Hermann Noordung (pseudonym for Capt. Potocnik of the Austrian Imperial Army) expanded the ideas of Hermann Oberth on space flight in a detailed description of an orbiting space observatory. The problems of weightlessness, space communications, maintaining a livable environment for the crew, and extravehicular activity were considered. Among the uses of such an observatory were chemical and physical experiments in a vacuum, telescopes of great size and efficiency, detailed mapping of the earth's surface, weather observation, surveillance of shipping routes, and military reconnaissance.

H. E. Ross proposed a manned satellite station in Earth orbit that would serve as an astronomical and zero-gravity and vacuum research laboratory. The design comprised a circular structure that housed the crew of the space laboratory (numbering 24 specialists and support personnel) as well as telescopes and research equipment. The station would be resupplied with oxygen and other life-support essentials by supply ships launched every three months.

H. H. Koelle's Aussenstation was a large circular structure consisting of 36 separate 5-m spheres arranged around a central hub, the whole structure rotating to provide an artificial gravity environment. Each sphere, launched via separate rockets, was a complete functional module. In this way the station could be made operational before fabrication was completed, and subsequent expansion of the structure could take place whenever desired. Total personnel complement of the station would range from 50 to 65 people.

The European Space Agency (ESA) became an increasingly important factor in space during the late 1970s and early 80s. Europe's 'Ariane' launch vehicle was a huge commercial success and ESA also built the 'Spacelab' pressurised laboratory module for the American Space Shuttle program. Spacelab contractors such as MBB and Alitalia started to examine possible follow-on manned projects, including independent ESA space stations. German and Italian companies had already proposed an integrated European manned spaceflight program named 'Columbus' when President Reagan invited other countries to join the US-led Space Station program. Columbus would have utilised modified Spacelab pressurised modules but it was not yet clear if the project should be carried out as an independent man-tended European space platform, or if Europe instead should provide an attached laboratory module to the US Station complex. The man-tended free-flying option would have consisted of a pressurised module, 'payload carriers' based on Eureca platform technologies and a new Resource Module that would provide power, communications, guidance, navigation and control to the other modules.

The European Space Agency formally joined the American Space Station project in May 1985, but the negotiations between ESA and NASA were often difficult. The Europeans complained that the Americans would not allow them to build any high-tech elements such as the pressurised modules. Technology transfer and the principle of non-discriminatory access to the Station for European users also caused problems. Congress initially insisted that the European laboratory module only be used for non-commercial life sciences experiments. The initial $80-million Columbus Phase B1 study in 1985 recommended (despite NASA's objections) that ESA build a Columbus laboratory that could be detached from the main Space Station complex for unmanned microgravity experiments. The Americans refused to accept the proposal, saying autonomous control of Columbus would be physically and technologically impossible.

In April 1986, Italy's Aeritalia finally proposed that the European Space Agency build a second free-flying pressurised module to be used with the Space Station. The Italian initiative was intended to break the NASA-ESA deadlock. The Man-Tended Free Flying platform (MTFF) would have been used for sensitive microgravity research while satisfying European needs for an autonomous manned space platform. In 1986, the estimated costs of the MTFF were $160-180 million in addition to the existing $1.6-1.8 billion Columbus space segment. The Americans grudgingly approved the MTFF although it would require additional communications, docking facilities, data processing and other Station resources. The Herm�s mini-shuttle would dock with the man-tended free-flyer to retrieve microgravity experiments.

Back in the heady days of 1987, Europe was making plans to build an autonomous space station derived from the Columbus Man-Tended Free-Flying (MTFF) platform as the next logical step after Space Station Freedom. The Herm�s mini-shuttle would have been used to ferry astronauts to it from Earth while a new docking node would have housed life support for a permanent crew (the MTFF did not carry such equipment). Finally, a crew escape vehicle capsule would have been added to return the astronauts safely in an emergency. But these grandiose plans were eventually cancelled in 1991-93.

British Aerospace Ltd. (BAe) investigated alternate European space station designs for the European Space Agency. One configuration would have consisted of self-contained modular 'building blocks' much like the Soviet Salyut and Mir space stations. Unlike the existing Columbus module design, each module could function as a free-flying spacecraft since it had its own solar panels, guidance and control capabilities etc.. The propulsion section at the base of each module would also be used on the Ariane (cargo-) Transfer Vehicle to achieve maximum commonality. In 1990, BAe's Long-Term Space Architecture Study group also investigated possible European contributions to President Bush's Space Exploration Initiative, including space stations in Earth and lunar orbit derived from their design.