What will ‘cosmic detective’ OSIRIS-Rex bring back on Sept. 24? | Explained

NASA's OSIRIS-Rex mission will drop a capsule of pristine asteroid material in the Utah desert on September 24. The astro-material may provide insights into how planets formed, what materials were present in the early Solar System, and how life on the earth began. OSIRIS-Rex had to precisely choreograph a celestial waltz with the asteroid Bennu, using Brian May's 3D maps, to find a landing spot. The sample capsule will help scientists understand the violent birth of the Solar System and possibly reveal organic molecules that could explain the origin of life.

Come September 24, and debris from an alien world will land on the earth. NASA’s asteroid hunting spacecraft OSIRIS-Rex – short for Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer – will drop a capsule containing pristine asteroid material in the Utah desert. OSIRIS-Rex, which is currently winging its way towards the earth after a close encounter with Bennu, a near-earth asteroid (NEA), “is a cosmic detective,” in the words of Dante Lauretta, the principal investigator of the mission.

“Asteroids are like cosmic treasure troves, containing a mix of raw materials like metals, water, and even organic compounds,” Dr. Lauretta told this writer in an email. The astro-material brought back by OSIRIS-Rex, he added, “may provide scientists with valuable insights into how planets formed, what materials were present in the early Solar System, and even how life on the earth might have originated.”

Many scientists believe that along with comets, carbon-rich asteroids like Bennu may have seeded the earth with primordial life as they smashed into the young planet more than four billion years ago.

Launched in 2016, the OSIRIS-Rex spacecraft completed a series of complex manoeuvres that included a return trip to the earth to use the planet’s gravitational pull for it to ‘slingshot’  itself back into space, with more speed. Scientists then injected the probe into orbit around Bennu in 2018 so that it whirled barely two kilometres above the space rock, even as both of them hurtled through space at 28 kilometres per second.

Mission controllers had to precisely choreograph this celestial waltz as Bennu’s frail gravity – so weak that it allows boulders to roll uphill on the asteroid! – could barely keep OSIRIS-Rex bound in orbit.

But even after achieving orbit, the mission almost ended in failure when the asteroid’s unexpectedly craggy surface rendered OSIRIS-Rex’s height-measuring instrument useless to attempt a landing. Controllers were forced to send the probe on an intricate holding pattern around Bennu for almost two and a half years as they tried to find a different landing spot.

Fortunately, they had an unlikely ally: the renowned lead guitarist of the rock band Queen, Brian May. A qualified astrophysicist, May used his expertise in stereoscopy to turn images taken by OSIRIS-Rex’s on-board cameras into detailed 3D maps of Bennu’s surface for locating potential landing sites.