In a previous post I described the pros and cons of using rockets to deliver raw materials to orbit. And, in the post before that, I explained that this part of a series of posts discussing the best ways to amass raw materials in orbit needed for space development. In this post, I will discuss the pros and cons of using mass drivers to accumulate a resource base in Earth orbit.
The biggest advantage to using mass drivers is that they are very efficient. That is, once they are set up and functioning well, no fuel is required to launch payloads into orbit. In theory, the mass driver can launch hundreds of times its own weight using only electricity.
Furthermore, extensive research has been completed on mass drivers, and their earthbound cousin, the railgun. The Space Studies Institute and Gerard K. O’Neill himself built a small mass driver in the 1970s basically proving that this idea will work. And today, the US Navy is working on an electromagnetic railgun to fire artillery shells which is basically a mass driver.
In practice, however, one cannot be sure that a mass driver will function as promised. It is, after all, a machine and machines require maintenance and upkeep. I am skeptical that mass drivers can function anywhere near their peak performance without a human presence on the moon to maintain them.
Which brings us to the biggest disadvantage to using mass drivers: they require a massive upfront investment in infrastructure. This infrastructure includes not only the kilometer-scale mass drivers but also megawatt-scale power systems (probably nuclear due to the long lunar nights – which means additional headaches), loading machinery, canister processing machinery and all the subsystems needed to make this structure work. Essentially, one must build a minor lunar base in order to construct, and possibly operate, a mass driver on the moon*.
So, bottom line, mass drivers are extremely efficient, but require a massive upfront investment in order to work.
*The fact that a mass driver may require a lunar base could be construed as either a positive or a negative, depending on one’s point of view. Positive because, hey, who doesn’t like moon bases, right? Negative because moon bases are expensive and, in this case, would simply be an overhead cost as we establish our raw material delivery system.