OSIRIS-REx’s Trailblazing Mission to Bennu and Beyond

NASA's OSIRIS-REx spacecraft captured this image of the asteroid Bennu using its MapCam imager on Dec. 12, 2018. (Image credit: NASA/Goddard/University of Arizona)

In the vast expanse of our solar system, a remarkable mission has been unfolding, capturing the imagination of space enthusiasts and scientists alike. OSIRIS-REx, the Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer, represents a bold endeavor by NASA to study, sample, and comprehend the mysteries of distant celestial bodies. In this comprehensive guide, we embark on a thrilling voyage through the key milestones, scientific achievements, and prospects of the OSIRIS-REx mission.

Unveiling Asteroid Bennu:

Launched on September 8, 2016, OSIRIS-REx embarked on a groundbreaking journey to the near-Earth asteroid Bennu. After a journey spanning millions of miles, the spacecraft reached its destination on December 3, 2018. Bennu, a captivating space rock with a diameter of approximately 1,650 feet (500 meters), holds within its rocky surface a treasure trove of information about the early solar system.

As OSIRIS-REx closed in on Bennu, the anticipation grew. The mission aimed to unravel the mysteries of this ancient wanderer and provide insights into the processes that shaped our cosmic neighborhood. The spacecraft’s instruments, meticulously designed and crafted, stood ready to explore Bennu’s composition, structure, and history.

What Is Osiris-Rex

On a historic day, September 24, 2023, NASA’s OSIRIS-REx achieved a groundbreaking feat by becoming the first U.S. mission to successfully deliver a sample from an asteroid to Earth. Launched on September 8, 2016, the spacecraft meticulously collected rocks and dust—approximately 8.8 ounces or 250 grams—from the surface of the asteroid Bennu on October 20, 2020. Commencing its return journey on May 10, 2021, after a thorough examination of the asteroid, the spacecraft is now carrying this precious material back to Earth.

This collection from Bennu serves as a remarkable time capsule, offering insights into the earliest days of our solar system. The anticipated analysis of this material holds the key to unraveling significant questions about the origins of life and the unique characteristics of asteroids, marking a pivotal moment in space exploration.

Why did NASA decide to study Bennu?

Scientists decided to study Bennu because it is a very old and primitive asteroid that has not changed much since the early days of the solar system. This makes it a valuable target for studying the formation and evolution of the solar system.

Bennu is also thought to be a potential source of organic materials, which are the building blocks of life. By studying Bennu, scientists hope to learn more about the origins of life on Earth. In addition, Bennu is a relatively close asteroid, which makes it easier to study than other asteroids that are farther away. This is why NASA chose Bennu as the target for the OSIRIS-REx mission.

What’s Bennu made of?

Bennu is a carbonaceous chondrite asteroid, which means that it is composed of a mixture of rock, dust, and organic materials. The exact composition of Bennu is still unknown, but it is thought to be similar to that of other carbonaceous chondrites that have been studied in meteorites.

Organic materials are compounds that contain carbon, and they are thought to be the building blocks of life. The presence of organic materials on Bennu is one of the reasons why this asteroid is so interesting to scientists. They hope that by studying Bennu, they can learn more about the origins of life on Earth.

In addition to organic materials, Bennu is also thought to contain water ice. Water is essential for life, and the presence of water ice on Bennu suggests that this asteroid may have once been habitable. Scientists are still learning about the composition of Bennu, and they hope that the samples that were collected by the OSIRIS-REx mission will provide more clues about this fascinating asteroid.

A Delicate Dance in Space:

OSIRIS-REx’s mission was far from mere observation. The spacecraft seamlessly slipped into orbit around Bennu on December 31, 2018, an intricate dance that allowed scientists to gather invaluable data about the asteroid’s shape, composition, and behavior. It was a testament to human ingenuity,y, marking the first time a spacecraft orbited such a  diminutive celestial body. This close encounter provided an unprecedented opportunity to unravel Bennu’s secrets.

As OSIRIS-REx circled Bennu, its instruments embarked on a scientific exploration that surpassed expectations. The Visible and Infrared Spectrometer (OVIRS) peered into the asteroid’s surface, hunting for traces of organic compounds and minerals. The thermal Emission Spectrometer (OTES) took Bennu’s temperature, mapping mineral and chemical abundances. The Camera Suite (OCAMS) captured stunning images, revealing the rugged terrain and potential sample collection sites. The Laser Altimeter (OLA) scanned the surface, creating highly accurate 3D models.

