Talk:Rocket propellant

Heptyl
Can anyone explain what is "heptyl" fuel is? I have seen a recent article about a Russian Proton rocket explosian scattering "heptyl" fuel around. The Proton rocket article does not list "heptyl" as a fuel. I can find nothing telling a formula or any details. Help would be appreciated. Kelly —Preceding unsigned comment added by 209.247.23.82 (talk) 05:56, 7 September 2007 (UTC)
 * The Proton uses UDMH and H2O4, which the Russians sometimes call Heptyl and Amyl respectively. DonPMitchell (talk) 05:40, 19 July 2008 (UTC)
 * That should be UDMH and N2O4 Evand (talk) 15:35, 24 March 2009 (UTC)

UDMH is Unsymmetrical Dimethylhydrazine ((CH3)2NNH2) - N2O4 is Nitrogen tetroxide — Preceding unsigned comment added by 66.215.160.146 (talk) 15:15, 2 July 2013 (UTC)

See http://en.wikipedia.org/wiki/Unsymmetrical_dimethylhydrazine — Preceding unsigned comment added by 173.226.123.97 (talk) 22:12, 2 July 2013 (UTC)

Garbled sentence
Not sure what this is about:

"Due to lower Isp, dense propellant launch vehicles have a higher the vehicle may well end up cheaper" —Preceding unsigned comment added by 195.224.127.66 (talk) 12:32, 26 February 2008 (UTC)

See http://en.wikipedia.org/wiki/Unsymmetrical_dimethylhydrazine — Preceding unsigned comment added by 69.181.3.227 (talk) 16:17, 2 July 2013 (UTC)

Not sure why it's mentioned here, but in practice this is true because a denser propellant requires a physically smaller rocket, with concomitantly smaller mass. So a very high Isp rocket, using, e.g., liquid hydrogen & oxygen, may be larger and less efficient than a lower Isp rocket, using, e.g., LOX and kerosene, because the rocket can be considerably smaller (lighter, less draggy, &c). In fact, this is frequently seen, particularly on lower stages of large rockets. — Preceding unsigned comment added by 146.174.238.100 (talk) 16:25, 2 July 2013 (UTC)

Liquid oxidizers
The recent edits make it seem like all liquid oxidizers are highly reactive or toxic. The discussion should probably include H202, and refrence the recent engines which use it largely because it avoids these problems. See also: High test peroxide. (sdsds - talk) 18:45, 10 July 2008 (UTC)


 * Peroxide and LOX are pretty much equally reactive (more or less). Peroxide can detonate with contamination, but so can LOX. LOX will safe itself when it warms up, but with peroxide lots of water does more or less the same thing. The only advantage that peroxide has is that it's stable at room temperature, and doesn't freeze water vapour, but then again, performance is lower.- (User) WolfKeeper (Talk) 18:59, 10 July 2008 (UTC)
 * Not the only advantage. Peroxide can be used as a monopropellant, it can be quasi-hypergolic if you use a catalyst, it has a higher O/F ratio than LOX which tends to help density impulse, it is excellent for powering turbopumps, it is space storable and can be transferred in space. Performance also doesn't have to be lower for first stages as the higher density impulse can cancel out the lower Isp. Peroxide also has its drawbacks of course, it's no panacea. Martijn Meijering (talk) 12:17, 26 June 2011 (UTC)
 * H202 provides lower performance than LOX, sure. But unlike LOX it is not cryogenic, and unlike nitric acids is neither highly toxic nor environmentally disasterous if spilled. I had not previously been aware of the assertion that peroxide is hypergolic (spontaneously detonates) with some contaminants. Which? (sdsds - talk) 03:45, 11 July 2008 (UTC)
 * A variety of contaminants are potentially problematic. Many metals and metal oxides promote decomposition, which can cause ignition of nearby organic materials.  Spills that aren't cleaned up thoroughly can (over extended periods) form explosive organic peroxides.  HTP is hypergolic with things like wood (especially treated wood), leather, some synthetic fabrics, plant matter, etc.  In short, organic contaminants are very bad, much like with LOX.  IMHO the hazards of the two are broadly comparable in magnitude and mitigation difficulty, but different in the details. Evand (talk) 15:34, 24 March 2009 (UTC)

