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DART: Double Asteroid Redirection Test


Ultimate Steve
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Someone on Twitter overlaid all the images to get the maximum possible resolution, and so I used that to put together an animation of the last five seconds prior to impact in real-time at the blazing speed of ten frames per second (which is at least enough to get a sense of motion).

ezgif-com-gif-maker-2.gif

I think I'll do an animation of the full impact but double the speed every five seconds, so it's 1x speed from T-5 to T-0, 2x speed from T-15 to T-5, 4x speed from T-35 to T-15, 8x speed from T-75 to T-35, and so forth. That should be nice for viewing.

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https://www.skyatnightmagazine.com/news/webb-hubble-nasa-dart-images/

nasa-dart-mission-webb-hubble-44d6c13.jp

nasa-dart-mission-hubble-sequence-aae4cf

 

 

Won't lie... Was hoping these would be more interesting. Kinda shows why Hera is necessary.  

The article is worth a read - the unexpected brightness of Didymos post-impact and the impression that some of the streamers curved is getting a lot of attention. 

Hera, btw, was initially supposed to have been on station for the impact... But it seems ESA has the same regulatory and funding issues we lament with NASA. 

Edited by JoeSchmuckatelli
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https://www.nasa.gov/press-release/nasa-confirms-dart-mission-impact-changed-asteroid-s-motion-in-space

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Prior to DART’s impact, it took Dimorphos 11 hours and 55 minutes to orbit its larger parent asteroid, Didymos. Since DART’s intentional collision with Dimorphos on Sept. 26, astronomers have been using telescopes on Earth to measure how much that time has changed. Now, the investigation team has confirmed the spacecraft’s impact altered Dimorphos’ orbit around Didymos by 32 minutes, shortening the 11 hour and 55-minute orbit to 11 hours and 23 minutes. This measurement has a margin of uncertainty of approximately plus or minus 2 minutes.

Before its encounter, NASA had defined a minimum successful orbit period change of Dimorphos as change of 73 seconds or more. This early data show DART surpassed this minimum benchmark by more than 25 times.  

 

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the investigation team has confirmed the spacecraft’s impact altered Dimorphos’ orbit around Didymos by 32 minutes, shortening the 11 hour and 55-minute orbit to 11 hours and 23 minutes. This measurement has a margin of uncertainty of approximately plus or minus 2 minutes.

NASA Confirms DART Mission Impact Changed Asteroid’s Motion in Space | NASA

3.2_dart_compass_draft2.png?itok=H-wGQSe

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22 hours ago, tater said:

That's just a shockingly huge change in period.

Prior to the impact, the period was 11.9216 hours with an eccentricity of 0.03. The periapsis velocity and distance would have been 0.1777 m/s and 1.1427 km while the apoapsis velocity and distance would have been 0.1674 m/s and 1.2134 km.

Assuming an impact near apoapsis, the dV change required to decrease the period to 11.38 hours would have been 0.00285 m/s or 2.85 cm/s.

Assuming an impact near periapsis, the dV change required to decrease the period to 11.38 hours would have been 0.00229 m/s or 2.29 cm/s.

Using the 5e9 kg mass estimate for Dimorphous, that's a change in kinetic energy of at least 13.11 kJ and a change in momentum of at least 11.45 million kg*m/s. DART itself, at 500 kg and a relative speed of 6.6 km/s, had a kinetic energy of 10,890,000 kJ and a momentum of 3.3 million kg*m/s.

So we are looking at a momentum gain factor of about 347% for an impact with a rubble pile. Extraordinarily good news. 

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1 hour ago, kerbiloid said:

Maybe the heat energy vaporized the matter around and caused a water steam rocket jet pulse, adding some delta-V.

Or the asteroid is hollow inside and is actually a captured cycler.

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?
 

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