Talk:Operation Plumbbob

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Original source: Public domain text from the U.S. Department of Energy Nevada web page http://www.nv.doe.gov/news&pubs/photos&films/0800021/Default.htm

manhole cover

There is still wildly inaccurate information in this section (Propulsion of steel plate cap). This link is to an essay by the man who actually made the velocity calculation, showing that the prospect of launching the cover into space was not taken seriously: [ http://nuclearweaponarchive.org/Usa/Tests/Brownlee.html ] It speaks for itself. I wish I had more time to make actual corrections! 2601:543:8101:1BB0:892:FE8F:FD87:F251 (talk) 16:51, 4 January 2020 (UTC) VRE, 4 January 2020

So my paragraph was quoted. Cool! I wikified it a little more and adapted the wording to the scope of this article - also put back "true" in the heading, since it's a part of the UL about the humble manhole cover "really" beating them all. Femto 15:56, 14 Oct 2004 (UTC)

I see someone has changed (with a sort of reliable source) this claim. Nevertheless I believe it is wise to watch [[1]] discussion. JunCTionS 06:25, 17 March 2008 (UTC)

Found another more conclusive argument here, will place it as source JunCTionS 06:38, 17 March 2008 (UTC)

The last line of this page -"This incident was not used as part of the technical justification for the Orion project." in the section entitled "the first nuclear propelled man made object in space" contradicts the article entitled "manhole cover" section "propelled into space" -"This incident was used as part of the technical justification for the Orion project." Somebody make up their minds!!

As "Robert Sneddon" recently pointed out (http://forums.theregister.co.uk/forum/2/2015/07/16/america_soviets_space_race/), the Pascal-B steel plate numbers don't add up. A 900 kg object with a speed of 66 km/s has a kinetic energy of 1.96 TJ. The yield of the Pascal-B explosion was only "300 t", which is 1.26 TJ. One would expect only a tiny proportion of the energy from the explosion to end up as kinetic energy of the projectile, so this is a big discrepancy. The story is not plausible.

Possibly; the qualitative decision that only "a tiny proportion of the energy ... ended up as kinetic energy" leaves me wondering how we manage to make shotguns work. The question becomes which number is wrong - the mass, the velocity or the energy imparted. Halving the velocity (measured from a single film frame) would more than compensate for any discrepancy and still leave the lid flying above escape velocity. The story may be plausible. SkoreKeep (talk) 17:59, 23 July 2015 (UTC)

I just backwards-math'ed it. The 300 ton Pascal-B explosion, exploding with 1.26 TJ of energy, will blast the manhole cover off of the shaft at 26.4 km/s, if it does this with 100% efficiency. This is over twice the escape velocity of earth (11.2 km/s). Now that being said, in reality the explosion would convert much of its energy into the sides of the shaft, and much energy would be lost through heating and instantaneous phasing of the air in the shaft and the material encapsulating the explosion. The manhole cover would then be subject to massive air drag and further heating on its journey upwards. Through no scientific means, my gut feeling tells me that at least 75% of the energy of the explosion would be lost through the aforementioned items, and therefore I believe that it is highly improbable that the manhole cover would have reached escape velocity. Wiki4Procrastination (talk) 05:02, 14 January 2016 (UTC)

There is some spurious maths going on here – who thinks that nuclear weapon engineers from the height of the atomic age were worse at math than random wiki contributors?

A 300ton yield represents approx. 1.255TJ. Slotting that into KE=1/2 * m * v2, gives an upper bound for the velocity of the plate (@900kg) of 52.8km/s – not far off the original calculated estimate of 66km/s.

Now who thinks that 300t yield is an exact figure? Nuclear weapon yields are notoriously difficult to A) calculate accurately for a built device, and B) measure directly from observing an explosion (including instrumentation). This makes perfect sense as tiny differences in the operation of the warhead can have significant effects on the released yield, and measuring the energy output of a ginormous explosion is difficult because it is only possible to sample a very small fraction of the released energy and they are not necessarily symmetric.

So it is safe to assume that the quoted 300t yield is an estimate of unknown accuracy – even if they intended the device to be 300t yield, it may have been 350t, or 500t or 200t (etc. ad infinitum). For example, the Castle Bravo test was calculated to have a yield of 4-8 megatons, but produced 15 megatons. Then there is the matter of secrecy and classification, it is entirely reasonable to assume that the *exact* yield may be kept a closely guarded secret (even though the *real* exact yield might not be precisely known) so a predicted yield of say, 327t (or 500, or 427 etc etc.) might be quoted as 300t.

