they should make a prototype technological city, to simulate the things a city/major space station would need in space /on the moon, or to ultimately recycle all matter to be sustainable.
a water purification system with algae and filters, to recycle and forever use the same hydrogen and oxygen molecules, by simulating the evaporation and precipitation using sunlight and mirrors to concentrate and constantly boil water into steam to be condensed back into water.
a hydroponics+oxygen generation system, using photosynthesis and a fan system and air ducts, to provide oxygen to the vessel, as well as food plants and medical herbs (not the ones you are thinking about!) using and recycling the nutrients and carbon, all waste in the sewage is cleansed with filters and bacteria, eventually yielding all waste a usable fertilizer, as well as all corpses being cremated, and the CO2 from it sent to the oxygen generation, and the ashes with nutrients used as fertilizer.
the exterior able to manage internal temperatures, while also being able to withstand time and small space debris and protect the sealed hull.
in order to melt down, recycle and make replacements for broken electronics it would need a giant recycling and forging factory center, able to fix and reuse the metals and elements and make new or repair objects. now, in space, the only way to get more matter and elements would to be to take on raw materials... aka ships or systems to secure and retrieve space debris and extract material from them.
intake and protection systems for the retrieval of debris, or space rock, and the ways for these buildings/units to link up and send and receive, as well as ways to send support oxygen or power to other units.
all of this would require energy, so solar energy systems would need to be implemented, as well as low energy using systems so that the amount of power brought in still can easily run everything.
for all of the things required it would require lots of advanced solar systems, and lots of spread out area to absorb maximum sunlight, unless some way to manipulate gravity to make constant energy was developed, in which case the gravity of the entire station could be enough to exploit in a way to generate electricity in its center of gravity.
finally, the fast internet and computer and radio and satellite receivers connected to the main CPU and computers to run, monitor, and link all systems together, as well as organize, record, and control the citizens.
this system could work for theoretically forever... well, until the sun goes...