Here's What You Need to Remember: Wear and tear and funding cuts took their toll on the Thor missiles, and in 1975 the Pentagon shut down Program 437.

In 1962, U.S. president John F. Kennedy was in a bind. He was eager to negotiate a nuclear test ban with the Soviet Union. But the Soviets had recently shattered a three-year test moratorium and now Kennedy was under pressure to respond with a display of strength.

One eventual result was America’s Cold War nuclear satellite-killer — a missile that could lob an atomic warhead into Earth’s orbit and fry enemy spacecraft. So-called Program 437 was active between 1963 and 1975 and remained a secret for a full year.

Bowing to pressure from his more hawkish advisers, Kennedy approved the Project Starfish atmospheric nuclear tests.

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The tests had an interesting and frightening side effect, as the Stimson Center’s Michael Krepon wrote:

At least six satellites were victimized by Starfish Prime: the British Ariel I, the U.S. Traac, Transit 4B, Injun I, Telstar I and the Soviet Kosmos 5. The most famous victim of Starfish Prime’s electromagnetic pulse effects was Telstar, which enabled the transmission of images across the Atlantic, just as the British music invasion of the U.S. airwaves was building.

 

Before the Beatles scored their first number-one hit and transfixed viewers on the Ed Sullivan Show, another British band, The Tornados, topped the U.S. charts with Telstar, an instrumental inspired by the satellite. Telstar was dying from nuclear effects while it was #1 on the Hit Parade.

 

The Pentagon was thrilled at the accidental proof that a nuclear device exploding in the high atmosphere could knock out spacecraft. Now America had a way of shooting down Soviet satellites. U.S. Air Force lieutenant colonel Clayton Chun described the resulting Program 437 in a paper for the Air University Press in 2000:

he Air Force was able to rapidly cobble together an operational system out of deactivated missile components, existing launch pads, and a space tracking system to create the capability to use nuclear antisatellite weapons in a direct ascent mode to destroy orbiting space vehicles. …

 

[Air Force] Secretary [Eugene] Zuckert’s operational concept for the program incorporated two bases, Johnston Island and Vandenberg [Air Force Base]. The Johnston Island site provided launch pads for two Thor [anti-satellite] boosters on continuous alert. The Air Force would use Vandenberg AFB as the support and training facility for Johnston Island.

 

The Air Force planned to airlift Thor boosters, crews, nuclear weapons and support equipment to Johnston Island as needed. As envisioned by Zuckert and others, the location of Johnston Island, west southwest of Hawaii, would allow the Air Force to intercept a hostile satellite before it reached the continental United States.

The Air Force established the 10th Aerospace Defense Squadron to operate the satellite-killers and conducted a series of non-nuclear tests.

In 1964, the Pentagon revealed the program to the public. But there were problems, Chun explained:

The use of an atomic weapon to kill an enemy satellite might inadvertently signal the start of a nuclear war. The U.S. might launch such an attack suspecting that the Soviets were launching a surprise strategic attack from space. The USSR in turn might react by launching an all-out nuclear offensive thinking the United States was preparing for a nuclear first strike.

 

Even if an ASAT mission were successful and did not start an all-out nuclear war, the residual radiation and EMP effects likely would have had unintended consequences. For example, such an ASAT attack might accidentally destroy friendly satellites as had happened during the Starfish Prime test.

Wear and tear and funding cuts took their toll on the Thor missiles, and in 1975 the Pentagon shut down Program 437.