Phase 1 - A subscale X-24A shape launched from a Cessna aircraft at the California City airport facility.

Phase 2 - A full scale, approximate X-24A shape without outboard fins and low-cost mockups. These will include parachute controls but no active vehicle control systems or aerodynamic surfaces (inert). These vehicles will be dropped from a C-130 at the Army test facility at Yuma, Arizona.

Phase 3 - Two full scale, approximate X-24A shaped vehicles to be launched from the DFRC B-52 on the Edwards Air Force Base test range. One of the vehicles will have fixed control surfaces; the second aircraft will have both an autonomous free-flight control system with movable aerodynamic surfaces, and parachute controls.

Phase 4 - A full-scale, modified X-24A shape with active vehicle controls and a parachute recovery system. This vehicle will be accelerated to the target altitude and speed with either a rocket booster or a high-altitude balloon. Space-qualified hardware in the eventual spacecraft layout will be used to the maximum extent possible.