Outer Space Treaty

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.