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  • On the list of all-time big picture questions, “Where did we come from?' has got to be near the top.

  • It's stumped philosophers and scientists since the beginning of philosophy and science.

  • Now though, one spacecraft, OSIRIS-REx, is going to take a run at answering this monumental question...

  • by attempting to collect a sample of our early solar system from an asteroid.

  • NASA's Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer,

  • or OSIRIS-REx, was launched in September of 2016

  • with the goal of collecting samples from an asteroid.

  • But not just any asteroidspecifically, NASA was interested in sampling a rare B-type asteroid.

  • B-type asteroids are primitive, meaning they haven't changed much since the Earth was formed 4.5 billion years ago.

  • This could mean they contain carbon-based organic molecules similar to those that led to life on Earth.

  • The specific B-type asteroid OSIRIS-REx was shot at was called 1999 RQ36,

  • though now it's known by the much handier nameBennuafter an ancient Egyptian bird deity.

  • Clearly with the spacecraft namedOSIRISwe're going for an Egyptian theme here.

  • The asteroid looks sort of like a lumpy misshapen ball of clay,

  • and is about 500 meters in diameter, a bit bigger than the Empire State building.

  • Since December of 2018, OSIRIS-REx has been surveying and orbiting Bennu,

  • mapping its surface, tracking its spin, and gaining experience flying close to a small body.

  • Since entering into orbit, OSIRIS-REx has been whizzing around Bennu doing all kinds of science.

  • For example, in 2019 it observed plumes of particles coming up from the asteroid's surface, a surprise discovery.

  • It also found that Bennu is densely covered in boulders, when astronomers expected it to be much smoother.

  • This discovery in particular complicated OSIRIS-REx's main mission:

  • touching down on Bennu and collecting a sample of its surface.

  • Still, through its surveys OSIRIS-REx identified four possible sample sites

  • where the spacecraft could safely pick up loose regolith,

  • eventually settling on the sight called Nightingale as the best option.

  • Keep in mind though, “best optionis a relative term,

  • and Nightingale is only about the width of three parking spaces and surrounded by enormous boulders.

  • NASA couldn't just send the spacecraft barging in there,

  • so the mission planned for two rehearsals before the actual landing to make sure everything would go smoothly.

  • The first rehearsal in April 2020 went off without a hitch,

  • with the spacecraft going through the first two of four steps in the sampling sequence.

  • And then the coronavirus threw a wrench in the works and the second rehearsal had to be pushed back to August.

  • Nonetheless, rehearsal two went through the first three steps of the sampling sequence,

  • up toMatchpointburn where OSIRIS-REx matches the rotation of the asteroid.

  • The spacecraft came within 40 meters of Bennu, even deploying it's sampling arm,

  • but backed away before making contact.

  • Keep in mind that Bennu is so far from Earth that it takes radio signals about 16 minutes to reach the spacecraft.

  • Performing the sampling manually is not an option, OSIRIS-REx must do it autonomously,

  • so the last rehearsal gave the onboard navigation systems as much detailed info as possible

  • and confirmed that yes, OSIRIS-REx could set its arm on Bennu's surface safely.

  • With two rehearsals in the bag, the next step is to go all the way and try and grab a piece of Bennu.

  • The first attempt is scheduled for October 20th 2020.

  • If the collection head makes contact with Bennu,

  • the collection arm will spray pressurized nitrogen gas to kick up dust and rocks for the spacecraft to grab before backing away.

  • The collection itself should only last about 5 seconds, a real quick touch-and-go, or TAG for short.

  • Once away from Bennu, OSIRIS-REx will leave its arm extended and spin.

  • Before collecting anything, OSIRIS-REx performed a spin with an empty sampling arm.

  • Comparing the difference in inertia of the empty and full spins

  • is NASA's way of measuring how much regolith was gathered, since you can't weigh the sample in space.

  • If the sample is under the targeted 60 grams of regolith,

  • OSIRIS-REx will try again.

  • It has three containers of nitrogen aboard, meaning it has three tries to get it right.

  • Assuming all goes well, OSIRIS-REx will send the sample back to Earth, arriving in September 2023.

  • Then we'll get a chance to look at something extraordinary:

  • a pristine piece of our early solar system.

  • Will the organic compounds held in the samples give us some clue as to where we came from,

  • or will the debate continue among philosophers and scientists?

  • We're just going to have to wait to find out.

  • Another reason to visit Bennu is it has a relatively high chance to collide with Earth late in the 22nd century,

  • so studying it up close can help us prepare to defend against it.

  • Hopefully it doesn't come to that and OSIRIS-REx is the closest humanity ever comes to this massive space rock.

  • If you want to learn about another spacecraft setting foot on foreign worlds,

  • check out this countdown to launch episode on Japan's aerospace agency's MMX,

  • which has its sights set on the moons of Mars.

  • Thanks for watching, be sure to subscribe, and I'll see you next time on Seeker.

On the list of all-time big picture questions, “Where did we come from?' has got to be near the top.

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