Talk:Atmospheric entry/Archive 2

"Citation needed" for being able to pick up hot Space Shuttle tiles. Easy.
There are plenty of sources to back up that claim, including here: http://www.youtube.com/watch?v=UJN0U-QBoyc and here: http://www.youtube.com/watch?v=sP94g8Dqzd8&p=0CBC0A870DD64497, but I don't know how to add them, so here ya go! — Preceding unsigned comment added by Cowcharge (talk • contribs) 17:33, 19 March 2011 (UTC)


 * Neither of these supports the claim (that used to be?) in the article, that had something to do with a lab tech handling, with bare hands, a fully heated, through and through, white hot shuttle tile. Not sure if that was the claim you are talking about, or some other Citation needed tag adjacent to some other claim.  Why would your sources be insufficient?  1) both sources are homemade YouTube videos; not acceptable for Wikipedia as a [{WP:RS|reliable source]] and, 2) the tile was only briefly heated, on one side, and picked up with bare hands on the cool unheated sides; so does not demonstrate the low conductivity (from tile to flesh) of a fully white hot tile (from long-term heating in a lab oven) that, it was claimed, won't conduct heat fast enough to burn bare flesh when picked up.


 * It is an entirely different claim to say that one hot side of a tile won't conduct heat through the tile to the back or sides of the tile; that is precisely what the ceramic was intended to do, and why it protects the metal structure of the Space Shuttle during reentry. Perhaps you could copy the entire claim that you are speaking of.  N2e (talk) 03:44, 14 November 2011 (UTC)

X-37B heatshield
Some info to add

"A new generation of high-temperature wing leading-edge tiles will also debut on the X-37B. These toughened uni-piece fibrous refractory oxidation-resistant ceramic (TUFROC) tiles replace the carbon carbon wing leading edge segments on the Space Shuttle. The X-37B will also use toughened uni-piece fibrous insulation (TUFI) impregnated silica tiles, which are significantly more durable than the first generation tiles used by the Space Shuttle. Advanced conformal reusable insulation (CRI) blankets are used for the first time on the X-37B."

http://www.boeing.com/defense-space/ic/sis/x37b_otv/x37b_otv.html

--Craigboy (talk) 03:58, 14 June 2011 (UTC)

http://www.nasa.gov/centers/ames/news/releases/2012/12-34AR.html

--Craigboy (talk) 03:41, 23 April 2012 (UTC)

Delete Reference to Sathwik?
Should the reference to Sathwik in the History section be deleted? A Google search of this name reveals only the exact same phrasing as used in this article (they even include the errors of not capitalizing Indian and Technology). Also, the reference cited for this sentence contains no mention of "Sathwik" of even "India". — Preceding unsigned comment added by 99.126.220.167 (talk) 01:16, 18 July 2011 (UTC)

Ballistic reentry mode of soyuz (either manual or auto)
Soyuz 5 — The service module failed to detach, but the crew survived. This is one of the standard 4 entry modes for the soyuz, and there have been a few more of them since, it should either mention all or nothing to keep up to date, or be correct... Penyulap  talk 22:09, 17 September 2011 (UTC)

Boeing Lightweight Ablator (BLA)
Does anyone have a good source of information for the Boeing Lightweight Ablator (BLA)? The BLA is mentioned in the CST-100 article, with no explanatory information, but with a source to a Boeing slideshow that would appear to indicate that this is the ablative heat shield Boeing has chosen for the new LEO-capable space capsule. But no real detail is given in that source. What is the ablative material? How light is the weight? Etc.? It does appear (per another source in the CST-100 article, the one on air bag tests in the desert) that Boeing intends to jetison (and presumably not reuse after a crash landing) the heat shield before each landing. Any help appreciated. N2e (talk) 14:17, 18 September 2011 (UTC)


 * The other source in the CST-100 article (SpaceUp HOU 2011 - Commercial Space Flight Panel, at 27:35) says that "BLA is proprietary system that Boeing uses in other programs ... we've used it before."

