DART, the NASA and the Johns Hopkins Double Asteroid Redirection Test

Mars_B4_Moon · 2022-09-26 16:32:22

DART is a joint project between NASA and the Johns Hopkins Applied Physics Laboratory (APL). The project is funded through NASA's Planetary Defense Coordination Office, managed by NASA's Planetary Missions Program Office at the Marshall Space Flight Center, and several NASA laboratories and offices are providing technical support. International partners, such as the European Space Agency (ESA), Italian Space Agency (ASI), and Japan Aerospace Exploration Agency (JAXA), are contributing to related or subsequent projects. In August 2018, NASA approved the project to start the final design and assembly phase. The DART spacecraft was successfully launched on 24 November 2021, with collision year 2022, due to happen tonight.

Searching topics containing 'dart AND asteroid' produces many results on newmars forums but I do not believe we have a dedicated topic

NASA crashed into a Comet in 2005 and Tempel 1's brightness increased by approximately 2 magnitudes post-impact.

2021 blog entry
https://blogs.nasa.gov/dart/2021/11/23/ … -asteroid/

Mars_B4_Moon · 2022-09-26 16:35:49

'APL’s Andy Cheng says there are 20, maybe 30 telescopes worldwide that plan to monitor the Didymos system after the impact to measure the change in the orbit of Dimorphos.'

https://twitter.com/jeff_foust/status/1 … 8233178134

tahanson43206 · 2022-09-26 17:30:32

IMPACT !!!! Impressive video by NASA .... And an impressive feat of space navigation.

Now comes the data analysis!

(th)

SpaceNut · 2022-09-26 19:51:23

Its already up on utube.... it's been deemed a success.

Mars_B4_Moon · 2022-09-27 05:22:42

They say Didymos is quite faint at 14th magnitude but the impact looked much brighter.

I'm surprised how bright it got from ground based scopes. Maybe NASA should have had a little more PR outreach with this news.

Pic
https://pic8.co/sh/KJnf5v.jpeg
mirror,
https://i.ibb.co/mFbDK1R/f.jpg

This guy has shared a vid from the ground
https://twitter.com/AvellSky/status/1574679094532313088

I think amateurs might have also seen this event. Amateur photos might appear on sites like
https://www.webastro.net/forums/forum/5 … res-astro/ , https://www.cloudynights.com/forum/97-a … her-media/ , https://www.deepskyforum.com/forumdispl … -Sky-Forum , https://forum.astronomie.de/forums/aktu … nomie.215/ there are also lots of amateur Japanese active on twitter doing photography
It briefly outsides the bright background star it was moving past. If you could see it with only a 12 inch scope then you wouldn't need an observatory, the front face size of the telescope would be something amateur photographers might have at their home within range of amateur telescope people. A scope to see it would be larger than your rim size on a small car like a Toyota Corolla like a small rim inside wheel on one of those US Chevy or Italian Sports Cars but smaller than your overall tire diameter. I expect lots of amateurs with observation as 12 inch is well within ability or the price range of amateur observer and photographer. Amateurs they could put the telescope and battery in the back of a car truck, you could need some star tracking feature on the scope or maybe Computerized GPS and find a light pollution free site at nighttime and some good camera equipment. I think you can get even free open source software like Stellarium or buy software like Celestial, Starry Night to find your way around the sky. There are many groups out there who go out to mountains and fields with their Cassegrain reflector telescope, homemade Newtonian telescope, Dobsonian telescope, or manufactured Meade, Orion, Celestron designs. Even an amateur could have made good scientific observations by attaching a spectroscope to one of their telescopes and done some spectroscopy science. You would calibrate your spectroscope on say something like a neon light bulb or obtain a set of known emission wavelengths for a gas that is available from a reference source, then your spectroscope is ready to observe the chemistry of the solar system from your own backyard.