Given all of the above, the 66km/s figure can and should be taken as a reliable estimate for what *could* have happened to the plate, given that the figure was produced by *the person who designed the experiment himself* and not a random internet user writing calculations on the back of a napkin. All this is moot of course, because even the lowest estimates of the plates velocity would have it being destroyed or vaporised within the lower atmosphere from compression heating effects, nobody of any import believes it made it to space. It is not accurate to say “the plate left travelling 66km/s” nor is it accrate to say “the plate could not have been travelling 66km/s” (or 33km/s or escape velocity or any combination thereof). The only thing that can be said with any accuracy is that there is a lower (calculated from the frame rate of the camera pointed at it) and an upper bound (66km/s – best estimate, provided by people on the ground) to the speed which the plate attained and the plate was probably destroyed before it travelled very far.

It always irks me to read amateur opinions, referring to scientists in extremely prestigious positions (Do they think that idiots are hired to build nuclear weapons? This was the height of the cold war.), read like “I don’t think that’s plausible.” Even a lay-person ought to assume that there might be something other afoot, than a cold war nuclear engineer getting KE=1/2*m*v2 wrong.178.15.151.163 (talk) 09:07, 11 April 2016 (UTC)

http://nuclearweaponarchive.org/Usa/Tests/Plumbob.html contains some discussion of the maximum speed of the gas form of the vaporized concrete plug, which correlates well with the estimates of the speed of the steel cover at the top of the shaft. Possibly, the official yeild estimates for the test were too low, and possibly the mass of the portion of the plate launched was less than the full 900kg. J.Mayer (talk) 13:41, 16 August 2016 (UTC)

It is completely impossible for the cover to attain anywhere close to 66 km/s. It wasn’t a barrel but just on top of it. This means that the blast would have to transfer approximately 400 tons of TNT worth of energy into a 900 kg object over a distance of just several meters (10 000× more than inside a battleship gun). Such an intense transfer of energy would completely shatter the steel and vaporize it instantly, emitting massive soft X-ray emissions. The gas hitting the underside of the cap would reach a temperature of about 1 million Kelvin. The rock near the nuclear device wouldn’t withstand this kind of pressure. Furthermore, the cap would deform or shatter immediately upon hitting the air, and it would be completely vaporized within a kilometer or so. If an object were to leave the NTS site at 66 km/s, it would create a glowing path similar to a bolide, visible from a large part of the US. And remember, the speed of sound in hot steel is just 6 km/s, so any attempt to push it beyond 12 km/s would be unlikely, regardless.ParallaxHunter (talk) — Preceding undated comment added 13:33, 30 March 2024 (UTC)

If you can find a source that says that, please provide it. Otherwise, it falls under original research. Angryapathy (talk) 20:22, 1 April 2024 (UTC)

The problem is that there is no credible, sourced claim of the "66 km/s" velocity. In fact, this is why I decided not to contribute to Wikipedia any further, because this platform lends credence to an enormous number of crazy statements.ParallaxHunter (talk) ParallaxHunter (talk) 08:52, 7 April 2024 (UTC)

Exactly! The source for the 66km/s is and account of how Dr. Robert R. Brownlee had a conversation with Bill Ogle:

Ogle: "What time does the shock arrive at the top of the pipe?"

RRB: "Thirty one milliseconds."

Ogle: "And what happens?"

RRB: "The shock reflects back down the hole, but the pressures and temperatures are such that the welded cap is bound to come off the hole."

Ogle: "How fast does it go?"

RRB: "My calculations are irrelevant on this point. They are only valid in speaking of the shock reflection."

Ogle: "How fast did it go?"

RRB: "Those numbers are meaningless. I have only a vacuum above the cap. No air, no gravity, no real material strengths in the iron cap. Effectively the cap is just loose, traveling through meaningless space."

Ogle: And how fast is it going?"

This last question was more of a shout. Bill liked to have a direct answer to each one of his questions.

RRB: "Six times the escape velocity from the earth." [2]https://nuclearweaponarchive.org/Usa/Tests/Brownlee.html 2001:56A:FAB9:4500:1060:1F0C:AF94:8EF3 (talk) 16:35, 30 July 2024 (UTC)

Here is an update I generated with chat gtp. If people are happy with general flow I will take time to incorporate the sources and have it make it fit the article. Im not wasting my time if people aren't in general agreement.

==Context and Speculation Around Cap Velocity==

In 1956, Dr. Robert Brownlee from the Los Alamos National Laboratory in New Mexico was tasked with investigating the possibility of underground nuclear detonations. This inquiry led to the Pascal A test, where a nuclear device was deployed in a 500 ft (150 m) borehole. The test yielded unexpectedly intense results, with a jet of fire shooting up hundreds of feet.

