Talk:Double Asteroid Redirection Test

Orphaned references in Double Asteroid Redirection Test

I check pages listed in Category:Pages with incorrect ref formatting to try to fix reference errors. One of the things I do is look for content for orphaned references in wikilinked articles. I have found content for some of Double Asteroid Redirection Test's orphans, the problem is that I found more than one version. I can't determine which (if any) is correct for this article, so I am asking for a sentient editor to look it over and copy the correct ref content into this article.

Reference named "targets":

• From AIDA (mission): "AIDA study". ESA. 19 December 2012. Archived from the original on 20 October 2014. Retrieved 2014-09-19. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
• From Don Quijote (spacecraft): "Sancho study: designing the minimum Earth escape spacecraft". ESA. 23 May 2012. Archived from the original on 15 May 2015. Retrieved 17 June 2015. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)

I apologize if any of the above are effectively identical; I am just a simple computer program, so I can't determine whether minor differences are significant or not. AnomieBOT⚡ 18:46, 20 January 2018 (UTC)

Interesting, thanks. But I see no "targets" reference now, so it looks like this was fixed a while ago. ★NealMcB★ (talk) 19:47, 25 November 2021 (UTC)

6 km/s impact - possible mistake - or not

In the article is written: " It is estimated that the impact of the 500 kg (1,100 lb)[12] DART at 6 km/s (3.7 mi/s)[4] will produce a velocity change on the order of 0.4 mm/s, which leads to a small change in trajectory of the asteroid system, but over time, it leads to a large shift of path"

6 km/s cannot be true as no extraterrestical probe can be slower than terrestical escape velocity ( v > v[sub]k2[/sub] = 11.2 km/s). -- 80.146.191.154 (talk) 07:20, 6 February 2019 (UTC)

Have you considered what the quoted velocities are relative to? — JFG ^talk 11:47, 6 February 2019 (UTC)

Also, the 11.2 km/s escape velocity is explained in this way: "Escape velocity decreases with altitude.... At the surface of the Earth, if atmospheric resistance could be disregarded, escape velocity would be about 11.2 km (6.96 miles) per second [relative to the Earth]." https://www.britannica.com/science/escape-velocity . As the object gets further from Earth, its velocity relative to the Earth decreases (as long as gravitational, or other, forces, etc do not happen or can be ignored). This new velocity will be the escape velocity at that point.

The 6 km/s is the relative velocity between the 2 objects that are impacting.

FrankSier (talk) 19:57, 23 November 2021 (UTC)

Significance - deflection distance

After doing the math, it looks like an inch a second leads to less than 500 miles a year, right? Not much compared to the size of the Earth? A few mm per second is less than that. Jokem (talk) 03:12, 26 November 2021 (UTC)

From my math, it looks like it is just under 500 (497 miles) if you take one inch per second then times it by 60 (minute) then times it by 60 (for an hour) then times it by 24 (for a day) then times it by 365. Jurisdicta (talk) 03:37, 26 November 2021 (UTC)

• "A miss is as good as a mile". It doesn't take much of a nudge to make a significant difference if you're trying to prevent a collision. 500 miles seems an adequate margin for a miss as that's twice the altitude of the ISS. Andrew🐉(talk) 09:52, 26 November 2021 (UTC)

• A potential impactor might need to be deflected (or delayed) by an Earth radius ? - Rod57 (talk) 12:08, 28 November 2021 (UTC)

• Since the Earth is about 8000 miles around, I don't see where 500 miles is much comfort. Instead of landing on Yuma, AZ, it lands on the outskirts of El Paso. Maybe I am missing someone's point here? Jokem (talk) 08:44, 9 December 2021 (UTC)

Mass breakdown - How much Xenon will NEXT-C use after dedicated F9 launch

Can we clarify : When planned as a secondary payload, DART would have used a long push from NEXT to get out of earth orbit and on its way to the asteroid. Now DART is a dedicated payload on F9, will it still use NEXT (and xenon) as much as originally planned ? NASA still seem to be hoping for a 1000 hours of operation. Since F9 put it on escape trajectory, is the NEXT thruster still essential for the mission, or just a bonus to cause a harder impact ? The article says craft is 610 kg, and implies impactor is 500 kg. Does that mean it will expend 110 kg of propellant en-route (including Xe) ? or that the craft includes a 500 kg passive ballast mass (copper?) ? Is there a breakdown of the 610 kg total launch mass ? - Rod57 (talk) 12:04, 28 November 2021 (UTC)

