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19

Hydrocarbons are largely interchangeable when it comes to performance, and as long as no single one beats kerosene with a large enough margin, the hassle of changing infrastructure is generally not worth it. Compared to RP-1, butane has slightly (very slightly) higher specific impulse, and somewhat lower density, largely cancelling each other out. Butane ...


17

The object of burning chemical propellant is to convert chemical energy to heat, using that heat to accelerate the propellant. If you are starting out with electrical power, you have no reason to limit the energy you put into a given mass of propellant to what you can store in it as chemical energy: just heat water directly, and you can reach temperatures ...


17

Partial answer: If one has solar electric power, one can use each kilogram of propellant much more effectively (i.e. higher delta-v through a higher Isp) if it is ionized and accelerated. Electrostatic acceleration can impart roughly 10,000 to 100,000 m/s (or higher potentially (pardon the pun)) velocity, versus circa 4500 m/s from an 2H2 + O2 chemical ...


9

HTP will sustain a combustion reaction without a catalyst once ignited, but it's not clear to me if the reaction proceeds quickly and smoothly enough to be a good idea for rocket combustion chambers. As MSalters comments above, hydrogen peroxide "will undergo potentially explosive thermal decomposition" before reaching its theoretical boiling point,...


2

Liquids are much better for cooling than gases. The VW beetle engine was the only one using air cooling between many other water cooled car engines. No modern car engine uses air cooling. (Sorry, don't have the reputation here to comment). I can think of two other air-cooled auto engines off the top of my head: Porsche and Corvair. Let's not forget all the ...


2

Yes, and there have been plans for commercial cargo to deliver water to a gateway, where it would be split by electrolysis to create propellant for a reusable descent/ascent vehicle. While electrolysis is energy intensive, the water can be split over weeks and stored, until it is used in minutes, so for a reusable system like this, the mass of the solar ...


2

Splitting water into hydrogen and oxygen using electric power is very inefficient. The internal resistance of the electrolysis cell is causing a large power loss. The resistance may be decreased by reducing the distance between both electrodes, but you need a minimum distance for the separation of hydrogen and oxygen. Using electrolysis you get gaseous ...


2

As mentioned in one of the previous answers and according to this source the directive to use anhydrous ammonia came from Dr. Paul F. Winternitz, a propellant scientist from Austria and chief of R&D department of Reaction Motors Inc. (RMI). According to his statement It was chosen because of a practical reasons: ’’I have worked with quite a few ...


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