Following this, the Pascal-B nuclear test in August 1957 involved an attempt to contain the nuclear blast with a 900-kilogram (2,000 lb) iron cap welded over the borehole. Dr. Brownlee was skeptical about the efficacy of this method for containing the explosion. During the planning and discussion phases, when pressed about the potential outcomes of the test, including the speed at which the cap might be ejected if the containment failed, Dr. Brownlee humorously conjectured that the cap could be propelled at velocities up to six times the escape velocity of Earth. This figure was not based on detailed calculations regarding the cap's ejection but was rather a spontaneous and exaggerated response to persistent inquiries from his colleagues.

Upon detonation, the cap was indeed ejected at a high velocity, observed in only one frame of a high-speed camera set up for the experiment, indicating a very high speed but not quantitatively confirmed. The comment about the cap achieving a velocity of six times Earth's escape velocity became part of the lore surrounding the test, reflecting the surprising and dramatic nature of the event more than a precise scientific assertion. 2001:56A:FAB9:4500:1060:1F0C:AF94:8EF3 (talk) 16:57, 30 July 2024 (UTC)

Continental Drift Reversed?

This is a quote of a caption of the photo of the Hood shot, as of june 21 2009: "and the flash was seen by an airline pilot flying over Hawaii, over 800 miles from the NTS." The caption says California's 300 miles away, true enough, but I had no idea those folks three time zones further than California were only 800 miles out to sea. 8000? Doubt that too. More like around 4000. —Preceding unsigned comment added by 75.170.51.236 (talk) 09:50, 21 June 2009 (UTC)

i just noticed that too. A couple of sources put the distance between Honolulu and LasVegas as about 2700 miles.[3][4] I'm going to go ahead and make that change.   Will Beback  talk  21:39, 15 October 2009 (UTC)

thunderwell

Why does thunderwell redirect here this has nothing to do with thunderwells 71.192.108.214 (talk) 02:00, 23 August 2011 (UTC)

Article says: "The use of a subterranean shaft and nuclear device to propel an object to escape velocity has since been termed a "thunder well". I guess there is no better article on the subject yet. --BjKa (talk) 23:35, 4 August 2012 (UTC)

Sixth test series?

The article currently says: "The operation was the sixth test series". Now, in my reckoning it would have come after Trinity, Crossroads, Sandstone, Ranger, Greenhouse, Buster-Jangle, Tumbler-Snapper, Ivy, Upshot-Knothole, Castle, Teapot, Wigwam, and a few others. How do you arrive at six for this test series? --BjKa (talk) 23:35, 4 August 2012 (UTC)

• Very good point!! 97.127.184.156 (talk) 02:13, 22 March 2013 (UTC)

Lassen

The table was saying 0.5 kilotons. Reality, in every source other than Wikipedia says 0.5 tons.

http://nuclearweaponarchive.org/Usa/Tests/Plumbob.html http://www.okgeosurvey1.gov/level2/nuke.cat.html

Maybe there was some confusion concerning the design yield of 600 tons? Lassen was a fizzle.

97.127.184.156 (talk) 02:12, 22 March 2013 (UTC)

More likely it was some well-meaning person "correcting" the omission of the "kilo-" prefix. We had that a lot on Operation Buster-Jangle with people changing the yield of Able to tons or kilotons, until I changed it to a direct quote with a cited source to keep it at <1 pound nuclear yield... rdfox 76 (talk) 02:33, 23 March 2013 (UTC)

Picture for series. Why not Hood?

Seriously, Priscilla??

Hood was the largest atmospheric test in the CONUS. Hood should be the picture for the article.

http://nuclearweaponarchive.org/Usa/Tests/PbHood1.jpg <-- Here's one, you can always find another though. 97.127.184.156 (talk) 02:23, 22 March 2013 (UTC)

Not only that, but is it really a picture of Priscilla? Looks a lot like Upshot-Knothole Grable to me.... Moletrouser (talk) 09:38, 5 May 2013 (UTC)

Totskoye?

Coinmanj added a new section:

See also

   Totskoye nuclear exercise, a similar test by the Soviet Union

just below the list of tests in Plumbbob. The question for me is, which test was Totskoye similar to? The Totskoye test is infamous for Beria ordering a bomb drop in a relatively populated farm area as part of an Army maneuver without warning; it was not otherwise technically different from tens of other drop tests. I really don't see the connection with any Plumbbob test, unless this is a pretty involved attempt at vandalizing the article by drawing a parallel with one of the Desert Rock tests (Hood or Smokey, perhaps). I'll revert the change in a week or so if no answers are forthcoming; at a minimum, the comment needs to be extended to point out the similarity. SkoreKeep (talk) 03:53, 4 August 2013 (UTC)

I see that johnfos put the section and the mention of Totskoye back in, with no reason given. Well, there it lies. SkoreKeep (talk) 05:04, 26 October 2013 (UTC)

Easteregg?

