The OSIRIS-REx spacecraft arrived at the asteroid Bennu on Monday, December 3rd, following a two-year journey. One of the highlights of the mission will be the collection of material from the surface of the ancient asteroid, which will be returned to Earth for research in 2023.

The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft will spend around 18 months orbiting the diamond-shaped asteroid, searching for the best place from which to collect the sample.

“For the past several months, Bennu has been coming into focus as I approached. Now that I’m here, I’ll fly around the asteroid and study it in detail. All the data I collect will help my team pick a spot to sample in 2020,” the OSIRIS-REx team tweeted as the spacecraft arrived at its target destination.

Technicians assemble the OSIRIS-REx spacecraft in 2015, preparing the vehicle for its historic journey. Image: Lockheed Martin

Sometime around July 2020, the vehicle will briefly touch down on Bennu, gathering between 60 grams (just over two ounces) and 2,000 grams (4.4 pounds) of material to return to Earth. After packing the material in a specially-designed capsule, OSIRIS-REx will soar back to Earth, sending the surface material to a landing in the Utah desert in 2023.

This asteroid is a relic from the earliest days of the solar system, believed to be more than 4.5 billion years old. Study of its composition could unravel mysteries about the birth and evolution of our family of planets.

A full view of the surface of Bennu, taken by the OSIRIS-REx spacecraft. Image: NASA’s Goddard Space Flight Center/University of Arizona

“Bennu is a leftover fragment from the tumultuous formation of the solar system. Some of the mineral fragments inside Bennu could be older than the solar system. These microscopic grains of dust could be the same ones that spewed from dying stars and eventually coalesced to make the Sun and its planets nearly 4.6 billion years ago,” NASA officials report on their Solar System Exploration website.

Fragments of asteroids regularly land on Earth, but as soon as they land, they become contaminated by materials and organisms from the ground, reducing their value for science.

Bennu is a near-Earth asteroid, coming close to our home planet on a regular basis. It is known to be carbon-rich, covered in organic material. Scientists hope study of the body could unravel secrets about the origin of life on Earth.

The mission is managed, in part, by researchers from the University of Arizona. To celebrate the arrival, the team was honored with the Bennuval event (an amalgam of Beenu and arrival), held at the Fox Theater in Tucson on December 1st. Festivities included talks on science, music, dancing, poetry, and insights into popular culture, including science fiction, history, and linguistics. Special guests included Dante Lauretta, principal investigator of the OSIRIS-REx program, and Geoff Notkin, Emmy award-winning host and producer of Meteorite Men.

Geoff Notkin, Emmy Award-winning host and producer of Meteorite Men, kicks off the Bennuval event in front of a packed house at the Fox Theater in Tucson. Photo by James Maynard/Maynard Modern Media.

Bennu and asteroids like it contain materials essential to science and industry, including aluminum, iron, and platinum. For this reason, governments and private business are looking to asteroids as a potential source of metals and minerals, as humans spread across the solar system.

Dante Lauretta, principal investigator of the OSIRIS_REx mission, talks about the science of asteroids at the Bennuval event held at the Fox Theater in Tucson, Arizona on December 1st 2018. Image: James Maynard/Maynard Modern Media.

Astronomers discovered Bennu in 1999, and have carefully studied this body since that time. The asteroid measures around 500 meters (1,640 feet) in diameter, and it travels around the Sun once every 1.2 years, at an average velocity of over 100,000 kilometers per hour (63,000 MPH).

The size of Bennu, put into perspective. Image: NASA’s Goddard Space Flight Center

Once every six years, BENNU makes a close approach with the Earth. In the year 2135, Bennu could pass closer to the Earth than the distance at which the Moon orbits, and may come even closer than that passage between the years 2175 and 2195. Although there is almost no chance of Bennu colliding with our planet during those close encounters, study of this asteroid could provide valuable information to astronomers learning how to protect our planet from dangerous bodies.

The spacecraft is scheduled to remain in orbit around the asteroid for seven years, collecting data, and sending it back to Earth. This is the first US-led mission to the surface of an asteroid.