Surprised we didn't already have a thread. DART launched successfully at 0621 UTC today (23 Nov 21). https://www.nasa.gov/planetarydefense/dart, encounter (as in collision) with small satellite of 65803 Didymos in late Sep/early Oct 2022.
Yay! We get to map two new objects for the price of one mission next September then try to blow one up as a cool experiment!
I remember watching Deep Impact live; what an experience, and finally to be replicated!
And of course, Hera will come after to survey the damage. It would have been nice for AIM to be funded and be there already as originally planned, but it's just as well, we really don't know how much debris will be produced, do we?
I had the thrilling good fortune to watch this launch from a (considerable) distance. It's quite an interesting mission… not really space "exploration" per se, at least in its primary intent.
True, but we will get some science nevertheless, at least in terms of imagery.
From NASA Twitter: 55 minutes into its flight, the DART Mission spacecraft has separated from the SpaceX Falcon 9 second stage, and will soon begin to orient itself toward the Sun. - https://twitter.com/NASA/status/1463407550087503875 (nice video and goodbye to this spaceship forever)
dose anyone have any news on any SPICE kernels for it's trajectory
we have ones for Lucy but what about DART
Good idea, since they are indeed closely related to each other. Thread title changed.
So much international effort almost serendipitously focused on this asteroid makes me so happy.
I love it when a plan comes together!
I recall that Hera (originally called AIM) and DART had their orders reversed, but the lack of funding on the former by ESA for several years (until restoration and renaming to HERA) meant that DART will now be the initial scouting mission. Seems a bit of a reversal (shouldn't one characterize the Didymos system fully with a scientific mission before trying to alter it with a technology demonstration?) But this approach has its advantages; DART's onboard targeting will still allow it to catch Didymos, and there is no need to shelter an expensive scientific craft from a debris plume of unknown size. LICIACube will take plenty of spectacular images, I am sure!
what would be the highest resolution image possible of the asteroids?
I assume you mean images from the LICIACube. Google is your friend--good to develop the skill to answer your own questions. Lots of information on this satellite including the two cameras Leia and Luke. The most detailed information I've come across in in this https://www.hou.usra.edu/meetings/lpsc2021/pdf/2051.pdf
"LICIACube is equipped with two optical cameras (narrow and wide FoV) that allow acquiring significant images and evidence of the DART mission fulfillment. The primary instrument, named LEIA (Liciacube Explorer Imaging for Asteroid), is a catadioptric camera composed of two reflective elements and three refractive elements with a FoV of ± 2.06° on the sensor diagonal. The optic is designed to work in focus between 25 km and infinity and the detector is a monochromatic CMOS sensor with 2048x2048 pixel. The latter is equipped with a Panchromatic filters centered at 650nm±250nm. The primary camera will acquire pictures from a high distance providing high level of details of the frame field.
The secondary instrument, named LUKE (Liciacube Unit Key Explorer), is the Gecko imager from SCS space, a camera with an RGB Bayer pattern filter, designed to work in focus between 400 m to infinity. The sensor unit is designed to contain the image sensor interfacing with a NanoCU, while the optics consists of a ruggedized, mission configurable aperture, lens and required spectral filters. Moreover, the hardware is capable of directly integrating the image data to the integrated mass storage."
I'll let you do the math to find the resolution.
Nice https://iopscience.iop.org/article/10.3847/PSJ/ac6f52/pdf on ESA's Hera expedition.
https://www.nasa.gov/feature/dart-sets-sights-on-asteroid-target
Not much given they were from from late July, but new observations were taken in August as well (not released yet).
Two and a half weeks left, where did the time go?
https://www.nasa.gov/feature/dart-s-small-satellite-companion-takes-flight-ahead-of-impact
https://twitter.com/JHUAPL/status/1572409029640716288
Jupiter!
Phil
Fascinated to see the results from this mission - 4 days to impact!
This brings me big memories of Deep Impact that summer of 2005, and watching the early webcasts (how quaint they were).
One of the press releases mentions LICIACube will take a few days to relay the plume images back, so it won't be quite the same in terms of immediate feedback, but still looking forward to it!
