Yes indeed. The SNAP program was the big one really, culminating with an actual reactor in orbit. https://en.wikipedia.org/wiki/SNAP-10A https://en.wikipedia.o

Yes indeed. The SNAP program was the big one really, culminating with an actual reactor in orbit. https://en.wikipedia.org/wiki/SNAP-10A https://en.wikipedia.org/wiki/SNAP-10A The NERVA program was one part (mostly for propulsion) with many reactor tests. https://en.wikipedia.org/wiki/NERVA https://en.wikipedia.org/wiki/NERVA The Soviets had a few dozen nuclear reactors in space powering satellites hunting submarines.