16

Until Masten Space Systems reveals the exact composition of the propellants, we can only speculate on the combinations they used. Based on what you have presented in question we can rule out options one by one, but we cannot be 100% sure – especially for fuels because if we miss the oxidizer, we’ll miss the fuel as well. The smoking gun here is a sentence “...


15

This is especially interesting considering that the Service Module and LM RCS used the same thruster hardware (Marquardt R-4D). The R-4D was originally designed for MMH and first flew on Lunar Orbiter 1: Marquardt experimented with a variety of liquid storable propellants. They selected NTO and MMH for their thrusters. However, government requirements led ...


10

There will likely be significant differences in the required tankage, if nothing else. The paper Lunar Lander Conceptual Design shows a comparison between landers with similar payload requirements and different engine systems. Note the different in tankage and propellant weights for the two options.


9

Generally, well-designed pressure-fed hypergolic engines are very reliable. However, failures of some designs have certainly occurred. Here are some recent examples: The Juno probe, currently in orbit around Jupiter, had to significantly change its mission plans due to concerns about potential catastrophic (as in explosive) failures due to stuck helium ...


7

A lander with storable propellants needs to keep them at close to room temperature, for a minimum of several days. A hydrolox system will take up much more volume due to the low density of LH2, and that big LH2 tank has to be kept at around 20 K. You are going to need a major structural redesign just to deal with the greater volume of the liquid hydrogen ...


6

To draw out a quote: Symmetrical dimethyl hydrazine turned out to be a dog (it's [sic] freezing point was only--8.9 [degrees]) Not only have I found a rare typo in the remarkable Ignition! (and in the second edition, to boot!), but there you go: SDMH was a good propellant, but it froze far too readily. To answer your question: yes, it was probably a ...


6

Our company (Malin Space Science Systems) is collaborating with Stellar Explorations to develop a very small biprop propulsion system for cubesat missions. There is a definite lack of options in this size range, mostly because cubesats have been prohibited from having significant propulsion systems by launch providers or primary launch customer rules up ...


6

TL;DR: The result will probably be mostly water with significant proportions of carbon dioxide and nitrogen gas. Small proportions of copper(II) oxide and hydrochloric acid may also be released. There could be other species like nitrogen oxides, chorine oxides, unburnt CuCl2, and other carbon compounds that I'm not considering. I'm not an expert on ...


5

The space shuttle's Orbital Maneuvering Engines (OMEs) were pressure-fed hypergolic engines burning nitrogen tetroxide and mono-methyl hydrazine. The combustion chamber was regeneratively cooled by hydrazine flow. The nozzle extension was radiation cooled. Source: Orbital Maneuvering System Training Manual


5

Regenerative cooling can be done with pressure-fed rockets just as it is with pump-fed rockets, the only differences are the source of the pressure driving the fuel (and sometimes oxidizer) through the cooling channels, and the lower pressures that are practical when the entire tank must be pressurized. Hypergolic engines can be either pressure-fed or pump-...


5

The combustion needs some time and enough heat to be complete, at least 99 or 99.9 %. The high temperature should be given before the combustion of N2O4 and hydrazin is started and should be hold some time after the end of combusting the hyergolics. A turbulent flow and a high pressure may enhance a complete combustion. So you need at hot hydrogen and oxygen ...


5

Yes it is possible to construct a hypergolic solid-liquid rocket propellants. Case in point a metal organic framework of imidazole derivatives with Zinc, Cadmium or Cobalt metals as the solid phase and concentrated nitric acid as the liquid oxidizer. Paper https://chemrxiv.org/articles/Hypergolic_Zeolitic_Imidazolate_Frameworks_ZIFs_as_Next-...


4

It's worth remembering a lot of the research John D. Clarke recalls in Ignition! was not primarily being conducted with the requirements of civilian space flight in mind. The military were interested in propellants that would allow munitions to be fuelled in the factory, then stored indefinitely, but ready for immediate use. Setting aside any risk of ...


4

Well, after useful comments and some research I can summarise: The chemical reaction of bipropellant hypergolic fuel is more complex: 1) There are more products of the reaction 2) Some part of the fuel remains unburned In this link by @Uwe is stated that exhaust plume contains microdroplets of unburned propellant, with size up to several micrometers. ...


4

This website suggests SDMH is incompatible with oxidizing agents, water. So it can be used for hypergolic purpose.This quote is from Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens: Properties of SDMH Forms explosive mixture with air. A strong reducing agent and strong base. Violent reaction with strong oxidizers, strong acids, metallic ...


