Winston
Lorenzo von Matterhorn
- Joined
- Jan 31, 2009
- Messages
- 9,560
- Reaction score
- 1,749
Among other reasons, because even DARPA gave up on it. I discovered its story because I somehow stumbled onto the ALASA program and found one of the statements made about the reason for program cancellation to be one of the funnier understatements I've read in a while. Acetylene dissolved in nitrous oxide. Wonderful idea to simplify a liquid propellant rocket engine without using an extremely toxic monopropellant like hydrazine... if you can keep it from blowing up.
Airborne Launch Assist Space Access
https://en.wikipedia.org/wiki/Airborne_Launch_Assist_Space_Access
Airborne Launch Assist Space Access, or DARPA ALASA is a canceled program of the US defense technology agency DARPA "designed to produce a rocket capable of launching a 100-pound satellite into low Earth orbit for less than $1 million." The program was conceived, then announced in 2011, and funded development work began in 2012. The project was terminated in late 2015.
...The rocket will also feature new design technologies to lower complexity and costs. It will be powered by a monopropellant, a combination of nitrous oxide and acetylene, and mixed together in one propellant tank slightly below room temperature; the propellant choice is a dramatic simplification of the complexity of the rocket vehicle.
DARPA Scraps Plan To Launch Small Sats from F-15 Fighter Jet
November 30, 2015
https://spacenews.com/darpa-airborne-launcher-effort-falters/
The magic in Boeings design, as DARPA officials described it, was the powerful nitrous oxide-acetylene propellant, also known as NA-7. The propellant would be pre-mixed to reduce the plumbing needed on the rocket, enabling it to carry more payload.
Boeing led two subsystem tests in Promontory, Utah one in August and one in April aimed at learning how the pre-mixed propellant reacted to different temperatures, pressures and atmospheric conditions. In both tests, the propellant exploded.
It did not go as predicted, Brad Tousley, director of DARPAs tactical technology office, said in a Nov. 23 interview. The finicky nature of the propellant led DARPA officials to believe it is too risky to store on piloted aircraft, Tousley said.
Acetylene
https://en.wikipedia.org/wiki/Acetylene
"Its most singular hazard is associated with its intrinsic instability, especially when it is pressurized: under certain conditions acetylene can react in an exothermic addition-type reaction to form a number of products, typically benzene and/or vinylacetylene, possibly in addition to carbon and hydrogen[citation needed]. Consequently, acetylene, if initiated by intense heat or a shockwave, can decompose explosively if the absolute pressure of the gas exceeds about 200 kilopascals (29 psi). Most regulators and pressure gauges on equipment report gauge pressure and the safe limit for acetylene therefore is 15 psig. It is therefore supplied and stored dissolved in acetone or dimethylformamide (DMF) contained in a gas cylinder with a porous filling (Agamassan), which renders it safe to transport and use, given proper handling. Acetylene cylinders should be used in the upright position to avoid withdrawing acetone during use."
Nitrous oxide fuel blend
https://en.wikipedia.org/wiki/Nitrous_oxide_fuel_blend
Patent application:
NITROUS OXIDE FUEL BLEND MONOPROPELLANTS
https://patentimages.storage.googleapis.com/pdfs/8996a6ac5ab6cfbdf990/US20090133788A1.pdf
NOFBX Monopropulsion Overview
https://web.archive.org/web/2011072...rg/pdf/industry/presentations/Greg_Mungas.pdf
Airborne Launch Assist Space Access
https://en.wikipedia.org/wiki/Airborne_Launch_Assist_Space_Access
Airborne Launch Assist Space Access, or DARPA ALASA is a canceled program of the US defense technology agency DARPA "designed to produce a rocket capable of launching a 100-pound satellite into low Earth orbit for less than $1 million." The program was conceived, then announced in 2011, and funded development work began in 2012. The project was terminated in late 2015.
...The rocket will also feature new design technologies to lower complexity and costs. It will be powered by a monopropellant, a combination of nitrous oxide and acetylene, and mixed together in one propellant tank slightly below room temperature; the propellant choice is a dramatic simplification of the complexity of the rocket vehicle.
DARPA Scraps Plan To Launch Small Sats from F-15 Fighter Jet
November 30, 2015
https://spacenews.com/darpa-airborne-launcher-effort-falters/
The magic in Boeings design, as DARPA officials described it, was the powerful nitrous oxide-acetylene propellant, also known as NA-7. The propellant would be pre-mixed to reduce the plumbing needed on the rocket, enabling it to carry more payload.
Boeing led two subsystem tests in Promontory, Utah one in August and one in April aimed at learning how the pre-mixed propellant reacted to different temperatures, pressures and atmospheric conditions. In both tests, the propellant exploded.
It did not go as predicted, Brad Tousley, director of DARPAs tactical technology office, said in a Nov. 23 interview. The finicky nature of the propellant led DARPA officials to believe it is too risky to store on piloted aircraft, Tousley said.
Acetylene
https://en.wikipedia.org/wiki/Acetylene
"Its most singular hazard is associated with its intrinsic instability, especially when it is pressurized: under certain conditions acetylene can react in an exothermic addition-type reaction to form a number of products, typically benzene and/or vinylacetylene, possibly in addition to carbon and hydrogen[citation needed]. Consequently, acetylene, if initiated by intense heat or a shockwave, can decompose explosively if the absolute pressure of the gas exceeds about 200 kilopascals (29 psi). Most regulators and pressure gauges on equipment report gauge pressure and the safe limit for acetylene therefore is 15 psig. It is therefore supplied and stored dissolved in acetone or dimethylformamide (DMF) contained in a gas cylinder with a porous filling (Agamassan), which renders it safe to transport and use, given proper handling. Acetylene cylinders should be used in the upright position to avoid withdrawing acetone during use."
Nitrous oxide fuel blend
https://en.wikipedia.org/wiki/Nitrous_oxide_fuel_blend
Patent application:
NITROUS OXIDE FUEL BLEND MONOPROPELLANTS
https://patentimages.storage.googleapis.com/pdfs/8996a6ac5ab6cfbdf990/US20090133788A1.pdf
NOFBX Monopropulsion Overview
https://web.archive.org/web/2011072...rg/pdf/industry/presentations/Greg_Mungas.pdf