Early on Sunday, September 24, the sample module of the OSIRIS-REx spacecraft will come face to face with the Earth's atmosphere for the first time since its launch in 2016. The cabin contains about 8.8 ounces (250 grams) of rock material collected from the surface of the asteroid "Bennu" in 2020. This is the first time NASA has collected an asteroid sample and the largest sample ever collected in space.
As it approaches Earth, the OSIRIS-REx spacecraft does not slow down while delivering samples. Instead, when it reaches a point 63,000 miles (or 102,000 kilometers) above the Earth's surface -- about one-third of the distance from Earth to the moon -- a message from an operator on the ground will trigger the release of the capsule, which will be sent spinning into the atmosphere below. Twenty minutes after landing, the spacecraft will start its thrusters, fly past the Earth, and fly to the asteroid Apophis, where it will continue to explore the solar system under a new name: OSIRIS-APEX (OSIRIS-Apophis Explorer).
OSIRIS-REx is NASA's first asteroid sample return mission. It was launched in September 2016 and embarked on a journey to explore a near-Earth asteroid called "Bennu". On September 24, 2023, the space capsule containing the Bennu samples will land in the western desert of Utah. This will be the exciting finale of this mission. Source: NASA
Meanwhile, after four hours in space, the capsule will penetrate the Earth's atmosphere at 8:42 a.m. Central Time (10:42 a.m. Eastern Time), traveling at about 27,650 miles per hour (44,500 kilometers per hour). At this rate, the compression of Earth's atmosphere would generate enough energy to envelop the capsule in an extremely hot fireball. The thermal barrier will help regulate the temperature inside the capsule, keeping samples safe in an environment similar to Bennu's surface temperature.
The parachute will allow the capsule to land at a safe speed. About 2 minutes after the capsule enters the atmosphere, a parachute will first be deployed to stabilize the transition to subsonic speeds. Six minutes later, about a mile (1.6 kilometers) above the desert, the main parachute will deploy, taking the capsule all the way down to a 36-mile by 8.5-mile (58-kilometer by 14-kilometer) area on a military range. When landing, the capsule will slow down to about 11 mph (18 km/h).
Finally, just 13 minutes after entering the atmosphere, the capsule will arrive on Earth for the first time in seven years, awaiting the arrival of the recovery team.
About 20 minutes before the capsule lands, while it is still high in the Earth's atmosphere, the recovery site team will board four helicopters and head toward the desert. Thermal instruments will track the infrared light of the capsule's heat signature until optical instruments can see the capsule, giving recovery teams a way to track the capsule's trajectory on Earth. The goal of the recovery team is to recover the capsule from the ground as quickly as possible to avoid contamination of the samples by the earth's environment.
Once the capsule is found and packed, it will be flown via helicopter to a temporary clean room at a military range, where it will undergo initial processing and disassembly in preparation for flight to NASA's Johnson Space Center in Houston, where the samples will be recorded, preserved, and distributed to scientists around the world for analysis.