Meet NASA's asteroid hunter

Brut America

Asteroid hunter is a real job at NASA. Brut spoke to one of them.

Transcript

00:00I have here a space rock. This is an asteroid that fell to Earth in 2017.

00:04And my job is to find objects like this when they're far away from us in space

00:08so that we don't accidentally get hit by one that we don't know about.

00:16Every 11 seconds, we look for anything that moves.

00:19Anything that moves against the background stars.

00:22If we see something that moves, we suspect it could be a candidate asteroid or comet.

00:26And so we go chase it down and figure out exactly what it is.

00:34A near-Earth object can be any asteroid or comet

00:37that gets within about 30% or more of the distance between the Earth and the Sun.

00:43The asteroids tend to be more rocky.

00:45Sometimes they can even be solid slabs of metal, more or less.

00:48Whereas the comets tend to be more of a mixture of ices and rocks, all mangled together.

00:57The Planetary Defense Coordination Office? Is that a real place?

01:02That really is a real thing.

01:04The job of this Planetary Defense Coordination Office

01:06is to basically coordinate all the activities that NASA has

01:10to search for the objects that can get close to the Earth,

01:13to make detailed predictions of their orbits and their trajectories,

01:17and also to coordinate with other governments around the world

01:20and other observers all over the place

01:22to try to keep an eye out for what is going on in the skies.

01:37Lucky for us, it is really, really, really unlikely

01:40that any sort of gigantist impact would happen.

01:43Something that's capable of wiping out a large fraction of life on Earth.

01:46We know where more than 90% of all the really large objects

01:51near-Earth asteroids are.

01:53These are objects that are larger than a kilometer across.

01:56So things big enough to cause really, truly global devastation.

01:59And none of them pose any impact hazard over the next 100 years.

02:02So that's great.

02:04But when we get down to smaller sizes,

02:06down to sizes of objects that are big enough to cause

02:08what I would call severe regional destruction,

02:11the news is not as rosy.

02:13We have found maybe between 30% and 40% of those objects,

02:16and the rest are still out there waiting for us to find them.

02:19When we get down to really small sizes,

02:21things say capable of causing damage to a city,

02:24there we only know of a few percent of the objects at best.

02:27So we still have a lot of work to do to map out what is out there in the skies.

02:39In 2013, there was an asteroid that exploded over Russia.

02:43And this was a very tiny asteroid, actually.

02:45It was only about 17 to 20 meters across.

02:48So that's about the size of a small house.

02:50It's not even a particularly big object.

02:52But it exploded high up in the Earth's atmosphere,

02:55and the shockwave broke a lot of windows,

02:57and it sent about 1,600 people to the hospital,

03:00mostly from flying broken glass.

03:09We have to find them far enough in advance,

03:12because if we don't have much warning,

03:14then there's a lot less you can do about it.

03:16But if we find these objects when they're years to decades away

03:19from any potential close approaches,

03:20now our option space opens up quite a bit.

03:23The simplest thing we could try is to simply bump a spacecraft into an asteroid,

03:27and we call that a kinetic impactor.

03:29NASA's DART mission, the Double Asteroid Redirection Test,

03:32is supposed to test that kinetic impactor technology

03:35by just bumping into an asteroid

03:37and just changing its orbit ever so slightly.

03:40You can have other techniques that are more complicated,

03:43such as just parking a really big spacecraft next to an asteroid

03:46and then just kind of let the force of gravity pull it aside.

03:50That takes a long time, though, and the object can't be too big.

03:53If the object is very large, or if we just don't have a lot of time,

03:57then the only option becomes to use some sort of nuclear device.

04:01Obviously, that is a last resort,

04:03and we'd really like to find the objects far enough in advance

04:05that we can use simpler and less invasive techniques,

04:08like the kinetic impactor technique.

04:13What are the chances of an asteroid and comet impact?

04:20Asteroid and comet impacts are really unlikely,

04:23so the probability is very low that something will happen,

04:26but the consequences can be high.

04:28And that, to us in the spacecraft world, means it's sort of a medium risk.

04:31You don't need to run around with your hair on fire,

04:33but you don't want to completely ignore the problem either.

04:36On the other hand, we have climate change.

04:38The probability of it happening is extremely high,

04:41and the consequences are high.

04:43That means this is a very, very risky thing that's happening to our planet.

04:47It's really urgent.

04:48We need to take steps now so that we can avert the worst possible consequences.

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