Radiation safety

U.S. tests ways to sweep space clean of radiation after nuclear attack

The U.S. military thought it had cleared the decks when, on 9 July 1962, it heaved a 1.4-megaton nuclear bomb some 400 kilometers into space: Orbiting satellites were safely out of range of the blast. But in the months that followed the test, called Starfish Prime, satellites began to wink out one by one, including the world’s first communications satellite, Telstar. There was an unexpected aftereffect: High-energy electrons, shed by radioactive debris and trapped by Earth’s magnetic field, were fritzing out the satellites’ electronics and solar panels.

Starfish Prime and similar Soviet tests might be dismissed as Cold War misadventures, never to be repeated. After all, what nuclear power would want to pollute space with particles that could take out its own satellites, critical for communication, navigation, and surveillance? But military planners fear North Korea might be an exception: It has nuclear weapons but not a single functioning satellite among the thousands now in orbit. They quietly refer to a surprise orbital blast as a potential “Pearl Harbor of space.”