Ascender Ascender is a proposed small two-seater
suborbital horizontal-takeoff, horizontal-landing (HTHL),
jet- and
rocket-powered spaceplane concept which is designed to be able to achieve altitudes of up to via a steep
sub-orbital trajectory.
Spacecab The Spacecab spaceplane design concept consists of a large crewed "carrier" aircraft with a smaller "orbiter" attached on top, both of which are derived from Ascender. The carrier would take off from an airstrip and use its turbofan engines to accelerate to mach 2 at which point it would switch over to its LOX/Kerosene rocket engines to accelerate to mach 4. The orbiter craft would then detach and accelerate to orbital speeds and altitudes using its
LOX/LH2 rocket. It would be capable of delivering up to 750 kg to
low Earth orbit, and also transporting supplies and crew to the
International Space Station, an increasingly important capability following the retirement of the
Space Shuttle. Spacecab can be thought of as the intermediate next step in development between Ascender and Spacebus, and like Ascender it does not require any new technology or materials and has been the subject of a 1994 feasibility study confirming this claim.
Spacebus The Spacebus spaceplane concept is the largest, most ambitious, costly, and difficult project proposed by the company. It has a similar, but scaled-up design to Spacecab with a "carrier" craft accelerating up to mach 4 with
Ramjet engines and then up to mach 6 with rocket engines. The smaller "orbiter" would then detach and accelerate into orbit with
LOX/LH2 rocket engines with a payload of up to 5000 kg or 50 passengers. Despite requiring a new Ramjet design and significant developments with the heatshield, rocket engines, hydrogen fuel system, and transparencies, Spacebus is still claimed to be more feasible than other ongoing spaceplane projects. == See also ==