Changed "Mishaps" to "Accidents"
When an unintentional event occurs that results in the lost of human life, the term "Accident" is used whereas a "Mishap" would be used when the event concerns the lost of objects or materials. Because the Columbia Disaster is listed in this list, I switched "Mishaps" to "Accidents" as "Accidents" is more fitting given Columbia's listing as well as it sounds more respectful than "Mishaps". Ham Radio 04:03, 28 September 2011 (UTC) — Preceding unsigned comment added by Ke5skw (talk • contribs)

Cork for victory
Why is cork not mentioned in the article? --Stone (talk) 08:52, 5 April 2012 (UTC)

V2 "re-entry"?
"For early short-range missiles, like the V-2, stabilization and aerodynamic stress were important issues (many V-2s broke apart during reentry), but heating was not a serious problem." I suspect that lots of them broke up, but not due to re-entry, rather to trying to push something new thorugh dense air. The peak height in their intended use was given as 55 miles which is below the conventional height regarded as above the atmosphere - the Karman line. I suspect it was aerodynamic stress and gyro wobbles rather than the phenomena about re-entry that destroyed them. Midgley (talk) 12:38, 26 May 2012 (UTC)

Photos in "sphere-cone" section
As I understand it, the photos in the #Sphere-cone section are rather suboptimal. For File:080201-F-0474R-012.jpg we say "Re-entry system of the LGM-30 Minuteman ICBM", but that's a misleading caption at best - as the image's information shows, the re-entry system is that red thing in the background at the left. So little of that can be seen that it is no better than the photo of the Mk-6 RV below it. So I think we should remove the Minuteman picture, move the Mk-6 up, and in the place held by the Mk-6 currently use File:W87 MIRV.jpg instead, as that's consistent with the section text's discussion of the development of RVs with smaller half-angles. Tell me if I'm misunderstanding, before I do this. -- Finlay McWalterჷTalk 11:10, 15 October 2012 (UTC)

Clarification needed regarding SpaceShipOne
IMHO it is important to point out that SpaceShipOne--a suborbital spacecraft--starts its descent from close to zero velocity. The amount of energy to be dissipated through atmospheric re-entry associated with SpaceShipOne is significantly lower than that with other types of re-entry vehicles. This is the primary reason for its lack of heat protection system. The current wording can mislead readers into thinking that the "feathered re-entry" configuration a la SpaceShipOne is a viable solution for orbital vehicles or vehicles returning from lunar orbit or beyond. — Preceding unsigned comment added by 220.233.158.186 (talk) 01:28, 7 January 2013 (UTC)

Now that the move is done...
Now that the move is completed, I removed the move tag and made a very slight copyedit to the lede. Much more work needs to be done in the article, starting with a lede that better covers the entire breadth of the topic, as well as possibly resectioning some parts of the article. Cheers. N2e (talk) 17:10, 4 February 2011 (UTC)

Item for possible inclusion in Deorbit disposal section Ekspress-AM4
Just wondering if this satellite that was deorbited should be included. Not being familiar with the topic I don't know if this particular event is notable just for being a deorbit or for its possible controversy. Also someone with knowledge could improve the Ekspress-AM4 article. - - MrBill3 (talk) 02:45, 8 August 2013 (UTC)

Fix rel disambig
https://en.wikipedia.org/wiki/Reentry_(disambiguation) "Atmospheric reentry, the movement of human-made or natural objects as they enter the atmosphere of a planet from outer space." Please delete "or natural objects" since there is here no information about the reentry of natural objects (e.g. meteors) - which I assume has been moved somewhere else. Kortoso (talk) 17:18, 6 September 2013 (UTC)
 * Several articles relating to meteorites and the like, point to this page for information re natural object atmospheric entry. Kortoso (talk) 17:33, 6 September 2013 (UTC)

Archive this Talk page?
I suggest that this talk page be archived. I have added the talk page header that will include a list of archive pages and a search function for the archives. I suggest using the Miszabot in particular the incremental archive explained in Example 2 incremental archives. - - MrBill3 (talk) 02:57, 8 August 2013 (UTC)
 * And this is why? Kortoso (talk)
 * See WP:Archiving. It has already been done. Links to the archives and a search box for them are at the top of this page. - - MrBill3 (talk) 02:25, 8 November 2013 (UTC)

