Even at present day, space assets are very valuable:
Our space assets, day by day, are growing by leaps and bounds. It's the value of that satellite to the economy. - Neil deGrasse Tyson
Historically, the US Space Command has been around since 1985, and has played several important roles and undergone restructuring over the years leading up to the 2018 reestablishment. Now, it's especially easy to conjecture that conflict in space will be a distinct possibility. Here is Neil deGrasse Tyson again on a 1967 space treaty:
Now that I'm old and tired, it's just: 'Why should we promise to not kill each other in space when we are not successful at doing that here on Earth.'
As Tyson articulates later, space weaponization is unlikely to start with weapons aimed at earth, for it would be far to difficult too implement. He argues, that conflict will likely start by targeting enemy space assets.
With the motivation mapped out, what then are the hardships of the endeavor of safeguarding space assets? Here is another Earthling's take:
If you give an Audi to the wrong person, and he/she uses it to hurt people, you've just made that Audi a weapon. So, what does it take to destroy something in space? It takes a satellite, a sensor and a maneuver capability. I've just described 90% of the US, Russian and Chinese on-orbit constellations. - General John Hyten USAF Commander
In the emerging theatre of operations that is space, what kind of space force would a state in the world I'm building strive for to protect its space assets, given Hyten's cautionary words that there are many points of attack?
Quality Metric: Solutions that are cost-efficient are preferable to budget-intense solutions. Also solutions that rely on highly speculative technology are weighted-down, and solutions that use better-documented emerging technologies are weighted-up.
- conflict hasn't started yet but will be inevitable
- lead time to build the space force is unknown, at most 10 years
- assume present to near-future technology (near as in a few decades from now)
- Budget is flexible, but quality metric prefers efficiency
- assume we advise a hegemony-esque state that is faces rising powers and rivals having an increasing presence in space but not quite as powerful as the hegemony (maybe that position doesn't sound too bad, but factoring in assymetric warfare threats, the hegemony is also assumed to be alarmed)