DART Mission to Reach Asteroid on Monday, September 26th

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Michael Watson

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Message 2107319 - Posted: 24 Sep 2022, 20:36:35 UTC
Last modified: 24 Sep 2022, 20:37:14 UTC

The DART (Double Asteroid Redirect Test) mission will reach and impact Dimorphos, the moon of asteroid Didymos on Monday, September 26th. This will occur at 7:14p.m. Eastern Daylight Time ( 4:14 p.m. Pacific Daylight Time; 23:14 Universal Time/Greenwich Mean Time).

The kinetic impactor is intended to alter the orbit of the asteroidal moon around its primary. Both are between seven and eight million miles distant. This will be the first time that an attempt has been made to alter the course of any natural object in space.

This mission can be considered a trial run at asteroid diversion. The knowledge gathered could come in very handy for the future, when an asteroid is headed directly for Earth!
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Profile Bob DeWoody
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Message 2107416 - Posted: 25 Sep 2022, 14:01:29 UTC

It seems to me they need to be very careful to be sure they don't redirect said asteroid the wrong way.
Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.
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Michael Watson

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Message 2107456 - Posted: 25 Sep 2022, 20:58:33 UTC

The mass of the DART probe is minuscule, compared to Dimorphos, the asteroidal moon. Even at impact speed, DART couldn't knock it away from the gravitational clutches of its primary, Didymos, no matter how it strikes it. In fact, the impact should reduce the size of Dimorphos' orbit; they hope, to a measurable degree.
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Message 2107512 - Posted: 26 Sep 2022, 21:54:39 UTC
Last modified: 26 Sep 2022, 22:03:48 UTC

NASA's live feed begins in 5 mins.

Just over an hour until impact.

Cheers.
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Message 2107517 - Posted: 26 Sep 2022, 23:37:44 UTC

It was a hit, but only time will tell if it did anything.

Cheers.
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Michael Watson

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Message 2107534 - Posted: 27 Sep 2022, 13:36:17 UTC
Last modified: 27 Sep 2022, 13:50:12 UTC

Yes, and not bad shooting! DART hit only 17 meters off-center, given the diameter of Dimorphos of 170 meters. That, at a distance from launch-point-Earth of 11 million kilometers, with the asteroid and Earth moving relative to each other at several km per second, and Dimorphos looping around Didymos, every 12 hours, or so.

Dimorphos appears to be a rubble-pile asteroid; loosely consolidated. Much of the impact may have been taken up in slightly rearranging that rubble, rather than changing the orbit. The new orbit will be observed and analyzed over the next few weeks. we're told, so time will tell.

In the meantime, the small satellite released before impact should soon supply a photograph of the impact crater made by DART.
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Message 2107542 - Posted: 27 Sep 2022, 15:53:54 UTC - in response to Message 2107534.  
Last modified: 27 Sep 2022, 15:56:27 UTC

Conservation of momentum of the overall systems means that the orbit of Didymoon Dimorphos around Didymos, and the orbit of the Dimorphos / (remains of) Didymos system, will have both been altered.

The beauty of this mission is that we can quickly measure the motion of Dimorphos to work out the new numbers.

I'm sure the Didymos - Dimorphos (remains) system will be measured over the coming weeks to see how that has been deflected overall.


Beautifully cleverly designed and a fantastic result!

Keep searchin',
Martin
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Message 2107543 - Posted: 27 Sep 2022, 16:03:58 UTC
Last modified: 27 Sep 2022, 16:06:17 UTC

See:

DART Asteroid Impact LIVE with Mission Team
wrote:
[NASASpaceflight] ... Today's special event is hosted by Elysia Segal (Public Programs Producer at Intrepid Museum) and John Galloway (Host and Producer at NASASpaceflight.com), with special guests Scott Bellamy (Mission Manager for NASA DART) and Andrew Cheng (Lead Investigator for NASA DART).

That's a beautifully informal yet informative livestream of events and beautifully a million miles away from the 'professional' inane media people spoiling the fun...

Fantastic they got the dedicated time in realtime from the two highest key people for that mission!


Enjoy real science in action with the (quirky) real people that make such things happen!!

