No point in wasting resources projecting those costs
The priority is handling the impact hazard.
One is shuttle operations.
Two is ISS.
Three is continuing those capabilities.
Four is impact.
Moon based facilities are the way to handle that.
You can use hydrogen/oxygen; hydrogen peroxide/alcohol; hypergolics; or nuclear steam. Doesn't matter, all show positive benefit/cost by about 300 times over.
If DoD wants to send nuclear power generators to L1 or L2, where they won't fall back to Earth, and are safe from attack, that is okay. But you can't run comet and asteroid detection scopes from there very efficiently.
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