5 hours to go......
https://www.youtube.com/watch?v=vxImS5CYHwM
Live Feed from NASA's DART Spacecraft on Approach to Asteroid Dimorphos - in 17 minutes:
https://www.youtube.com/watch?v=-6Z1E0mW2ag
https://dart.jhuapl.edu/
Can't see the binary distinguished yet... but soon! Quite a bit of 'bouncing' for now.
On the stream they just mentioned that they're seeing Dimorphos now. So that might be real.
Target lock!
Didymos is already looking irregular now....
Beginning to see possible structure on the terminator.
Phil
interesting shape, with a clearly protruding part at the bottom
Precision lock achieved!!!
A bit more detail. The protrusion will probably resolve into a big boulder.
Phil
IMPACT.
Absolutely incredible terminal images.
Wow! Takes me back to 14 years old....
And that thin streak on the lower left (top of an enormous boulder, just barely in the Sun?)
Now we wait for LICIACube (and Hera, eventually)
The final partial frame:
What is that light "bar" on the lower left side of Dimorphos? Present in multiple images, doesn't seem to be a camera artifact. Another object behind Dimorphos?
Top of a huge boulder, mostly in shadow?
Press conference in about 15 minutes.
Imaging of the DART impact plume from an Earth-based telescope.
Fascinating fact from the presser: looks like the ion engine would have been used in the case of a miss to hit Didymos 2 years from now for a second attempt!
It seems to me that fragments of Didymos's surface are a bit like Helene's surface - I see there a kind of fragmentary "surface crust" (???)
Nice view of the impact:
https://twitter.com/fallingstarIfA/status/1574583529731670021
Phil
This is the best stack of images I could wrangle from the video at https://www.nasa.gov/feature/dart-s-final-images-prior-to-impact
Since there are no other craters, I don't think the isolated bright object is a crater rim. More likely, I think, is a large rock sticking up into the sunlight. There was a very prominent rock on Itokawa like that. Explorer1 already suggested the same thing.
I hope we will be getting better versions of the primary asteroid images as well. It looks a bit like Itokawa with rough and smooth areas.
Phil
I think Ranger 9 was the only one people actually got to watch.
https://sservi.nasa.gov/articles/live-video-from-ranger-9/
(the video link doesn't work on that site but it is on Youtube)
Phil
PNGs of a few images and downloadable 1080p video from pre-impact available from JHUAPL DART site
https://dart.jhuapl.edu/News-and-Resources/article.php?id=20220926
Don't know why there is horizontal flip between video and still images.
That impact debris/plume sequence is extraordinary. Is that about what we expected to see? I wonder is Dimorphos is still in one piece
https://www.nasa.gov/feature/dart-s-final-images-prior-to-impact
So it looks like the view from the impact video and all the frames pasted here are mirror-inverted
I notice that the final partial frame appears somewhat out of focus. This makes sense because the frame width is apparently 16 meters and the telescope aperture is 0.21 meters, so the frame is only about 80 apertures wide. For a camera focused at infinity, the size of the focus spot should be equivalent to the aperture.
John
https://asitv.it/media/live
Pictures!
Wow, those streamers, it looks quite catastrophic! Much more violent than the SCI on Ryugu, as expected!
pictures are for example here:
https://www.asi.it/2022/09/liciacube-conferenza-stampa-con-le-prime-immagini/
conference recording (on LICIACube results) - here:
https://asitv.it/contenuti/download/live/1ed3e75f-3f2f-69ae-8f47-63e163abba25/files
and here is video from the ATLAS telescopes:
https://www.youtube.com/watch?v=gaSXHVGCYZ8
I think it's fair to say, however, there has been a not-insignificant loss of mass; a portion of the debris is on an escape trajectory, another portion will remain in orbit around Didymos, eventually impacting either body or escaping later on, and a portion will have settled back down or not been moved at all. I know there will be more LICIACube images to come (such as seeing the other side system!), but otherwise we will have to wait for HERA to figure out the ground truth of what 'We' just did, and the ratio of these portions, more exactly.
By the way, I added the scale indicators to this image: https://www.nasa.gov/sites/default/files/thumbnails/image/penultimate_dart_0401930049_43695_0.png
(based on the NASA description - width of the image is 31 m - to better visualize the size of what we see on the last full frame of Dimorphos):
these stones are really big ...