A Commons file used on this page or its Wikidata item has been nominated for deletion

The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for deletion:

• Dart Deployment.png

Participate in the deletion discussion at the nomination page. —Community Tech bot (talk) 21:15, 30 November 2021 (UTC)

Image Description

The first image of the article titled "The DART impactor and CubeSat ... " has a description text that includes dates, that do not include the year. This makes it a little confusing when newly reading the article and will be exasperated when the article moves into historical context. SquashEngineer (talk) 13:57, 14 February 2022 (UTC)

 Not done This file is hosted on commons. Any requested changes should be directed to the specific image talk page [1]. Pabsoluterince (talk) 23:03, 14 February 2022 (UTC)

Possible inconsistency?

In the 'Sequence of operations for impact' segment there is a picture from 3 seconds before impact, but the impact is still a day or two away from now. The picture appears to be from an official press kit, so I assume it's a render or artist's interpretation for illustrative purposes, but that is not disclosed here. Shouldn't we make clear that this is just a placeholder image, or wait for the real thing? 2603:8080:5701:9E54:E0FB:BA41:E1D9:182B (talk) 16:52, 25 September 2022 (UTC)

Indeed, those images are intended to simulate/illustrate what DART will see leading up to the impact. I feel that including these images here can be misleading, so I've removed them for now. That final simulated image at T-3 seconds is a Hayabusa close-up image of 25143 Itokawa, whose image happens to be copyrighted on Wikipedia... Nrco0e (talk) 18:11, 25 September 2022 (UTC)

Confused by various terms used for the same (?) thing

To me the various indications “asteroid”, “double asteroid”, “minor planet”, “moon” are confusing. In the section “Effect of the impact on the orbit of Dimorphos and Didymos” is written that the hit must be directed opposite to the asteroid’s motion. But isn’t only the minor-planet moon Dimorphos to be impacted, as stated in the initial section?Redav (talk) 13:50, 26 September 2022 (UTC)

Why change context to “was”?

The mission just started with all the data analysis? 65.36.113.88 (talk) 23:19, 26 September 2022 (UTC)

Yes, I agree. The mission has not been completed yet (they still have to gather data and complete other things). 64.67.42.115 (talk) 23:42, 26 September 2022 (UTC)

"Was" refers to the spacecraft at points on the page that are spacecraft specific. The craft was destroyed on impact, as planned. It is no longer "is" but "was". Randy Kryn (talk) 14:22, 27 September 2022 (UTC)

Shouldn’t be flagged for “contains an unencyclopedic or excessive gallery of images”

Okay, maybe it can be edited down slightly, but IMHO this should set the standard for maximum number of “encyclopedic” photos.

DART at scale pic still absurd

For reference (deleted by Flight time because "not a forum"): "While a bus may be 14m long it certainly isn't 14m tall. And it certainly isn't nearly the same height as One WTC's 185-foot tall (56m) concrete base. I know NASA created this pic but come on..."

Wikipedia talk pages used to be a useful *forum* for discussing meaningful changes to a page. Fine if you're okay with it but shouldn't you wiki power trip nerds be concerned w/ accuracy? 99.140.59.60 (talk) 00:44, 28 September 2022 (UTC)

User:FlightTime was refering to WP:NOTFORUM: "bear in mind that article talk pages exist solely to discuss how to improve articles; they are not for general discussion about the subject of the article". I would class your comment as general discussion as given there was no discussion of how to improve the page. Pabsoluterince (talk) 01:54, 28 September 2022 (UTC)

I don't see how this falls under WP:NOTFORUM; IP is talking about an image in the article. I agree with them that it's a bit silly; why would you show the front of a bus when comparing objects to the bus's length? It's not like there's insufficient space. I would prefer a different to-scale image, were a compatibly licensed one created or found. Ovinus (talk) 03:16, 30 September 2022 (UTC)

PSA: Correct image orientation of DART images

Earlier NASA published a mirrored version of Didymos and Dimorphos in their official press release right after the impact. They've recently fixed them to match the original images that were livestreamed, so all's good. Now to correct all of the wrongly mirrored images uploaded on Commons... Nrco0e (talk) 02:06, 29 September 2022 (UTC)

