Rocket Lab's Monopropellant: l Viscous Liquid Monopropellant

[RuBisCO]

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

[kerbiloid]

Spoiler

A rocket fueled with sparkling napalm.

 

[DDE]

10 hours ago, RuBisCO said:

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?

None of these, I’m afraid. The electrics are pushing them out of the small satellite market, whereas the larger you go, the more attractive MMH+NTO becomes.

[DDE]

That, and I can’t imagine the heterogenous monoprop is not a major explosion hazard. The components must slowly react even in storage.

Edited July 2, 2019 by DDE

[RuBisCO]

4 hours ago, DDE said:

That, and I can’t imagine the heterogenous monoprop is not a major explosion hazard. The components must slowly react even in storage.

No more then standard solid propellants possibly. I'm pretty sure electrics is not going to land MSL class rovers on Mars, or flying drone on Titan or provide attitude control and trajactory correction for such in transfer orbit, MSL by the way used hydrazine.  

Edited July 2, 2019 by RuBisCO

[DDE]

19 hours ago, RuBisCO said:

I'm pretty sure electrics is not going to land MSL class rovers on Mars, or flying drone on Titan or provide attitude control and trajactory correction for such in transfer orbit, MSL by the way used hydrazine.  

You might be surprised. Apparently there’s a slow line of inquiry into electrically-fired, electrically-throttled solids; we’ve skycraned people with solids, and electrical attitude controls actually debuted on an early Venera probe.

[magnemoe]

5 hours ago, DDE said:

You might be surprised. Apparently there’s a slow line of inquiry into electrically-fired, electrically-throttled solids; we’ve skycraned people with solids, and electrical attitude controls actually debuted on an early Venera probe.

electrically-throttled solids sound interesting but not very high isp compared to advanced monoprop. 
Ion owns the low trust segment. 

[Nuke]

On 7/1/2019 at 9:17 PM, kerbiloid said:

  Reveal hidden contents

A rocket fueled with sparkling napalm.

 

Spoiler

i love the smell of napalm in the morning. it smells like victory.

 

[kerbiloid]

On 7/3/2019 at 7:38 PM, magnemoe said:

electrically-throttled solids sound interesting but not very high isp compared to advanced monoprop. 
Ion owns the low trust segment. 

Lunar dust for lunar thrust.

[wumpus]

On 7/3/2019 at 7:15 AM, DDE said:

You might be surprised. Apparently there’s a slow line of inquiry into electrically-fired, electrically-throttled solids; we’ve skycraned people with solids, and electrical attitude controls actually debuted on an early Venera probe.

Were all the people skycraned with solids sitting on top of exploding rockets?  I'd accept a much lower degree of safety from a rocket that would get me off an exploding rocket.  I can't think of another use case, unless you are talking about the rockets that reduce the landing impact in a Soyuz (presumably the cosmonauts survive even if the solids fail).

[YNM]

On 7/2/2019 at 9:38 AM, RuBisCO said:

Rocket Lab might have the monopropellant of the future. 

Time can only tell, as always...

On 7/3/2019 at 6:15 PM, DDE said:

electrically-throttled solids

I kept hearing it but I haven't heard of one actually doing something in space.