If numbers get repeated often enough, like in this gallery of commercial space opportunities, they start to be believed. Business 2.0 as part of a big spread on space investment opportunities in their March cover story retells some whoppers.

Space Hotels: $5B/year by 2015

This is inconsistent with Futron and world launch capabilities and expense. First let’s see if someone wins the America’s Space Prize. Expensive travel means very little revenue. By 2025, very possible if space access costs drop. $2M/month would get a lot of takers if we can get 600kg worth of people, spaceship and consumables to orbit at $3000/kg including payload. A Progress at 2000-3000kg of payload lasts 2-3 months with three eaters.

Mars: $400B in exploration by 2030

If you just put NASA spending in line with US GDP growth and put 12 years of it to “Mars” you get about $400B.

Orbital labs: $10B/year by 2015

NASA can’t even come up with a business case to finish ISS. So far the only demand has come from Greg Olsen so he could take a tax writeoff on his vacation. Hmm, maybe it will be a conference destination.

Solar sats: $100B/year by 2020.

You have to beat the marginal cost of hydrocarbons to make money on this. Julian Simon’s Ultimate Resouce 2 indicates heavily against this. Methane hydrates, coal and uranium would have to be taxed to a standstill (which is not impossible) for this to be this big. Space elevators flip it.

Space elevator: $2B/year by 2021

If it works much bigger. It will probably be bigger than solar sats or asteroid mining. Without competition, almost all profits from solar sats and asteroid mining will accrue to the elevator owner.

Asteroid mining: $10B/year by 2030

The space access and demand curve math does not really work except for local consumption in space. But it would be a great place to colonize along with the Moon and Mars.

Moon: $104B in exploration by 2018, $250B in helium mining by 2050

The exploration comes from extrapolating the NASA budget: good bet; the He3 requires us to run out of uranium or patience for it. Not likely.

Microsats: $1.5B/year by 2018

Likely an underestimate as miniaturization, space access costs and dedicated launchers for microsats come into their own

Space Tourism: $1B/year by 2023

This will be bigger than hotels, which is not to say that it will be more than twice Futron’s prediction repeated here. (The factor of 2 selfishly comes from games. The transport to and from the hotel is more expensive than the hotel stay.)