I'm paying attention to nofbx, I think it's a promising propellant .I haven't got any information about it since 2013.
This whole "green propellant" movement is really a push for "nontoxic propellant" and is based on an exaggerated fear of the conventional fuels. In the space shuttle program there was one serious spill that zorched a few tiles, and one leak that kept a crew shut up in the Orbiter for 90min after landing. Pretty good for 135 missions.
..Beyond the risk of an accident, working with such horrendously toxic propellants still just isn't cheap.
H2O2 has a safety record far worse that hydrazine or N2O4. It was strongly promoted by one Dr. Helmut Walter in Nazi Germany, and was widely copied around the world due to the unjustified reputation German engineering had in those days. The problem is that it blows up on contact with anything organic plus a lot of common metals. It has been dropped in torpedos, in submarine engines, and in military missiles. NASA dropped it after Mercury. The UK rocket program dropped in the 1950s. Probably the worst H2O2 disaster was RNS KURSK.
The water weight of HTP makes it very very thrusty when used to oxidize hydrocarbons (with which it is hypergolic), and its decomposition can be used to run a turbopump off a catalyst, so it seems like a pretty good solution all-around.
Quote from: sevenperforce on 03/27/2017 12:44 pmThe water weight of HTP makes it very very thrusty when used to oxidize hydrocarbons (with which it is hypergolic), and its decomposition can be used to run a turbopump off a catalyst, so it seems like a pretty good solution all-around.I'm fairly sure that HTP isn't hypergolic - that is, self-igniting, with hydrocarbons in rocket use.All of the research I found on this when looking at it about a decade ago all agreed that either an ignitor or catalyst pack was needed.You can't just spray H2O2 and kerosene and have it ignite. (at least not other than as a possible accident)
Well as far as simplicity goes, you can't really beat a solid fuel system. Solid rockets are extremely reliable , quick to start. Although I feel that's against the tide of this thread.
Quote from: smfarmer11 on 04/20/2017 05:14 pmWell as far as simplicity goes, you can't really beat a solid fuel system. Solid rockets are extremely reliable , quick to start. Although I feel that's against the tide of this thread.Not reusable or testable, dead mass in a nominal flight, dangerous to work with on the ground, and tends to result in excessive acceleration.
A few people have mentioned AF-M315E, the GPIM propellant. This is a very promising option for satellite propulsion (high ISP, high density, more easily storable than most other fuels, cheap), but isn't close to relevant to OPs question. The most powerful thruster in serious development so far with that propellant produces a whopping 22 newtons of thrust, you can never achieve a TWR greater than 1 with engines of that size even if you used thousands of them. Maybe in a few decades someone will come up with something, but for now there is zero design history relevant to an abort motor, and not even any concepts I can find for how to make such a thing work
Coming back to this, if the concept is tested and works as advertised, what would be the problem with scaling this up?...
Quote from: Dante80 on 06/10/2017 06:53 pmComing back to this, if the concept is tested and works as advertised, what would be the problem with scaling this up?...The big problem I was thinking of those is that this is a catalytic monopropellant, you've got to get the entire propellant stream to contact the catalyst bed. Thrust scales roughly with propellant volume, but the volume of propellant that can be usefully burned scales with surface area. Thats a problem. Hypergolic bipropellants are easy by comparison, just contact the 2 chemicals together. I don't know how quickly this will stop scalability, but given we're talking roughly a 4000x scaling factor between the current "high thrust" GR-22 and SuperDraco, I'd be surprised if it'll scale *that* far.Do you have any information on it being used in missiles? I couldn't find anything on the subject. I'd take a guess (given that the US military has long preferred solid fueled missiles for a variety of reasons) this is just for roll control thrusters or a final targetting upper stage, neither of which needs thrust hugely greater than whats already demonstrated
Quote from: speedevil on 04/05/2017 12:23 pmQuote from: sevenperforce on 03/27/2017 12:44 pmThe water weight of HTP makes it very very thrusty when used to oxidize hydrocarbons (with which it is hypergolic), and its decomposition can be used to run a turbopump off a catalyst, so it seems like a pretty good solution all-around.I'm fairly sure that HTP isn't hypergolic - that is, self-igniting, with hydrocarbons in rocket use.All of the research I found on this when looking at it about a decade ago all agreed that either an ignitor or catalyst pack was needed.You can't just spray H2O2 and kerosene and have it ignite. (at least not other than as a possible accident)Hot decomposed HTP is hypergolic with Kersosene though. Any fuel-oxidizer composition is hypergolic if you just make the temperature high enough.