All three of the orbital spaceplanes successfully flown to date utilize a VTHL (vertical takeoff, horizontal landing) design.

"HL" comes from "horizontal landing" and 10 is for the tenth lifting body model to be investigated by Langley.

It consists of a mixture of wooden and concrete flights in a straight path, about 5.5 feet wide, separated by three horizontal landings.

In August 1973, the X-24B proved that an unpowered spaceplane could re-enter Earth's atmosphere for a horizontal landing.

The vehicle was launched vertically like a conventional rocket, and the orbiter glided to a horizontal landing like an airplane, after which it was refurbished for reuse.

It has gear for horizontal landings.

There was also work on a craft that took off and landed vertically, as opposed to the horizontal, glider-like landing of the shuttle.

Other modifications considered included the addition of wings or a parasail to the spacecraft, in order to enable it to make a horizontal landing.

The horizontal landing was smooth.

The M2-F1 program demonstrated the feasibility of the lifting-body concept for horizontal landings of atmospheric entry vehicles.