Naked eye can see about 4th magnitude but it depends on good eye sight and light pollution, they say magnitude 6 around the limit of normal good vision under ideal conditions Uranus and Vesta had most probably been seen in ancient time in human history but could not be recognized as planets because they appear so faint even at maximum brightness; Uranus' magnitude varies from +5.3m to +5.9m. 10x50 binoculars can go to 9th magnitude, if the object is 14th magnitude I think you would need 10 or 12 inch, 10 inches goes to 254 mm but it looks like it was bright enough for an 8 inch or 6 inch, 100mm is too small 3.9 inches, at 11 inch you could see stars with magnitudes ranging from 15 or even dimmer. A view magnified again and magnified again in a small scope can become too blurry and faint to be useful, Theoretical Resolving Power of a Scope is the angular size of the smallest detail you can see at high magnification and Focal Ratio (f/number) is the lens or mirror’s focal length divided by its aperture, telescope can magnify twice its aperture in millimetres or 50 times the aperture in inches. The higher the magnitude, the fainter the star. Magnitude scale is reverse logarithmic so the brighter an object is, the lower its magnitude number, our Moon and Venus are so bright they are minus numbers, Venus at −4.2 or Sirius at −1.46, a bright once in a lifetime Comet, the an Iridium Satellite flare or Space Station can go as bright as minus number −5.9 or more. For example, a 1st-magnitude star is 100 times brighter than a 6th-magnitude star. It would be interesting to what level of brightness it got to, there are limits to what a small telescope can do but I have seen some amazing stuff done with something as small as an 'ETX' or Large Binocular. They sometimes use post photo software or filters to enhance what they see and results can be amazing among the amateur community.

Here are some ETX pics

http://www.weasner.com/etx/guests/guests_hale-bopp.html

Perhaps NASA missed an opportunity to promote something that could have been a global observation event among even the amateur community.

If I have any time will maybe pop into twitter and try watch the hashtags # Amateur Astronomy or Astro-Photography or even '小惑星' or 'Ein Teleskop' or 'Un asteroide' today and see if anything pops up.
https://twitter.com/hashtag/amateurastronomy , https://twitter.com/hashtag/astrophotography

Last edited by Mars_B4_Moon (2022-09-27 07:48:51)

Mars_B4_Moon · 2022-09-27 05:23:50

Last night, Nicolas Erasmus (SAAO) and Amanda Sickafoose planetarysci
successfully observed DART's impact with Dimorphos using the Mookodi instrument on the SAAO's 1-m Lesedi telescope.
https://twitter.com/SAAO/status/1574688994201255936

Citizen astronomers in ReunionIsland captured the DARTMISSION impact
https://twitter.com/NewsFromReunion/sta … 1434647553

Réunion is an island in the Indian Ocean that East of east of the island of Madagascar East of Africa, South of the Indian Sub Continent and North of Antarctica, the island has six hydroelectric infrastructures have a capacity of 133 MW it is an overseas department and region of France. The woman who posted seems to be an Ex-Pat a French to English translator. The guy who posted is involved in astronomy he in his twitter feed has SETI in his profile and 'Unistellar' a French manufacturer of computer-connected telescopes that allow non-professional skywatchers to observe astro objects, I'm not sue if this is amateur or professional work he is sharing, maybe its professional observation but some amateurs have such high tech equipment and make such good photos that lines sometimes blur between amateur and professional.

' The impact brightening is obvious and the cloud of material as well. '
https://twitter.com/AllPlanets/status/1 … 4790642688

Seems like it was seen even in light pollution cities like Shanghai

Observatory in the Middle of Shanghai
http://www.shao.cas.cn/2020Ver/xwdt/kyj … 17472.html
online translator -
'September 27, 2022, Shanghai successfully used domestic telescopes to capture nearly 100 images before & after the impact event. Dust generated by the impact event was illuminated by the sun, resulting in a significant increase in the brightness of the target, an increase in magnitude of about 2.5 magnitudes and a corresponding increase in brightness of about 10 times. (Figure 2) '

This twitter account claims to have a NASAWebb timelapse, its a Portugese Brazilian account with astronomy news and 'Scientific dissemination'
https://twitter.com/CeuProfundo/status/ … 8256164865

Canberra Deep Space AsteroidImpact
https://twitter.com/CanberraDSN/status/ … 4979665921

ATLAS observations of the DART spacecraft impact at Didymos!
https://twitter.com/fallingstarIfA/stat … 9731670021

Last edited by Mars_B4_Moon (2022-09-27 08:40:34)

Mars_B4_Moon · 2022-09-27 08:53:34

NASA's DART spacecraft successfully slams into asteroid in historic test of planetary defense

https://www.nbcnews.com/science/space/n … -rcna49413

A twitter user Rae Paoletta is sharing pictures

'Some newly released images of yesterday’s DART approach/impact of Dimorphos from the Italian Space Agency’s LICIACube'

https://twitter.com/PAYOLETTER/status/1 … 5640073218
archived,
https://web.archive.org/web/20220927151 … 1562339329

