A Spacelab module dedicated to the operation of a suite of international experiments researching the effects of microgravity on materials processing and life sciences. IML 1 was launched aboard the Discovery space shuttle on 22 January 1992 for an eight-day mission with a crew of six. A second IML was launched aboard the Columbia space shuttle on 8 July 1994, for a 14-day mission with a seven-person crew. Experiments included the observation of the effect of microgravity on crystal growth and chromosome behaviour.

IML was developed by six international space agencies: NASA, the National Space Development Agency, the Centre National d'Etudes Spatiales (National Centre for Space Studies), the European Space Agency, the Canadian Space Agency, and the Deutsches Zentrum für Luft- und Raumfahrt (German Aerospace Centre).