Rocketplane XP Credit - Rocketplane Kistler

The Rocketplane XP Vehicle was a proposed suborbital manned spaceplane with accommodations for four crew. The vehicle would take off from a conventional airfield using turbojets, then use a rocket engine to accelerate to 1100 m/s, which would allow it to zoom to 100 kilometers and provide three to four minutes of zero-G.

The fighter-sized vehicle was fitted with a delta wing and a V-tail which provided good flight characteristics both subsonically and supersonically. The cabin environment was designed to maintain a comfortable temperature and pressure for the occupants while providing an excellent view of the Earth from space. It was constructed with many of the same systems as a conventional jet aircraft, but included features required for flight in space including a rocket engine, reaction control system (RCS), and internal air supply to provide a 0.7 atmosphere cabin pressure.

The thermal protection system, wing propellant tanks, and other systems were designed with the possibility of eventual upgrade to a longer-range aircraft.

In a typical mission, rocket ignition would take place between 6000 and 9000 m altitude with the spaceplane in horizontal jet flight. A 3 to 4-G ascent profile would be flown, with engine cut-off at Mach 3.5 at 45,000 m after 70 seconds of rocket powered flight. After up to four minutes of weightlessness, the passengers would pull 3 to 4 G's on re-entry, followed by a glide to a landing at the departure airfield after a one-hour flight. After a three to five day turnaround, the rocketplane would be ready for another flight.

Rocketplane XP subsystems included:

• Environmental Control and Life Support System using cryogenic liquid nitrogen and liquid oxygen and a chemical scrubbing agent to remove carbon dioxide.
• Two CJ610 business jet engines, derived from the military J-85, for takeoff and ascent to rocket ignition altitude.
• A Polaris Propulsion AR-36 160 kN liquid oxygen / kerosene regeneratively-cooled rocket engine with the injector based on the Atlas sustainer engine design. All composite tanks in the aft fuselage would be helium pressurized. A Barber Nichols turbopump, driven by hydrogen peroxide monopropellant, would deliver the propellants to the combustion chamber.
• A Space Vector reaction control system consisting of 12 cold nitrogen gas thrusters placed in opposing pairs.
• A Utah State University Flush Air Data System to determine pressure, airspeed, air density, alpha, and stall warning at all speeds, attitudes, and altitudes.
• An all electric, fly-by-wire flight control system with an elevon and aileron on each wing, and all-moving tail. Pilot inputs were processed by triple redundant flight control computers. Electromechanical actuators operating on 270VDC power drive the control services.
• An Electrical Power System mainly driven by a set of large lithium-ion batteries.
• An advanced fault tolerant BD Systems GN&C control and navigation system which takes inputs from the Flush Air Data System, a Global Positioning System (GPS), and an Inertial Navigation System.
• An ARINC, Data Acquisition and Integrated Vehicle Health Management System
• A thermal protection system to handle the 300 deg C re-entry heating, consisting of titanium leading edges and control services, and a special ceramic paint with a 93% emissivity on the rest of the aircraft.