The Quest for a Touchdown:

The pinnacle of OSIRISfor-REx’s mission was a dramatic and nail-biting touchdown on Bennu’s surface on October 20, 2020. Using its Touch-And-Go Sample Acquisition Mechanism (TAGSAM), the spacecraft deftly collected a sample of the asteroid’s regolith—a mixture of dust and broken rock. This intricate operation lasted a mere six seconds but yielded a wealth of information that scientists eagerly await.

The TAGSAM’s delicate dance with Bennu’s surface marked a historic achievement. It was a culmination of years of planning, engineering, and scientific expertise. The spacecraft’s precision and the team’s dedication led to the successful collection of more material than anticipated. OSIRIS-REx not only met its primary goal of 2 ounces (60 grams) but surpassed it, demonstrating the capability to achieve ambitious scientific objectives in the unforgiving environment of space.

When – and where on Earth – did the sample capsule land?

Osiris rex sample return mission
DUGWAY, UTAH – SEPTEMBER 24: In this handout provided by NASA, from left to right, NASA Astromaterials Curator Francis McCubbin, NASA Sample Return Capsule Science Lead Scott Sandford, and University of Arizona OSIRIS-REx Principal Investigator Dante Lauretta collect science data shortly after the sample return capsule from NASA’s OSIRIS-REx mission landed at the Department of Defense’s Utah Test and Training Range, on September 24, 2023 at the Department of Defense’s Utah Test and Training Range in Dugway, Utah. The sample was collected from the asteroid Bennu in October 2020 by NASA’s OSIRIS-REx spacecraft. (Photo by Keegan Barber/NASA via Getty Images)

At precisely 6:42 a.m. EDT (4:42 a.m. MDT) on September 24, 2023, OSIRIS-REx initiated the release of its sample capsule toward Earth’s atmosphere. Positioned 63,000 miles (102,000 kilometers) away from Earth’s surface, approximately one-third of the distance from Earth to the Moon, the spacecraft entered a critical phase of its mission.

Traveling at an impressive speed of 27,650 mph (44,500 kph), the capsule made a significant atmospheric entry at 10:42 a.m. EDT (8:42 a.m. MDT) off the coast of California. Descending from an altitude of around 83 miles (133 kilometers), it expertly landed at the Department of Defense’s Utah Test and Training Range near Salt Lake City by 10:52 a.m. EDT (8:52 a.m. MT). Throughout the descent, two parachutes were deployed to effectively stabilize and decelerate the capsule, ensuring a gentle touchdown speed of 11 mph (18 kph).

Advanced radar, infrared, and optical instruments, both airborne and ground-based, carefully tracked the capsule’s trajectory within a designated 36-mile by 8.5-mile (58-kilometer by 14-kilometer) area on the range. A recovery team was swiftly dispatched to inspect and retrieve the capsule, confirming its integrity and safety for approach within minutes. Rapidly, within 70 minutes, the team secured and prepared the capsule for safe transportation to a temporary clean room on the range. On September 25, 2023, the unopened canister containing the Bennu sample was transported by air to NASA’s Johnson Space Center in Houston. Curation scientists will systematically disassemble the canister, extract and weigh the sample, compile an inventory of the rocks and dust, and subsequently distribute fragments of Bennu to scientists worldwide over time.

ALSO READ: ‘I literally broke into tears’: The Scientist’s Greatest Day with OSIRIS-REx

NASA’s Measures Against Earthly Contamination during Entry, Descent, and Landing in Utah

Osiris rex sample return mission
Osiris rex sample return mission

The mission’s success depended heavily on preventing contamination of the Bennu sample from Earth. Any contamination could make the results unreliable as scientists searched the sample for organic molecules suggestive of life. During the sample’s entry, descent, and landing (EDL) phase, NASA enforced a strict contamination control strategy to allay this worry.

As the capsule descended through Earth’s atmosphere, it actively introduced filtered air through dedicated vents, efficiently eliminating contaminants such as water vapor, organic compounds, and dust. This meticulous filtration process ensured that the sample remained pristine, untouched by Earth’s atmospheric constituents.

Upon landing, the recovery team swiftly retrieved the sample capsule and transported it to a temporary clean room established within the Utah Test and Training Range. Here, the OSIRIS-REx team connected the capsule to a reservoir of nitrogen, an inert gas that doesn’t readily interact with other chemicals. A continuous flow of nitrogen purged the capsule, effectively displacing any residual air and maintaining a contamination-free environment.

These comprehensive measures, meticulously planned and executed by NASA, safeguarded the Bennu sample from Earth’s contamination. The integrity of the sample was preserved, allowing scientists to embark on their quest to unravel the mysteries of life beyond Earth.

What happened to the OSIRIS-REx spacecraft after it delivered the sample to Earth?

