The space-grant colleges are educational institutions in the United States that comprise a network of fifty-two consortia formed for the purpose of outer space-related research. Each consortium is based in one of the fifty states, the District of Columbia, or Puerto Rico, and each consists of multiple independent space-grant institutions, with one of the institutions acting as lead. Similar programs include sea-grant colleges (instituted in 1966) and sun-grant colleges (instituted in 2003).