Although the captions in NASA's press release mention the original DRACO images were horizontally mirrored from reality, I'm sure that the original DRACO images are actually true to reality rather than the mirrored versions posted in JHUAPL's website. According to Figure 2 in Rivkin et al. (2021) (you'll have to rotate the diagram upside down), DART should be seeing Dimorphos to the right of Didymos's illuminated side; this is indeed the case for this unflipped DRACO imaged published by NASA. Furthermore, the DRACO live feed shows Dimorphos orbiting clockwise (north pole down) and toward DART, which is also what is shown in the Figure 2 diagram. Nrco0e (talk) 03:24, 29 September 2022 (UTC)

@Mykhal and Huntster: I concede my argument for the DRACO images. Since NASA states that the JHUAPL mirrored version is correct, should we flip all DRACO images (and videos) of Didymos and Dimorphos on Commons to clear up this confusion? I would like everything to be accurate. Nrco0e (talk) 02:36, 30 September 2022 (UTC)

I'm wondering if the correct approach would be to leave images derived from the livestream alone in their orientation but fix the end-result science images? I'm not necessarily keen on "fixing" all images unilaterally. — Huntster (t @ c) 03:05, 30 September 2022 (UTC)

Formatting

This file: File:DART article screenshot.jpg shows the problem with the formatting of the text with large graphics on both the right and left - often only one or two words per line in the thin column. The article needs better formatting. Bubba73 ^{You talkin' to me?} 00:14, 29 September 2022 (UTC)

Resolution of final partial image

Someone should ask NASA what the frame size and pixel dimensions are for the final partial image frame. Vrw35a (talk) 17:57, 30 September 2022 (UTC)

Numbers concerning the Deep Impact mission

Hey Chinakpradhan! You've reverted my removal of these numbers excavated a crater up to 150 m (490 ft) wide, decreased the perihelion of Comet Tempel 1 by 10 m (33 ft), changed orbit by 10 cm (3.9 in), and a predicted 0.0001 mm/s (0.014 in/h) velocity change after impacting the comet at the speed of ~10.2 km/s (6.3 mi/s) on 4 July 2005. - I'm more than happy to keep them, but 1. the source now cited looks like lecture notes, that's not the best source for astronomical values and 2. I didn't find these numbers in that pdf. Can you please point me where exactly in that lecture changes of Tempel 1 orbit were discussed? I'm sure that if the numbers are right they ahould be in some real paper published by Deep Impact mission team, though I didn't find it. Artem.G (talk) 21:25, 8 October 2022 (UTC)

i have no problem if its not true no.s. So looks like we should also change the asteroid impact avoidance image caption. i thought since these no.s are on that wikipedia page from a very very long time, i thought they are right to be placed on dart page to show comparison. the image caption says that:-

The 2005 Deep Impact collision with the eight-by-five-kilometer (5 by 3 mi) comet Tempel 1. The impact flash and resulting ejecta are clearly visible. The impactor delivered 19 gigajoules (the equivalent of 4.8 tons of TNT) upon impact. It generated a predicted 0.0001 mm/s (0.014 in/h) velocity change in the comet's orbital motion and decreased its perihelion distance by 10 m (33 ft).

i think i must change to words in your edit then, isnt it??

@Artem.G Chinakpradhan (talk) 02:32, 9 October 2022 (UTC)

hmm, NASA's page (source 7) says only that The impact generated an explosion the equivalent of 4.7 tons of TNT and a crater estimated to be about 490 feet (150 meters) in diameter. and not It generated a predicted 0.0001 mm/s (0.014 in/h) velocity change in the comet's orbital motion and decreased its perihelion distance by 10 m (33 ft). I'll remove these numbers as they are not reliable and unsourced - I'll look for better assessment of the impact later, but I'm not sure such measurements were done (and that's why DART was launched, hopefully this time such orbital changes will be measured properly). Artem.G (talk) 09:18, 11 October 2022 (UTC)

References

I'll look through sources today or tomorrow, thanks! Artem.G (talk) 07:47, 9 October 2022 (UTC)

Welcome back!! Chinakpradhan (talk) 17:07, 9 October 2022 (UTC)

Results vs Predictions

Were there any precise calculations of how much the orbital period was expected to be reduced? Can we include a detailed comparison of predicts vs actual results, on all available parameters? 69.157.84.190 (talk) 00:40, 14 October 2022 (UTC)

Didymos brighter still?

