Type: aerial refueled, rocket-powered single-stage to orbit vehicle
Significant date: 1993
The Black Horse was a proposed design for a single stage to orbit (SSTO), reusable launch vehicle. The key idea behind the Black Horse was that it could be aerially refueled from a tanker such as the USAF KC-135. This caused some people to describe it as 'stage-and-a-half' rather than a true SSTO vehicle. It was to take off and land horizontally from a runway, and be piloted by human pilots. Two demonstration vehicles were planned as stepping stones to the Black Horse, called the Black Foal and the Black Colt. The Foal would demonstrate aspects of the technology and provide proof of concept. The Colt would fly to half orbital velocity and utilize an off-the-shelf `kick-stage' to put satellites in orbit.
The "Black Horse" study began with a bar napkin at the White Sands Missile Range Officers’ Club on May 12th, 1993. The original concept was developed by then Air Force Captain Mitchell Burnside Clapp, who envisioned an aerial refueled, rocket powered single-stage to orbit (SSTO) vehicle using jet fuel and hydrogen peroxide. This concept seemed a natural match for the Air Force’s TransAtmospheric Vehicle (TAV) mission and studies began at the USAF Phillips Laboratory. Burt Rutan and noted aircraft designer Dan Raymer contributed input to the development of the design. During the winter of 1993-94, the U.S. Air Force's Phillips Laboratory conducted a six-week study with WJ Schafer Associates and Conceptual Research Corporation which developed the Aerial Propellant Transfer (APT) concept further. This concept used existing components, existing tankers, landing gear, and conventional technology as much as possible.
The Black Colt was a somewhat different APT concept developed at Martin Marietta during January through May 1994, this one of a near-term suborbital X-Plane that could serve as a demonstration vehicle for the APT concept. Because the vehicle was about half the size of Black Horse, it was decided to call it "Black Colt." This concept used an existing NK-31 RP/O2 rocket engine with two Garrett F-125 turbofans used for takeoff, loiter during aerial propellant transfer, and landing propulsion. Also, rather than push for the very high performance required to achieve true SSTO operation, the Black Colt was a suborbital vehicle, with the 1000 lb payload then being delivered to orbit by means of a Star 48V upper stage. For some observers, the Black Colt, would certainly be a close match for what everyone has called "Aurora": smaller than the shuttle, but similar in mission, providing a quick way to place a camera or sensor in a suborbital trajectory, or a higher orbit via kickmotor.
Although originally conceived as a military vehicle developed for the United States Air Force, political realities made it impossible for USAF to proceed with the Black Horse program, and no vehicle was built. Mitchell Burnside Clapp left the Air Force in 1996. Teaming up with Robert Zubrin (co-author of the Martin Marietta Black Colt study) and financier Charles Lauer, he founded Pioneer Rocketplane. To help the new company get started, it allied with Dr. Zubrin’s research company, Pioneer Astronautics, in Lakewood, Colorado. General Tony McPeak, now retired from the Air Force, joined the company as Chairman of the Board. Pioneer Rocketplane developed several subsequent SSTO programs such as the Pathfinder (which lost the X-34 competition), the Bantam-X, the RASCAL (which Rutan also worked on) and the Pioneer-XP.
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