Enjoy!
Martin
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Michael Watson

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Message 2107660 - Posted: 29 Sep 2022, 15:38:22 UTC
Last modified: 29 Sep 2022, 15:42:15 UTC

A video of the debris being thrown out from Dimorphos by the DART impact, as seen by ground-based telescopes, is now available. The video is linked below:

https://spaceweatherarchive.com/2022/09/28/dramatic-ground-based-images-of-darts-asteroid-strike/
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Message 2107728 - Posted: 30 Sep 2022, 13:51:04 UTC
Last modified: 30 Sep 2022, 14:48:30 UTC

Dimorphos has now sprouted a narrow tail, apparently in response to DART's impact, making it look rather like a comet. It presumably continues to lose material, even after the large cloud of initial impact debris has dissipated.

A short stub substantially offset from the main tail could be a secondary tail. The longer tail points directly away from the Sun. Reasoning by comparison to the structure of comets, this could be vapor from ices exposed by the impact. The shorter tail could be dust.

Two images of Dimorphos, with its tail, are linked below:

https://spaceweathergallery.com/indiv_upload.php?upload_id=188818
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Message 2107818 - Posted: 1 Oct 2022, 17:56:28 UTC

Given the much-larger-than-expected amount of debris blown off Dimorphos by DART's impact, I predict that the change in the orbital period will also prove to be substantially greater that expected. Dimorphos' orbital period is given as 11.921 hours , or 715 minutes.

The previously predicted change was that the orbital period would shrink by about 1 percent, which is 7.15 minutes. (A round figure of 10 minutes is usually given.)

The greater the true change turns out to be, the more useful small impactors will be in future asteroid diversions, at least where loosely consolidated asteroids, like Dimorphos, are concerned.
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Message 2107949 - Posted: 3 Oct 2022, 21:25:40 UTC

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Message 2107972 - Posted: 4 Oct 2022, 1:32:18 UTC

Both the new image from the SOAR telescope, and the earlier one from the 'Telescope Live' instrument show Dimorphos with a long narrow tail, and what appears to be another, broader one, at similar acute-angle, orientations to one another. I assume that the long tail in the SOAR image is pointing directly away from the Sun, as was explicitly noted to be the case in the 'Telescope Live' image.

It would be a notable coincidence if a dust tail were to occupy the same bearing usually reserved for one of ionized gas, in conventional comets.

Given what we know about 'active asteroids', which sometimes spontaneously show comas and even tails, it doesn't seem too much to suspect that the DART impact both loosened dust, and exposed some ice on Dimorphos. Both of these are conceivably being driven away from it by the solar wind, the latter, of course, in the form of vapor.
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Message 2108046 - Posted: 5 Oct 2022, 13:09:16 UTC
Last modified: 5 Oct 2022, 13:24:54 UTC

The ionized gas tail of a comet streams out directly away from the Sun. The dust tail tends to follow behind, in the orbital path of the comet, being somewhat influenced by its motion. The same might reasonably be assumed in the case of active asteroids. It appears that Dimorphos has been turned from a normal asteroid to an active one by the impact of DART.

Dimorphos' tail is now reported to be up to 50,000 kilometers long, and may still be growing in length. Considering that the tail had previously been widely reported as 10,000 km in length, its continued growth appears a reasonable possibility.
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Message 2108098 - Posted: 6 Oct 2022, 14:07:41 UTC
Last modified: 6 Oct 2022, 14:33:31 UTC

Bistatic radar imaging and measurement of Didymos and Dimorphos has begun, using the Goldstone facility in California as the sender, and the Byrd Telescope at Greenbank, West Virginia as the receiver.

It may be possible, as the observers hope, to determine the new orbit of Dimorphos, well before this could be done using optical methods. Observations were made on October 2nd, and are scheduled for today, October 6th, and also the 9th, 11th, 13th, and 15th, 16th, and 19th.


A total of 27 & 1/4 hours of observing time has been scheduled. Resolution of 75 meters of the Didymos-.Dimorphos system is anticipated, using a 3.5 centimeter wavelength.
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Message 2108366 - Posted: 11 Oct 2022, 20:30:20 UTC

At today's press conference, NASA announced that the orbit of Dimorphos around Didymos had been changed by 32 minutes, by the impact of DART. This is about four and a half times the predicted 7.15 minute change!

NASA observed that a substantial potion of the orbit-changing thrust was due to the rocket-like trail of debris streaming away from the asteroidal moon. Originally, they had only taken into account the direct effect of DART's mass impacting against Dimorphos.

This mission has proved to be a very auspicious start to the science of asteroid deflection. And for all we know, the eventual change of Dimorphos' orbit may become every larger. The debris tail is still blasting away from Dimorphos, as I write this.
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Message boards : Science (non-SETI) : DART Mission to Reach Asteroid on Monday, September 26th


 
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