With SpaceX launching and landing their 50th rocket, it is interesting to look at what could be the cheapest possible future alternative launch systems that could be developed.
Present-day launch costs are relatively expensive, ranging from $2,500 to $25,000 per kilogram per launch to obtain low Earth orbit. This means that for companies launching satellites, these launch costs become a large percentage of the cost of the entire endeavor. If launch can be made cheaper, the total cost of space missions will be reduced.
What options are currently within technological achievement with current technology? What future technology could help provide humanity with easier access to space in a cheaper and maybe more environmentally friendly fashion?
There are a few options for alternative launch systems at this time, but the most advanced alternatives are either a space gun or a modified ramjet engine. The use of a ramjet engine might not be more effective or efficient, but could be the first step in providing alternatives. Nevertheless, the best alternatives to rockets would be to provide a system that doesn’t utilize propellants and is as close to 100% reusable as possible. This means utilizing new technologies and ideas that have yet to be developed, but have been widely discussed.
One possible opportunity to reduce launch costs and be environmentally friendly would be to build a tower that is tall enough to drop payloads off the top. Therefore, the tough part would be getting the payload to the top of the building as once at the top, the payload could just be dropped off the top into the proper orbit. This isn’t feasible considering that there aren’t any materials currently available that would allow humanity to build that tall. Nevertheless, if humanity could build buildings this tall, there are other cheaper and more feasible options to more affordably launch space vehicles.
If humanity is able to build structures tallied stable enough to simply drop payloads into space, there would also be other feasible technology available such as space elevators or space hooks, would would be more environmentally and economically friendly in the long run. This would be because there would be no large amounts of fuel needed to expend to move payloads into space. That said, these technologies are well defined and designed on paper, but it will take many years for these technologies to get created and become functional. The big concerns are the lack of materials and other design considerations, as well as the immense cost of the construction of these megastructures. Even if it could be developed, it would be a good idea to test the designs on somewhere else, like the moon, rather than on Earth. That said, there might be very few companies with the resources to build these structures when they could become possible.
There are a few reviews of some of these options by Kurzgesagt