Range on Sunday morning.
The release command will come from spacecraft maker Lockheed Martin’s control center in Colorado. Shortly afterwards, the mothership will steer away and take off to explore another asteroid.
Once everything is deemed safe, the capsule is taken by helicopter to a makeshift clean laboratory at the shooting range. The next morning, a plane will transport the sealed container full of debris to Houston, home of NASA’s Johnson Space Center. NASA will broadcast the touchdown live.
Where will it be studied?
A new laboratory at Johnson will be confined to the Bennu debris to avoid cross-contamination with other collections, NASA curator Kevin Righter said.
Building 31 houses all the moon rocks brought back by the Apollo astronauts between 1969 and 1972, as well as comet dust and solar wind specks collected during two previous missions, and Martian meteorites found in Antarctica.
The asteroid samples will be handled in nitrogen-purifying glove boxes by personnel in head-to-toe cleanroom suits. NASA is planning a splashy public unveiling of Bennu’s riches on October 11.
Are there any other asteroid missions underway?
This fall, NASA is calling Asteroid Autumn, with three asteroid missions marking major milestones.
The OSIRIS-REx touchdown will be followed by the launch of another asteroid hunter on October 5. Both the NASA spacecraft and its target – a metallic asteroid – are called Psyche.
A month later, NASA’s Lucy spacecraft will encounter its first asteroid since lifting off from Cape Canaveral, Florida, in 2021. Lucy will fly past Dinkinesh in the main asteroid belt between Mars and Jupiter on November 1.
It will be a warm-up for Lucy’s unprecedented journey past the so-called Trojans, swarms of asteroids that shadow Jupiter around the sun.
Neither Psyche nor Lucy will be collecting souvenirs, and neither will OSIRIS-REx on its next mission, to explore the asteroid Apophis in 2029.
Has NASA delivered asteroid samples before?
This is NASA’s third sample to return from space, not counting the hundreds of pounds of moon rocks collected by the Apollo astronauts.
The agency’s first robotic sampling ended with a bang in 2004. The capsule containing solar wind particles crashed into the Utah desert and shattered, endangering its contents.
Two years later, an American capsule landed with cometary dust intact.
Japan’s first asteroid sampling mission returned microscopic grains from asteroid Itokawa in 2010. The second trip returned about 5 grams – a teaspoon or so – of the asteroid Ryugu in 2020.
The Soviet Union transported lunar samples to Earth in the 1970s, and China returned lunar material in 2020.