Plutonium

NASA to allow nuclear power systems for next Discovery mission
Citing progress in producing plutonium-238, NASA will allow scientists proposing missions for an upcoming planetary science competition to use nuclear power sources.

Plutonium supply for NASA missions faces long-term challenges
While NASA and the Department of Energy have restarted production of a plutonium isotope used to power some space missions, a new report warns of challenges that could threaten its long-term supply.

Full-scale production of plutonium-238 still years away
The United States has begun manufacturing nuclear spacecraft fuel for the first time in a generation, but full production of the stuff is still seven years or so away.

Plutonium Still Scarce, Production Restart Still Slow for Needy NASA
The U.S. Department of Energy will start producing new plutonium-238 for space missions around 2019, but production will ramp up slowly, and NASA still has not committed to sparing any for small missions.