Program 437

These missiles had been modified for greater range, but even with these modifications the system could only intercept satellites that flew very close to the base, with a maximum altitude around 150 nautical miles (280 km; 170 mi).

Though the program would routinely run successful tests with unarmed Thor missiles, the only high altitude nuclear explosions were conducted through Operations Argus, Hardtack I, and Dominic/Fishbowl between 1958 and 1962.

It was eventually concluded that the due to the wide radius of damage, wartime deployment of Program 437 would result in indiscriminate destruction of friendly and enemy satellites, potentially destabilizing or escalating otherwise non-nuclear conflicts.

Furthermore, the United States Air Force had a limited supply of Thor missiles, and all military resources (especially financial) had become increasingly strained with the US involvement in the Vietnam War.

Test launches were no longer run, and the weapons system would take fourteen to thirty days to intercept targets, requiring components stored at Vandenberg Air Force Base to be airlifted by a C-124 Globemaster II to Johnston Island for deployment.

The program became fully repaired and restored by 29 March 1973, and remained in standby status until the anti-satellite mission on the Johnston Island facilities were ceased on 10 August 1974.

In January 1977, at the end of his term of office, then President Gerald Ford issued a directive for the DoD to again enter research and development on an operational anti-satellite program.