Shortly after NASA got word from the spacecraft that its arm had touched down safely, Dante Lauretta, a planetary scientist at the University of Arizona and the principal investigator of the mission, said he felt “transcendental, I mean I can’t believe we actually pulled this off. ... History was made tonight.”
The spacecraft backed away safely, officials said, with what NASA hopes will be the largest extraterrestrial haul since the Apollo era — a sample of up to two kilograms that scientists will study for years to come once the spacecraft returns to Earth in 2023. But NASA won’t know for sure how much material it collected for a few days. “We have some work to do to determine how much sample that we have collected,” Lauretta said.
If successful, the mission would be the first time NASA has ever taken a sample from one of the estimated 1 million asteroids in our solar system, which scientists believe could shed light on how the universe was formed and how water ended up on Earth.
As big as the Empire State Building, Bennu looks like a giant, spinning walnut that’s more than 4.5 billion years old and believed to be laden with a trove of scientific riches, including carbon and water locked inside clay materials.
“These asteroids are really relics of the earliest material that formed the planets in the solar system,” Lori Glaze, NASA’s planetary science division director, told reporters Monday. “They hold the key information to unlocking our understanding of how the solar system formed, and how it evolved over time.”
The mission began in 2016, when an Atlas V rocket launched the OSIRIS-REx (which stands for Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer) spacecraft from Cape Canaveral. It arrived at Bennu two years later, and soon scientists realized the asteroid was different in one key respect than they had anticipated: It was far rockier, making landing and sample extraction far more difficult.
“It’s not the sandy beach we all hoped we would see initially,” said Thomas Zurbuchen, NASA’s associate administrator for the science mission directorate. Instead: “Rocks on rocks on rocks.”
NASA and Lockheed Martin spent two years studying the surface, hunting for the best place to touch down as well as studying the asteroid.
“Exploration and surprise have a lot in common,” Zurbuchen said. “And this was no exception.”
Ultimately, the team settled on a crater called Nightingale about the size of a tennis court where there is material that could be extracted by the spacecraft’s arm.
While it would be a first for NASA, two Japanese spacecraft, Hayabusa and Hayabusa2, have collected asteroid samples, with the second mission to return to Earth later this year. Those were relatively small samples, compared with what NASA hopes to collect. But Glaze said the countries are working together, “exchanging portions of each other’s samples so that we can maximize the science.”
Scientists are also interested in Bennu because it is one of a family of asteroids that “present a hazard to the Earth,” as Ellen Stofan, director of the Smithsonian National Air and Space Museum, put it in a NASA broadcast.
Scientists estimate there is a 1 in 2,700 chance it could hit Earth sometime between the years 2175 and 2199. That could change, but NASA said it is keeping a close eye on it.