On Sept. 24, NASA’s OSIRIS-REx spacecraft will come hurtling again by way of Earth’s environment after a years-long journey to Bennu, a “probably hazardous asteroid” with a 1 in 2700 likelihood of smashing cataclysmically into Earth, the very best odds of any recognized area object.
The objective of the mission? To see whether or not life on Earth got here from outer area. However for a nail-biting 22 months, scientists questioned whether or not they’d be capable to land the spacecraft on the asteroid in any respect.
That the mission finally succeeded is partially because of Queen guitarist Brian Could, who meticulously created 3D photographs of the rubble pile to assist the mission leaders establish protected touchdown spots. Due to that protected touchdown, OSIRIS-REx is now getting back from its mission with a 2-ounce pattern (60 grams) of Bennu’s floor that might comprise extraterrestrial precursors to life on our planet.
“You suppose asteroids are items of junk on the market which may hit us and we’re very fearful of them — no matter. You do not understand that really, they’re most likely accountable for us being right here,” Could, who additionally has a PhD in astrophysics informed Stay Science. “There would most likely be no biosphere with out asteroids. And presumably the precise seeds of life got here from them as nicely — it is an unbelievable thought. So asteroids grow to be completely the middle of the whole lot: If we perceive asteroids, we’ll perceive ourselves.”
Bennu: Bringer of loss of life, God of creation
Seen from a distance, Bennu appears to be like like an inert, debris-flecked spinning prime suspended in area. Categorized as a rubble-pile asteroid, Bennu is an 85.5 million-ton (77.5 million metric tons) assortment of rock chunks and boulders barely held collectively by weak gravity — a cosmic ball pit that swallows any object that lands too exhausting on its floor, and sends something that springs too forcefully from it careering into area.
But draw nearer, as OSIRIS-REx did on its first method in 2018, and an altogether stranger image emerges. Veins of carbonate rock 3 ft (0.9 meters) lengthy criss-cross a floor spattered with carbon-rich natural materials — proof that Bennu’s dad or mum physique, a 60-mile (96 kilometers) extensive object which fashioned throughout the earliest years of the photo voltaic system and break up roughly one billion years in the past to type the asteroid, was as soon as house to torrents of sizzling water and the earliest constructing blocks of life.
Bennu is called after an historic Egyptian god of creation, and the flight of OSIRIS-REx (brief for the Origins, Spectral Interpretation, Useful resource Identification, Safety-Regolith Explorer) to the asteroid was no much less mythic an odyssey. It blasted off from Florida in 2016 and slingshotted round Earth earlier than reaching Bennu’s orbit in December 2018.
Sticking the touchdown
Nevertheless, OSIRIS-REx did not simply must get to Bennu: the actual trick was touchdown. Preliminary thermal surveys of Bennu appeared to recommend it was composed of fine-grained materials, very similar to a seaside, in line with the mission chief Dante Lauretta, a professor of planetary science and cosmochemistry on the College of Arizona.
However when OSIRIS-REx lastly arrived, it encountered a craggy asteroid strewn with sharp boulders that rendered the unique touchdown technique, which trusted a height-measuring laser altimeter, utterly ineffective. As a substitute, the workforce nudged the spacecraft into a decent orbit utilizing Bennu’s feeble gravity — making 1000’s of passes over the rock’s floor to seek for a protected touchdown spot.
“Yeah, we have been challenged to discover a protected location on the asteroid to ship our billion greenback spacecraft down to gather a pattern,” Lauretta informed Stay Science. “I imply, this isn’t a simple choice, and it was my choice, proper? I used to be on the hook for this.”
To discover a appropriate parking spot on Bennu, the OSIRIS-REx scientists used their spacecraft’s on-board cameras to meticulously map its floor options right down to the centimeter. Then, by taking pairs of photographs aspect by aspect from one another, Brian Could and his collaborator Claudia Manzoni clipped them collectively to create stereoscopic photographs (made by stitching two images collectively to recreate the depth notion of two eyes) — enabling the workforce to completely assess the security of potential touchdown websites.
“We’re flat photographs and considering: ‘Properly, that is perhaps okay, that appears fairly protected and flat,’ after which impulsively it pops out in 3D we’re like: ‘Err, no,'” Lauretta mentioned.
“Brian was processing scene after scene and I used to be fearful we have been by no means going to discover a sampling location,” Lauretta added. “Till lastly, we noticed these small craters formed like bowls, possibly 10 or 20 meters throughout, stuffed with this wonderful grain materials. Then I knew we have been onto one thing.”
After 22 months of fraught deliberation, the researchers settled on a website they named Nightingale, which OSIRIS-REx touched down upon on Oct. 20, 2020. To stay the touchdown and keep away from utterly sinking by way of the rubble-pile asteroid’s floor, the spacecraft fired a fast blast of nitrogen fuel from its Contact-and-Go Pattern-Acquisition Mechanism (TAGSAM).
Apart from providing the spacecraft a precarious foothold on Bennu’s floor, TAGSAM despatched mud and damaged rock flying in all instructions, most significantly into OSIRIS-REx’s pattern chamber, which collected a lot extra of the fabric than anticipated that it briefly had bother closing.
What’s within the field?
What precisely is hiding among the many rocks collected in OSIRIS-REx’s pattern is anybody’s guess, the mission scientists say, however the prospects are thrilling.
“We do not know until we get it, however simply trying on the photographs that Dante and Brian have despatched again, it appears to be like prefer it’s stuffed with a number of totally different sorts of rock, a few of that are actually fragile, which implies they’d by no means have gotten to Earth as meteorites,” Sara Russell, a professor of planetary sciences and chief of the Planetary Supplies Group that might be analyzing part of the pattern on the Pure Historical past Museum, London, informed Stay Science. “My hope is that it’s going to inform us one thing that we did not even know that we did not know.”
The story of the asteroid Bennu and OSIRIS-REx’s journey is informed in a brand new ebook brimming with Brian Could’s photographs. It additionally encompasses a 3D eye-piece designed by the rock god himself. “Bennu: 3-D Anatomy of an Asteroid”, written by Could and OSIRIS-REx principal investigator Dante Lauretta, is on the market within the U.S. from College of Arizona Press and within the U.Ok. from London Stereoscopic Firm.