My chemistry is rubbish but I assume that ammonia/acetylene is the fuel in some appropriate mix but there is still an oxygen oxidizer. Is that correct?Would the exhaust products be safe?
The cost gain is massive, but only on the fuel side. Fuel, however, isn't the cost factor for rockets, engines, structures, software, integration etc. are. Atsetam engines would only really help, if there is a new approach to launching rockets (the "little reliability, cheap, throw away rocket" approach, which has been advocated for decades, but never put into reality).
This fuel seems like a good alternative to RP-1/LOX because it eliminates the cryogenic concerns of LOX.
Quote from: Nathan on 05/05/2012 11:39 amMy chemistry is rubbish but I assume that ammonia/acetylene is the fuel in some appropriate mix but there is still an oxygen oxidizer. Is that correct?Would the exhaust products be safe?Yes, atsetam is a mixture of NH3 and C2H2. It replaces RP-1 (kerosene) as the fuel for the RD-161, where RP-1 can be approximated as C12H24 (of course its a mixture of all kind of hydrocarbons) and will still require LOX (so yes, in some sense this is a tripropellant, because ammonia and acetylene do not combine massively to a new molecule when mixed).As you can see, depending on the right mixture, atsetam can be carry more hydrogen in its total mass than RP-1. I think the article's 30% efficiency gain compares to the RD-161, a kerosene engine. The cost gain is massive, but only on the fuel side. Fuel, however, isn't the cost factor for rockets, engines, structures, software, integration etc. are. Atsetam engines would only really help, if there is a new approach to launching rockets (the "little reliability, cheap, throw away rocket" approach, which has been advocated for decades, but never put into reality).
So this fuel mixture is still a gas at STP, right?
So why not use straight ammonia, which has a greater mass fraction of hydrogen and a lower condensation pressure than acetylene? No coking issues, either. Worked for X-15...
Anyone got any thoughts on safety and ISP?
I'd be interested to know why ammonia was chosen as a diluent, but I would guess its high hydrogen content would be the key.