There is currently no alternative to rockets for getting cargo into orbit. However, it is incredibly expensive to launch rockets. Even now that SpaceX has developed ways to reuse the first stages of rockets still costs tens of millions of dollars per rocket launch, and the cost of delivering 1 ton of cargo into orbit, although gradually decreasing, is still a fabulous cost and does not allow you to dream of serious astro engineering projects.
Not many people know that there is a whole direction in space engineering engaged in development of rocketless delivery of cargoes to orbit. One of the methods of such cargo delivery is the space cannon.
The space cannon is essentially an ordinary cannon that takes a projectile into orbit by shooting it upwards along a ballistic trajectory. This idea is extremely simple and was first proposed by Jules Verne in his famous novel “From the Gun to the Moon.
However, it is not that easy to implement. The first attempt to build something like this was made in Nazi Germany. The aim of the Vau-3 project was a huge artillery gun with a barrel length of 124 meters. Of course, the purpose of the VW-3 was purely military — to bombard London from the French territory, but calculations show that with its barrel pointing vertically upwards, the projectiles could reach heights of 110–120 kilometers, which is above the generally accepted boundary of space, i.e. theoretically this gun could be used for suborbital space launches. Several examples of the VW-3 were built…
