Asteroids doubtless formed the trajectories of different worlds within the photo voltaic system and past. “In the event that they actually did deliver water and natural supplies to Earth, then presumably they’d have introduced them to Mars. They’d have introduced them to Venus,” Andy Rivkin, a planetary astronomer on the Johns Hopkins Utilized Physics Laboratory who research asteroids, advised me. “And people kinds of processes would presumably be happening in different photo voltaic techniques.”
Sampling an asteroid is a harmful process, and, in some sense, the OSIRIS-REx isn’t outfitted for the actual challenges of Bennu. Telescope observations from afar had prompt that Bennu’s floor would resemble a sandy shore, and engineers designed the mission with that picture in thoughts. The spacecraft as a substitute revealed a rugged, boulder-filled panorama that occasionally ejects coin-size particles into area. “That was a scary second,” Kaplan stated of the crew’s actuality test. “How are we going to get a pattern again from this factor?”
The crew finally chosen a sampling website that appeals to not solely the scientists on the crew, who wish to accumulate essentially the most intriguing samples, but additionally the engineers, who want to keep away from destroying the spacecraft. Propelled by its thrusters, OSIRIS-REx will depart its cozy orbit round Bennu and navigate to a small clearing in regards to the dimension of some parking spots, surrounded by boulders the scale of buildings. In a matter of seconds, a robotic arm will fire up the regolith with nitrogen gasoline after which sweep the floating detritus into its grasp, earlier than the spacecraft returns to its orbit.
NASA gained’t know the way a lot materials the spacecraft could have scooped up immediately. Later this week, engineers will command OSIRIS-REx to spin itself round, a intelligent transfer to calculate how a lot new mass the probe has acquired. If mission managers really feel they’ve sufficient, the samples will likely be stowed away till the spacecraft’s return to Earth in late 2023. If not, they might want to determine whether or not to try a second—or perhaps a third—landing. Olivia Billett, a techniques engineer and the OSIRIS-REx science lead from Lockheed Martin, which constructed the spacecraft, considers this the worst-case situation, for the reason that descent places the spacecraft in danger. “That’s a choice that I actually hope we don’t need to make,” she advised me. The mission is designed to fetch simply greater than two ounces (about 60 grams) of fabric. In astronomy, scientists are used to working with tiny samples, extracting cosmic insights from even the smallest grains. However whenever you’ve traveled tens of millions of miles, you wish to deliver residence as many souvenirs as doable.
The journey residence will likely be extra acquainted, however nonetheless dangerous. Keiko Nakamura-Messenger, a NASA scientist who will curate the Bennu samples, remembers the ache of 1 NASA mission within the early 2000s, the company’s first sample-return try for the reason that Apollo period. A spacecraft had efficiently sampled photo voltaic wind, the solar’s fixed stream of high-energy particles, however the return capsule crash-landed after its parachute didn’t deploy. The crew spent days scouring a Utah desert for remnants of the capsule and washing away contaminants. They recovered sufficient materials, even after this minor catastrophe, each to disclose new details about the solar and the photo voltaic system, and to retailer some particles for future scientists to review. Compared, the haul from Bennu may very well be a treasure trove.
“It doesn’t matter what, it’s going to be actually, actually valuable,” Nakamura-Messenger advised me. “We’re not going to waste a single grain.”