> Ground based mirrors are very large, in the 10s of meters, and those mirrors are extremely heavy, like tons.
Seemingly fantastically - SpaceX is currently constructing a system designed to launch 100 tons to LEO, for as low as $35/kg [1]. Musk says this capability is what the Starlink business is to pay for. It appears lately, more realistic than it has sounded.
One of the things I'm most excited about related to Starship is its landed mass capability for science purposes. Imagine being able to build radio and optical telescopes in the Daedalus crater on the central lunar far side. They'd be shielded from the optical and radio noise of the sun for 2 weeks out of 4, and permanently shielded from Earth. Or imagine infrared telescopes at the bottom of permanently shadowed polar craters, where ambient temperatures are even colder than in interplanetary space. No need to design and deploy a complex sunshield and worry about maintaining spacecraft orientation. The science potential of reusable heavy-lift rockets can't be understated.
Seemingly fantastically - SpaceX is currently constructing a system designed to launch 100 tons to LEO, for as low as $35/kg [1]. Musk says this capability is what the Starlink business is to pay for. It appears lately, more realistic than it has sounded.
[1] https://caseyhandmer.wordpress.com/2019/10/29/the-spacex-sta... ( https://news.ycombinator.com/item?id=21397285 )