Under ESA's charter participation in microgravity research programs, which were formally established in 1982, is optional for member states. Significant activities did not begin until the flight of Spacelab 1 on the US STS in 1983. To date the majority of ESA's materials science programs remain linked to STS, including ESA's orbital free-flying EURECA satellite which is designed for deployment and retrieval by STS. In 1994 microgravity research emphasis was shifting toward parabolic aircraft flights and away from space missions. The recent elimination of the Columbus independent platform and the rescoping of the Hermes spaceplane program will limit future ESA experiments in this field until the International Space Station is operational. In the meantime, ESA astronauts have the opportunity to conduct materials science experiments on the Russian Mir space station (Reference 742).
Following the ESA Ministerial Meeting at The Hague in November, 1987, the long-term, 4-phase microgravity program was revised taking into account the effects of the Challenger accident of 1986. Phase 1 (1982-1985) had already been completed with the first flights of Spacelab. Phase 2 (1986-1992) and its extension included additional Spacelab missions and the first flight of EURECA. Phase 3 (1989-1997), termed the pre-Columbus phase, envisioned continued operations of Spacelab and EURECA while developing the Man-Tended Free-Flyer. Phase 4 (1998-2000) was called the Columbus Utilization Period, during which the volume and sophistication of materials research would be greatly expanded. In 1993 ESA's Microgravity Program Board approved a restructuring of the agency's microgravity activities into "two distinct financially independent elements: a basic European Microgravity Research Program (EMIR) and a program to develop microgravity experimental facilities for Space Station/ Columbus (MFC)" (References 743-744). Although the pace of the program has not met expectations, a strong commitment for materials science research remains within ESA.