Spacelab

Spacelab was a reusable laboratory used on certain spaceflights flown by the Space Shuttle. The laboratory comprised multiple components, including a pressurized module, an unpressurized carrier and other related hardware housed in the Shuttle's cargo bay. The components were arranged in various configurations to meet the needs of each spaceflight.

Spacelab components flew on a total of 32 Shuttle missions. Spacelab allowed scientists to perform experiments in microgravity in earth orbit. There was a lot of different hardware so a distinction can be made between the major Spacelab program missions with European scientists running missions in the Spacelab habitable module, missions running other Spacelab hardware experiments, and other STS missions that used some component of Spacelab hardware. There is somewhat of variation in counts of Spacelab missions, in part because there was different types of Spacelab missions that have a large range in the amount hardware flown and nature of each mission. There was at least 22 major Spacelab missions between 1983 and 1998. In addition, some hardware like the used on a number other missions, and some of the Spacelab pallets were flown as late as 2008.

In August 1973, NASA and ESRO (now European Space Agency or ESA) signed a Memorandum of Understanding to build a science laboratory for use on Space Shuttle flights. Construction of Spacelab was started in 1974 by the ERNO (subsidiary of VFW-Fokker GmbH, after merger with MBB named MBB/ERNO, and part of EADS SPACE Transportation since 2003). The first lab module, LM1, was donated to NASA in exchange for flight opportunities for European astronauts. A second module, LM2, was bought by NASA for its own use from ERNO.

Construction on the Spacelab modules began in 1974 by what then the company ERNO-VFW-Fokker.

Spacelab is important to all of us for at least four good reasons. It expanded the Shuttle's ability to conduct science on-orbit manyfold. It provided a marvelous opportunity and example of a large international joint venture involving government, industry, and science with our European allies. The European effort provided the free world with a really versatile laboratory system several years before it would have been possible if the United States had had to fund it on its own. And finally, it provided Europe with the systems development and management experience they needed to move into the exclusive manned space flight arena.

...
Wikipedia