See http://en.wikipedia.org/wiki/Unsymmetrical_dimethylhydrazine — Preceding unsigned comment added by 69.181.3.227 (talk) 16:19, 2 July 2013 (UTC)

Tridyne, or Nitro-dyne, rocket fuel
Might want to add to the article something about a rocket fuel that is considered safe for being in the interior of human-habitable enclosed spaces in outer space: Tridyne, or Nitro-dyne. I was unsuccessful in finding anything about it on Wikipedia.

Both this NASA source (on pp 18 of 23, NASA JSC Presentation: Human Spaceflight Affordability: Advanced In-house Development Portfolio January 2011) and this blog post by Jon Goff (ISS Micro-Return Vehicle Concept, January 2011) discuss the fuel and the small rocket propulsive systems that might use it. Goff calls it "'a non-toxic propulsion system. Both JSC and Altius came to the same solution of using a Tridyne (well technically Nitro-dyne) warm-gas system. “'Tridyne'” is a gaseous mixture of dilute amounts of hydrogen and oxygen in a suitable buffer gas (Helium or Nitrogen). The idea is the hydrogen and oxygen are at such low concentrations that the mixture is not flammable in air, and the two components cannot ignite due to the buffer gas, except in the presence of a suitable catalyst.  The resulting “flame” is cooler than even a H2O2 monopropellant thruster, with corresponding worse performance–somewhere in the 120-140s vacuum Isp.  While you wouldn’t want to use this for a high-delta-V mission due to poor achievable propellant tank to propellant mass ratios and low Isp, it is probably adequate for the small station departure and deorbit burns (100-150m/s according to the presentation). The complexity of the system ends up being even less than a hydrazine monopropellant system (no need for heaters, pressurization systems, etc) and avoids toxicity issues.'"

NASA says only a few words about the propulsion part of their "ISS Return Capsule": "'Propulsive System: Facilitates safe operation inside pressurized vehicles, departure from the ISS, re-entry insertion, and landing at a specified landing location. Will be pressurized cold gas shystem.  Current leading candidate is Tridyne.'"

Is anyone familiar with this low-Isp/poor-propellant-tank-to-propellant-mass-ratio rocket fuel? Cheers. N2e (talk) 19:50, 2 February 2011 (UTC)

As added information to this section: Tridyne is considered for use as a pressurant gas to pressurize propellant tanks. The high temperature gas generated is more efficient for pressurization than a gas that is just rapidly expanded (and thus cools down and becomes denser). Rocketdyne filed a patent for this system in 1973 (patent number US37779009). It is said to have been used on the AUSROC-2.5 rocket of the Australian Space Research Institute (ASRI), as specified in their system requirements document for this rocket. This last claim is backed by Swiss Propulsion Laboratory, who on their website claim that they have patented a cascaded version of this system in Switserland (I could not find it in the Swiss online patent database, but that might be due to my limited ability in German/French). Furthermore, the "Scorpius Space launch company" claims to use the tridyne system as pressurization method on the main page on their website, but the subpage gives a 'page not found' error. Finally a NASA brochure entitled "Warm gas pressurization of propellant tanks" for their White Sands range and Lyndon B. Johnson space center indicated that tridyne systems are available there for pressurization and that they are considered a good idea for pressurization of propellant tanks for a Mars return vehicle.

On the usage of it as a propulsion system, my own opinion (as rocket engineering student) is that tridyne is probably better than a cold gas thruster, as long as you can get the catalyst bed small and light enough. However I could imagine that you can achieve higher efficiency still by using an electrical system heating a gas to higher temperatures.

