So, to start the question, I want to have a small assumption here:
Let us assume that we are an interplanetary civilisation. We have spammed much of the Solar System, but it is not all sunshine and flowers (if it was, I would not be asking this question). According to Atomic Rockets, the first two steps for a Space Force are strategic assumptions and goals, which I will provide an example for very soon. But first some more context on the assumptions for this situation.
You have a growing insurrection on Mars, the Belt, the Galilean Moons and the Saturn Moon System, with Mars having a population more than 700 million, the Belters having 160 total colonies, which combined make up a population of 40 million, while the combined Outer Solar System populations are basically around 100 million.
Now, the problem is......those 840 million colonists are NOT wanting to stick with the 12.9 billion people on Earth, mainly due to growing secessionist sentiment, Earth getting desperate for phosphorus deposits on Mars, Deimos and other C-type asteroids, which are controlled by various large corporations, whom also dominate other industries, in addition to the mining of phosphorus, a growing cultural divide, and failed negotiations between the UN, its member states and autonomists.
We also have a combined threat of "pirates" in Cislunar Space, Martian orbital space and the Trojans, which also host a lot of black market activity and is often a terrorist haven.
And finally, we have the problem of spacecraft permits, since civilians can now get their own spacecraft, albeit with some degree of expense, not to mention bureaucracy.
This gives the UN's space forces four key priorities:
- Protect commerce to keep the phosphorus flowing to Earth.
- Enforce the laws and regulations of the UN's member states and UN treaties on international law.
- Ensure that asteroids are not able to smash Earth.
- Power Projection to crush any potential uprisings.
Another thing I should point out is that most UN space force assets are contributions from UN member states, with it only being mandatory in the event of an emergency (such as the ongoing uprising), while the UN itself keeps a small directly controlled cluster, and three Espatier divisions (Espatiers are basically space marines) to deal with goals 2 and 3 (at least for now).
To be clear, the UN's member states of the planet with settlements and thus, space forces by order of interplanetary influence are:
- United States
- European Union (mainly British, French, German and Italian, with the ocassional settlement by other EU member states)
- The Gulf States (under the Islamic Space Alliance, led by Saudi Arabia)
- Latin America (under the Pan American Space Organisation, led by Brazil)
- ASEAN (led by Indonesia)
- South Africa
These nations and space alliances all have space forces, and can enforce laws and regulations within the colonies, so long as they comply with international treaties, even though the UN member states have fought armed conflicts against each other in space via proxy prior to 2367, but since then, the UN has been more influential.
As for the UN member states, I should point out that although they all have national interests at heart, they do agree that independence for the colonies in a total sense could spell disaster, especially the Big 5 (previously, the Big 6), even though they also have autonomist sympathisers, though mainly moderate autonomists. This proved to be a factor in failed negotiations with the autonomists, which in turn, led to hostilities becoming more official as secessioonists became more and more radicalised. However, since we are focusing on both the unofficial and official state of hostilities, we need to account for the autonomists playing a role.
Given that, will the capabilities of the UN space force be efficient in performing the specified goals, especially with the basis of its assumptions (both in terms of security and fiscal environments), especially goals 1 and 4, as the undeclared war becomes less and less undeclared and more official? More importantly, how can it operate efficiently under its security concerns and fiscal restraints?