The Concept X RLV (Reusable Launch Vehicle) relies on dual-propulsion systems to reach orbit. Concept X RLVs take off from a runway using jet engine power and fly to approximately 40,000 feet to 55,000 feet elevation. The second propulsion consisting of rocket engine(s) ignition(s) would be used to complete its flight into orbit. The Concept X RLV returns for a horizontal landing by either restarting its jet engines or by means of a controlled glide. The Concept X RLV is anticipated to be capable of providing suborbital flights for passengers and/or commercial/scientific payloads.
The Concept Y RLV relies on single-propulsion systems that ignite rocket engines for horizontal launch takeoffs, which are adjusted to vertical trajectories. Concept Y RLVs remain under rocket power until engine cutoff during ascent of suborbital trajectory. The Concept Y RLV utilizes a controlled glide to land horizontally. The Concept Y RLV would be capable of providing suborbital flights for passengers and/or commercial/scientific payloads.
The Concept Z RLV utilizes a parasitic launch consisting of a reusable carrier aircraft and a reusable or an expendable space vehicle. The carrier aircraft is powered by jet engines and designed and/or modified to carry the space vehicle to a safe location and high altitude (approximately 40,000 feet), where the two components detach and the rocket engine of the space vehicle is ignited. The carrier aircraft flies back to the spaceport and lands under jet engine power. The space vehicle, which can be either suborbital or orbital, returns for a horizontal landing by gliding or is expended into the ocean.