This week is SciShow Space's first birthday!

Exactly one year ago, in the very first episode of SciShow Space News, I told you how by 2025 NASA planned to capture an asteroid and bring it into lunar orbit for study. They called it the Asteroid Redirect Mission, or ARM.

At the time the mission was in the very earliest planning stages. But now, almost exactly a year later, NASA has decided on the specifics of the mission. And we're still here to tell you about it!

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The original plan for NASA's asteroid redirect mission was to send a probe to an asteroid that was about 500 meters across, and then use the probe to sling the asteroid into orbit around the moon. Then we'd launch some astronauts up there to study it and learn all about what kinds of resources asteroids might hold.

It was going to be difficult, and expensive, and ambitious. But that's kind of normal for space exploration.

And the new mission is still all of those things. But according to NASA's new ARM plan, announced by NASA officials last week, their priorities have shifted a little. We'll still be capturing a space rock and bringing it closer to home. But the new plan will not only be a little simpler, in the long term it'll make the mission much more useful.

For one thing, the rock we'll be studying is going to be smaller, and the focus won't be just on learning more about asteroids.
Instead we're going to use this opportunity to test the technologies we'll need when we eventually send people to Mars. And while we're at it, we'll also be trying out a new planetary defense strategy so we can be better prepared to fend off rogue rocks out there that might mean us harm.

The new plan is to send a probe to an asteroid in 2020. We won't decide which one until 2019, but the three candidates so far are near-Earth asteroids called 2008 EV5, Itokawa, and Bennu.

The probe will touch down on the asteroid's surface and start looking around for a good sized boulder. Then it'll pick it up and head back out into orbit around the asteroid, boulder in tow.

The probe will orbit the asteroid for about 400 days, collecting scientific data because we don't get to visit asteroids all that often! Meanwhile, it'll use that time to alter the asteroids orbit a little, using something called a Gravity Tractor.

The idea of a Gravity Tractor is based on the fact that everything with mass has gravity, even a relatively small probe. By maintaining what's known as a Halo orbit around the asteroid, NASA scientists think that the probe will be able to use it's gravitational pull to actually change the asteroid's orbit.

They're not looking to send it flying off in an entirely new direction or anything, they just want to prove that the technology works, so if we every spot a potentially extinction-causing asteroid headed for Earth, we'll be able to deflect it. I mean nobody wants a repeat of the recent unpleasantness at the end of the Cretaceous, am I right?

Once the probe is finished moving the asteroid around, it will head into lunar orbit with the boulder. Then in 2025, we'll send up two astronauts in the new Orion SLS launch system. The Orion capsule will dock with the probe and the astronauts will do a bunch of EVAs to study the boulder. That will let NASA test a number of deep space technologies, like brand spanking new space suits and their system for collecting samples.

After about a 25 day trip, the astronauts will fly home with their samples and data. The new information collected will help us safely plan the first manned mission to Mars.

Now that NASA has the over-all goals of the Asteroid Redirect Mission figured out, the next step is to decide on the individual pieces of the mission, like where they'll get the propulsion system. They hope to do that over the next year. So we'll keep you posted on that.

Thank you for joining me for SciShow Space News, and thank you to all of our viewers for being part of SciShow Space in our first year. Whether you're a new viewer, or have been with us from the beginning, we're hoping you're enjoying this journey as much as we are. Thank you.