Mini plutonium battery with high performance in the long term: NASA wants even more

We know it from the video game series "Fallout". Here, every car is powered by a nuclear fission engine, which repeatedly leads to devastating explosions and a lot of released radiation in the course of the game.

It is therefore not surprising that thermoelectric radioisotope generators (RTG) are only used far away from inhabited areas, more precisely on missions to the outer planets. After all, plutionium-238 is a powerful alpha emitter with a half-life of just under 90 years.

It would be a particularly deadly element, especially in direct contact, i.e. in the food chain. It could also be used to create a chain reaction, i.e. ultimately construct a nuclear bomb.

It's just as well that alpha radiation can be blocked with little effort, so that Pu-238 can be put to practical use. Leaving our planet for this, is probably not a bad idea.

A battery based on plutonium converts the emitted energy into energy in the form of infrared light. Such RTGs were previously quite heavy, but at the same time could only supply a few watts of electricity. The simple reason for this is that it is not advisable to combine too much Pu-238, as this could set off unpredictable and uncontrollable nuclear fission processes.

NASA has therefore tried to increase the efficiency with a predefined limit, which has been remarkably successful in initial studies. The new battery can generate 8 watts of electricity from just over 100 grams of Pu-238 - and can do so stably for decades. All that is needed is an area of just under 30 by 30 centimeters (one by one foot) to emit the infrared light.

The second phase of research is now set to bring further improvements. Currently, the plutonium battery is almost five times as efficient as its predecessors. With the use of improved materials, a further increase by the same factor should be possible.

Above all, this would then lead to a further reduction in the size of the structure in order to be able to construct satellites that have to manage without sunlight as small and light as possible. The power supply for electronics and additional measuring instruments would still be ensured over an enormously long period of time.

Although the performance values of such a battery are likely to be absolutely impressive, there is always a risk that the satellite, energy source and Pu-238 could fall directly back to the earth's surface. And if that happens, it should be in the smallest possible doses, which would otherwise be better off near Saturn, Neptune or in the Oort Cloud.