(This is an essay about a specific, in-development game.)
In most space games, you have science and money. You discover gravitic sensors, now everyone in your space nation has access to them, and you can slap them onto ships as fast as your money allows.
In The Galactic Line, it's a bit different. Every colony has a tech economy, basically a bunch of different economies stacked up. Each one represents a specific level of technology.
You never "research computers" or "research gravitic sensors". If you have an economy capable of producing them, you are producing them. If not, you aren't. To simplify this, individual technologies are clumped into "tech tiers" - you don't track 10,000 different specific production lines, you just have a few "economies" that produce that tier.
This gives us a lot of potential play.
Let's say you start a game as 1960s Earth. The planet has a tech level 0 economy of 100. This represents all the mining, smelting, truck-building, pipe-laying, glass-making, food-growing, etc. The earth economy is more complex than that, of course, especially because the planet is divided against itself. But that 100 represents it.
When we decide to build a space station (say, the ISS) or a space ship (say, a moon landing mission), we assemble it out of ship components using the construction system. Each component has a cost attached to it. So we build a small crew cabin (0.5 T0), the solar panels (0.2 T0 each), the cooling system (0.2 T0), the docking elements (0.1 T0), scanners and comm rigs (0.3 T0), medical chamber (0.2 T0) etc, etc. At the end of it, we have a final cost, something like 3.5 T0.
So our T0 economy drops from 100 to 96.5. If we wanted to, we could have built a much larger station and ground our economy to a halt funding it, but that's generally not a great idea. This also reduces the number of gainfully employed people - a bunch of people now have jobs as advertising execs, instead.
What's the point? Building space ships and space stations actually harms your economy! Why would you build them?
Well, the space station has a number of missions it can take. For example, monitoring the astronauts for medical changes due to micrograv, radiation exposure, and so on. This mission arises from and is enabled by our medical chamber. This mission, if successful, teaches Earth to make more advanced medicines. Functionally, it exchanges 5 T0 economy for 1 T1 economy.
If you spend some time and take that mission ten times in a row, you'll end up with 46.5 T0 economy and 10 T1 economy.
The T1 economy represents computers, phones, lasers, industrial robots, plastics, particle accelerators, magnets, and so on. We are now capable of building a much more advanced space station, if we want, or maybe a new ship.
Of course, losing that much T0 is pretty bad. We probably wouldn't want to just have that one mission running over and over. Mix in a few Earth-scanning sensors - their missions help to bolster T0 economies by finding new resources, monitoring dangerous weather or pollutants, providing phone/TV signal relays, and so on. Each of these is also a mission which has specific constraints and difficulties.
So we might provide signal relays. This is a relatively easy, short mission. So we cycle those while we do our medical research, and in the end we have 100 T0 and 5 T1.
I'm simplifying the actual gameplay process, because we're discussing the back end. In terms of the player experience, these missions are similar to the "day jobs" in The Sims. While they affect the world, the real purpose is to give your crew something important to do while they live their lives. So the explanation I just gave is very similar to having a house in the sims and saying "this guy works a day job as a cop to earn cash for the house, this guy is trying to be a musician."
The missions have limits on how strong they can make the local economy. If you're trying to increase the T1 economy, then the difficulty is based on the current T1 economy. Same with the T0 economy and improving it. Higher difficulties not only increase the amount of effort required to complete the mission, but also increases the chance of failure when you do finish the mission. Every time we repeat our medical study, it takes longer and is more likely to fail. Basically, there's an upper limit on how effective these techniques can be.
There are a lot of things that can increase these limits. More people and more medical bays will make the missions go by faster. Adjunct missions can increase your chance of success - for example, a computer core can have a mission to correlate and organize the data, a residential hub can have a mission to account for secondary variables, etc. These also take people and facilities, so you'll need larger and larger space stations. Of course, more expensive facilities have less difficult missions: the T1 medical facility has a lower-difficulty version of the T0 medical bay research.
This is like in The Sims, how your jobs pay more but require more skill as you rank up.
But the scaling isn't linear, and it doesn't makes sense to simply build bigger and bigger stations. Instead, colonization is an impetus.
That crappy T0 medical bay might not be able to get your homeworld above a T1 economy of 10, but it could get fifty asteroid bases up to a T1 economy of 10. Since they all belong to Earth, Earth's local T1 economy might only be 10, but it has a total T1 economy of 510 thanks to 50 asteroid bases. This is like if your Sims houses could share their bank accounts with each other.
"But", you say "that's at least 50 space stations. And if we want more efficiency, we'll have to build hundreds of ever-more-expensive space stations-"
Yeah. Did I mention that The Galactic Line is mostly a space ship game?
Build one expensive space ship, send it to each asteroid in turn, bring their T2 economies up. Or their T1 economies to 50. Whatever you need. And the whole time, the people on the ship have lives and look out the window at the asteroid below and chat with whoever is on the asteroid, talking about how mnamnamumblemna and moomumblemoomum.
Space ships have a lot more capabilities than that, too, because a lot of missions are only available in specific situations. For example, building to T3 economies is really rough. The easiest way to do it is to analyze space wedgies. But space wedgies are temperamental. You might be able to find one or two permanent ones and build colonies nearby, but usually you'll want to send out a well-equipped science ship when a temporary space wedgie pops up. They do the mission, return to a planet for the finale, and that colony gets some T3 economy even though it's nowhere near a space wedgie.
Now, this is the simple version. In practice, there are many things I could do to make things more complex and interesting. But don't you think it's already complex and interesting enough?