ROCKET-POWERED DUCTED FAN (RPDF)
To address the need for a propulsion system that provides a cost-effective, rapid transportation system to low Earth orbit, the four imperatives directing the design effort are simplicity in design, manufacturing, operation, and maintenance. Of course, the ideal solutions are propulsion systems such as electric, plasma, or ion systems. However, these systems are all in their infancy and not capable of providing the thrust and lift capabilities the industry is seeking. So we look to the possibility of creating a system using available and proven technologies, delivering a promising path to meet all of the design goals.
The design will also give us the ability to conduct multiple Low Earth Orbit human and cargo delivery operations in one day, using the same vehicle and propulsion system. The ideal system will be a propulsion system powering an aerospacecraft like the retired space shuttle. The propulsion system will allow the craft to take off from existing commercial or military runways, and deliver powered accent to low Earth orbit—as well as powered reentry to its destination airport, accompanied by 25% reserved fuel to loiter or land on an alternate runway.
The concept is a single unit propulsion system with a high-bypass, single stage fan assembly backed by a single nozzle rocket engine. This combination of propulsion system will provide airliner-like performance up to 45,000-50,000 feet. At this altitude, the rocket engine will start to work with a gradually increasing rocket thrust rate dictated by the gradual decrease in air density due to increasing altitude. The system will be in full rocket mode at 10,000 feet and higher.
The system will use jet fuel for operation from runway altitude to 50,000 feet. At 50,000 feet and higher, the fuel will be a mix of jet fuel and liquid oxygen. There will be no need or little demand for rocket thrust for reentry: the aerospacecraft will start the jet fuel powered high-bypass ducted fan unit at any altitude below 40,000 feet for approach and landing to the destination airport.