GARDEN
The earth is now being restored to it's natural state using a huge variety of robots, it is also being maintained by these machines and is basically being used as a garden
People are no longer allowed to "live" on the earth. Vacationning on earth is highly controlled
Colonies on mars are apparently still in their infancy, and construction using countless robot workers is constant
Technology has evolved to allow travel between earth and the moon to take hours instead of days, and travel between the moon and mars to take days instead of months (during the time when transit to mars is optimal)
Power from space, or from the sun to be exact, is collected, concentrated, and transmitted to earth and the moon in the form of intense beams of microwave energy
Set far in the future, humans now live on the moon, which is entirely covered by one huge city.
Special electromagnetic devices have eventually allowed humans to adjust to the gravity on the moon, but strange physical characteristics and/or deformaties are common and gradually becoming more extreme
The city is largely underground and is designed in a way so that it resembles being on earth.
Construction of robots and collection of solar power is done in space to take advantage of weightlessness and optimal exposure to the energy from the sun
After the construction of the numerous types of robots destined for earth, they are loaded into special containers and dropped into the atmosphere where other robots intercept them and slow them down while absorbing the momentum energy (energy is collected in every way possible)
(THIS IDEA MIGHT BE BETTER AS A SERIES)
This idea is mainly observing the monitoring and maintenance of extremely complex automated systems