Double Asteroid Redirect Test - DART

#1
Yazata Online
This is a nasa Planetary Defense experiment that proposes to crash a small spacecraft at high relative velocity (~15,000 mph/24,000 km/h) into a small asteroid called Dimorphos about 160 meters across. The small asteroid orbits a larger asteroid called Didymos like a tiny moon. The larger asteroid is about 780 meters across.

It must be emphasized that neither asteroid represents a danger to Earth. The Planetary Defense people just want to see how much they can deflect Dimorphos's orbit with a high-speed collision. Dimorphos can be observed with Earth based telescopes which have been characterizing its orbital characteristics very precisely and will do so after the collision.

Prior to DART's collision with the asteroid it will release a little cubesat called LICIACube, which will observe the impact and hopefully return imagery.

I was skeptical about this at first, thinking how much energy can a small spacecraft impart to an asteroid. (DART is ~500 kg) It turns out quite a bit. Kinetic energy is proportional to the mass of the impactor and to the square of its velocity. So if you can impact something with even a modest mass at high enough velocity, it represents very high energies.

KE = 1/2mv^2

The DART vehicle is to be launched at 10:21 PM PST this Tuesday, 1:21 AM Wednesday EST and 06:21 Wednesday UTC. It will be launched from Vandenberg Space Force Base in California atop SpaceX Falcon 9 B1063. B1063 is on its third flight and will be recovered by OCISLY which is stationed out of Long Beach in the Pacific now. Expect livestreams in the usual places like spacex.com and maybe nasa-live.

https://nextspaceflight.com/launches/details/1373

https://dart.jhuapl.edu/

https://www.nasa.gov/planetarydefense/dart

This photo is a solid block of aluminum that was struck by a two ounce (56.7 gram) piece of plastic traveling at 15,000 mph (24,140 km/h) in a test. Even small masses can pack quite a punch.


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[Image: EV5S5cgU8AAaCQg?format=jpg&name=900x900]

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#3
Zinjanthropos Offline
Hope they don’t make a mistake. Is there more chance of making an error than the rock hitting the Earth?
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#4
C C Offline
(Nov 24, 2021 05:04 PM)Zinjanthropos Wrote: Hope they don’t make a mistake. Is there more chance of making an error than the rock hitting the Earth?


The Russians sure as heck make mistakes -- or is it just an inherent recklessness of theirs, as well as China's falling rocket debris?

https://www.scivillage.com/thread-10663-...l#pid47174

At any rate, be glad those guys are testing their ability to prod asteroids (for the time being).
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#5
Yazata Online
(Nov 24, 2021 05:04 PM)Zinjanthropos Wrote: Hope they don’t make a mistake. Is there more chance of making an error than the rock hitting the Earth?

They had a Q&A before the launch and somebody asked one of the mission scientists about that.

The reply was that they won't be hitting the bigger asteroid Didymos, just its tiny 160 meter moon Dimorphos. And the impact won't be energetic enough to knock Dimorphos out of orbit, it will just change the shape and period of that orbit in measurable ways. Didymos will continue on the same path it was going before the collision, which wasn't any danger of hitting earth. And Dimorphos will continue to follow Didymos.

From the Daily Hopper


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