My research has been focused on one thing, opening the Solar System to rapid reliable transportation. I see chemical rockets similar to first gear in a car. They give the thrust needed to overcome earth’s atmosphere into low Earth Orbit. Second gear is nuclear electric. Spacecraft that can perform missions to Mars/Solar System, come back, refuel and do the trip again. Cargo haulers that can expand space into humanity’s backyard.
I believe that electric propulsion is ideal for second gear. Electric propulsion means that electricity is needed to make the device work. In a chemical rocket the energy is provided by the combustion of the fuel so no electricity is needed. Electric propulsion is really cool because it uses propellant very efficiently. This means that you don’t need to carry as much propellant with you. The efficiency can be throttled up and down in order to achieve more thrust.
The limiting factor of electric propulsion is the available power. More power means more thrust (faster) and better efficiency (less propellant). With better power sources missions can be completed in less time.
Moore’s law is the idea of explosive growth. For example computers today typically two as fast as the computer a year ago and four times faster than those of two years ago. The idea is that reactors get better over time which means that spacecraft using those reactors will get faster and carry more as well.
So when nuclear electric technology is developed there will be rapid improvements in the second and third generation. Chemical rockets can’t achieve this. The rockets we have today are only marginally better than the first rockets developed in the Space Race. There are other possibilities for second gear, but I believe nuclear electric to be the most imminent. The engines are already well developed, solar electric propulsion has been proven. The missing piece is the nuclear power source.