The systems are used for missile warning and space surveillance, detecting, identifying and tracking objects in space.
BAE Systems provides a variety of services in support of the systems, including operations and maintenance services.
"This work is important for national security, communications and space research," said Gordon Eldridge, vice president and general manager of Aerospace Solutions at BAE Systems.
"Our record of success on these programs also demonstrates our strong capabilities in facilities management and O&M for critical U.S. infrastructure assets."
Systems in use include the Solid State Phased Array Radar System, a complex network of radars that tracks approximately 10,000 objects orbiting Earth. BAE Systems maintains the radars at five locations in the United States and abroad.
The contract modifications are worth more than $60 million. They extend BAE Systems' work on the radars and telescopes through Fiscal 2013.