Viscous Liquid Monopropellant, new non-explosive and non-toxic rocket fuel (2019)

So I came upon Rocket Labs patent for their monopropellant, the one they may or may not have flown on their Photon Satellite Bus 

https://patents.google.com/patent/US20120234196A1/en

To sum it up: the monopropellant consist of particles of solid oxidizer, particles of a metal to raise the temperature of combustion and be the primary combusted material (thermic agent) and a mix of binding liquids and dissolved gasses that act as propellant mass and turn what would normally be a simple solid fuel into a Non-Newtonian fluid or gell. This gell is pushed either via pressurized gas against a bladder membrane or a metalic piston that can be cranked mechanically (just like a caulk gun). Thanks to its Non-Newtonian fluid properties via the careful choice of surfactants, binders, Rheology Modifiers, it can be pushed into an atomizer, sprayed into the combustion chamber and burn without combustion blow back (it only combusts when atomized and thus the combustion front can't crawl back up the line and into the fuel tank and blow everything up). The gas dissolve in it is most likely Nitrogen Oxide which can be heated by the combustion chamber and sent back to compress the fuel tank. 

This stuff is pretty advance! Much safer then Hydrazine (stardard monopropllant) and way denser, up to 1.72 g/ml! Compared to other advance monopropellants such as ionic solution AF-M315E which is flying right now on Green Propellant Infusion Mission which was just launched into orbit, Rocketlabs fuel has higher density (~1.72 vs 1.47) and potentially has higher Isp, maybe, not known, nowhere can I find rocketlab reporting the Isp of their fuel. Also unlike AF-M31E this stuff can't be used as combustion chamber coolant, not directly at least, the gas in its can be heated and sent back as pressurizer or bleed off to wick heat. 

What we see now is a move to replace hydazine, the standard monopropellant, will it be RocketLab's VLM, will it be NASA AF-M31E, or the ESA's LMP-103S? LMP-103S has less Isp and density than AF-M31E, but VLM has even higher density and maybe even higher ISP. Rocket labs test rocket is claimed by the patent to use 30% carrier-fluid that would put the Isp somewhere between 250-260 if we count the carrier-fluid as binder in a standard solid rocket fuel, but the patant allows for a range of binder (carrier-fluid) types and precentages that could, possible, bring the ISP even higher: 10-15%  binder/fluid would bring the Isp to over 300 if ammonium dinitramide is the oxidizer. 

In short Rocket Lab might have the monopropellant of the future. 

Edited July 2, 2019 by RuBisCO

from Hacker News https://ift.tt/3qv62JE