Energy

 Because its fun to talk about energy this is what I am going to go over.

So, in the media star ships always have like a core thing. The great thing about this subject is that this is kinda true, but only in the sense that in the center (kinda) of the ship is where the energy will be produced. Now when we talk about a ship that can exist in the next 100 to 150 years this core will either use fusion. Either way it will need to produce massive amounts of energy and radiation. This star ship could also use solar energy but that wouldn't have a core and would not produce nearly as much energy. Now if you are reading this keep in mind that nuclear power is currently the cleanest form of energy, it does produce radioactive waist but we would have ways to to deal with that.

Hopefully we will have Fusion as a source of energy and we could then use that. Hypothetically there is Antimatter, and if we could make large amounts of this substance (grams at a time) we could have a much larger and cleaner form of energy.  But as far as i know the only way to create Antimatter is by speeding matter up to near the speed of light and then slamming it into equivalent mass traveling at the same speed. Unfortunately I must say we cant count on rotating crystal pyramids to get energy from so for this example we will be hopeful and say that we have Fusion unlocked and ready to be used in this sort of situation.

This core would have to be placed in the center or the center back bottom. I give two options because the center would allow for the most protection, where as the center back bottom would give less radiation to the rest of the ship.

Because Fusion runs on Hydrogen you never have to worry about running out of fuel. This might sound absurd but if we used hydrogen as fuel your exhaust would be helium. If you did enough reactions to produce enough helium to fill a normal balloon, it would be enough power to light an average light bulb for 300 years. And because hydrogen is the most abundant element in the universe its something you don't have to worry about.  Large gas giants like Jupiter are made mostly out of hydrogen and helium so any ship with the tech could stop by one of these as a refueling station.

With this form of energy as a fuel we would be able to move with relative speed throughout the galaxy.