What follows is a simplified path to developing small space settlements in equatorial low earth orbit (ELEO): a space settlement roadmap.
Specifically, what is laid out here is the path to building a hotel/facility/large space station (call it what you will) that could, theoretically, be converted into a settlement where people permanently live. It’s not the ideal settlement, as it will still be a bit cramped, but it could work.
The reader may want to read previous posts here, here and here to obtain some helpful background information.
New scientific research, new launch technology and new commercial developments are overturning long-held beliefs about orbital space settlements. Space settlements no longer have to be massive kilometer-long structures requiring asteroid mines or moon bases to construct. They need not cost trillions of dollars and mass billions of tons. And they don’t have to be located at the Earth-Moon Lagrange points.
Instead, the aforementioned developments indicate that space settlements can be much smaller: roughly comparable in size to the International Space Station (in terms of length of structure, not volume). Such small settlements could feasibly be built using materials boosted up from Earth. And they could be fabricated and assembled using additive manufacturing and telerobotic techniques that are being developed in space right now.
Bottom line, a small orbital space settlement – literally a village in space – could conceivably be built in the next ten years, assuming certain key technologies are successfully developed. Let’s see how (in very broad brushes. Warning, lots of hand-waving here, this is for brainstorming purposes only):
Step 1: Build and launch a cubesat probe to ELEO to characterize and confirm the radiation environment.
Step 2: Establish a 3D printer business at the ISS to manufacture cubesat components. Customer: small sat mega constellation operators. Note: Made In Space is already basically doing this, except with NASA as customer, not sat operators. Ways to minimize need for astronauts to do the work: design and deploy a telerobotic rig inside the space station to operate the 3D printer remotely from earth. Feedstock can be delivered remotely as well, via the soon-to-be installed Nanoracks airlock. If this 3D printer/teleoperated rig is too big or in the way, rent space out in the essentially unused and uncrewed BEAM module (although access/logistics to/from this module may be tricky).
Step 3: Develop a larger, more capable 3D printer/telerobotic rig for use outside the station in vacuum. Again, Made In Space is already working on this. Provide more and better services for the satellite operators.
Step 4: With revenues from the ISS-based fabrication facility, raise funds to 3D print and telerobotically assemble a scale model of the key components of the eventual first settlement. Make a proof of concept for rotating ring-hubs, elevators, airlocks, etc. Maybe even fluid management parts e.g. active thermal management system. Test printing and assembling more complex parts like solar panels.
Step 5: Attempt and then successfully 3D print and assemble an inter-orbital transfer vehicle to transport vehicles from ISS to ELEO 500km. Fueled with propellant gun-launched to ISS orbit from Earth (same as how 3D printer feedstock gets to ISS). This could be a more robust and long-lived version of ULA’s ACES vehicle.
Now the hand-waving really picks up:
Step 6: Leverage existing revenue streams, raise funds to 3D print and assemble the hub and support bus of the hotel (future posts will show a graphic of the hotel/settlement being described here). Transfer this so 500 km ELEO using the dedicated inter orbital vehicle manufactured in step 5.
Step 7: Using the 3d printer factory in the hotel/settlement hub, 3D print the remainder of the structure: the minimum viable product necessary to begin crewed operations in 500 km ELEO. The hotel/settlement is modular and can be expanded as needed up to its design capacity of 70 persons.
Subsequent posts will describe the geometry of the hotel/settlement described above as well as an innovative funding mechanism to pay for steps 1 through 4 (by which time hopefully the facility is raising enough revenue to leverage in order to obtain the really big money needed for steps 5 and 6).