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DART: Double Asteroid Redirection Test


Ultimate Steve

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On 10/12/2022 at 3:57 PM, magnemoe said:

it generated an comet tail, I say it probably generated a lot of trust pushing out mass from the asteroid. 
I wonder if something like an DU long rod would penetrate deeper even if turned into plasma on contact, or hitting an large area like an shotgun shell as in blowing up the probe like an air burst shell would work better?

The difference in impactor mass and target mass are so disparate that it's almost a pure energy analysis, I think. Even with a DU penetrator, the actual penetration depth is going to be significantly smaller than the crater depth.

Given that momentum exchange is not the primary driver, I'd think that relative velocity is more important than impactor mass. Momentum is linear to velocity; energy is quadratic.

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At 6 km/s any impactor is an energy blast.

At  the meteoroid 10+ km/s even any crater is circular, not elongated, because the momentum doesn't play a role.

3 hours ago, cubinator said:

Particles. Lots of them.

It should be dropping FPS very much. They should use polygons instead.

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Spoiler

The peaceful civilisation of Apophys is appalled by the tragic accident happened to the fraternal people of Dimorphos.

Yet a little is known about this horrific event, but the Apophysan astronomers share the opinion that its was a collision with another celestial body.

Presumably, the fateful object arrived from the vicinity of Third Planet and impacted on the illuminated part of Dimorphos, when the Dimorphan telescopes were blinded by the daylight and thus were not able to sound the alarm in time.

The Apophysan scientists state that it's not the first and the only such accident caused by an dangerous object having come from the Pale Blue Doom, as the Third Planet is named in the chronicles.

While most of such incidents took place on its only moon or other two Big Planets, everybody remembers the infamous incident happened to the Twin Peaks comet several years ago, when something consisting of metal had hit it, then bounced off, then fell back, and hit again.

We still can't establish the contact with either of these two celestial bodies, and the conspiracy theories are raising their heads.
While all serious scientists on Apophys are sure that the impactors are of absolutely natural origin, and had been captured and redirected by the Third Planet gravity, the adepts of pseudoscience are loudly ensuring everyone that the Third Planet is populated by a civilisation of bloody monsters throwing projectiles at the other celestial bodies intentionally.

On the wave of hype, our Apophysan conspirolgists already have established a cult which is waiting the End of the World every time our lovely Apophys is passing close to the Planet Of Doom.
They are sure that either our homeworld will crash into the planet, or the planet will throw another projectile to crash our Apophys.
And the Dimorphos was selected by the Third Planetarians as a test target before eliminating our dear Apophys.

Of course, it's just a silly tale, but now on every close encounter with the Third Planet, almost a panic starts on Apophys.

We could ask the Dimorphan neighbours, the Didymosans. But they now don't respond, and we still don't know, what happened to them.
But the new-born ominous bright dust tail after it makes us presume that we need to fly there and see the details.

 

Edited by kerbiloid
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  • 2 weeks later...
On 9/27/2022 at 7:37 PM, tater said:

Only first post in a thread, but it likely contains valuable information as it progresses given the source.

 

On 10/6/2022 at 6:13 PM, tater said:

 

The 'streamers' (aka 'Crater Rays') was a big deal after the Dart impact. 

Check this out, from Mars:

221027145036-04-mars-impact-crater-split

Before and after, taken by Mars Recon Orbiter.  Presumed to be the cause of the marsquake detection by InSight last December. 

https://www.cnn.com/2022/10/27/world/mars-nasa-meteoroid-impacts-scn/index.html

The article doesn't mention the interesting pattern made by the ejecta - but it does note big (boulder sized) chunks of ice were scattered about - noteworthy b/c of how close it is to the equatorial region. 

See also this 2018 report on 'crater rays' referencing Tycho, among otjers: https://www.astronomy.com/news/2018/08/crater-rays

 

Edited by JoeSchmuckatelli
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  • 4 months later...

NASA’s DART Data Validates Kinetic Impact as Planetary Defense Method | NASA

 

DART mission more successful than expected

 

"Both Didymos and Dimorphos are more squishy in shape—looking more like peanut butter M&Ms and less like peanut M&Ms—than we expected," Sunshine said. "This shape also challenges some of our preconceptions about how such asteroids form and complicates the physics behind DART because it prompts us to rethink our current models of binary asteroids."

In addition to Dimorphos' irregular shape, the scientists also noticed that the asteroid's surface was noticeably bouldery and blocky. This geomorphic quality likely influenced crater formation, the amount and physical properties of ejecta (debris expelled from impacts), and the momentum of a DART-like impact.

"The Deep Impact mission collided with a comet whose surface is made up of small, mostly uniform grains," Sunshine explained. "Deep Impact resulted in a more uniform fan of debris than the filamentary structures seen after DART's impact into bouldery terrain. As it turns out, the movement of DART-caused ejecta really had a profound effect on the success of DART's mission."

 

The DART spacecraft was not the sole provider of momentum in the impact with Dimorphos; an additional shove was caused by violent spews of debris when the spacecraft slammed into the diminutive asteroid moon.

"There was so much debris ejected from the impact that Dimorphos was pushed approximately 3.5 times more effectively compared to being hit by the DART spacecraft alone,"

New NASA DART data prove viability of asteroid deflection as planetary defense strategy (phys.org)

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  • 4 months later...
5 hours ago, steve9728 said:

The cue ball just made a break shot

Yes the impactor made an huge crater, large rocks however did not get an high velocity and low velocity dust is carried away by solar wind, its probably also plenty of gravel there to small to see but to large for solar wind to easy push away. 

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  • 1 month later...

Observations from 20–30 days after the collision are finding Dimorphos's orbital period is 1 minute shorter than originally reported post-impact, which some sources are reporting as a subsequent or continuing change.

Quote

"We find that no mechanism previously presented for this system can account for this large of a period change, and drag from impact ejecta is an unlikely explanation."

Quote

"Therefore, whatever effect was causing the orbital decay before the collision cannot account for the discrepancy we observe; this includes the binary YORP effect, mutual tides, differential Yarkovsky force, nodal precession, and mass loss."

So far I'm finding no indication of peer review having happened yet, so the customary grain of salt should be taken with this news; at least one source reported the margin of error of the original measurement was 2 minutes.

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