How to manufacture spare parts in orbit

In his book, Men from Earth, Buzz Aldrin relates one of the many ways in which the Apollo 11 mission narrowly avoided disaster:

We discovered during a long checklist recitation that the ascent engine's arming circuit breaker was broken off on the panel. The little plastic pin (or knob) simply wasn't there. This circuit would send electrical power to the engine that would lift us off the moon...We looked around for something to punch in this circuit breaker. Luckily, a felt-tipped pen fit into the slot.

Three men were spared a slow death on the moon's surface, 200,000 miles away from their homes, but for the help of a flimsy plastic pen.

The modern astronaut's typical hardware dilemma is a bit less dramatic, but occurs with much higher frequency. During its construction and years in service, the International Space Station has required countless parts to be sent from Earth. Its supply and repair missions have drawn a tremendous amount of resources from the shuttle program, and with that winding down, guided NASA's plans to fund privately run resupply missions going foward.

Some ISS repairs can be carried out immediately by crew, with tools and parts available onboard. For everything else, they have to call in a delivery--an expensive, and not always timely, proposition. But what if parts could be manufactured on orbit? A new company called Made In Space claims that NASA could--and should--adopt technology that lets astronauts do exactly that. Space.com reports:

Made in Space wants to launch 3D printers into orbit and use them to make parts for spacecraft and space stations, which would be assembled in zero gravity.

3D printing technology has been around for a while, ranging from lab-grade rapid prototyping devices to homebuilt plastic printers for hobbyists, like the MakerBot. The printers Made In Space is hoping to adapt all use the same printing method, called additive manufacturing, in which layer upon layer of material--often ABS plastic--is repeatedly deposited to create a finished object.

The advantages of creating parts in space are manifold. Launching parts, or anything, really, into orbit is extremely expensive, and in an emergency situation assistance from Earth can be a long time coming. Made In Space, which claims to have already built aerospace grade parts using existing technology, will soon begin examining which rapid prototyping products are most suitable for use in zero gravity.

Since the parts would be printed from plastics, their applications will be limited. And, as critics will immediately point out, the raw material for printing, called feedstock, must be launched somehow, too. Made In Space makes the case that the material, stored in liquid form, is easier to transport than pre-made parts, some of which must be specially designed to withstand the stresses of launch.

Beyond the ISS, the company thinks this concept has value to longer term projects as well: evidently, certain types of lunar soil could be used as a feedstock, making 3D printing feasible for a potential moon settlement.

Should the company move forward with its plans, though, the results will likely be modest. 3D printers as we know them now are small and limited in the types of materials they can use, able to create small, precise, sturdy-but-not-strong objects.

Like, let's say, a plastic pin on a circuit breaker.

Image of the Thing-o-Matic 3D printer courtesy of MakerBot Industries

This post was originally published on Smartplanet.com