You see the flash produced by the impact of Dart

'Si vede il flash prodotto dall’impatto di Dart'

https://twitter.com/ASI_spazio/status/1 … 7073572865

One of the best parts of the DARTMIssion was probably the paparazzi trailing behind in the form of a little CubeSat named LICIACube
who documented the whole thing!
https://twitter.com/stellerarts/status/ … 7293957120

' What an awesome set of images! Congrats to the team!
I took the liberty to remove the banding noise from the one in the other post! '
https://twitter.com/stim3on/status/1574809875799998466

image post
https://twitter.com/alexwitze/status/15 … 1516512261

Very interesting read this post

Dr. Phil Metzger

Planetary scientist at UCF. CoFounder NASA KSC SwampWorks. Space Mining. Space Settlement.
https://twitter.com/DrPhiltill/status/1 … 3888334858
' I’m shocked by the streamers in the ejecta. In ordinary granular splash experiments we see nothing like this. A few musings about this in a thread… /1 '
18/ twitter feedposts

Last edited by Mars_B4_Moon (2022-09-28 04:54:51)

Mars_B4_Moon · 2022-09-27 11:45:42

Learn more about the DARTMission and what happens next
https://twitter.com/JHUAPL/status/1574570893916905497

GW Johnson · 2022-09-27 14:47:17

Not much hard info in the news stories usually. Just that it hit the target. There was one story I saw somewhere that said the looser the rubble pile, the bigger the crater, and the larger the effect on post impact speed that they expect, based on simulations.

GW

GW Johnson · 2022-10-02 09:37:32

I’m pretty sure Dimorphos is a very loose, dry rubble pile. I have to wonder whether the blurred image of it at (and right after) impact represent debris plumes or if the asteroid itself was almost disrupted.

It’ll be a while before we get enough cubesat images and images from Hubble and Webb to determine if its overall shape has changed. Radar may help, too.

GW

Mars_B4_Moon · 2022-10-02 16:11:40

New asteroid strike images show impact 'a lot bigger than expected'

https://www.spacedaily.com/reports/New_ … d_999.html

GW Johnson · 2022-10-02 16:46:05

This is the disruption scenario that I have been warning about. If Dimorphos was "destroyed", or even just "severely redistributed", what you are looking at for asteroid deflection purposes is converting a single bullet strike into a shotgun blast, which is way more damaging if done too close to Earth.

You have to do this so far out that much of the debris cloud misses the Earth because of spreading. That is a severe constraint upon when it is that you actually have to act, if you should detect one of these things on a collision course. The track record on that detection, is poor at best. So far.

I posted about this on my "exrocketman" site a long time ago. Multiple times, actually, but the most recent is "Asteroid Threats", dated 30 August 2020. If you go to the site, use the navigation tool on the left side of the page. Click on the year, then the month, then the title.

I do have a lunch-and-dinner presentation on this topic. Not much has changed at all, since I attended an asteroid defense conference with a poster paper, back in 2009, in Granada, Spain.

GW

Last edited by GW Johnson (2022-10-02 16:52:49)

SpaceNut · 2022-10-02 18:04:27

This is also showing that what we thought was a lose rubble pile of rocks was way more solid.

GW Johnson · 2022-10-03 13:05:30

I'm not at all sure it shows a "more solid" asteroid. They seem to have gotten a larger spray of debris into space than they expected. Their simulations indicate less solidity is associated with more debris spallation. For whatever such simulations might be worth.

GW

Mars_B4_Moon · 2022-10-04 07:20:56

Will bits of Dart shower the Earth and even land on the planet Earth?

If so it would be a unique and different way to return a sample of material from a small near-Earth asteroid or sample a Comet? They said year’s best meteor shower will be the Quadrantids, there are also Tau Herculids and Leonids, there were also showers from Perseids and the Geminides. Through human history comets were often associated with a foretelling of some events maybe even a supernatural omen, meteor showers today seem to captivate public interest more than most other events. Maybe a chunk of space rock might hit the ground on Earth? the first man made meteor shower a celestial event in which a number of meteors are observed to radiate, or originate, from one point in the night sky. 'Meteorite Shower' refers to something much closer to the ground.

