[18][19][20][21] OSIRIS-REx left Bennu on 10 May 2021[22][23] and returned its sample to Earth on 24 September 2023,[24] subsequently starting its extended mission to study 99942 Apophis, where it will arrive in April 2029.

In particular, Bennu was selected because of the availability of pristine carbonaceous material, a key element in organic molecules necessary for life as well as representative of matter from before the formation of Earth.

Organic molecules, such as amino acids, have previously been found in meteorite and comet samples, indicating that some ingredients necessary for life can be naturally synthesized in outer space.

The principal investigator is Dante Lauretta[28] from the University of Arizona, having taken over in 2011 after the original PI Michael Julian Drake died four months after the mission won approval from NASA.

The capsule landed by parachute at the Utah Test and Training Range on September 24, 2023 and was transported to the Johnson Space Center for processing in a dedicated research facility.

[34] OSIRIS-REx entered the cruise phase shortly after separation from the launch vehicle, following successful solar panel deployment, propulsion system initiation, and establishment of a communication link with Earth.

Between 9 and 20 February 2017, the OSIRIS-REx team used the spacecraft's MapCam camera to search for the objects, taking about 135 survey images each day for processing by scientists at the University of Arizona.

[37][39] On 12 February 2017, while 673×10^6 km (418×10^6 mi) from Jupiter, the PolyCam instrument aboard OSIRIS-REx successfully imaged the giant planet and three of its moons, Callisto, Io, and Ganymede.

[41] On 3 December 2018, NASA confirmed that OSIRIS-REx had matched the speed and orbit of Bennu at a distance of about 19 km (12 mi), effectively reaching the asteroid.

Preliminary spectroscopic surveys of the asteroid's surface by the OSIRIS-REx spacecraft detected the presence of hydrated minerals in the form of clay.

[42][43] OSIRIS-REx entered orbit around Bennu on 31 December 2018 at about 1.75 km (1.09 mi) to start its extensive remote mapping and sensing campaign for the selection of a sample site.

[29] The descent was very slow, minimizing thruster firings prior to contact to reduce the likelihood of asteroid surface contamination by unreacted hydrazine propellant.

[47] Upon surface contact by the TAGSAM instrument, a burst of nitrogen gas was released to blow regolith particles smaller than 2 cm (0.8 in) into the sampler head at the end of the robotic arm.

A five-second timer limited the collection time to mitigate the chance of a collision, and the probe then executed a back-away maneuver to depart safely.

[29] The plan was then for OSIRIS-REx to perform a braking maneuver a few days later to halt the drift away from the asteroid in case it was necessary to return for another sampling attempt.

The samples contain a nearly equal mix of left-handed (L) and right-handed (D) amino acids, raising questions about whether asteroids like Bennu helped shape Earth's biochemistry.

The spacecraft will perform a maneuver, similar to sample collection at Bennu, by using its thrusters to disturb Apophis's surface, in order to expose and spectrally study the subsurface and the material beneath it.

Dante Lauretta, deputy PI of the mission, was called "a mythology buff" by the mission PI Michael Drake: "he was doodling on a pad and trying to capture the principal themes of what we are trying to do with this mission—study life origins, identify resources, planetary security in the form of asteroid deflection—and he realized he got the name of Osiris out of that, an ancient god of Egypt who may have been one of the first pharaohs.

[99] In addition to its telecommunication equipment, the spacecraft carries a suite of instruments to image and analyze the asteroid on many wavelengths,[101] and retrieve a physical sample to return to Earth.

The Planetary Society coordinated a campaign to invite interested persons to have their names or artwork on the mission's spirit of exploration saved on a microchip carried in the spacecraft.

[101] The wavelength range, spectral resolution, and radiometric performance are sufficient to resolve and identify silicates, carbonates, sulfates, phosphates, oxides, and hydroxide minerals.

[citation needed] Based on the performance of Mini-TES in the dusty surface environment of Mars, OTES was designed to be resilient to extreme dust contamination on the optical elements.

[101] REXIS was a collaborative development by four groups within Massachusetts Institute of Technology (MIT) and Harvard University, with the potential to involve more than 100 students throughout the process.

During orbital phase 5B, a 21-day orbit 700 m from the surface of Bennu, a total of at least 133 events/asteroid pixel/energy band were expected under 2 keV; enough to obtain significant constraints on element abundances at scales larger than 10 m.[citation needed] On 11 November 2019, while observing the asteroid with REXIS, university students and researchers involved in the mission unexpectedly discovered an X-ray burst from a black hole named MAXI J0637-430 located 30,000 light-years away.

The data collected by OLA will also be used to develop a control network relative to the center of mass of the asteroid and to enhance and refine gravitational studies of Bennu.

[citation needed] OLA has a single common receiver and two complementary transmitter assemblies that enhance the resolution of the information brought back.

Laser pulses from both the low and high energy transmitters are directed onto a movable scanning mirror, which is co-aligned with the field of view of the receiver telescope limiting the effects of background solar radiation.

[109] The sample-return system, called Touch-And-Go Sample Acquisition Mechanism (TAGSAM), consists of a sampler head with an articulated 3.35 m (11.0 ft) arm.

[citation needed] Highlights of the TAGSAM instrument and technique include: Hayabusa2 is a similar mission from JAXA to collect samples from near-Earth asteroid 162173 Ryugu.

Because the two missions were similar and had overlapping timelines (OSIRIS-REx was still in the return phase), NASA and JAXA signed an agreement to collaborate on sample exchange and research.