Satellite

1950s engineer Jerry Pournelle proposed dropping tungsten rods from satellites. Project Thor ("Rods from God") drops 6.1 m × 30 cm rods at Mach 10 with ~11.5 tonnes of TNT energy. Not a nuke, so no fallout — and the 1967 Outer Space Treaty's ban on "WMDs in orbit" doesn't apply.

The Kessler syndrome is a scenario where space debris hits a satellite, creating fragments that destroy more satellites in a chain reaction until orbit is choked with junk. Losing GPS and communications could set civilization back to 1970.