Hermes was a proposed spaceplane designed by the French Centre National d'Études Spatiales (CNES) in 1975, and later by the European Space Agency (ESA).

In 1992, Hermes was cancelled due to high cost and unachievable performance, as well as a partnership with the Russian Aviation and Space Agency (RKA) which reduced the need for an independent spaceplane.

[4] A space plane would simplify recovery by having the necessary cross-range manoeuvrability to reach a given point on the Earth within a single day, while providing for a less challenging re-entry environment for the crew and payload.

[4] Critical technologies identified included thermal protection, environmental controls, life support systems, aerodynamics, and power.

[3] On 18 October 1985, CNES appointed French aerospace company Aérospatiale as the primary contractor for Hermes, the name that had been given to the spacecraft.

[7] The work share was attributed 15% to West Germany, 13% to Italy, 7% to Belgium, 5% to the Netherlands, 4% each to the United Kingdom, Spain, and Sweden, and 2% or less to Switzerland, Austria, Denmark and Ireland.

Hermes would not be able to place objects into orbit because its cargo hold could not be opened, That option was abandoned due to weight concerns.

Although Hermes was originally viewed as fully reusable (up to 30 re-entries before major service), the limited capacity of the Ariane 5 launcher forced it to leave the Resource Module in orbit.

When both Russia and ESA joined with NASA to build the International Space Station, the need for a European crew transport system was eliminated because Russian and American needs were already satisfied.

Hermes was intended as a reusable launch system to transport astronauts and moderate-size cargo payloads into low Earth orbit (LEO) and back.

Prior to the 1986 redesign, Hermes was a single spaceplane containing (front to back) a crew compartment for six, an airlock, an unpressurized cargo hold similar to Buran's and the Shuttle's, and a service module.

[4] The development of the Ariane 5 was strongly influenced by the requirements of Hermes, such as the extra aerodynamic loads along with an increased reliability factor of 0.9999, while retaining minimal impact on the launcher's commercial competitiveness on non-Hermes missions.

[4] It did not share the ogival planform of the Shuttle, instead opting for a highly-swept delta wing complete with wingtip devices, similar to the proposed Boeing X-20 Dyna-Soar spacecraft.

[13] The vehicle would have been powered by a pair of 2,000N-thrust liquid propellant rocket motors identical to those used on the L4 low-energy upper stage of the Ariane 5.

[5] According to CNES, Hermes would have been subject to more extreme re-entry conditions than the Space Shuttle due to its smaller size exposing the vehicle to higher aerothermal pressures.

In order to gather valuable data in the face of Europe's lack of experience, Dassault proposed validating the aerodynamic properties of the vehicle by completing a 1.4-tonne, 1-scale aerothermal demonstrator, named Maia, to be launched by an Ariane 4 for re-entry studies.

[17] Other potential landing sites were mooted, including Guiana Space Centre, Martinique Aimé Césaire International Airport on the island of Fort de France and unspecified airstrips in Bermuda.

With the end of the project in 1993, this mockup was transferred to ENSICA (École nationale supérieures d'ingénieurs de construction aéronautique) in 1996.