(difficult terrain for any eventual lander, rover or human explorer)
Indeed, as I mentioned this is a job for gory-details calculations. I did find it interesting and surprizing, though, that the one energy is ~1000 times the other.
My vague understanding of the justification of this was that the models vary by factors of order unity in predictions of the delta v imparted to the moon, due to the uncertainties in the mechanical properties etc, and they wanted to pin down those factors somewhat. I'd still worry that those factors might be significantly different for different asteroids, impact geometry, etc, so indeed it isn't clear what you've learnt...
Yeah, it was cool.
Given the above discussion, it may have been a missed opportunity not to have observed the other side of Dimorphos before the impact to check for effects at the antipode (or the location of any putative exit wound, if you will). If the asteroid is that loosely bound, it seems like the spacecraft drilling through the asteroid (or, still more likely, the spacecraft being embedded/destroyed and causing ejecta to leave the antipode) would be a more likely outcome than breaking the asteroid apart. But everyday intuition fails in a case like this, and the theory may not be much better.
Very interesting hypothesis here : https://twitter.com/dr_thomasz/status/1574928508715143169?s=21&t=uhi9zu3uEVuWHohPUlr6YQ
Here is a video compilation of 3 LICIACube pictures: https://twitter.com/i/status/1574784696311025664
One wonders if the large overexposure of the LICIACube images was intentional or accidental.
In a way, this continues the theme of Insight's failed drilling: While mechanics in space are incredibly predictable, mechanics in heterogeneous solid bodies are incredibly unpredictable.
https://dart.jhuapl.edu/News-and-Resources/article.php?id=20220929
Hi,
A question arises. What is left of Dimorphos ?
Despite the spectacular amount of debris, I've heard rough estimates of the total volume of ejected material being equivalent to a crater ten or so meters across, so Dimorphos is probably alive and well. We'll know soon, when mutual events are detected (or not...).
John
Yes this makes sense as my rule of thumb is a crater is around 20 times the diameter of the impactor.
The density and structure of Dimorphos makes it hard to compare with larger bodies with known impacts. This paper
https://academic.oup.com/mnras/article/515/2/2178/6634251
estimates a density of 2.2. Chondrites have a density of about 3.5, which would make Dimorphos about one third empty space. Lunar regolith is even less dense than that, but for any significant craters, the surface soil is an insignificant fraction of the volume. In a nutshell, there's probably, in comparison to the Moon, etc., more room (literally and figuratively) for Dimorphos's regolith to compress rather than eject, which could make a crater smaller, while creating a mascon of significant size compared to the entire body of the asteroid.
Something like "mini-panoramas" of the Dimorphos surface (unfortunately not very clear) - just for fun
From this picture: https://www.nasa.gov/sites/default/files/thumbnails/image/all_dimorphos_dart_0401930040_12262_01_iof_imagedisplay-final.png
Nice mini-panoramas! But I noticed something in the image you linked to, and here I post it with some severe image brightening off the terminator... there is some detail to be seen in reflected light. The large boulder is reflecting light to its upper right in this view, clearly revealing a smaller boulder in shadow beneath it. There are other suggested details which might be picking up some light from Didymos - I think the geometry is correct for that. It will be interesting to see the raw data for these images, which might be more suitable for this kind of processing.
Phil
Also... check out this wonderful family portrait by Roman Tkachenko:
https://twitter.com/_RomanTkachenko/status/1577016827993288704
Phil
This is a better image of the night side of Dimorphos. There is lots to see. Too bad this won't work on Didymos, where there is no suitable light source.
Phil
I vaguely recall hearing that another presscon was coming, with more LiciaCube images, with more scientific interpretation/results. Was I imagining that? Because I can't find anything to confirm that on the internets.
So we wouldn't have more pictures of Didymos? :- /
I tried to compare Didymos ad DimorphoS with other recently visited asteroids:
That's a brilliant montage Daniele!, thanks for your time composing it
It's easy to forget that the reconnaissance of the asteroids in our solar system is fairly well-advanced these days. Psyche and Lucy will really add to our knowledge in the next decade.
I feel really lucky to be along for the ride in this era of discovery. On the year I was born (1967), we had some pretty decent images of the moon, and that was about it.
