A couple of hypothetical power sources that could someday solve the energy problem of the interstellar spacecraft.

The main problem with interstellar spacecraft is the energy source. Nuclear power is of course ideal power source. But if we think that the lifetime of the nuclear reactor is about five years. And then the nuclear elements must change. That time is limited if we think that the journey to the target takes about nine years. The antimatter and fusion engines are not included in this text. 

There is written so much about them. And self-sustaining fusion reactor does not seem successful. So the fusion rocket requires the fission reactor for pumping energy to the laser system. The laser system will detonate the fusion ampules, which are shot through the engine. And there is the possibility that the fusion material like lithium is closed in the plutonium or some other fissile material core, which makes the system easier to handle. 

But the main problem with the power source is that the power output of the system must be bigger than the power that is loaded into the system. That is the requirement that the system can be self-sustain. So the next futuristic power sources can possible be somewhere in the future. 

When we are thinking about the form of the interstellar spacecraft. There is more probable that those systems are automatized robots that are controlled by artificial intelligence than manned systems. The problem with interstellar spacecraft is that the energy for the systems is needed. Things like ion and antimatter engines need power. And the main problem is how to get electricity for the systems when the craft is in their target. If we are sending interstellar probes someday, there must be some special solar system for research. 

And the journey to Alpha Centauri would be the general training for calibration and testing the systems that are required in the more complicating missions. The unmanned probe doesn't require that the crew will give the ultimate sacrifice. And the persons who are making that thing and operate with it can stay on Earth. 

(1)The quark-gluon engine (Is the reason why the UFO is triangle this type of engine?)

The protons are forming three quarks, and the gluons are jumping between them. What if somewhere in the future is possible to separate those quarks into three different points. And then the gluons are starting to jump between those points. 

There is the possibility that the gluons can isolate more energy from the quantum fields than they use while they are jumping between those quarks. The quark-gluon engine bases the idea that the proton is separated into three different points, and the gluons are put to jump between them. So maybe someday in the future, this type of system is possible. 

(2)The laser propulsion

The laser ray will put to jump between mirrors and the purpose of the system is to collect the energy from the radiation that impacts those laser rays. Theoretically, this kind of system requires only the mirror that has 100 % reflection and the laser ray must just travel long enough that the radiation emission from the stars is higher than the resistance of the electric circuits. The same way the radio maser or plasma field can collect the energy for the spacecraft. 

The radio maser will send the radiation to the target by using a frequency. That makes the outcoming radiation pump energy to it. Then the energy level of the radiation can rise higher than the power of the transmitter is. And that is the requirement of the self-sustaining energy production system. 

(3)The cosmic turbine

In some visions, the interstellar spacecraft which are unmanned probes, are controlled by artificial intelligence. Are traveling between stars with their reactors shutdown. When the system closes the target star it will need the start power for re-activating the nuclear power. 

This is the most conventional of this kind of system. In the spacecraft will put the rotor and another side of the flaps is put the iced helium. When the temperature of the helium ice is rising the steam will push the generator to move. 

This system can work in a vacuum where the temperature is zero kelvin. That thing can use to make the power for the system. When the craft is closing its target. The light of the target star will conduct to helium ice, and that thing will make the start power to the craft that is traveling between stars. When the system is giving electricity to the computers and other systems. That allows starting the nuclear reactor. 

Image:()https://futurism.com/scientists-project-manhattan-land-saturn-1970