'DART AFTERMATH: The SOAR Telescope in Chile, operated by NSF’s NOIRLab, imaged the more than 10,000 kilometers long trail of debris blasted from the surface of Dimorphos two days after the asteroid was impacted by NASA’s DART spacecraft.'
https://twitter.com/marsboy/status/1577014935317422080

Last night, SARA_Obs Chile: Didymos/Dimorphos dust trails. 7x5m tracked on asteroids, stars filtered. WNW trail extends to 165", projecting to ~8600 km. (0410-0500 UT 30 Sept., ~78 hours after impact, R band)
https://twitter.com/ngc3314/status/1575964911523729408

Meteor radio wave reflections are also called meteor echoes, or pings, the Meteors leave streams of gases, electric and ionized air and vaporized material in their wake. To listen to meteor echoes, you can find an online station or you need a powerful transmitter in VHF band, a cheap Stereo receiver should detect several meteor spikes per hour, your ordinary AM/FM car radio or FM stereo you already have can also work well, a distant station might ping in from another part of the world or the meteor trail is capable of reflecting radio waves from transmitters located on the ground.

GW Johnson · 2022-10-04 08:31:59

From “Daily Launch” for 4 October 2022:

DART Impact Gives Asteroid Debris Tail

CNET News (10/3) reports that following the impact made by NASA’s DART mission, the asteroid Dimorphos has been spotted with a tail from the debris created by the impact. CNET reports, “On Sept. 28, astronomers Teddy Kareta from Arizona’s Lowell Observatory and Matthew Knight of the US Naval Academy used the Southern Astrophysical Research (SOAR) Telescope in Chile to observe Dimorphos. They were able to calculate that its new tail is at least 10,000 kilometers (6,000 miles) long.” In the coming weeks, astronomers plan to use these observations to calculate the amount of debris created by the impact.

My take on it: looks like the impact was far more severely disruptive to the rubble pile asteroid than they expected. At least this kind of outcome would suggest that, especially when you consider that their simulations showed bigger cratering the looser they assumed the rubble pile.

GW

tahanson43206 · 2022-10-04 09:53:46

For Gw Johnson re 16 and entire topic

This was a "scientific" experiment in every sense of the word.

It was carried out by a superb/world-class engineering team.

Absolutely NO one alive on Earth in 2022 had more than a faint clue about what to expect.

It appears that this is translating into a rich learning experience.

The young folks who write simulations (and particularly those who wrote ** this ** one) are adding new data into their models.

If all goes well, the ** next ** experiment will be preceded by better simulations, but (I expect) it will be quite some time before the simulations are accurate.

Something similar seems to be happening with the global weather simulations, with competing teams from several nations approaching the problem in slightly different ways that often produce surprisingly different forecasts. Never-the-less, all the models seem to be improving as new data is added, and as adjustments are made to the running software.

Your observations and assessments are much appreciated!

(th)

GW Johnson · 2022-10-11 16:35:16

Impact events are characterized with (among other things) a ratio K of the effective momentum change imparted to the body, to the momentum of the impacting object, as measured relative to the body.

A part of this at K = 1 is just the momentum of the impacting body. At K > 1, there is both the momentum of the impacting object, plus the momentum reaction to the mass and velocity of material ejected from the crater. The bigger the K, the more effect, the bigger the momentum of spalled material, and the bigger the crater.

You don't often see this in the news releases, but I did see where the looser the rubble pile, the bigger the crater they expected, according to their simulations.

They were expecting to shave 10 minutes off the 10 hr 55 period of Dimorphous about Didymus. What I read says they shaved 32 minutes, plus or minus 2 minutes. A much bigger effect than was expected.

That implies a bigger cratering event than expected, a larger momentum of spalled material than expected. In turn, based on their simulations, the rubble pile asteroid was a lot less bound together than they expected.

My expectation: when they do finally get a probe there, the crater will have a size that is a major (!!!) fraction of the asteroid size. They nearly disrupted it. A larger and/or faster impactor might well have disrupted it.

If that's the case, and the majority of asteroids we have seen are the same type C, you can deflect only with a series of smaller impactors. You will not be able to use large impactors, or adjacent nuclear explosions. Those will disrupt rather than deflect the threat. Done too close, it converts a bullet strike to a shotgun last, and that does even more damage.

Asteroid deflection is NOT simple! But understanding that it is NOT simple, IS simple!

GW

SpaceNut · 2022-10-11 17:18:49

Since calculation was so far off, they estimated the mass as being much heavier than it really was. That would happen when you guess based on surface material spectrum and not a deep core sampling.

tahanson43206 · 2022-10-11 17:45:04

With a nod to SpaceNut for post #19, with an interesting question ....

