The problem with Moonbase is how to give supply for it.

The Moon would be a perfect place for nanotechnical and biological laboratories. We cannot use the minerals of the Moon very much, because that makes it too light. And if our Moon turns too light that causes problems for tidal waves. But the Moon would be the perfect place for antimatter and Helium 3 production. The cosmic radiation will just make antimatter that can use in spacecraft. 

One thing that limits the lunar base programs is the budget. Launches to Lunar injection are expensive. And if the developers want to give service to those lunar bases they must use some other method than just some chemical rockets. 

In some visions, some artists created an idea about the Lunar Highway. The idea was that they would make the bridge between Moon and Earth. What makes this kind of bridge impossible? 

Earth's spin is not synchronizing with the Moon. And that makes the highway to the Moon impossible. The idea was that a nanotechnical string will pull from the Moon to Earth's upper atmosphere. These kinds of systems require so many materials that they are not reasonable. 

Those fantasy ideas gave the idea for a space tower on the Moon. The tower can use archimedean screws or magnetic tracks or slingshots (catapults) to accelerate capsules on the journey to the Moon. 

The idea was that the string was equipped with strong magnets. And the capsule where is a channel through it will be put around that string. That string can connect with a satellite.  That is somewhere behind the gravitational wall of the Moon. The Earth's gravitation elongates that string straight. Then that magnetic tower pulls capsules to Earth. 

But magnetic or kinetic systems can be suitable for spacecraft that are used for the Lunar base service. Giant magnetic accelerators can position on the Lunar's equator. That system can be a particle accelerator that travels around the Moon. 

That magnetic cannon can use solar panels as the power source. And that system can send spacecraft into the entire solar system, but sending small spacecraft to Earth needs much smaller systems. Lunar space elevators could be magnetic cannons that shoot capsules to Earth.

The accelerators must only give so much punch that they send the capsule to Earth. So the mechanic catapult can make the same work as magnetic accelerators. 

Another version of that futuristic transportation is the kinetic accelerator called cosmic slingshot. The Norwegian startup tries to use the slingshot called spin launch to send spacecraft to Earth orbiter. If that spin launcher will put on Moon, that allows to shoot capsules to Earth at very low costs. The fact is. That the same system can use on Moon, or it can connect to the space station. 

Lunar space elevators are one of the systems that could transfer people between the Moon and Earth. Other versions of this system could be a tower there is connected to a slingshot. The slingshot accelerates the spacecraft to a speed that is high enough that it can travel to Earth. 

And another slingshot on the Earth orbiter would transfer the craft to the Moon injection trajectory. In that system, the giant space station pulls  Earth Orbiter using a space hook. Then that station could throw the craft to the main station. And then the lunar slingshot throws that capsule to the Moon.