MIT Lincoln Lab 300 GHz Radar Dish Structure

Football-field-sized aluminum structure, tolerance of ~3 mm over 100 yards. Project budget grew from $20M to $100M. No welding shop would bid because tolerances were beyond imagination. Eventually fabricated by a firm doing Electric Boat submarine work. Belmonte's prior firm helped design it. Used to illustrate joint efficiency, gusset-plate design, and welding-shop capacity limits.

MIT used to have, in the physics department, something called Millstone — a great big radar dome. They had it as a physics experiment, kind of ran out its course, and they gave it away. MIT Lincoln Laboratory took a $20 million project, which turned into a $100 million project with overruns, so they could do 300-gigahertz radar into space. Why do they want to do that? There are all kinds of little things flying up there in space in these little satellites, and the Russians didn't always send us a photograph and a spec sheet on each one of these satellites.

Air Force wanted to retrofit the old MIT Millstone steel pedestal/bearing with a new 150-foot aluminum radar dish at sub-quarter-inch tolerances. No shop would bid; ex-Electric Boat welding company eventually took the contract and succeeded. Used to illustrate (1) the scarcity of qualified aluminum welders in New England and (2) the use of many fillet welds and gussets rather than groove welds in precision aluminum structures.

Student: Tom, were you the one saying you had to have qualified aluminum welders?

It's harder to find qualified aluminum welders. I was doing something for MIT Lincoln Lab. The Air Force wanted to take the old MIT Millstone radar — MIT has this little peak out in Millis, Massachusetts, just north of Boston. They had built this radar antenna back in the 50s for research purposes for the MIT physics department. That type of physics went away or got exhausted, so they had this big steel bearing that could hold this thing, and they were trying to find some application for it.