Other places where the costs of making a inhospitable environment tolerable for humans turns out to be a HUGE percentage of the costs.
For Example ... Imagine super deeply buried nuclear power plants, run entirely by robotic AI. You run it for 50 years or 100 years, you keep the waste down there, and then in the end, seal the hole.
What about robotic based deep sea waste burial? take the waste DOWN deep, dig a deep hole, bury it. Contamination potential is pretty small that deep. BUT nearly impossible for HUMANS to do, but not that hard for robots.