Lack of cites
I may be the only one who is bothered by this. It seems like the bulk of this article is written by some professor who is reciting the facts from memory, or making up stuff? Kortoso (talk)
 * I agree that there is need for citations for much of the content. You may want to consult with editors who have previously worked on the article.
 * Please sign your talk page posts with four tildes and/or modify your signature so it includes a time stamp.WP:Signatures Also please use edit summaries.Help:Edit summary - - MrBill3 (talk) 02:34, 8 November 2013 (UTC)

No meteors!
Why is the image of a meteor included in this article? There is nothing about meteors here. Suggest renaming to "human spacecraft re-entry" or including more meteor information. Kortoso (talk) 16:30, 27 June 2014 (UTC)

Requested move (1)

 * The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section. 

The result of the move request was: not moved Dpmuk (talk) 12:49, 10 January 2011 (UTC)

Atmospheric reentry → Spacecraft atmospheric reentry — This article is solely focused on spacecraft reentry. It should be moved to another title, since the introductory paragraph states it also applies to natural objects. Once moved, the introductory paragraph, and a small summary of this article should be created at this current name on top of the resulting redirect, and a new intro paragraph be written for the current article. 184.144.161.173 (talk) 13:01, 2 January 2011 (UTC)

Survey

 * Feel free to state your position on the renaming proposal by beginning a new line in this section with  or  , then sign your comment with  . Since polling is not a substitute for discussion, please explain your reasons, taking into account Wikipedia's policy on article titles.




 * Oppose; if a split is necessary, it should be the other way around; this article should talk about all types of atmospheric reentry, and a new article should be split off to speak specifically to reentry of spacecraft. However, I don't think a split is actually necessary, since very few natural objects can be said to reenter Earth's atmosphere!  Powers T 15:47, 2 January 2011 (UTC)
 * Actually, using the definition provided in the introductory sentence, many thousands of natural objects every year, in relation to Earth, experience the process described. You will note that the definition provided in the article makes no specification that an object had to ever leave that atmosphere in the first place. All it has to do is enter it. And the term is used for entering the Martian atmosphere for manmade objects, which certainly is not a "re"-entry, since they did not launch from Mars either. 184.144.161.173 (talk) 20:13, 2 January 2011 (UTC)


 * Oppose per Powers. If anything, this should be left here and your new article created at atmospheric entry with a clear disambiguating hatnote. -- G W … 20:20, 2 January 2011 (UTC)


 * Oppose -- Atmospheric reentry is a good general article that covers the broad topic quite well. As others, if sufficient non-spacecraft atmospheric entry (not re-entry) occurences happen and are notable, then would encourage a new article to cover (in detail) only that narrower aspect of the subject.  Also, there are certainly some other topics contained within this large article that might benefit from a separate article:  for example, Thermal protection systems currently is a redir to Atmospheric reentry.  TPS might profitably be handled better in its own article.  N2e (talk) 20:26, 2 January 2011 (UTC)
 * Oppose . That's not how naming conventions work. If there were multiple articles, one for natural articles one for spacecraft, then it would be worth discussing how to resolve disambiguating them. But it's not clear there's a need for another article, so until then there's just this article and its name should be the commonest name for the phenomena.-- JohnBlackburne wordsdeeds 20:41, 2 January 2011 (UTC)

Discussion

 * Any additional comments:


 * Comment -- Since the term "reentry" implies that it started in an atmosphere, this rules out pretty much any "natural object" anyway.. so the nominator appears correct in that the article doesn't really cover "natural objects", as the first sentence claims it does. I'm not sure how much there is to say about the atmospheric entry of Meteoroids, and whether the concept deserves its own article. I suspect any such information could be contained in the article "Meteoroid". In short, I think the problem could be solved by removing "natural objects" from the opening sentence, and maybe adding a hatnote linking to Meteoroid in the case of natural objects. Mlm42 (talk) 20:47, 2 January 2011 (UTC)
 * The aeronautic science behind everything is the same. As for how much there is to be said about it, modelling of killer asteroids seems to be a topic of research, especially concerning the dinosaur killer, as much research has gone into determining what burns up in entry, what survives, what would be a threat to life on Earth, etc. And there's the research from the impact of Shoemaker-Levy 9 into Jupiter. 184.144.163.241 (talk) 11:32, 3 January 2011 (UTC)
 * I see; then maybe it's better to rename this article to "Atmospheric entry", and add a section on the content you've suggested (i.e. "natural" cases of atmospheric entry)? Since the underlying concepts are the same, we should probably only have one article. Mlm42 (talk) 05:57, 4 January 2011 (UTC)
 * The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Suggested move
The recent requested move discussion, in particular JohnBlackburne's comment, prompted me to do a Google search comparing the terms "Atmospheric entry" vs. "Atmospheric reentry". One can observe two things: 1) There are about 10 times more hits for "entry", and 2) in the "Atmospheric entry" search, by scanning the first 50 or so hits, over 3/4 are spaceflight related. This suggests to me that in fact "Atmospheric entry" is the more common term. Also, the current title with the word "reentry" makes it awkward to include content relating to "natural" entry phenomena; but since the concepts are basically the same for natural phenomena and spacecraft, this article seems like a good place for the natural concepts as well. For these reasons, I'm suggesting we move Atmospheric reentry -> Atmospheric entry, and expand the content related to natural phenomena. Mlm42 (talk) 00:36, 13 January 2011 (UTC)
 * Support the move. 'entry' seems to be the broadest term, handling any objects entering the earth's atmosphere, whether manmade, natural, (or alien?).  N2e (talk) 06:09, 13 January 2011 (UTC)
 * Support shouldn't this be opened as a formal move request? 64.229.103.232 (talk) 10:50, 23 January 2011 (UTC)
 * Yeah, good idea. Mlm42 (talk) 19:54, 23 January 2011 (UTC)

Superceded by requested move below.

Requestion move (2)

 * The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section. 

The result of the move request was: page moved. Vegaswikian (talk) 22:01, 30 January 2011 (UTC)

Atmospheric reentry → Atmospheric entry — The term "Atmospheric entry" appears a little more common, based on a Google search. Also this would allow the article to include phenomena related the natural events (like meteors), which obviously aren't "reentering" the atmosphere. The concepts for atmospheric entry of spacecraft and natural phenomena are really the same, so they should be in the same article. --Mlm42 (talk) 19:53, 23 January 2011 (UTC)


 * Support the move. 'entry' seems to be the broadest term, handling any objects entering the earth's atmosphere, whether manmade, natural, (or alien?).  Moreover, entry seems to have a less Earth-centric point of view, avoiding the implication that the object must first have left the same objects' atmosphere, and so applies also to the entry of objects into, say, the Martian or Venusian atmospheres; thus a more nuetral point of view also.  N2e (talk) 22:05, 23 January 2011 (UTC)
 * Support per expanded coverage for functionally the same base concepts. 64.229.103.232 (talk) 05:18, 24 January 2011 (UTC)
 * Weak oppose, I would prefer a split. -- G W … 23:05, 25 January 2011 (UTC)
 * Could you elaborate on what split you would prefer? Mlm42 (talk) 01:01, 26 January 2011 (UTC)
 * A general article at Atmospheric entry, and a more specific one here covering the recovery of spacecraft. -- G W … 22:48, 26 January 2011 (UTC)
 * Move and if separate articles are written for spacecraft versus meteors, both above titles would be ambiguous anyways. But we can deal with that problem when we actually have two articles. D O N D E groovily   Talk to me  00:30, 28 January 2011 (UTC)
 * The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Soyuz 11 was not a reentry accident, but is listed as one
Under "Notable atmospheric entry accidents" the Soyuz 11 depressurization disaster is listed as a reentry failure, when in reality the spacecraft depressurized outside the earth's atmosphere. While technically this was caused by the retrofire and separation process, the failure had nothing to do with the act of reentry.

