Near-future Space Industries

Many people have written about commercial opportunities in space. The big ones are power satellites (beaming zero-carbon-footprint energy to earth), zero-G industrial processes (things that can't be cheaply made in a gravity field, such as foamed steel), and tourism (I'm looking forward to Disneymoon, and that first Hyatt with an out-of-this-world view).

Another significant opportunity exists in communication satellites and research. It is much cheaper to maintain / repair / service satellites from an orbit near them. It's even cheaper to build them there. Send the expensive components to low Earth orbit, assemble them in space, and launch to a higher geo-synchronous orbit using in-space resources (fuel made from asteroids & comets). It is much cheaper. An asteroid-based satellite assembly factory in a thousand-mile-high orbit could easily perform those functions. Another asteroid near geo-synch orbit could perform maintenance functions.

Astronomers take note: such a space-based satellite assembly factory could also build a really huge space telescope by assembling a collage of launchable mirror segments. Imagine the resolving power and light-gathering capabilities of a fifty-meter version of the Hubble Space Telescope. Add the convenience of a nearby maintenance crew that could swap out new instruments for old, replace failing gyroscopes, perform routine repairs. If desired, the maintenance crew could be positioned permanently between the sun and the telescope to shade it from those pesky thermal cycles due to the contrast between the sun's heat and the cold of space.

In the long run, the biggest space industry is likely to be the same as on Earth: people, their entertainment, their housing, their food and water (and air), and information. As mankind expands into the cosmos, there is no need to make money by sending products home to Earth, just as the economy of the USA is not entirely dependent upon sending products back to mother Europe. An expanding population creates its own wealth as there are always opportunities for us to help one another (and make a buck in the process).

In the relatively near term, supporting Earth's needs will be paramount and will fund the expendables and technologies needed to thrive in space. Soon after, mining, housing, and food (recycling) will be the major industries. But after the space population exceeds some critical threshold (I don't know if it is ten thousand, or a million, or even tens of millions), it will become completely self-sustaining. Expanding humanity's presence in space will become the fundamental driving force of the space-based economy. And from then on, there's no looking back.