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The first flight mission for planetary defense, NASA's Double Asteroid Redirection Test (DART) seeks to validate a method to protect Earth from the threat of an asteroid impact. By smashing a spacecraft into the smaller member of the binary asteroid system Didymos, DART aims to shift an asteroid's orbit through kinetic impact.

Credit: NASA/Johns Hopkins APL
Transcript
00:00 [MUSIC PLAYING]
00:02 DART is the Double Asteroid Redirection Test.
00:05 The Earth is hit by asteroids and pieces of asteroids
00:09 all the time.
00:10 Every year or so, we get hit by things
00:12 maybe the size of a table.
00:14 The kind of object that DART is going to visit
00:17 is an object that's about the size of the Washington
00:19 Monument.
00:20 Those kinds of objects hit us every few thousand years,
00:23 and they would cause severe damage on a regional scale.
00:27 We chose to do this demonstration at a binary
00:30 asteroid.
00:31 It's called Didymos.
00:32 This is actually approximately the shape of the main asteroid.
00:37 It's called Didymos A. And it's moon, Didymos B.
00:41 What DART will do is DART will hit the second DART.
00:46 When it hits the moon, it will change the orbit period.
00:49 And when it changes the orbit period,
00:51 it affects the timing of when the moon moves in front of
00:55 or behind the primary.
00:58 Mostly what we're looking to do is change the speed
01:02 of the incoming object by maybe a centimeter per second or so.
01:06 That's not very fast, but if you do it enough seconds in advance,
01:09 you can cause it to miss the Earth entirely.
01:12 DART is a part of a larger collaboration called AIDA,
01:16 which pulls in all the experts of the world who
01:20 can help their governments predict and understand what it
01:24 is that they can do and should do in the event
01:28 that there was an incoming threat.
01:30 The DART mission that APL is pulling together
01:32 will be the first mission in that flight line.
01:34 DART is the first mission to fly the next sea ion engine.
01:41 It is the first mission to demonstrate smart navigation,
01:43 which means we're going to be guiding ourselves
01:46 into the asteroid autonomously.
01:49 At about four hours out from impact, smart nav is kicked in.
01:53 And what it does is it uses the imagery
01:55 from the optical payload, basically
01:57 the camera that's on DART.
01:59 And from the imagery, we are able to discern Didymos A
02:02 from Didymos B. We have a targeting algorithm
02:05 that differentiates the two, and we are aiming for Didymos B.
02:10 The other part of this is the propulsion system
02:12 that we're demonstrating.
02:14 The Next Sea Propulsion System is
02:16 utilizing a new generation of gridded ion propulsion
02:20 technology.
02:21 And it's what we're using to allow
02:23 us to get to the asteroid, but also
02:26 allow us a flyby of an object prior to our actual encounter.
02:31 For this vehicle to be able to supply
02:33 the power for the electric propulsion engine,
02:35 we needed higher power output.
02:38 ROSA allows us to be able to have a very compact and light
02:42 mass for launch, and then deploy these really large arrays once
02:47 we're out there in space.
02:49 Our planetary launch window opens on June 15, 2021,
02:53 and will impact the asteroid in 2022.
02:56 We're very excited to be NASA's first planetary defense
02:59 mission.
03:00 (dramatic music)

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