Media briefing at 2 p.m. EDT, Tuesday, Oct. 11 - https://www.nasa.gov/press-release/nasa-to-provide-update-on-dart-world-s-first-planetary-defense-test
As Italian Space Agency (ASI) President Giorgio Saccoccia will be among the participants of the briefing, I really hope to see some new pictures from LICIACube (and other pictures) ...
And maybe some new results from telescopic observations (?)
EDIT:
Tuesday, Oct. 11 at 20:00 Italian time - https://www.asi.it/2022/10/alla-conferenza-stampa-che-la-nasa-ha-convocato-per-martedi-11-ottobre-alle-ore-2000-italiane-ci-sara-anche-il-presidente-dellagenzia-spaziale-italiana-giorgio-saccoccia-per-parlare-della-m/
The conference will be broadcast live on the ASI TV website at: https://www.asitv.it/media/live
I missed the briefing, but I see remarkable images like this one posted at https://www.nasa.gov/feature/nasa-dart-imagery-shows-changed-orbit-of-target-asteroid:
I'll let you know when I've watched the whole briefing; I only caught the last third or so, and it wasn't mentioned during that portion.
The briefing video is here: https://www.youtube.com/watch?v=Zhzn0U2m5wQ&t=2352s
Great new images; we can see a bit of the other side of Didymos too! Some enormous boulders on that side too (unless it's the same ones from a different angle)
So:
1. DART slowed down Dimorphos by over half an hour - 32 minutes (although it was assumed that 10 minutes would be a success) and the tiny moon now orbits several dozen meters closer to Didymos
2. Dimorphos survived - it is still in one piece (against some fears) and ready for HERA's arrival :
The twitter user landru79 created a couple of animations from the available imagery https://twitter.com/landru79/status/1579925959708676097 and https://twitter.com/landru79/status/1579930045975789571 which show in splendid detail the 3D geometry of the system just after the time of impact. Truly glorious work, and enough to show that my interpretation of the images was quite wrong.
Those animations are very instructive- thanks for the link! It really looks like the "anomalous" brightness of the Dimorphos-facing side of Didymos extends above the surface, consistent with it being due to kicked-up dust. Fascinating...
John
Centrifugal scree 'slopes' on opposing hemispheres? Compared with talus features on Ceres:
It seems like it'd be more efficient than that to have a rocket full of fuel hit the asteroid and explode on contact, combining the kinetic energy of the craft with the chemical energy with the explosion. There's no need to make a nice, controlled burn that the rocket survives.
In practical terms, this becomes a problem in terms of lead times & complexity even if compositional variables aren't considered. It would be difficult to built, test, and launch a powered redirect mission with a short lead time, but a DART-like impactor would be comparatively easy. In fact, building & storing (with ongoing maintenance & testing) a powered system for short-notice launch would be considerably more expensive than doing the same for an impactor mission.
Hard to say what, if anything, will eventually be decided here re an operational asteroid deflection system. But DART definitely provided a baseline set of interesting questions to ponder.
Hubble is seeing a double tail around the Diddy-twins. A tail from the debris cloud could have been expected, but it seems that this tail and companion tail imply that there are active processes at work beyond the impact ejecta.
It will be interesting to see post-impact images from Hera.
https://hubblesite.org/contents/news-releases/2022/news-2022-056
"Near-Earth Asteroid Deflection Strategies", by Dan Mazanek of NASA LRC, https://sservi.nasa.gov/wp-content/uploads/2014/05/AGC_2014_NEA_Deflection_Mazanek1.pdf is a good summary of various approaches. Direct propulsion is not the most effective according to this; short of nuclear weapons, kinetic impactors were judged the most effective.
All of this is for the unlikely scenario that an object large enough to do serious damage is on course to collide soon. Objects large enough to make kilometre-sized craters are expected on intervals of thousands of years or longer, and the fraction of those that would hit densely populated areas is tiny.
It's still sensible to plan for those rare events, but likely we'll be in a very different regime for the next major strike: thousands of years from now we'll (hopefully) detect the objects well in advance with future surveys so there won't be any rush to launch an interceptor, and no disadvantage to the slower avoidance methods.