Kind regards, Rjghermsen (talk). 12:53, 27 January 2016 (UTC)

Monopropellant is not Hybrid
The "Delchev" motor reference should be removed as it is a one component Monopropellant. The MnO2 catalyst to ignite the mixture is not a solid fuel component but an igniter for non-hypergolic fuel system, similar to a glow plug for Nitromethane-Methanol or Methanol-Ammonium Nitrate solutions. A reference to [Messerschmitt_Me_163] would be nice because the high energy of decomposition of Hydrogen Peroxide is the primary propellant, not attitude control (see [list_of_stoffs]). Also see [water_injection] as a method of increasing usable energy obtained from engine systems (e.g. used on takeoff by early model jet aircraft).

In hydrogen-oxygen liquid fuel rockets, theoretical impulse is not reached because the dissociation temp of water is ~2000 degrees and the combustion temp inside the engine is over 2500 degrees, a major part of the Hydrogen burning externally. Shjacks45 (talk) 14:51, 17 January 2012 (UTC)

SpicyItalianMeatball uh, no, the article is terrible and I can fix it. It will take some time because it is so bad. I know physics and propulsion and orbital mechanics and also have a friend at NASA who thinks I should trash the whole thing and start over. Actually...that would be easier. We are going to get this thing right. Bwtranch (talk) 06:12, 14 October 2012 (UTC)

Rocket Propellant

 * I've removed this template; RfC's are for when there is a specific question that current editors cannot agree on. Since there is no question here, the template doesn't do anything. Qwyrxian (talk) 07:53, 14 October 2012 (UTC)

You can do what you want...still looks like a kid wrote it. I offered professional writing skills and you just blaze that over. Well, I don't give a rat's behind anymore ...so I'm going to write a decent one myself and you guys can wallow in your playpen as much as you want. Bwtranch (talk) 20:13, 14 October 2012 (UTC)

Ambiguity
I am having difficulty understanding the below lines taken from the last paragraph of the "Overview" section:

" Lower stages will usually use high-density (low volume) propellants because of their lighter tankage to propellant weight ratios and because higher performance propellants require higher expansion ratios for maximum performance than can be attained in atmosphere. "

For the first part, lower tankage-to-propellant-weight ratio means same weight -> less volume (because higher density) and thus smaller size tank -> ~less weight and drag, i guess.

But how does the part in bold should translate really? higher performance propellants (e.g. LH2+LOX) require higher nozzle expansion ratios (which means a longer/larger/heavier nozzle) for maximum performance than can be attained in atmosphere.

So nozzle size is a constraint, because you can not use a too large nozzle in atmo, because additional thrust it generates must outweigh the additional weight of a longer nozzle, and therefore expansion ratios that are required to expand higher performance propellants optimally are not attainable in atmosphere? — Preceding unsigned comment added by 85.110.21.21 (talk) 04:25, 28 February 2014 (UTC)

Methane
Can methane be mentioned at the page; there is some current research going on on using this fuel. Appearantly, it is more environmental to use, and 30% cheaper Engines using it: TsSKB, and SpaceX (Raptor) — Preceding unsigned comment added by KVDP (talk • contribs) 15:38, 23 November 2014 (UTC)

Clark
Reference nr. 5 is simply to "Clark, Chapter 12". Presumably this is "IGNITION" by John D Clark? — Preceding unsigned comment added by 87.145.168.137 (talk) 20:58, 6 September 2017 (UTC)

Merger proposal with Propellant
The article Propellant was exclusively about rocket propellants. I have initiated a revamp of that article to cover propellants in general, and have moved the current content to Rocket propellant. However, that section is far too long, and it should be merged with this article. Someone with familiarity with this Rocket propellant article would be much more efficient than I in identifying which material is redundant, and can be deleted, vs. which material is not redundant, and should be transferred to this article. SSSheridan (talk) 11:20, 25 November 2021 (UTC)
 * There is a lot of content there that is missing from this article, but that content is in summary form and would need to be expanded for this article. Also, I think the content at Propellant should remain there as summary information for that broad concept article.  Sparkie82 ( t • c ) 19:56, 25 November 2021 (UTC)
 * Closing, given that any remaining actions have no support and the discussion is stale more more than a year. Klbrain (talk) 11:48, 17 December 2022 (UTC)