After reading all of these replies, here is a simplified way that I could see it working:
Make it a bit more special than a project, I say add a tab under Baseball titled 'Space Exploration' or something. Once you click on it, you're faced with this:
1. In order to get started with space, you must build a research facility. $100,000,000 + 10,000 steel + 5,000 aluminum + 2,000 gasoline (etc. this will also help stimulate the economy with prices dropping day by day).
2. Once you've unlocked the space center, you now must spend money and resources on building a rocket. (If you want to play off of the baseball mechanic, you could upgrade your facility and be assigned researchers that you can pay to upgrade. An upgraded facility can lower the initial investment cost of rockets and higher skilled researchers will increase the rockets chance of success)
3. Once you have a rocket that works, you can do some of the following;
- Launch a military satellite
Nukes now require 10 MAP's to fire, 30% resistance to spies, +30% increase in personal spy effectiveness, (and more, these are all just suggestions)
- Launch an asteroid mining device
- Now you can mine from asteroids! Expand from cities but watch out for missiles(?)
- Start building a Space Station
- Cool in theory, can't think of any details
- Colonize the moon / mars!
- Build cities on the moon and possibly open up to new resources? Maybe each nation that makes it to the moon or mars can unlock a second nation? Like a sub nation linked to their original profile. New resources, new market, new alliances.
All in all, I feel this has a lot of potential to hook old players and bring in new members.
Offers a something for everyone style, almost like a massive DLC.
Old players will have something new to invest time and money into as well.
Stimulates the in game economy
New opportunities for VIP perks.