NASA spacecraft returns to Earth with pieces of an asteroid

A small capsule carrying pristine specimens from an asteroid parachuted to a landing in the Utah desert Sunday, capping a seven-year voyage through the Solar System to bring home samples for eager scientists seeking clues about the origins of life.

NASA’s OSIRIS-REx mission brought back the largest unspoiled sample of material ever returned to Earth from beyond the Moon, probably on the order of about 250 grams, or roughly 8 ounces, according to estimates. The spacecraft collected the samples from asteroid Bennu, a loosely bound rocky world about the size of a small mountain, during a touch-and-go landing in October 2020.

It’s the third asteroid sampling mission in history, and the first for the United States, following two Japanese spacecraft that returned a smaller quantity of asteroid specimens to Earth in 2010 and 2020.

The OSIRIS-REx mission was tinged with suspense and drama from start to finish. The project’s original lead scientist died in 2011, months after NASA selected his mission concept for funding. In 2016, the spacecraft was stacked on top of its United Launch Alliance Atlas V rocket awaiting liftoff from Cape Canaveral, Florida, when a SpaceX Falcon 9 rocket exploded during a ground test barely a mile away. That sent thick plumes of black smoke over the Atlas V launch pad and briefly knocked offline an air conditioning system needed to keep OSIRIS-REx safe before launch.

Then, in 2020, when OSIRIS-REx collected its sample from Bennu, the spacecraft overfilled its collection chamber. The asteroid was made of much looser material than scientists predicted, so diffuse that the spacecraft could have kept plowing into Bennu had it not performed a pre-planned back-away maneuver.

At the end of its 4 billion-mile celestial journey, the OSIRIS-REx mothership spacecraft released a 32-inch-wide (81-centimeter) sample return capsule early Sunday as it darted toward Earth. More than four hours later, the capsule landed at the US Air Force’s Utah Test and Training Range southwest of Salt Lake City at 8:52 am local time (10:52 am EDT or 14:52 UTC).

Scientists working on NASA’s $1 billion OSIRIS-REx mission watched anxiously as the capsule came back to Earth, braving temperatures of more than 5,000 degrees Fahrenheit after slamming into the atmosphere at 27,650 mph (12.3 kilometers per second).

Radar sensors and infrared tracking cameras glimpsed the capsule as aerodynamic forces rapidly decelerated the vehicle, subjecting it to 32 times the force of Earth’s gravity before an orange and white main parachute opened at an altitude of about 20,000 feet (6,100 meters).

This was about four times higher than predicted, with the chute deployment triggered by a sensor on-board the capsule measuring its deceleration. It wasn’t immediately clear whether a drogue parachute meant to stabilize the capsule actually opened before the main chute, as was designed.

In any event, the main parachute did its job and delivered the capsule to the desert surface for a relatively gentle landing at about 10 to 11 mph (17 kilometers per hour). Within minutes, a safety official from the military test range approached the blackened capsule with a safety engineer from Lockheed Martin, which built the OSIRIS-REx spacecraft for NASA.

https://arstechnica.com/?p=1970704