4

There are some in the Space Shuttle Systems Handbook, Vol II (JSC 11174) - Section 11. Here's an excerpt.


3

The ISS can be refueled with UDMH and N2O4 by visiting vehicles, initially the ATV: http://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/ATV/Premiere_for_Europe_Jules_Verne_refuels_the_ISS The propellant transfer is done through the docking connector, through pipes that run outside the pressurized portions of the ISS.


3

Pressure fed engines of PSLV's fourth stage (PS4) are hypergolic (MON/MMH) and their combustion chamber is regeneratively cooled with their Columbium alloy nozzle being cooled radiatively. They are modified versions of PSLV first stage (PS1) Roll Control Thrusters. Here is a good view of cooling channels machined on combustion chamber walls. Image sources: ...


3

An alternative to regenerative cooling is film cooling. Film cooling has been in use for small pressure fed thrusters for decades, not least on the Marquardt R4D used on the Apollo Service Module for attitude control - see the photo below. This was a 490N MMH/Mon engine that has also been used on countless other programmes. The principle has also been used ...


3

Apart from the mechanical aspects of tankage, ullage, ignition, and the like, there's a significant safety issue. Unless you're starting a Moon colony, the "and return them safely to Earth" bit is pretty important. Hypergolic engines can be made extremely simple and reliable -- the Apollo LM ascent engine was basically a pair of valves, a combustion ...


3

I'm going to say yes, depending on how loose you want to be with definitions. Hydrogen peroxide as rocket fuel is decomposed by passing it through a metal catalyst screen, producing water, oxygen, and heat. At 90% concentration the temperature is around 800C (see figure 2). The autoignition temperature for kerosene is 210C. It worked for the Bristol Siddeley ...


2

My advice is to synthesize some Chromyl Chloride from a oxidized salt of Chromium as it is hypergolic with methanol and sulfur. You can also get about a liter of the liquid with just a days work and it isn’t too toxic to handle. Sadly I couldn’t find a reliable propellant mix using n2o.


2

Most if not all hypergolic fuels are toxic to varying degrees. Hydrazine, mono- methyl hydrazine, and unsymmetrical dimethyl hydrazine are all in this category. Virgin Galactic Space Ship One used nitrous oxide with aluminum grain but needed an igniter. A venting problem on Apollo-Soyuz return knocked out one astronaut and all three had to be hospitalized ...


2

This is a mix that apparently could work. "When passed over a warm ruthenium catalyst bed, gaseous nitrous oxide and an ethylene-ethane gaseous blend combust instantly" Supplies could be found for the following:Ruthenium and Ethane But I could not find sources for Ethylene, but it seems to be available for industrial uses. This could disqualify this ...


2

Yamal 601 launched this year looks as if it may be a candidate. Its not clear from the references though some sources seem to have a reason to claim there was a problem with the main 400N thruster as it transferred to complete is GTO transfer on 10N engines. Sources: Gunters "During orbit raising to geostationary orbit, a possible irregularity occured ...


2

As far as I know the answer is no. The autoignition temperature of Hydrogen is 536 °C according to Wikipedia. Although this temperature could vary with pressure, I am also unaware of LOX/LH2 being hypergolic, hence adding water to the mixture (you asked about hydrogen peroxide) should not make things that much easier.


2

I did find on Astronautix several examples of pressure fed kerosene-LOX engines, some of them built, others "notional": AABS Liberty KSR-3 P4-1 RS-36 PF RP-1 Sea Dragon-1 Microcosm 22N As well as some gas generator hypergolics, mostly Russian vernier thrusters: 8D423/11D423 (UR-100) RD-0207 (UR-200 vernier) RD-0230/RD-0257 (SS-18 vernier) RD-0236/RD-0251 (...


1

Supposedly Rocket Lab is using such a fuel for their kick stage using the Curie rocket engine. Likely it is using their proprietary Viscus Liquid Mono-propellant.


1

It depends what you mean by green. All rockets end up producing vast quantities of greenhouse gases of a variety of types and degrees of harmfulness to the environment (even water vapor is a greenhouse gas). But apart from greenhouse gas emissions many fuels are also dangerous chemicals in their own right that leave toxic residues or pose leak risks or have ...


1

The bright particles you see flying from the Souyz nozzle are the pieces of the "nozzle cowling". It is kinda ceramic material coating of the nozzle. The amount of coating is calclulated for the nozzle operation. It wears off gradually during the nozzle serving time.


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