Who needs the Guardians of the Galaxy when we have OSIRIS-REx?

An artist’s rendering of the OSIRIS-REx Touch-And-Go Sample Arm Mechanism collecting a sample of asteroid Bennu. Photo Credit: NASA / Goddard Space Flight Center

Last week, a spacecraft arrived at one of the smallest objects ever visited by a NASA mission—asteroid 101955 Bennu—after a multi-billion mile journey around the Solar System.

NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) is designed to help scientists acquire deeper insights as to how planets form and life began, the U.S. space agency stated recently. NASA went on to note that one of OSIRIS-REx’s goals is to “improve our understanding of asteroids that could impact Earth.” It is hoped that the spacecraft can achieve these goals over an approximately two-year orbital mission before collecting samples and returning them to Earth in 2023.

Costing around $800 million, the spacecraft was launched on Sept. 8, 2016, atop a United Launch Alliance Atlas V 411 rocket. More than 1.2 billion miles (2 billion kilometers) later, on Dec. 3, 2018, OSIRIS-REx arrived at the 1,600-foot (492-meter) wide body, placing itself at 11.8 miles (19 kilometers) from its surface initially. According to NASA, Bennu is the smallest object ever orbited by a spacecraft.

This image of Bennu was taken by OSIRIS-REx from a distance of about 50 miles (80 kilometers). Image Credit: NASA / Goddard / University of Arizona

The importance of OSIRIS-REx’s findings could potentially be insurmountable, as they could play an extremely important role in helping scientists understand the threat asteroids pose to Earth.

There are currently 1,885 known potentially hazardous asteroids as of 2018 that have an orbital intersection distance from Earth of 0.05 astronomical units or less. Approximately 8 percent of these asteroids have been estimated to have a diameter larger than a kilometer. According to NASA’s Jet Propulsion Laboratory (JPL), asteroids as small as 105 feet (35 meters) in diameter can potentially play a serious threat to populated areas.

According to Southwest Research Institute asteroid expert William Bottke, one of the most crucial elements OSIRIS-REx is designed to study is the Yarkovsky effect and the role that it plays on the orbital projection of Bennu and other potentially-hazardous asteroids.

Named after the Polish engineer who discovered it, the Yarkovsky effect is a force created by thermal energy radiating from the Sun acting on an object in space. Scientists at JPL believe that by further understanding this effect and the impact it has on asteroid orbital paths, they could have the ability to better predict the orbital trajectory of Earth-threatening asteroids.

Using the OSIRIS-REx Thermal Emission Spectrometer (OTES), the spacecraft can effectively capture mineral and thermal data critical in measuring the impacts of the Yarkovsky effect on Bennu. If successful, this would mark the first time this theory has ever been tested on a tangible asteroid.

The spacecraft is expected to use a myriad of instruments and equipment in order to conduct the most expansive study that has ever been completed on an asteroid. Each instrument performs a specific function critical to obtaining information about the life and future path of Bennu.

The PolyCam, MapCam, and SamCam make up the spacecraft’s vast array of cameras (OCAMS) that provide a sight picture of the asteroid, as well as scoping out potential sample and extraction sites. Other instruments used in tangent with the OTES and OCAMS include the OSIRIS-REx Laser Altimeter (OLA), the Visible and Infrared Spectrometer (OVIRS), and student-created Regolith X-ray Imaging Spectrometer (REXIS).

Surface samples of Bennu are expected to be collected using the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) developed by Lockheed Martin, and should have the ability for up to three sampling attempts. Once gathered, TAGSAM uses an arm to place the samples into the Sample Return Capsule (SRC).

Upon mission completion, the SRC with the collected samples will be the only part of the OSIRIS-REx spacecraft that returns to Earth’s surface to help providing a better understanding of the formation, life, and projected trajectories of asteroids. Should everything go as planned, it is expected re-enter the atmosphere and parachute down to the United States Air Force Test Training Range in Utah on Sept. 24, 2023.

Tagged: Asteroid Bennu asteroids NASA OSIRIS-REx The Range

Cullen Desforges

Having a life-long interest in crewed space flight, Desforges’ passion materialized on a family vacation in 1999 when he was able see the launch of Space Shuttle Discovery on STS-96. Since then, Desforges has been an enthusiast of space exploration efforts. He lived in Orlando, Florida for a year, during which time he had the opportunity to witness the flights of the historic CRS-4 and EFT-1 missions in person at Cape Canaveral. He earned his Private Pilot Certificate in 2017, holds a degree in Aviation Management, and currently works as an Operations Analyst in the aviation industry in Georgia.