A small but significant increase in the price of search and surveillance weather radar systems would not cause a significant number of customers to substitute other products. The development, production, and sale of search and surveillance weather radar is a line of commerce and a relevant product market within the meaning of the Clayton Act. Reaction and Momentum Wheels 16. Reaction and momentum wheels are mechanical devices that move and stabilize satellites by spinning and generating torque. The desired combination of torque and momentum generated by changes in wheel speed repositions the satellite.
Satellites typically have one to three reaction and momentum wheels.
The wheels, which are about four inches thick and have diameters ranging from 8-16 inches, are made of solid metal with electromechanical devices allowing them to spin. No substitute exists for reaction and momentum wheels on spacecraft. A small but significant increase in the price of reaction and momentum wheels would not cause a significant number of customers to substitute other products. The development, production, and sale of reaction and momentum wheels for the U.S. military and commercial space industries is a line of commerce and a relevant product market within the meaning of the Clayton Act. Inertial Systems 19.