00:02DART is the double asteroid redirection test.
00:05The Earth is hit by asteroids and pieces of asteroids all the time.
00:10Every year or so we get hit by things maybe the size of a table.
00:14The kind of object that DART is going to visit
00:17is an object that's about the size of the Washington Monument.
00:19Those kinds of objects hit us every few thousand years
00:23and they would cause severe damage on a regional scale.
00:26We chose to do this demonstration at a binary asteroid.
00:31It's called Didymos.
00:32This is actually approximately the shape of the main asteroid.
00:37It's called Didymos A and it's moon, Didymos B.
00:41What DART will do is DART will hit the secondary.
00:46When it hits the moon, it will change the orbit period.
00:48And when it changes the orbit period,
00:50it affects the timing of when the moon moves in front of
00:55or behind the primary.
00:58Mostly what we're looking to do is change the speed of the incoming object
01:03by maybe a centimeter per second or so.
01:06That's not very fast, but if you do it enough seconds in advance,
01:09you can cause it to miss the Earth entirely.
01:12DART is a part of a larger collaboration called AIDA,
01:16which pulls in all the experts of the world
01:19who can help their governments predict
01:23and understand what it is that they can do
01:25and should do in the event that there was an incoming threat.
01:29The DART mission that APL is pulling together
01:32will be the first mission in that flight line.
01:37DART is the first mission to fly the next sea ion engine.
01:41It is the first mission to demonstrate smart navigation,
01:43which means we're going to be guiding ourselves into the asteroid autonomously.
01:49At about four hours out from impact,
01:51SmartNav is kicked in.
01:53And what it does is it uses the imagery from the optical payload,
01:56basically the camera that's on DART.
01:58And from the imagery, we are able to discern Didymos A from Didymos B.
02:04We have a targeting algorithm that differentiates the two,
02:07and we are aiming for Didymos B.
02:09The other part of this is the propulsion system that we're demonstrating.
02:14The next sea propulsion system is utilizing a new generation
02:18of gridded ion propulsion technology.
02:21And it's what we're using to allow us to get to the asteroid,
02:25but also allow us a flyby of an object prior to our actual encounter.
02:31For these vehicles to be able to supply the power for the electric propulsion engine,
02:35we needed higher power output.
02:38ROSA allows us to be able to have a very compact and light mass for launch
02:43and then deploy these really large arrays once we're out there in space.
02:48Our planetary launch window opens on June 15, 2021,
02:52and will impact the asteroid in 2022.
02:55We're very excited to be NASA's first planetary defense mission.
02:59We'll see you next time.
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