18 votes
Accepted

What is the MXP-351 storable bipropellant?

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 ...
user avatar
  • 2,145
15 votes
Accepted

What was the reason to use different fuel for the Apollo Service Module propulsion system and reaction control system?

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 ...
user avatar
10 votes
Accepted

How difficult is it to convert a hypergolic based Moon human lander to a cryogenic one?

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 ...
user avatar
9 votes
Accepted

How reliable are pressure fed hypergolic engines?

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 ...
user avatar
  • 9,919
7 votes

How difficult is it to convert a hypergolic based Moon human lander to a cryogenic one?

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 ...
user avatar
6 votes
Accepted

What's up with the lack of subminiature chemical rockets?

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 ...
user avatar
  • 2,139
6 votes

Would symmetrical dimethylhydrazine work as a hypergolic fuel?

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 ...
user avatar
  • 9,635
6 votes
Accepted

What is the products of a catalyzed reaction between Hydrogen Peroxide and Ethanolamine with Copper(II) Chloride?

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 ...
user avatar
5 votes

How do pressure-fed engines stay cool?

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 ...
user avatar
5 votes

How do pressure-fed engines stay cool?

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 ...
user avatar
5 votes
Accepted

Burning Up Hydrazine and N2O4 for Safety

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 ...
user avatar
  • 46k
5 votes
Accepted

Are there any hypergolic solid/liquid fuel combinations?

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 ...
user avatar
  • 5,606
4 votes

Why were hypergolics tanks vented manually?

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 ...
user avatar
  • 141
4 votes

Exhaust products of hypergolic propellants

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 ...
user avatar
  • 8,446
4 votes

Hypergolic Propellant Combination

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 ...
user avatar
  • 4,007
4 votes
Accepted

Would symmetrical dimethylhydrazine work as a hypergolic fuel?

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: ...
user avatar
  • 1,485
4 votes

Hypergolic Engine Diagram

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

How do pressure-fed engines stay cool?

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 ...
user avatar
  • 1,432
3 votes

How do pressure-fed engines stay cool?

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 ...
user avatar
  • 8,848
3 votes

How difficult is it to convert a hypergolic based Moon human lander to a cryogenic one?

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 ...
user avatar
  • 11.5k
3 votes

Is present-day plumbing technology enough to make refueling of hypergol rockets safe? What about only in space?

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/...
user avatar
2 votes

Is nitrous oxide hypergolic with anything reasonably safe and obtainable?

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 ...
user avatar
2 votes

Is nitrous oxide hypergolic with anything reasonably safe and obtainable?

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 ...
user avatar
  • 89
2 votes
Accepted

Is nitrous oxide hypergolic with anything reasonably safe and obtainable?

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 ...
user avatar
  • 2,531
2 votes

How reliable are pressure fed hypergolic engines?

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 ...
user avatar
  • 8,848
2 votes

Hypergolic Propellant Combination

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 ...
user avatar
  • 1,849
2 votes
Accepted

Rocket engine propellant/cycle combinations

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 ...
user avatar
1 vote

Is there a "green" hypergolic propellant?

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.
user avatar
  • 118k
1 vote

Is there a "green" hypergolic propellant?

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 ...
user avatar
  • 5,606
1 vote

Hypergolic Propellant Combination

No. For a propellant (i.e. oxidizer and fuel) combination to be hypergolic, either one of the following two conditions need to be met: One of the propellants reacts rapidly and exothermically with ...
user avatar

Only top scored, non community-wiki answers of a minimum length are eligible