Concepts of reusable spacecraft

This page is far from complete... preliminarily:

HTHL - Horizontal Take off, Horizontal Landing

SSTO - Single Stage To Orbit

• Hotol
• NASP - National Aerospace Plane

TSTO - Two Stage/with Booster

• small Hotol, launched piggyback from an Antonow-225
• Kellyspace want to tow a small Orbiter into the stratosphere with a normal plane
• X-34 (a small technology demonstrator for X-33)
• Sänger - a small Orbiter, launched piggyback from an airbreathing carrier plane at a height of 40km at Mach 8

VTHL - Vertical Take off, Horizontal Landing

SSTO

• X-33 (Prototype of Venture Star)
• Venture Star

TSTO

• Space Shuttle (USA, only orbiter and booster reusable)
• Buran (Russia, Launch rocket: Energija, only orbiter reusable)
• Hermes (only orbiter reusable)
• Horus (only orbiter reusable)

VTVL - Vertical Take off, Vertical Landing

SSTO

• Delta Clipper DC-Y (the small prototype DC-X(A) absolved a couple of flights)
• Rotary Rocket Company's Roton uses a rotating, centrifugal force-pumped aerospike engine for launch and a deployable, unpowered rotor for landing. (Payload ca. 3100 kg to LEO.)

TSTO

• Kistler Aerospace Corporation's K-1 has two stages (powered by russian NK-33 and NK-43 resp.) which will land at the launch site using parachutes and airbags.

Only Shuttle and Buran do exist, X-34 and X-33 are being built.
Kelly, Kistler and Rotary Rocket plan to perform the first test flights in the next years (1999/2000). Hermes probably doesn't have a chance - some design work has been done, but it's far too small; Horus is similar, and there doesn't seem to be serious development on it right now; NASP was apparently never intended to be realised; Hotol depends on Alan Bonds hybrid engines, which are patented and secret... Nobody's planning to built DC-Y /DC-I right now.
There are models of Sänger but neither plans nor money to build it.