The Millstone Hill Steerable Antenna, or MISA, is a fully steerable dish antenna, in diameter, designed by the Stanford Research Institute (SRI) in 1959. It is currently located at MIT Haystack Observatory in Westford, Massachusetts.
MISA was originally installed at the Sagamore Hill Radio Observatory in Hamilton, Massachusetts in 1963. The antenna operated at that location until 1978, at which time it was relocated to Millstone Hill. Since that time it has been primarily used as a UHF radar antenna to provide measurements of the near space environment using the incoherent scatter radar technique. It is one of two surviving dish antennas of this type in the world with the other antenna being located at the Stanford University radio science field site in Stanford, California. MISA is used to provide wide radar coverage in latitude and longitude.
MISA is a broad-based observatory capable of addressing a wide range of atmospheric science investig