International aerospaceplane efforts

Although the U.S. began the first reusable space booster effort in the late 1950's, it is no longer an exclusive field. All of the technologically advanced nations, and several groups of nations, have one or more reusable booster efforts in progress. A listing of the entries in the field is presented. The list is somewhat misleading, because it includes both fully reusable and partially reusable boosters, both manned and unmanned, and both flight test and operational proposals. Additionally, not all of the projects are funded, and only a few of the projects will survive. The most likely candidates are the following: France/ESA, Germany/ESA, Great Britain/ESA/(USSR), USSR(past), and Japan. A discussion of the preceding projects is provided.