Bear Down 100: Tagging an asteroid
Dreamed up by the late Michael Drake and principal investigator Dante Lauretta, and led by the U of A's Lunar and Planetary Laboratory, the OSIRIS-REx mission launched on Sept. 8, 2016. Sample collection took place on Oct. 20, 2020.
As part of the 100th anniversary of our motto, "Bear Down," the University of Arizona is looking back at several of the most remarkable moments and accomplishments in the university’s illustrious history, with an eye toward the "Bear Down" moments of the future.
Made from the leftover material of a solar system that took shape more than 4.5 billion years ago, asteroid Bennu holds clues to some of the biggest questions still hidden in the mysteries of our vast cosmos. When it came time to actually land on that asteroid and collect a sample, it took the scientific know-how and meticulous dedication found in University of Arizona researchers to make that mission a reality.
Dreamed up by the late Michael Drake and principal investigator Dante Lauretta, and led by the U of A's Lunar and Planetary Laboratory, the OSIRIS-REx mission launched on Sept. 8, 2016. The team guided its arrival at Bennu on Dec. 3, 2018, and sample collection took place on Oct. 20, 2020. The capsule returned to Earth on Sept. 24, 2023, where Lauretta and his team eagerly awaited its arrival in Utah.
Life's building blocks
Scientists around the world immediately began analyzing the Bennu sample – an estimated 8.8 ounces, or 250 grams, of surface material – and discovered that the asteroid likely originated from a salty world containing the chemical precursors necessary for life to evolve.
Ranging from calcite to halite and sylvite, scientists identified 11 minerals that comprise a complete set of "evaporites" from a brine, or salt-saturated water. These evaporites form as water containing dissolved salts evaporates over long periods of time, leaving behind the salts as solid crystals. Finding evaporites indicates that the interior of Bennu's ancestor was warm enough to support liquid water for a substantial amount of time.
From OREX to APEX
After making history as the first U.S. mission to return part of an asteroid to Earth, the OSIRIS-REx mission transitioned to OSIRIS-APEX. The spacecraft is now scheduled to rendezvous with another asteroid, Apophis, and study it for 18 months after its close approach to Earth on April 13, 2029. The new mission is led by Dani Mendoza DellaGiustina, assistant professor of planetary science.
The mission to Bennu provided scientists with an unprecedented sample of a carbon-rich asteroid, while the flight to Apophis offers something else entirely: high-resolution data of a stony asteroid after it passes near the Earth. The spacecraft will study how the surface of Apophis could change by interacting with Earth's gravity, leading to a better understanding of other potentially hazardous celestial bodies.
On a recent flyby, OSIRIS-APEX swung by Earth within 2,136 miles before heading into deep space for another trip around the sun. A so-called Earth gravity assist, the first of three such maneuvers planned for the remainder of the mission, is essential to ensure the spacecraft will rendezvous with Apophis in 2029. During its approach and as it passed Earth, the spacecraft looked home using its suite of three cameras to capture images and data of our planet to help calibrate its instruments.
Unfortunately, the craft does not have hands in the traditional sense and could not flash the Wildcat hand symbol and say, "Bear Down" in its selfie, but we all know that was the intended message.
Explore more Bear Down 100 moments at Arizona.edu/BearDown.
