[Michael Thayne]

Some math that may be useful for designing relatively hard sci-fi settings.

Spaceships 2 gives the interface rate (cost of launching stuff into orbit on an Earth-sized planet) of $50,000 at TL9. This appears to be based on assuming something like the Conestoga-class heavy lift vehicle, and that such a thing is reuseable. It's not obvious from the description that the Conestoga is in fact reuseable, but the math checks out: fully fueling it costs $6,000/ton x 13 fuel tanks x 50 tons/tank, or $3.9M. It carries 80 tons of cargo, so that's $48,750.

Now what if we replace the HEDM rockets with laser rockets from Spaceships 7? Ablative plastic costs $80/ton, so fuel cost drops to $650/ton. Unfortunately, we'll need two 1TJ lasers to get it up there. As SM+15 major batteries, these will cost $15B each. If powered by fission reactors, those will cost $10B each. Spaceships 2 suggests the costs of running a spaceship—or, presumably, a laser launch facility—can be handwaved as 1.5% of purchase price per month, including bank payments. That's $750 million per month.

After that, the question is how many launches you can do per day. Spending the entire delta-V of the Conestoga can be done in just over 6 minutes. It can't be used 100% of the time, let's say you manage an average 5 launches per hour (perhaps more in peak hours, with it lying dormant in early morning). That's about $200K per launch, or $2,600 per ton. That's $3,250K with fuel costs. That's notably less than what Spaceships 2 lists at the price for a trip on on a TL9 space elevator, though less than it lists for a TL10 space elevator. Not sure what that means, since I'm not sure where the space elevator numbers come from, but if you don't like the TL10 number, the laser-lift number is good to know.