Westford, MA

Massachusetts Institute of Technology, Haystack Radar Antenna Elevation Structure


Massachusetts Institute of Technology/Lincoln Laboratory initiated a major upgrade of the Haystack radar antenna requiring replacement of the elevation structure. The upgrade program was jointly sponsored by the United States Air Force and the Defense Advanced Research Projects Agency.

The Haystack radar antenna is a 120 ft diameter Cassegrain system designed and built in the 1960s. To provide a more stable response for 100+ GHz operational frequency, an upgrade program requiring replacement of the elevation structure was undertaken. The new millimeter-wave radar will use an innovative transmitter design and signal processing to achieve image resolution that is about ten times better than the predecessor radar.

SGH worked on replacing the entire elevation structure with a newly designed structure supported on the existing yoke and tower. The design of the new elevation structure required numerous rounds of optimization on both the dish-shaped space truss of the elevation structure as well as the 104 smaller space trusses, which support the new antenna surface on the elevation structure. The optimization achieved the desired performance characteristics while minimizing weight, controlling frequency, and limiting differential movement due to thermal lag as temperatures within the radome fluctuate.

Following optimization and member selection, each connection was designed and analyzed with detailed finite element models to ensure that behavior of the connection matched (within +/- 5%) the node-to-node behavior of the members as idealized in the optimization runs.

Project Summary



Completion Date


New Construction | Repair & Rehabilitation
Advanced Analysis
Science & Defense
L-3 Communications
Specialized Capabilities
Science & Defense

Key team members

Frank Kan
Frank Kan