From chapter 19:

Harper said. “Project Defender, the missile defense program, is really important, but as you said, probably not too interesting to your constituents.

In the 1960s Project Defender and the Ballistic Missile Boost Intercept (BAMBI) concept replaced land-launched Nike missiles with missiles to be launched from satellite platforms orbiting directly above the USSR. The BAMBI missiles would deploy huge wire meshes designed to disable Soviet ICBMs in their early launch phase. No solution to the problem of how to protect the proposed satellite platforms against attack was found, however, and the program was canceled in 1968.

—https://en.wikipedia.org/wiki/United_States_national_missile_defense