The United States has launched a couple of dozen nuclear-powered space missions. But only one used nuclear fission – the process that powers commercial power plants on Earth. Called Snapshot, it was launched 60 years ago today.

The Atomic Energy Commission had been experimenting with nuclear power systems for space for years. It came up with a couple of alternatives. One used the decay of radioactive elements to generate heat, which is converted to electricity. That system has powered many missions throughout the solar system.

The other design used nuclear fission – it split atoms apart, releasing energy. The commission developed a reactor called SNAP-10A. It was launched on April 3rd, 1965. And it quickly went to work, as explained in a commission film about the project:

During the second orbit, less than four hours after launch, a radio command signal to activate the startup circuits was transmitted. Approximately six hours after initiating the startup command, the reactor was operating. At the beginning of the ninth orbit, a little more than eight hours after reactor startup, the SNAP-10A system was at full power, producing more than 500 watts of electricity. Mission accomplished.

Snapshot operated for 43 days. The United States hasn’t launched another fission reactor since then. But it’s considering reactors for future missions to the Moon and Mars – descendants of a “snapshot” in space.

Script by Damond Benningfield