In what month and year was the ISS Intergovernmental Agreement signed?

The ISS Intergovernmental Agreement was signed in January 1998.

More precisely, representatives of 15 governments signed it in Washington, D.C., on January 29, 1998. The partners were the United States, Russia, Japan, Canada, and 11 European Space Agency member states. The treaty created the government-level framework for designing, developing, operating, and using the International Space Station.

The agreement followed the decision to bring Russia into the partnership formed around earlier American, European, Japanese, and Canadian station plans. It also addressed practical legal questions, including ownership of station elements, jurisdiction over people and hardware, intellectual property, and each partner’s responsibilities.

A common mix-up is confusing the 1998 agreement with the earlier 1988 IGA, which supported the planned Space Station Freedom partnership before Russia joined. Another date sometimes mentioned is March 27, 2001—the date the 1998 treaty entered into force—not the date it was signed.