Even if less efficient (and considering the result last September, it seems quite effective!), multiple KIs could work just as well for more massive objects, just sending one after the other in a sequence (Shoemaker-Levy-9) style. One can separate the impacts by enough time for debris to dissipate to ensure the next one hits the target without running into (of course, a KI can be completely inert by the time it makes contact; as long as it has mass that's all that's needed).
(And I'm sure the PDCO and many others have already considered everything we discuss here anyway)
On October 27, 2022, a new ASI event will take place: „LICIACube, un mese dopo!” [LICIACube, one month later!]: https://www.asi.it/event/liciacube-un-mese-dopo/
„...One month after the DART LICIACube mission (...) ASI is organizing a public event to present the contribution of the Italian scientific community. The event will be held at the Auditorium of the ASI headquarters on October 27, 2022, at 10.00 (...) LICIACube is still downloading the acquired images, data storage and processing is managed in the Science Operations Center (SOC), at the Space Science Data Center (SSDC) of ASI...” [with agenda - in Italian]
Maybe we'll see some new images and / or interpretations???
There's a case to be made for diverting smaller impactors down to Chelyabinsk-sized, though. Those demonstrably not only can cause extensive damage & injuries, they can also too easily be misinterpreted as military actions. Certainly long lead time detection & characterization of these smaller objects would mitigate the latter aspect, but it might be a good idea to be prepared to intercept them if they have a high probability of affecting a population center or other important/sensitive location.
Seven possible future targets for LICIACube being examined: https://pbs.twimg.com/media/FgEHo1jXwAE35_o?format=jpg&name=large
The closest one could be for next March (2000 YA) but 14827 Hypnos seems most exciting to me (a possible extinct comet). Obviously the cameras on LICIACube are not as good as DART's was, but it's always a good opportunity to use a perfectly functional spacecraft!
Yes, LICIACube has quite limited technological capabilities - we have to remember that this mini-satellite is about the size of a microwave oven, but the opportunity to "squeeze" more scientific results out of it is exciting!
BTW, there is a new potential opportunity to hear about the new LICIACube results from the Dimorphos impact observation:
Festival delle Scienze 2022 = Science Festival 2022, November 21, 08:00 - November 27, 17:00
https://www.asi.it/event/festival-delle-scienze-2022/
Saturday, November 26 at 19:00, Guest Room: "LiciaCube" conference:
„...A few months after the detachment of the LICIACube nanosatellite from the DART probe, the meeting will present the contribution of the Italian scientific community to the NASA mission at the Festival. A successful mission that opens up new perspectives in asteroid monitoring and exploration policies in the context of planetary defense...”
An instructive https://az659834.vo.msecnd.net/eventsairwesteuprod/production-atpi-public/ad6af3cb5dbf4074ace7fdba20e15702 on the two Hera Cubesats and their integration with the Hera spacecraft.
Reportedly, https://twitter.com/deepbluedot/status/1594461523971567617?cxt=HHwWgsDThd2T1aAsAAAA (Critical Design Review) last week. Though I am not fond of ESA's way and venue to communicate such important project milestones, the reply section of this tweet is somewhat funny.
AGU22: Press Conference "Pioneering Planetary Defense: What Comes Next After DART’s Asteroid Impact?" Decmber 15, 2022
https://www.youtube.com/watch?v=FF-5B7_FMfY
https://dart.jhuapl.edu/News-and-Resources/article.php?id=20221215
https://www.asi.it/2022/12/un-prestigioso-riconoscimento-per-dart/
Some quotes from the presentations given at the press conference:
Andy Rivkin (DART Investigation Team Lead, Johns Hopkins Applied Physics Laboratory)
"...An estimate of how much material was blasted off of Dimorphos by DART and we think it is about a million kilograms of material at the least. So this is enough to fill six or seven railway cars of gravel (...) This number is a minimum, it could be twice that, it could even be as much as 10 times that according to same estimates..."
Cristina Thomas (DART Observations Workin Group Lead, Northern Arizona University):
"...The two spectra [of Dimorphos and Didymos] looked very similar. Thay have a lot of these consistent features (...) which are consistent with it being an analog for something like an ordinary chondrite (...) So, we see that these two objects [Dimorphos and Didymos] are in fact similar in composition. You'll notice that there are some slight differences that are tied to a lot of other questions that we are going to be investigating in the coming months, but they do not actually impact the way that we think about it compositionally..."
