NASA's OSIRIS-REx returns to Earth with asteroid Bennu samples
September 24, 2023
— The first U.S. mission to sample an asteroid has landed back on Earth.
Descending under an orange and white parachute, NASA's OSIRIS-REx sample return capsule (SRC) touched down within the Department of Defense's Utah Test and Training Range on Sunday morning (Sept. 24). The mission collected the largest asteroid sample brought back to Earth, with a half a pound (8.8 ounces or 250 grams) of rocks and soil estimated to be on board.
"We have touchdown! I repeat... the SRC has touched down!" declared Tim Priser, chief engineer for deep space exploration at Lockheed Martin, reporting from the control room in Utah.
The landing at 8:52 a.m. MDT (10:52 a.m. EDT or 1452 GMT) ended a seven-year journey to the asteroid Bennu and back, including two years mapping the carbonaceous space rock, which is about the size of New York City's Empire State Building (1,610 feet or 490 meters in diameter).
"Its shape is particularly intriguing," Dante Lauretta, principal investigator for the OSIRIS-REx (or Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer) mission at the University of Arizona in Tucson, said at a pre-landing press briefing. "It literally is a droplet made out of rock, gravel and boulders that are barely held together by their own microgravity."
"I call it the trickster asteroid as it has challenged us every step of the way. 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," said Lauretta.
That fluidity, though, turned out to be fortuitous, as it enabled the probe's "touch-and-go" mechanism to collect as much as a four times the amount of asteroid material than what was needed for the mission to be a success.
The delivery of the samples to Earth began about four hours before they landed, when the OSIRIS-REx spacecraft released the return capsule at 63,000 miles (102,000 kilometers) above the planet. The spacecraft then fired its thrusters to divert it away from Earth, beginning its extended mission — referred to as OSIRIS-APEX (or OSIRIS-Apophis Explorer) — to study the asteroid Apophis after its close encounter with Earth in 2029.
Meanwhile, the sample return capsule entered the atmosphere at 10:42 a.m. EDT (1442 GMT) traveling 27,650 miles per hour (44,500 kilometers per hour) at 83 miles (134 kilometers) above the surface. Two minutes later, a drogue chute was scheduled to deploy.
The capsule's 24-foot (7-meter) main parachute deployed at about 20,000 feet (6 km) above the Utah desert, 15,000 feet (4.6 km) higher than expected though in line with the capsule's descent rate. The chute was designed to slow the capsule's descent to just 11 mph (18 km/h) when it met the ground. The entire descent took about 10 minutes, a few minutes faster than had been anticipated.
After taking several minutes to pinpoint the capsule's location on the ground, NASA and Lockheed Martin personnel arrived at the touchdown site by helicopter. After ensuring it was safe to approach (both from the risk of heat and outgassing from the capsule and the possible but unlikely presence of unexploded ordinance on the range), the teams got to work preparing the SRC for its retrieval.
The capsule will spend its first night back on Earth in a temporary clean room at the Utah Test and Training Range. On Monday, the capsule and its contents are scheduled to be flown by a C-17 military transport plane for delivery to NASA's Johnson Space Center in Houston, where a new permanent clean room has been built in the center's Astromaterials Laboratory for the study of the samples.
NASA has scheduled a press conference for Oct. 11 to provide a first look at the samples and the preliminary findings by its science team.
OSIRIS-REx is the first U.S. and third worldwide spacecraft to return asteroid samples to Earth after Japan's Haybusa and Hayabusa 2 missions in 2010 and 2020, respectively. In addition to bringing back the largest sample of asteroid material, the OSIRIS-REx return is also the largest extraterrestrial sample delivery since the six Apollo missions that landed moon rocks and lunar soil on Earth.
NASA's OSIRIS-REx sample return capsule touched down in the Department of Defense's Utah Test and Training Range on Sunday, Sep. 24, returning from asteroid Bennu. (NASA/Keegan Barber)
OSIRIS-REx sample return time line detailing the first U.S. recovery of asteroid material. (University of Arizona/Heather Roper)
NASA's OSIRIS-REx curation team rehearse opening of the sample canister in the curation lab at the Johnson Space Center. (NASA)
The OSIRIS-REx Touch-And-Go Sample Acquisition Mechanism as seen just before making contact with asteroid Bennu. (NASA)
The sample return capsule from NASA's OSIRIS-REx mission is seen shortly after touching down in the desert, Sunday, Sept. 24, 2023, at the Department of Defense's Utah Test and Training Range. (NASA/Keegan Barber)
From left to right, Lockheed Martin Mission Operations Assurance Lead Graham Miller, Lockheed Martin Recovery Specialist Michael Kaye, and Lockheed Martin Recovery Specialist Levi Hanish, prepare the sample return capsule from NASA's OSIRIS-REx mission for transport, Sunday, Sept. 24, 2023, shortly after the capsule landed at the Department of Defense's Utah Test and Training Range. (NASA/Keegan Barber)
The sample return capsule from NASA's OSIRIS-REx mission is seen en route to the cleanroom, Sunday, Sept. 24, 2023. (NASA/Keegan Barber)
Curation teams process the sample return capsule from NASA’s OSIRIS-REx mission in a cleanroom, Sunday, Sept. 24, 2023, at the Department of Defense's Utah Test and Training Range. (NASA/Keegan Barber)