The parent asteroid Didymos, as seen from Earth, brightened dramatically after the impact, presumably because of a cloud of debris that did not escape Didymos' weak gravitational field. Has that brightening persisted? If not is there any information on how fast it decayed?--agr (talk) 16:38, 2 December 2022 (UTC)

Reminder that wikipedia is built upon other sources, However you do make a good point, I would advise researching to find sources on the brightening. PerryPerryD Talk To Me 18:17, 2 December 2022 (UTC)

I did try a google search with no luck and I inquired here to see if anyone knew of such work, with sources of course.--agr (talk) 18:55, 2 December 2022 (UTC)

Picture orientation:

Could someone re-orient the image at T-2 sec so that the sun is in the same direction as the other 2 above it? I am really confused when looking at those 3 pictures. For the images at T-11 and T-3 seconds look like the sun was about between 1 and 2 o'clock, but at T-2 the sun looked to be between 10 and 11 o'clock. Also, it would be really helpful to place an "X" or a box in the images for T-11 and T-3 seconds on exactly where the impact would be just seconds later.

→Agree. Just noticed this and was very confused. The scale in these images is hard to comprehend even on the best of days; one image being mirrored makes it much worse. 98.97.153.35 (talk) 04:34, 20 February 2024 (UTC)

I agree. The final image is oriented 180 degrees relative to the previous two and obvious from the shadows off of the rocks. 129.162.15.247 (talk) 18:54, 24 June 2024 (UTC)

This was discussed above, September '22 (#12 in Table of Contents). The "T-2 seconds" image is currently shown in its "true" orientation (unflipped). But the "T-11 seconds" image is shown flipped, as supplied and explained by NASA at https://www.nasa.gov/solar-system/darts-final-images-prior-to-impact. I believe the "T-3 seconds" image is a DIY version by a Wikipedia editor who used a freeze frame from the previously supplied NASA time lapse video to impact. T-11 and T-3 could both be flipped to true orientation (without uploading new images) by using the appropriate file name in the following wikicode in the wikitable in the "Sequence of operations for impact" section of the article:

<div style="position:relative; {{mirrorH|display=block}}">[[File:All dimorphos dart 0401930040 12262 01 iof imagedisplay-final.png|frameless|center]]</div>

The above image of "T-11 seconds" is the "true" orientation resulting from the wikicode I show that flips the image supplied by NASA, which said of the picture it published: "This image is shown as it appears on the DRACO detector and is mirror flipped across the x-axis from reality." DonFB (talk) 03:54, 25 June 2024 (UTC)

Featured picture scheduled for POTD

Hello! This is to let editors know that File:Dart impact replay.webm, a featured picture used in this article, has been selected as the English Wikipedia's picture of the day (POTD) for November 24, 2024. A preview of the POTD is displayed below and can be edited at Template:POTD/2024-11-24. For the greater benefit of readers, any potential improvements or maintenance that could benefit the quality of this article should be done before its scheduled appearance on the Main Page. If you have any concerns, please place a message at Wikipedia talk:Picture of the day. Thank you! Cowboygilbert - (talk) ♥ 23:31, 26 September 2024 (UTC)

The Double Asteroid Redirection Test (DART) was a NASA space mission aimed at testing a method of planetary defense against near-Earth objects. The target object, Dimorphos, is a 160-meter-long (525-foot) minor-planet moon of the asteroid Didymos. DART was launched on 24 November 2021 and successfully collided with Dimorphos on 26 September 2022 while about 11 million kilometers (6.8 million miles) from Earth. The collision shortened Dimorphos's orbit by 32 minutes and was mostly achieved by the momentum transfer associated with the recoil of the ejected debris, which was larger than the impact. This video is a timelapse of DART's final five and a half minutes before impacting Dimorphos, and was compiled from photographs captured by the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO), the spacecraft's 20-centimeter-aperture (7.9-inch) camera, and transmitted to Earth in real time. The replay is ten times faster than reality, except for the last six images, which are shown at the same rate at which the spacecraft returned them. Both Didymos and Dimorphos are visible at the start of the video, and the final frame shows a patch of Dimorphos's surface 16 meters (51 feet) across. DART's impact occurred during transmission of the final image, resulting in a partial frame.

Video credit: NASA / Johns Hopkins APL

Recently featured:

• Finding in the Temple
• Wait for Me, Daddy
• Red-lored whistler