Alessandro Rossi (LICIACube Science Team Member, Instituto di Fisica Applicata Nello Carrara):
"...[LICIACube] startet science operations 71 seconds before impact (...), [and was] 58 km from the system at closest approche...
...Enhanced color images: the left one was taken about 3 minutes after the impact, (...) we are looking at the south pole of Didymos and you see the ejecta cloud almost face on. A few seconds after LICIACube has moved and we see the plume from a different perspective and we clearly notice the cone shape of the ejecta coming out of the surface of Dimorphos and we also can notice a kind of dark arc over the surface of Dimorphos which we believe is related to the shadow of the plume itself on the surface of Dimorphos....
...We can enhance the level of saturation of the images and it is in this image you see the saturated part of the image in black, but in that way other features of the ejecta plume come to your vision, and here we clearly see some very interesting structure in the ejecta plume. You see linear filaments of material being ejected from the surface, but we also see clumps of materials possibly related to agglomerates of two particles in the process of being disrupted and also nodules that we attribute to the presence of larger boulder being ejected. Take a looking at images at different times we can be able to compute the velocities of these objects, which we count on the order of tens of meters per second in these cases..."
Andy Cheng (DART Investigation Team Lead, Johns Hopkins Applied Physics Laboratory) - on the results of momentum transfer calculations
Credit: ASI/NASA
EDIT: I replaced the second picture with a better quality one - officially published on the NASA website (but with a wrong description, which concerns the first picture, not published there by NASA): https://www.nasa.gov/feature/imagery-of-early-results-from-nasa-s-dart-mission
The yellow circles indicate: "two clumps of materials possibly related to agglomerates of two particles in the process of being disrupted" and two possibly "larger boulders being ejected".
Some surface features on Dimorphos have been assigned names, with the theme being drums from various cultures.
Drums because we hit the asteroid ... get it?
https://planetarynames.wr.usgs.gov/Page/DIMORPHOS/target
Some results published in https://www.nature.com/articles/d41586-023-00601-4 One number reported is that the momentum imparted to Dimorphos was around 4 times that of DART, due to the ejecta.
And https://www.nasa.gov/feature/nasa-s-dart-data-validates-kinetic-impact-as-planetary-defense-method and https://dart.jhuapl.edu/News-and-Resources/article.php?id=20230301 is a model showing the DART's alignment as it hits the surface of Dimorphos
"...the spacecraft body hit between two large boulders while its two solar panels impacted those boulders..."
Credits: NASA/Johns Hopkins APL
Nature has published a cover story about DART, with five open access papers.
https://www.nature.com/nature/volumes/616/issues/7957
I have made a set of LICIAcube images of Didymos (plus one from DART itself). All LICIAcube images are from ASI.
The sequence starts at bottom left and moves to the right, then up a row and to the right again.
Also an image pair showing common features between the DART and best LICIAcube images (latter showing the south polar area)
Phil
Thanks! It's really the mission teams that should get on this, not the agencies. It would only take a willing grad student with access to the images.
Phil
Here is an experimental map of Didymos, made for my LPSC poster. The coordinates are from a preprint by Barnouin et al.:
https://www.researchsquare.com/article/rs-3399230/v1
Two names were recently added.
Phil
Interesting, the opto-mechanical design of the https://www.youtube.com/watch?v=fDhfPyl92SU&t=161s of Hera's https://az659834.vo.msecnd.net/eventsairwesteuprod/production-atpi-public/2d8d49fa68204ff9a35da4240d816a49 (p. 13bl) instrument seems to be quite different to the https://iopscience.iop.org/article/10.1088/1757-899X/1226/1/012094/pdf. EDIT: Apparently, for some unknown reason, they changed the altimeter to a serial-produced https://www.jenoptik.com/products/lasers/laser-distance-sensors/dlem from Jenoptik.
https://www.esa.int/Space_Safety/Hera/Hera_asteroid_mission_s_side-trip_to_Mars
According to the http://spice.esac.esa.int/webgeocalc/#NewCalculation, https://www.esa.int/Space_Safety/Hera could make a Deimos flyby as close as 300 km from its center, although with a whopping speed of more than 8.8 km/s, on 2025-03-12T12:11 or 2025-03-15T00:47 UTC respectively.
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