Matt Levine has discussed similar theme for sub surface gold on earth[1]. NatGold is the company mentioned which tokenizes that.
Obviously pre-mined should trade lower than earth mined gold. Price should be something like Earth gold pricing- mining cost - cost to transport back to earth (or location based prcing, we are some time away from space based economics). Basically you will be trading rights for mining for a particular space mine.
If there is iffy interest coverage for the debt and assets might be a stretch to cover (principal + interest), why will someone sponsor the debt here ?
Also, rates seems to be high, at least compared to recent history, to be favorable for this kind of LBO.
If nothing else, at least these should be choice of users to let them choose based on their values and requirements.