Thread by @cstross

I think a self-sustaining colony on Mars within 50 years is bullshit. I'm not even sure humans can survive 12 months beyond the Van Allen belts.

And forget Lunar He3 mining—it's nonsense.

BUT.

Very soon, a whole lot of new industries are going to open up between LEO and L5. /1

Starting with: global low-latency internet broadband from orbit, on a scale that compares to today's comsats the way post-1945 civil aviation compared to the 1918-29 era of mail service in two-seater biplanes.

And then …

/2

PV cells are ridiculously efficient and disgustingly cheap by 1970s standards. If it's possible to make money by farming them in orbit, SpaceX can do it. No need to mine materials and fabricate at L5—shipping up from the ground is viable now. So, solar powersats (maybe).

/3

Note: the reason for wanting orbital solar power sats is that they're not in shadow (night) half the time. Also, they get the energy otherwise absorbed by the atmosphere. *And* they can potentially be used for geoengineering (to address our heat pollution problem).

/4

We also have the opportunity to build cheaper semiconductor fab lines in high orbit—no need for ultra-clean rooms on Earth, just build a working wake-shield system. (NASA's first experiment didn't work right, was never repeated.) en.wikipedia.org/wiki/Wake_Shie…

/5

For space manufacturing, products need to be low weight/high value. Semiconductors are a huge market and fit the bill perfectly. (Pharmaceuticals … maybe, but I see that as a second or third wave space industry. Manufacturing in orbit is overkill for bioisolation.)

/6

A final point: Musk has integrated several key industries that are prerequisites for space industrialization—don't discount Solar City. If it's feasible, he's positioned to go the distance (if he doesn't self-destruct along the way, which is also an option). /7 ENDS