On Earth, nuclear power is controversial - but for deep space missions it is a necessity. However, the plutonium driving spacecraft power systems is invaluable not only for its ability to keep electricity flowing where solar cells cannot; Pu-238 is also in short supply. So rare is it that European Space Agency work on radioisotope power systems spearheaded by the agency's new UK facility will initially be done without the key ingredient. Nuclear power is critical to the 2018 ESA-NASA ExoMars Martian rovers mission and the UK's Moonlite project. Moonlite is on hold for budgetary reasons, but would use a...