I propose the removal of this bullet point. 602p (talk) 16:27, 7 November 2014 (UTC)

Selected atmospheric re-entries section is all outdated -- Delete?
The section "Selected atmospheric re-entries" is all stuff from before 2013. I don't see why this is here and propose it for repopulation or deletion. What do people think should be done? As it is I can't see what it has to do with the article or why these particular things are highlighted (besides being large.) Additionally, perhaps this section could be merged with "Uncontrolled and unprotected reentries" 602p (talk) 16:27, 7 November 2014 (UTC)

Request: Comparison of densities/mass properties for ablative/heat soak/active shielding
As mentioned in the article, "The thermal conductivity of a particular TPS material is usually proportional to the material's density [...] SLA in SLA-561V stands for super light-weight ablator" - that actually opens up more questions than it answers ;) What exactly qualifies as "super light weight"? How does SLA compare to the reportedly "featherweight" Shuttle tiles? How do the different shielding approaches relate to each other in direct comparison? What percentage of a spacecraft mass needs to be allocated to heat shielding, and how does that differ between the available (and possible future?) technologies? — Preceding unsigned comment added by 188.174.63.128 (talk) 03:21, 2 July 2015 (UTC)
 * I suspect that that may be marketing jargon by Lockheed Martin, who manufactures the product. I would suggest inquiring from them. Geogene (talk) 17:45, 2 July 2015 (UTC)
 * Thanks for the reply, however this request was not so much about the specifics of SLA in and of itself, but rather about the mass properties of the various heat shielding materials in general, since the article lacks any numbers in that regard. Of course, examples, or ideally a table providing an overview over many different types would be very welcome. — Preceding unsigned comment added by 188.174.63.128 (talk) 04:44, 5 July 2015 (UTC)

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Overgeneralized statement
In the "Sphere-cone" section, there is a sentence reading "The vehicle enters cone-first."

The Mk-2 RV, however, entered with the spherical section leading, as clearly shown in the nearby figure where the spherical section is marked as providing "heat protection" and the conical section is marked as "afterbody".

The choice between wide-end-first to pointy-end-first continues to exist today, and is basically determined by whether the capsule needs to slow down. ICBM RVs don't; cargo and crew capsules do.

At least that's my take. Maybe whoever wrote that sentence would like to suggest some other way to clarify it. 2600:100C:B22D:19D3:6D70:8849:1420:3EA8 (talk) 23:55, 30 May 2017 (UTC)

Nothing on supersonic parachutes
Intro says "Manned space vehicles must be slowed to subsonic speeds before parachutes or air brakes may be deployed" but this is not explained or qualified in the rest of the article. Supersonic parachutes were used in the Mars_Science_Laboratory on Mars - why arent they used in earth reentry ? - Rod57 (talk) 22:38, 10 January 2018 (UTC)

Caption of Apollo re-entry image
Directed to, who reverted my revert of his change:

In your edit description, you claim "There are no words here that are used in a manner that is specific to the technical context at hand." This is not true; the words "aspect departing" as used in your version must make absolutely no sense to an average reader with no special technical education. I have an aerospace/mechanical engineering degree, and I cannot make sense of your caption. I can only assume it's some strange technical language (WP:JARGON) you are used to. I don't know your education level, or if you are a native speaker of British (or other non-American) English. Wikipedia must be made understandable to the widest possible audience.

"Propose simpler words if you prefer." I prefer the original wording: is simple and understandable, and correct (not inaccurate). How can you object to it and defend your more obscure rewording? JustinTime55 (talk) 13:18, 13 April 2018 (UTC)


 * "not inaccurate" is not an appropriate standard to be applying; the purpose here is to actually explain what is going on. The word "aspect" and "departing" are being used within their normal dictionary definitions; they do not derive any meaning from the technical context. Do you want me to explain them for you? I'm not willing to continue this discussion if you do not rescind your claim on some arbitrary wikipedia policy which does not apply. The fact is that you just don't like my version, and you've cherry picked the first policy which you think applies. 213.137.16.121 (talk) 21:10, 13 April 2018 (UTC)
 * Moreover, you haven't actually provided the supposed specific technical definition which is being used here. You claim is presented without evidence. 213.137.16.121 (talk) 21:12, 13 April 2018 (UTC)
 * I've just noticed that you've gone through and reverted all my edits with a fictitious justification. I'm done talking to you. 213.137.16.121 (talk) 23:34, 13 April 2018 (UTC)


