In the future, we're gonna be doing all kinds of industrial activities in space.
To get there in the short-term, we'll need lots of energy. Mostly rocket fuel. Rocket fuel can be surprisingly simply. It's mostly a mixture of liquid oxygen and hydrogen. Both elements by themselves combust violently. These components can be found in water. Undoing the chemical bonds of water molecules isn't hard, it just requires some energy. This is where land-based photovoltaics come in for the initial boot-strapping steps required for the kinds of inter-planetary industrial activities I'll be discussing here.
Once an orbiting manufacturing plant has been established, construction of inter-planetary robotic vehicles can begin.
Getting the components for automated manufacturing into high-earth orbit will be pretty expensive. That's what the rocket fuel is for. Once the bootstrap plant and initial raw materials are in place, this step will not need to be repeated.
Robots will mine asteroids in the solar system for precious metals and also for raw material. Primarily, the raw material will be used to construct heat shields, photovoltaic cells, and of course more robots.
The precious metals can be collected into orbit around the planet, and heat shields fabricated and deployed to protect payloads from burning up during re-entry when returning to the surface of Earth.
Space-faring asteroid-mining robots will be comprised of several components.
First, ion thrusters.
Second, photo voltaic cells.
Third, onboard battery cells, charged by the PV cells.
Fourth, onboard computer system.
Fifth, some sensors including radar, thermal imaging, radioactivity gauges, video cameras, and audio recording devices.
Sixth, a payload container.
Seventh, robotic arms wielding drills and grasping apparati.
The stored electricity in the batteries will be used to power the thrusters, onboard computer systems, sensor arrays and mining tools.
There are lots of complicating factors at play here. Each complicating factor is an opportunity for a whole new industry in addition to the asteroid mining industry and the high-earth orbital robot manufacturing industry.
For one, there is currently a crisis developing in the mid-earth orbital regions above our planet. Over the past few decades, various space agencies have launched over a dozen thousand satellites, into low, mid, and high earth orbit. Those agencies have been able to collaborate to keep track of all of these projectiles whizzing around above our heads at thousands of miles an hour. Unfortunately, every once in a while, a satellite which loses its ability to steer itself, or which never had such an ability, will collide at high speed with another object. This creates hundreds or thousands of smaller projectiles also spinning around at thousands of miles an hour. It is nearly impossible to accurately track those particles. When those particles eventually collide with other satellites, even more debris is created, and it quickly becomes mathematically impossible to track that debris.
Soon, a point of no return is reached, and debris is flying around at extremely high velocities in random directions violently colliding with other objects in space, creating more and more debris in a chain-reaction. Eventually, mid-earth orbit where most of the current satellites are deployed will become entirely filled up with high-velocity debris.
It will soon become impossible to travel into this region of earth orbit without experiencing a high-velocity collision with some debris from previous space vehicles.
At those velocities, any collision with debris no matter how small will be cataclysmic and will cause complete destruction of any vehicle in its path.
Getting material into orbit to build a manufacturing plant will be nigh impossible with a barrier of other material spinning around the planet like space piranha.
In order to fix this, an entire enterprise dedicated to the removal of such debris material from orbit will be required. It will be necessary to create orbital robotic garbage collectors whose responsibility it is to seek and intercept all debris in orbit, and force this debris down back into the atmosphere where it will burn up upon re-entry, avoiding collision with any other satellites or vehicles along the way.
Once the initial debris is cleared to the point where travel back and forth from the surface to crucial locations like the mining robot manufacturing plant in high-earth orbit and the material collection station from which return-to-earth drops will be initiated, there will need to be a continued enterprise of garbage collection and orbit decay management.
Such vehicles can be surprisingly simple. They may be comprised of these components:
First, ion thrusters for maneuvering.
Second, PV cells.
Third, onboard battery cells, charged by the PV cells.
Fourth, onboard sensors including radar and infrared imaging.
Fifth, onboard computer system for navigation, trajectory tracking, and object identification.
Sixth, rudimentary docking ports and shock absorbers for low-speed contact with debris once a speed and attitude match has been acquired. (This might also be done with electromagnets.)
These robots will basically perform tugboat-like maneuvers for vehicles, satellites, and debris in space orbit around the earth and other bodies where inter-orbit travel is necessary.
Once a solar-system raw material supply chain is established, the large-scale boot-strapping of the planet's surface energy harvesting apparatus can begin.
This initial step is necessary to acquire the energy necessary to begin large scale inter-orbital construction of larger and more effective solar-energy harvesting infrastructure.
Long-term, there will be many obstacles to success for our civilization due to its ever-expanding population.
Jevon's Paradox states that no matter how many energy and technological advances our industrial system makes, there will be an ever expanding consumption of the surplus energy generated by such efficiencies.
What this means for our civilization is simple, if we are to avoid an Eugenic struggle amongst our own species, then we must develop a number of efficiency maximizing technologies, and soon.
These include room-temperature super-conductors; super high-capacity, super fast-charging batteries; ever more efficient and cheap solar photovoltaic cells; and eventually some form of inter-stellar travel.
If we do not, then our civilization is doomed to self-cannibalization. There will be an upper limit on our ability to produce new energy and effectively utilize it across an ever-expanding population.
The sooner these old-school, baby-boomer, ignorant lawyer politicians in the House of Representatives who want to continue to underfund NASA's budget get voted out of office, or just die, the better.