The spacecraft fired its engines to change its course away from Earth about 20 minutes after releasing its sample capsule above Earth’s atmosphere. After that, the spacecraft launched a brand-new mission named OSIRIS-APEX (OSIRIS–Apophis Explorer) to study the asteroid Apophis, which it will reach in 2029.

A Glimpse into the Past and Future:

To truly appreciate the significance of OSIRIS-REx, we must delve into its origins and aspirations. The mission was born out of a visionary concept, selected from a pool of remarkable contenders, under NASA’s New Frontiers program. In 2009, OSIRIS-REx emerged as the chosen one, joining the ranks of space exploration alongside missions to study Venus and the Moon.

The journey commenced on September 8, 2016, with OSIRIS-REx’s launch. A momentous occasion that marked the fusion of advanced technology, scientific curiosity, and human ambition. The spacecraft undertook two deep-space maneuvers and a gravity-assist flyby of Earth, building momentum for its ultimate rendezvous with Bennu.

The First Orbit, the Closest Approach:

On December 3, 2018, OSIRIS-REx’s arrival at Bennu signaled a new era in asteroid exploration. The spacecraft’s instruments, including the Visible and Infrared Spectrometer (OVIRS), Thermal Emission Spectrometer (OTES), and Camera Suite (OCAMS), worked in harmony to capture unprecedented data about Bennu’s surface, composition, and thermal properties.

As OSIRIS-REx circled Bennu, it achieved not one but two remarkable records. It became the first spacecraft to orbit such a small celestial body, a testament to the expertise of the mission’s engineers and scientists. Moreover, its closest orbit of just 1 mile (1.6 kilometers) from the surface granted us an intimate view of Bennu’s rugged terrain.

A Delicate Grasp, A Wealth of Knowledge:

The climax of OSIRIS-REx’s mission, the Touch-And-Go (TAG) sample collection, showcased the pinnacle of precision and coordination. On October 20, 2020, the spacecraft’s TAGSAM extended and briefly contacted Bennu’s surface, while a burst of nitrogen gas disturbed the regolith. This masterful maneuver yielded a bounty of material—far surpassing the primary goal of 2 ounces (60 grams)—a triumph that highlighted both engineering expertise and a scientific breakthrough.

ALSO READ: Senate Puts NASA on Notice: Concerns Rise Over Mars Sample Return Mission

A Beacon of Inspiration:

OSIRIS-REx has made a grand homecoming, marking a new chapter in human exploration. This incredible feat showcases our adventurous spirit and the endless possibilities of science. As we eagerly anticipate the secrets Bennu holds and the start of OSIRIS-APEX’s mission, we are reminded of humanity’s endless curiosity and our unwavering quest to unlock the universe’s mysteries.

More than just a spacecraft, OSIRIS-REx is a symbol of our unwavering dedication to pushing the boundaries of what we previously believed was possible, our shared quest for knowledge, and our insatiable thirst for discovery. Its tale acts as a timeless source of motivation, inspiring us to aim high, bravely explore uncharted territory, and accept that the universe, with all of its wonders and mysteries, is within our grasp.


The OSIRIS-REx mission has been an extraordinary journey of exploration and discovery, pushing the boundaries of our knowledge and understanding of the cosmos. From its launch in 2016 to its triumphant return to Earth in 2023, this remarkable mission has captivated the imaginations of people around the world and cemented its place in history as a groundbreaking scientific endeavor.

The successful collection and return of a sample from the asteroid Bennu marks a watershed moment in space exploration. This precious cargo holds the potential to unlock the secrets of our solar system’s origins and provide insights into the building blocks of life itself. The scientific community eagerly awaits the opportunity to analyze this pristine material, unraveling its hidden secrets and rewriting our understanding of the universe.


Arizona Board of Regents. (2022.) OSIRIS-Rex: Asteroid Sample Return Mission – Galleries. Accessed Nov. 10, 2022, from: https://www.asteroidmission.org/galleries/ 

Lockheed Martin. (2022.) OSIRIS-REx: Discovering the Origins of the Solar System. Accessed Nov. 10, 2022, from:  https://www.lockheedmartin.com/en-us/products/osiris-rex.html

NASA. (2020, Oct. 23.) NASA’s OSIRIS-REx spacecraft collects a significant amount of asteroids. Accessed Nov. 10, 2022 from:  https://www.nasa.gov/press-release/nasa-s-osiris-rex-spacecraft-collects-significant-amount-of-asteroid

NASA Science. (n.d.) OSIRIS-REx. Accessed Nov. 10, 2022, from: https://solarsystem.nasa.gov/missions/osiris-rex/in-depth/


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