 * First, I have not "gone through and reverted all your edits with a ficticious justification". I did not revert you when I moved UARS from "Deorbit disposal" to "Uncontrolled reentries" because it was uncontrolled, and not sent to a deliberately targeted area.
 * Second, I am not "cherrypicking" policies or using "some arbitrary Wikipedia policy which does not apply". You have not addressed the issue by explaining exactly what "aspect departing" means. You haven't explained it by saying both words appear in the dictionary. (See our policy page section WP:SYNTHESIS to see another practice we do not allow here). People don't commonly put the two words together like this; since it is your phrase, the burden is on you, not me to define what it means. JustinTime55 (talk) 12:35, 16 April 2018 (UTC)

Artistic Rendition?
'Artistic' tends to mean 'non-representational', to do with an aesthetic object, not a technical diagram or illustration. It refers to a personal view by the artist, not necessarily accurate, but visually pleasing or interesting.

The term wanted here is probably 'artist's impression', meaning an image created by an illustrator depicting something which could not be directly observed, or which has not yet taken place. 2001:44B8:3102:BB00:39:A9D1:6FFB:226C (talk) 00:37, 12 August 2018 (UTC)

section - technology definitions and jargon
links propulsive to: prokinetic agent / gastroprokinetic agent. this is a hilarious joke but not correct for space stuff. pls change the link to something rocket fuel related. thx. 89.134.199.32 (talk) 09:14, 14 June 2020 (UTC).


 * never mind. i changed the link so it goes to propulsion. now it is in context. (eg.: instead of laxatives goes about rocket fuel.) 89.134.199.32 (talk) 12:06, 14 June 2020 (UTC).
 * That was a good catch. Thanks for that edit. JustinTime55 (talk) 15:22, 15 June 2020 (UTC)

Problem in "Real (equilibrium) gas model" section - Isentropic Heating
The Real (equilibrium) gas model section refers to isentropic heating. Isentropic heating is a contradiction in terms. By definition of isentropic, the change in entropy is zero, dS=0. Therefore the heat change is $$\delta Q=T\,dS=0$$. There is no heating. I am guessing the author meant temperature increase. — Preceding unsigned comment added by ArtKalb (talk • contribs) 08:55, 21 December 2020 (UTC)

Slower reentry ?
This is a long article. Does it explain why it wouldn't be possible to "fly down" (even the Space shuttle required a heat shield). Is there no theoretical alternative with wings and speed reducing engines ? Something resembling the shuttle, but that had both rocket fuel for speed reducing and then a jet engine that would make late turn around possible too ? This question has from time to time existed in my mind during some 50 years by now. Boeing720 (talk) 05:25, 19 August 2019 (UTC)
 * The article may not explain, but it would require a huge amount of fuel to effect a useful speed reduction from orbital speeds. The Space Shuttle wings were heavy. - Rod57 (talk) 18:01, 14 March 2020 (UTC)

The energy to dissipate on entry is as large as the energy it took to bring the object into orbit. It takes a rather large rocket.

Compared to take-off any orbiter entry is slow and got a shallow angle. And Mach 25 is slow compared to meteorites, going up to Mach 200 and having steep entry angles. The issue is to dissipate forward impulse in a very thin environment. The regime of Mach 25 is unimaginable. It is impulse-dominated, far from friction and flight. Even turbulence does not happen underneath the vehicle but only in its wake. The article is not clear about the dissipation mechanism, as "loss to friction" is as always just the ultimate process. Re-entry is more like a leaking piston engine where the downside surface is the pistonhead. It is hot and violent and does bad things to wings meant to fly. Yet a piston engine doesn't break Mach 1, now consider Mach 25.

Also from the piston model you can see how greater objects have more problems to dissipate impulse, because their cross-section grows faster than their circumference. What leads to to greater pressure and higher temperature. It helps to make a rod-shaped space shuttle. The space shuttle does not fly at all but it glides at best, with a touch-down speed of Mach 2. A space shuttle is not a plane, but it is the largest brick you can drop from orbit without breaking it. — Preceding unsigned comment added by 77.173.226.152 (talk) 17:04, 15 February 2021 (UTC)