Millstone Hill Radar (MHR)

Contributing sensors are not under USSPACECOM's operational control; however, they provide observation data on satellites to USSPACECOM on a contributing basis. There are two contributing sensors located at Tyngsboro, Massachusetts. The Haystack radar is an X-band radar. The other contributing sensor at Tyngsboro, is the Millstone L-band radar, operating at 1,295 MHz. Millstone is contracted by the USAF for about 80 hours per week. MHR is a mechanical tracker. Built as a BMEWS prototype, it was the first US radar to track Sputnik 1957.

When the Millstone Hill radar was upgraded to operate at L-band, its UHF transmitter and receiver were retained and were connected to a 220-ft-aperture- diameter fixed zenith-pointing paraboloid. This radar has been used extensively for scientific research on the properties of the ionosphere. A 150-ft-diameter steerable paraboloidal antenna that was no longer needed to support research at a U.S. Air Force facility was moved to Millstone Hill. This antenna has also operated as part of a UHF radar, sharing the same radio-frequency equipment with the zenith-pointing UHF antenna.

The current status of Millstone Hill as a broad-based observatory capable of addressing a wide range of atmospheric science investigations has evolved over the past two decades in keeping with community recommendations and support. The incoherent scatter radar facility at Millstone Hill has been supported by the National Science Foundation since 1974 for studies of the earth's upper atmosphere and ionosphere. During that time the facility has evolved from a part-time research operation sharing radar cooling and power supply elements with the M.I.T. Lincoln Laboratory Millstone satellite tracking radar, to a separately funded, operationally independent system dedicated to upper atmospheric research. The scientific capability of the Millstone Hill facility was greatly expanded in 1978 with the installation of a fully-steerable 46 meter antenna to complement the 67 meter fixed zenith pointing dish.

The favorable location of Millstone Hill at sub-auroral latitudes combined with the great operational range afforded by the steerable antenna permit observations over a latitude span encompassing the region between the polar cap and the near-equatorial ionosphere. Since 1982 the Haystack Observatory Atmospheric Sciences Group has been supported for operating the Millstone Hill research radar as a part of the incoherent scatter radar chain and for associated studies of the auroral and sub-auroral ionosphere and thermosphere.