This week, half a century ago, a rocket was blasted into space from coast in California, careering into space, the first and only space nuclear reactor from the US, SNAP-10A, which has been orbiting the Earth ever since and will continue to circle for another 3,000 years.
In 1960, NASA launched Systems for Nuclear Auxiliary Power (SNAP). The program launched the primary radioisotope thermoelectric generators, a technology which up to now is still used in space probes like Voyager and Curiosity today. Radioisotope thermoelectric generators aren’t nuclear reactors, though they harness the heat from a decaying element, such as plutonium-238.
SNAP 1o-A is a functioning reactor with controlled fission reaction inside. It contained enough uranium fuel to create up to 600 watts of energy for a year. On April 3, 1965, twelve hours after takeoff, it settled 500 kilometers into orbit above Earth and ground crew switched on the reactor remotely.
Initially, everything functioned smoothly. But 43 days after takeoff mission, the electrical system on the satellite carrying it botched, and the reactor shut down. It is has remained in orbit up to the present. Providing its current trajectory, NASA calculated that it will keep orbiting for another 3,000 years.
In November 1979, an “anomalous event” occurred to SNAP-10A with the parent satellite shedding pieces. In the subsequent six years, another six extra anomalous events occurred, releasing about 50 track able pieces. “Release of radioactive is possible but not confirmed,” reads a NASA report. Though, these events have not been documented in great detail, but they may have integrated a collision.
NASA has been toying with nuclear reactors in space, most remarkably the SP-100 in the 70s. But safety issues and funding troubles terminated the plan. The U.S. has only SNAP-10A, even though Russia have been able to send dozens of satellites with nuclear reactors into space, the most controversial crashed and scattered radioactive debris in Canada in 1978.
And that is why sending nuclear reactors into space is not a fantastic thought.