Why the "New Horizons" Pluto probe is still going strong

However, the rotten Democrat-controlled Congress has denied increased production of the metal for space missions. Ass----- that they are.

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New Horizons '​ radioisotope thermoelectric generator (RTG) at the Kennedy Space Center’s Payload Hazardous Servicing Facility

A cylindrical radioisotope thermoelectric generator (RTG), protrudes from one vertex in the plane of the triangle. The RTG will provide about 250 W, 30 V DC at launch, and is predicted to drop approximately 5% every 4 years, decaying to 200 W by the encounter with the Plutonian system in 2015. The RTG, model "GPHS-RTG," was originally a spare from the Cassini mission. The RTG contains 11 kg (24 lb) of plutonium-238 oxide pellets. Each pellet is clad in iridium, then encased in a graphite shell. It was developed by the U..S. Department of Energy at the Materials and Fuels Complex (formerly Argonne West), a part of the Idaho National Laboratory in Bingham County, near the town of Arco and the city of Idaho Falls.[14] Less than the original design goal was produced because of delays at the United States Department of Energy, including security activities, that held up production. The mission parameters and observation sequence had to be modified for the reduced wattage; still, not all instruments can operate simultaneously. The Department of Energy transferred the space battery program from Ohio to Argonne in 2002 because of security concerns. There are no onboard batteries. RTG output is relatively predictable; load transients are handled by a capacitor bank and fast circuit breakers.

The amount of radioactive plutonium in the RTG is 10.9 kg (24 lb), about one-third the amount on board the Cassini–Huygens probe when it launched in 1997. That launch was protested by a number of people. The United States Department of Energy estimated the chances of a launch accident that would release radiation into the atmosphere at 1 in 350, and monitored the launch[15] as it always does when RTGs are involved. It was believed that a worst-case scenario of total dispersal of on-board plutonium would spread the equivalent radiation of 80% the average annual dosage in North America from background radiation over an area with a radius of 105 km (65 mi).[16]