The development of a Lunar Soil Propellant lead to the idea of mixing common earth fuels into liquid oxygen (LOX) to form a monopropellant for use in rocket engines. Such a monopropellant would eliminate half the propellant systems which would save weight and reduce the cost of launch vehicles. Under NASA funding, the company explored a variety of fuels such as kerosene, motor oil, coal, methane and even ground up automobile tires. All of the fuels were solid while suspended in the LOX.
The monopropellant was successfully test fired in a small rocket engine without flashback from the combustion chamber to the propellant tank as shown on the right
Shown at left is a video of a LOX monopropellant with motor oil as the fuel. The motor oil gives the mixture a yellow color unlike the kerosene/LOX monopropellant, which looks white. LOX monopropellants burn like solid propellants as a function of pressure. The video shows the burn rate being measured at atmospheric pressure. Burn rate trip wires are located axially down the side of the container holding the monopropellant. The monopropellant sits in a liquid nitrogen bath.