Rockets are wrong
One of the first science fiction stories that I read, and absolutely loved was Web Between the Worlds by Charles Sheffield. One of the protagonists is Darius Regulo who runs a fleet of rockets, he’s a shipping magnate essentially. On his desk are various light up sayings, one is “rockets are wrong”. He goes on to explain why and in the process sells the idea for a space elevator. The book was read a long time but the quote has stuck.
The problem with rockets is that they are expensive and really touchy, SpaceX are doing wonders with getting the price down but they are always going to be complicated beasties. I also think that they will also always be necessary as well. I do think that there is another option that needs to be explored for the low earth orbit version of the freight train.
Sometimes you just need to move big lumps of stuff around cheaply. So much work is done to optimise anything being sent to space not only to reduce the mass of complex components but also the resources that it uses. Ion drives are a good example of this.
In space energy is essentially free, until you get a long way from the sun at least. If you wanted to very simply propel something from one place to another you get a load of water and a parabolic mirror to heat it up. This doesn’t happen at the moment because water in LEO or anywhere else in space is very rare and valuable. Rare because getting it there is expensive and valuable because oxygen and well water are both useful things for people.
One other key fact about water and many other materials and resource is that its quite hard to break. This may sound a little flippant but the fact is that you can subject it to as many G’s as you want, where as people and satellites are a little intolerant of anything more than 8g or so.
So here’s my version of the catch phrase, “Rockets are wrong, for some stuff”. Not quite so catchy but still.
Space elevators are hard, its going to be a while before anyone builds one. In the mean time we need a way of very cheaply getting lots of raw materials into LEO.
Enter the space gun. Which to be quite honest I love if only because of the name. The principle is simple, escape velocity is 7200 m/s, stick something in a damn big gun and shoot it out at that speed. Now obviously this is not something you are going to do with people because, well, jam. But as I said water is hard to break.
One of the most interesting version of this idea is the Quicklauncher project. The idea being that instead of building the supporting structure for the gun barrel you float the whole thing under the sea and only expose the muzzle at the surface.
The initial costs quotes by the project are a “10 Million two year project to launch to orbit a 1 kg payload each time”
With current rocket costs, 1 Kg would cost you something like $20,ooo to get to orbit. If you can build a gun that can do that all day, day in day out that going to add up pretty quickly.
Large amounts of cheap material in LEO will make a huge difference with any project being planned. I really don’t know why this option isn’t being explored.