For GW Johnson ... was the mass of the object well known?

I would assume it was because the orbital mechanics could be (and I believe was) accurately measured.

SpaceNut has asked if the mass was accurately known (or at least that is how I interpret post #19)

If I understand your observations in Post #18 correctly, what was (apparently) ** not ** known was the consistency of the mass.

There ** should ** be a message or two added to this topic to clarify the question(s).

Update:

https://en.wikipedia.org/wiki/Double_As … nd_Didymos

The mass of the Didymos system is estimated at 528 billion kg, with Dimorphos comprising 4.8 billion kg of that total.[19] O

Note: Reference 19 is ** not ** available. An attempt to access the reference generated an error on a NASA web site.

If anyone sees an update to the mass calculation, based upon the impact, please add it to the topic.

I would assume (pending clarification) that estimates of the masses of the bodies would have been based upon orbital mechanics, which would themselves have been based upon careful observations of the objects.

(th)

GW Johnson · 2022-10-12 08:54:45

My impression is that they had a fairly reliable estimate for the masses of the two bodies, because of orbital mechanics. That would be in response to each other, and with other bodies (notably the sun). I don't understand how such an estimate is generated, but the astronomers seem to do it all the time, where one object orbits another.

The big unknown was the K-factor for momentum transfer during an impact. Cratering with ejection generates more momentum than just the impactor's momentum. How much K you get depends upon how easy it is to crater and expel ejecta. Their simulations (for whatever those are really worth), indicate that the looser the rubble pile is bound together, the bigger the crater & ejecta, and the bigger the momentum effects.

What no one but me is talking about is the indicated result that the dry rubble pile was very loose indeed, pretty much only bound by gravity, which at that mass, is weak indeed. That means you can only hit the thing so hard, before you disrupt the entire asteroid (crater diameter = size). It becomes a cloud of small particles instead of a single object.

A stream of smaller impactors might have a larger effect, but if you try to use one big impactor (or a nuke), you just disrupt the thing. Generating a whole string of sequenced impactors requires more launches than just sending one bigger one (or a nuke). Disruption done too close, and you just made the damage worse by converting the single bullet strike to a shotgun blast. Anything bigger than about a quarter inch size will get to the surface. Anything bigger than a basketball will create a crater with explosion.

GW

Last edited by GW Johnson (2022-10-12 08:59:33)

Mars_B4_Moon · 2022-10-14 16:38:19

So outside of NASA an online astrophysicist, game programmer and audio engineer 'Scott Manley' has an interesting updated vid where he calculates its movement, he's a reputable guy and has an asteroid was named after him in recognition of his work as a public communicator and science out reach. He calculates it moved one Earth distance in 10 thousand days, he says it proves it is a viable technique, one image seems to suggest orbiting material and a dark region maybe even 'a ring' I might log in during the week and share his vid later. Very interesting results from NASA and Johns Hopkins and other contributing space agency which will be studied far into the future.

Mars_B4_Moon · 2023-03-02 09:40:42

A natural satellite Didymos the Dimorphos loss of mass

Asteroid lost 1 million kilograms after collision with DART spacecraft

https://www.nature.com/articles/d41586-023-00601-4

Mars_B4_Moon · 2023-03-23 13:59:01

First results from ESO telescopes on the aftermath of DART's asteroid impact

https://www.spacedaily.com/reports/Firs … t_999.html

GW Johnson · 2023-07-27 17:31:54

As I have already posted on these forums, the risk hitting a small rubble pile asteroid like "Didymoon" was disruption. Some of the latest news stories hint that this risk came closer to truth than previously thought. There was a news story on the CBS News site about NASA finding some 37 large boulders "flying formation" with "Didymoon". The story raises the question of these rocks doing more damage, if this had been a real diversion attempt.

What that sighting indicates is a near-disruption event. You can bet on there being lots of other rocks knocked loose by the impact, that are just too small to be seen. Odds are, there number goes up exponentially as size goes down. My prediction is that the next arriving spacecraft (and there is one, but I forget which, or whose) will find little or nothing of an impact crater. The little asteroid apparently came nearly apart, and reassembled gravitationally, instead.

All that being said, I am certainly glad to see the forums come back! I have missed them in their recent absence.

GW

Last edited by GW Johnson (2023-07-27 17:33:09)

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DART, the NASA and the Johns Hopkins Double Asteroid Redirection Test

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