Pathfinder / Rocketplane XP - Pioneer Rocketplane

Drawing on the heritage of the proposed Black Horse military spaceplane of 1993, Pathfinder was proposed by Pioneer Rocketplane of Lakewood, Colorado as a potential design for the X-34. While not selected for the X-34 contract, Pioneer Rocketplane has nevertheless continued development of the Pathfinder vehicle as a commercial concept.

Pathfinder is a spaceplane operated by a crew of two and is powered by both air-breathing jet engines and LOX/kerosene rocket engines. Using in-air fueling, the Pathfinder rocketplane would take on liquid oxygen (LOX) to power several Russian-designed RD-120 engines and then fly to an altitude of 130 km to deploy its payload with an expendable upper stage.

The 23-meter long vehicle takes off horizontally using turbofan jet engines. When it reaches an altitude of 6 km, the Pathfinder meets a tanker aircraft that transfers about 59,000 kg of liquid oxygen to the Pathfinder's LOX tanks in a method identical to air-to-air refueling. After disconnecting from the tanker, the spaceplane ignites its RD-120 rocket engine and climbs to an altitude of 112 km at a speed of Mach 15. Once out of the atmosphere, the Pathfinder can open its cargo bay doors and release its payload with a conventional liquid rocket upper stage.

The payload is then carried into orbit as the spaceplane re-enters the atmosphere. After deceleration to subsonic speeds, the Pathfinder re-starts its jet engines and lands horizontally. The Pathfinder's maximum payload capacity to a space station orbit is 2,300 kg. The Pathfinder vehicle uses primarily existing technology and components. The propulsion system uses proven jet and rocket engines (two GE F404 turbofan engines and one kerosene/oxygen-burning RD-120 rocket engine), and the avionics systems are derived from existing military aircraft.

Pioneer Rocketplane envisions using Pathfinder as a fast package delivery system or as a vehicle to carry passengers to the edge of space as tourists. The liquid oxygen in-air fueling systems remains the largest technical challenge for their spaceplane. As of 2002 Pioneer Rocketplane expected it will require about $100 million in investment to develop Pathfinder.

In June 1997, NASA awarded one of four $2 million contracts to Pioneer Rocketplane for the Pathfinder. These awards were conducted under the Bantam program, which was intended to develop preliminary designs and conduct wind tunnel tests for concepts to launch small satellites. The other three awards went to Universal Space Lines, Inc. of Newport Beach, Summa Technology, Inc. of Huntsville, and Aerojet-General Corp. of Sacramento. These NASA Low Cost Boost Technology Program contracts were to develop detailed preliminary designs and conduct wind-tunnel tests for concepts to launch small satellites. The Low Cost Boost Technology program was later canceled.

In September 1998, Pioneer Rocketplane announced that it had completed a system design review and concluded that all components and systems fit together properly. In May 1999, Pioneer was also awarded a $40,000 grant by the State of California to conduct a study on the possibility for Pathfinder to launch from the California coast.

Rocketplane XP

Rocketplane Limited is developing the Rocketplane XP, a scaled-down version of its original Pathfinder vehicle concept. The Rocketplane XP is a four-seat fighter-sized vehicle powered by two jet engines and one pressure-fed LOX/kerosene rocket engine, enabling it to reach altitudes of 107 kilometers (66 miles).

In 2004, Rocketplane Limited signed a marketing agreement with Incredible Adventures to sell suborbital tourist flights. The company is currently taking reservations for Rocketplane flights and hopes to make its first tourist flight in 2007. The spaceflight experience as currently envisioned includes 5 days of training and team social events, with the spaceflight on the sixth day. In addition to space tourism flights, the company is pursuing other markets, including microgravity research and military applications, including small satellite deployment.