Suborbital flight / Model XP specifications

Model XP sub-system

Cabin
The XP cabin is designed for safe, enjoyable space travel. XP features room for 3 passengers and a pilot with one passenger sitting up front along side the pilot and 2 passengers in the aft seating area. Each seat features a 5-point harness system to ensure that the passengers are secure during high-G portions of the flight. Passengers also have an intercom system to hear the pilot and speak with each other, as well as monitors where they can view the external and internal cameras and view position and trajectory information as well as flight milestones.

Environmental Control and Life Support System (ECLSS):
Passengers onboard the XP are provided clean, dry air, at a comfortable pressure, and with the right mixture of gasses, especially Oxygen and Carbon Dioxide. The passengers and all the electronics in the XP also create a lot of heat that needs to be removed. XP features an Environmental Control and Life Support System that uses a chemical scrubbing agent to remove Carbon Dioxide, a condenser to remove excess water vapor, and a filter to remove any foreign items such as dirt, hair, or vomit that may be released in the cabin. The ECLSS uses cryogenic liquid nitrogen and liquid oxygen to replace the oxygen and nitrogen lost to respiration and to outflow, controlling both oxygen levels and cabin pressure. The cryogenic nature of these fluids also allows them to be used to absorb excess heat from the cabin air.

Windows and Doors:
The XP windows afford an excellent view, and they block out harmful Ultraviolet (UV) rays from the Sun, survive the heat from reentry, and withstand the pressure and temperature differentials throughout the flight. The XP windows and doors are a “plug” design with layers of high temperature glass and Lexan. Special coatings on the windows keep out harmful UV rays. They provide redundant protection from both the heat of reentry, and double-walled containment for the internal pressure.

Propulsion System:
The Rocketplane® XP is designed to operate on both turbojet and rocket power.

Turbojets:
The turbojet propulsion plant consists of modified CJ610 jet engines that have a history of reliability and ruggedness. As a part of the J-85 engine family, these engines also have a high thrust-to-weight when compared to other turbojets. The turbojets draw jet fuel from tanks within the wings and are used by the XP for takeoff and climb to the rocket ignition point before being shutdown shortly after rocket ignition. Although not necessary for a safe and successful mission, the turbojets are reignited following reentry allowing the pilot more margin and flexibility. RLI and its contractors have done extensive research and analysis to ensure the turbojets will survive the trip into space repeatedly and reliably with little or no additional wear compared to normal atmospheric flight.

Rocket Propulsion:
The XP is powered on its ballistic ascent by a 36,000lbf Liquid Oxygen and Kerosene (LOX/RP) rocket engine based upon the successful Atlas family of engines. This new rocket, dubbed the “AR-36” is being developed in cooperation with Polaris Propulsion and is regenerative cooled and adopts several key features from its heritage including injector design to ensure a stable, reusable, efficient, and cost effective engine. Propellant for the rocket ascent is stored in all composite LOX and RP tanks located in the aft fuselage, with helium providing ullage pressurization and purge gas. The propellant is fed via a Barber Nichols turbopump, which utilizes Hydrogen Peroxide for drive gas, resulting in long turbopump life, lower maintenance, and safe rocket abort capability.