The L-301 HGV was intended to be a follow-on to the X-15 and X-24 (specifically the X-24B) programs, to take lessons learned from both and integrate them into an airframe capable of at least reaching Mach 8 and engaging in hypersonic skip-glide maneuvers for long range missions.
The L-301 HGV was designed to succeed the X-15 and X-24 (specifically the X-24B) programs, integrating knowledge from both and aiming to achieve at least Mach 8 speeds for long-range missions with hypersonic skip-glide capabilities.