Talk:Project HARP

Project Babylon
The section on Project Babylon isn't directly tied to the topic of HARP. Project Babylon already has its own separate page, making the paragraph here redundant. I propose deleting the section in its entirety. Epark251 (talk) 20:29, 15 January 2020 (UTC)

May 2006
Other links:
 * Canadian Broadcasting Corporation historic video clip
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To the person which added the photo, are you affilated with the site it was from???
 * http://home.att.net/~Berliner-Ultrasonics/ordsuper.html
 * http://www.astronautix.com/articles/abroject.htm

180 km *and* 112 miles?
The paragraph with 180km and 112 miles is poorly written. Since the two heights are the same, can we presume they refer to the same event? Kenmayer (talk) 19:52, 3 July 2013 (UTC)

The article states: "The project was based on a flight range of the Seawell Airport in Barbados, from which shells were fired eastward toward the Atlantic Ocean using an old U.S. Navy 16-inch (410 mm), 50 caliber gun (20 m); it was later extended to 100 caliber (40 m)." Calibre is the measure of a gun barrel's diameter, not its length. The reference to 50cal is incorrect and should be removed.

[JEmerick]72.92.38.182 (talk) 03:44, 16 June 2014 (UTC) This isn't true of naval guns where caliber is used to describe the length of the gun as a multiple of the bore. I think this is the description being used here. That is a 16"/50 caliber gun would have a length of ~800". See the 16" gun description of the IOWA class main armament. Mark 7 gun

Escape Velocity
In the article it say 9,000 m/s is the escape velocity, where I believe the correct number is 11,200. "11.2 km/s (approx. 40,320 km/h, or 25,000 mph" from Wikipedia escape velocity.--Mark v1.0 (talk) 16:19, 29 June 2015 (UTC)
 * For near Sea Level, that is correct. — Preceding unsigned comment added by 24.223.130.32 (talk) 21:40, 14 May 2016 (UTC)

Delta-v and muzzle velocity are not the same thing
The sentence "While the speed was not nearly enough to reach orbit (less than half of the 11,200 m/s delta-v required to reach low Earth orbit)..." suggests that the delta-v required to reach low earth orbit is directly comparable to the muzzle velocity of a launch gun. They aren't the same thing. The kinetic energy at sea level that equals the potential plus kinetic energy of a satellite in minimum stable orbit (~160 km altitude) is equivalent to 12,140 m/sec, but the delta-v to be propelled by a rocket consuming propellant on its way to LEO is about 10,000 m/sec. The reason for this difference is that a rocket does not lift and accelerate all of its propellant to the final orbit. In fact, the muzzle velocity needed to reach a particular orbit is somewhat larger than the delta-v required to reach that orbit. Punching through the atmosphere to reach the vacuum of space will exact yet another penalty making the required muzzle velocity still higher.

I'm not sure this erroneous implication is worth correcting as the statement is pedantically correct as it is. — Preceding unsigned comment added by Cuhlik (talk • contribs) 23:17, 3 March 2017 (UTC)

External links modified
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 * Added archive https://web.archive.org/web/20132220172700/http://www.astronautix.com/lvs/marlet3a.htm to http://www.astronautix.com/lvs/marlet3a.htm

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Successor
Almost certainly not yet notable, but worth listing here, I think:


 * https://www.wired.com/story/inside-spinlaunch-the-space-industrys-best-kept-secret/ -- John Broughton (♫♫) 00:32, 1 February 2020 (UTC)

Implausible altitude for launch velocity

 * altitude of 3000 meters in 58 seconds with a launch velocity of 1,000 m/s

That does not seem plausible. What do we do with this?

Project Babylon
Could anybody explain to me (especially those, who are reverting edit based on "RW" or "HG"), what is the problem with my edit to amend a short explanation to the project in the "See also" section. Why is it such a horrible edit which need to be reverted and why are these people not willing to discuss their reverts on my/their talk page (1, 2, 3). Few days ago I made a very similiar edit in the Project Babylon page (The Fist of God) which seems no problem at all. What makes the difference? Thanks, 2001:4C4C:20A1:C400:0:0:0:1000 (talk) 19:30, 25 January 2022 (UTC)

are they all propelled?
The whole article is rather vague on this important point. For starters if these are rocket propelled projectiles it should say so right in the lede. Or are the 1 - 2,a,b,c variants not propelled. It should say that clearly. Then the table should say which type.. Gjxj (talk) 23:03, 6 February 2023 (UTC)