It is not apparent to me in Operation Plumbbob how exactly the code:

   [ [Effects of nuclear explosions#Thermal radiation|thermal pulse] ] ----> "thermal pulse"

is an EasterEgg. Your change makes it

   [ [Effects of nuclear explosions#Thermal radiation] ] pulse ----> "Effects of nuclear explosions#Thermal radiation pulse"

which is grammatical nonsense. I think we'll leave it the way it was, as there is no hidden meaning or inside joke, or even much jargon, involved. I'm aware you dislike piped links, but all I can suggest is to get over it. SkoreKeep (talk) 17:01, 24 April 2014 (UTC)

OK, now you've changed it again with the explanation "(WP:EASTEREGG (you're mistaken: this has nothing to do with hidden meanings or inside jokes).)", to:

   [ [Effects of nuclear explosions#Thermal radiation|thermal radiation] ]  ---->  "thermal radiation"

That change I can support; it actually makes grammatical sense, and it didn't change the meaning of the sentence very much. It certainly isn't the change you first essayed. However, I'm somewhat flumoxed by your interpretation of "Effects of nuclear explosions#Thermal radiation|thermal pulse" as an Easteregg, which seems to be defined as "Do not use piped links to create 'easter egg links', that require the reader to follow them before understanding what's going on". First, I don't see how it applies, and second, you didn't remove the piped link, all you did is replace "thermal radiation" for "thermal pulse", leaving the piped link as it was. I could agree and won't argue with the edit but your explanation this time is gibberish. But, nevermind, don't try to explain, you've confused me quite enough. SkoreKeep (talk) 19:15, 25 April 2014 (UTC)

Controversy

The opening paragraph describes this as being, among other things, the most controversial test series. It would be nice to have a section discussing the controversies, and whether they were controversies at the time, or only became controversial later on, when more information about the tests specifically as well as generally became known.Wschart (talk) 13:42, 30 July 2014 (UTC)

The table on this page is generated by database

The table on this page and the contents of any nuclear tests infobox are generated from a database of nuclear testing which I have maintained and researched for a number of years. The table is automatically generated from that database by a Visual Basic script, and then has, periodically, been inserted into the page manually. I began doing this in October of 2013.

Recently a user complained (politely) to me about the practice. It seems to him that it removes control from all editors besides myself over the content. He believes it is tantamount to WP:OWNED of the pages affected. He also points out that there is no public mention of the fact anywhere on wikipedia, and that is true, through my own oversight, until now.

There was no intent that the pages affected should be owned by myself; in fact, one of my reasons for building these pages was to solicit (in the wikipedia way) criticism and corrections to the data, perhaps additional references that I had been unable to locate. I have regenerated the tables twice in the days since they were originally placed. Each time I did so, I performed a diff between the current version and the version that I put up in the previous cycle; all corrections were then either entered into the database or corrected in the programming, as appropriate. As may be guessed, the programming corrections were frequent to start out as suggestions about the table formatting were raised, and most incorporated. I have not made judgements on the "usefulness" of corrections; all have been incorporated, or I have communicated directly with the editor to settle the matter. In fact it was in pursuing such a correction that this matter came up.

I am posting this comment on the Talk page of every page containing content which is so generated. If you would like to comment on this matter, please go to the copy on Talk:List of nuclear tests so the discussion can be kept together. I will also be placing a maintained template on each Talk page (if anyone would like also to be named as a maintainer on one or all pages, you are welcome). I solicit all comments and suggestions.

SkoreKeep (talk) 02:21, 18 August 2014 (UTC)

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Yield of Pascal-B?

The CMR Nuclear explosion database lists the Yield of Pascal-B as 0.

The DOE/NV-209 lists it as slight in the Dec 2000 version but as 1 gram in the Sept 2015 version.

The DNA Plumbbob Series Document lists it as 0.3kt.

What is going on here? Abnormalandroid (talk) 06:51, 3 December 2022 (UTC)

Hahafunny

Just imagine the Manhole Cover flying into some alien planet with life. The aliens are wondering "what is that thing that might hit our planet" and its just a steel plate that wipes out the alien civilization. — Preceding unsigned comment added by 50.86.125.130 (talk) 15:41, 19 April 2024 (UTC)

Missing Steel Bore Cap

What is with these dates?

In 2956, Robert Brownlee, from Los Alamos...
During the Pascal-B nuclear test of August 1557....

And what is this about?

The plate was found in Okay O.K. in January of 2025.... Thecelt001 (talk) 08:44, 27 December 2024 (UTC)