• 5 months ago
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
00:00DART 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 is an object that's about the size of the Washington Monument.
00:20Those kinds of objects hit us every few thousand years, and they would cause severe damage on a regional scale.
00:27We chose to do this demonstration at a binary asteroid.
00:31It's called Didymos. This 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.
00:49And when it changes the orbit period, it affects the timing of when the moon moves in front of or behind the primary.
00:59Mostly what we're looking to do is change the speed of the incoming object by maybe a centimeter per second or so.
01:06That's not very fast, but if you do it enough seconds in advance, you can cause it to miss the Earth entirely.
01:12DART is a part of a larger collaboration called AIDA, which pulls in all the experts of the world who can help their governments predict
01:23and understand what it is that they can do and should do in the event that there was an incoming threat.
01:30The DART mission that APL is pulling together will be the first mission in that flight line.
01:38DART is the first mission to fly the next sea ion engine.
01:41It is the first mission to demonstrate smart navigation, which means we're going to be guiding ourselves into the asteroid autonomously.
01:49At about four hours out from impact, smart nav is kicked in.
01:53And what it does is it uses the imagery from the optical payload, basically the camera that's on DART.
01:59And from the imagery, we are able to discern Didymos A from Didymos B.
02:04We have a targeting algorithm that differentiates the two, and we are aiming for Didymos B.
02:10The other part of this is the propulsion system that we're demonstrating.
02:14The NEXE propulsion system is utilizing a new generation of gridded ion propulsion technology.
02:21And it's what we're using to allow us to get to the asteroid, but 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, we needed higher power output.
02:38ROSA allows us to be able to have a very compact and light mass for launch and then deploy these really large arrays once we're out there in space.
02:49Our planetary launch window opens on June 15, 2021, and will impact the asteroid in 2022.
02:56We're very excited to be NASA's first planetary defense mission.

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