As I have mentioned previously, I was very conscious in writing Newton's Ark to keep the science as real as possible. The most speculative technology I included was probably the micro fusion reactor - a small, highly portable fusion reactor that could power a sattelite for decades.
This technology requires us to find a way to build a self-sustaining fusion reaction that produces positive net energy. And then you have to miniaturize it - I'm going to ignore that challenge assuming we can solve the main problem.
This technology has been a decade away for the past sixty years. Will we ever solve this problem? Who knows. It may really be a only decade away, it may be another sixty years away or it may never happen. It's hard to extrapolate from the experience to date. There has been some progress but not enough to be completely confident that the fundamental challenge can be overcome.
It is still an active area of research though. In fact I recently received an assignment to design a biometric security system (iris recognition) for an experimental fusion reactor facility!