Will 3D printing help make spacefaring a common industry?
It seems to be a pretty sure bet that 3D printing will be a fundamental element of spacefaring logistics.
Planetside, industrial casting, forging, and extrusion systems are vastly more efficient, and produce stronger (and more precise) items than 3D printing systems, at least for the next decade or so. That said, the real world often sets a high exchange rate for flexibility over efficiency (and absolute tensile strength); the necessary capability at the right opportunity can mean life over death. Current 3D printing capabilities compare to mass production methodologies (casting, extrusion, etc) much the same as a Leatherman (“multi-tool” to the uninitiated) compares with a dedicated set of tools… The Leatherman does 17 things (or more) poorly, but it can be extremely useful in a pinch. Most people don’t or cannot carry a full set of tools around with them, but a Leatherman fits in a pocket, on a belt, or in the glovebox. Thus this “Leatherman flexibility” will undoubtedly be a boon for space-going operations. There are plenty of old (and new) Sci-fi stories wherein warships carry stores of raw materials with them (or the reuse damages material) and simply produce armor and tech as needed after battles, as opposed to heading back to port for ‘proper retro-fitment’. But much like the Leatherman analogy, proper retro-fitment is often provided via the less flexible means of dedicated production methods.
For those folks living in a Technotrogloditic cave, here are some of the basics (feel free to update or correct me, with links, in the comments section):
Overview of 3D Printing Tech/history:
Most folks are surprised to learn 3D printing has actually been around for decades. Obviously the ‘stacking layer upon layer to construct things’ method is pretty old, having been employed by humans long before the pyramids in Egypt :-). Printing objects in three dimensions has been around since at least 1980. when one Doctor Kadama in Japan attempted to patent an RP method (he failed to complete his filing though). Six years later, Chuck Hull, the pioneer of modern production 3D printing, was issued his Stereo Lithography patent. While the idea was demonstrable in the early 1980’s, 3D printing was not practical across the broad spectrum of industries, scales, and methodologies until some fundamental technologies really matured (became ubiquitous commodities), including micro-controllers, digital stepper motors, computing power, accessible software (i.e.; open-source software), and the Maker Movement. These elements all had some time to stew, reach their respective critical masses, and then poof: The hockey stick of 3D printing ubiquity arrived around the same time as Doctor Bowyer’s open source RepRap project, somewhere during the first decade of the 21st century. I consider the explosion of desktop 3D printing to be the pivot point. There are plenty of reasons for this, but my primary reason is simple: lots of Gen-X’ers and their kids could afford to buy or build, operate, and repair their own systems. As of this writing, at the end of 2015, you can build a functioning 3D printer for less than $100USD. And those kids? They will grow up thinking 3D printing is as normal as hockey in Canada, hotdogs and fireworks on Independence Day, or firecrackers and dragons on Chinese New Year. These are the same kids who have never had to ‘dial up’ and have only ever used “smart phones”. As these “Millennials” grow up, they will greatly expand the spectrum of 3D printing. There is little doubt the Replicator of Gene Roddenbury’s Star Trek will happen, and it will happen a lot sooner than most people probably realize.
I think desktop 3D printing is the area to watch for space-going 3D printing technologies and methods, the reasons are indicated below. Here is an overview of this type of printing:
In a nutshell: Desktop 3D printing is 3D printing geared for the masses. Typically these printers are small, about the size of a large home printer. Like their industrial brethren, most designs for desktop models use the 3-axis stepper motor design. With a rectilinear structure, X/Y/Z stepper motors move a gantry back and forth to lay down layers of plastic, once a layer is complete, the gantry is raised (or the bed/table is lowered) and another deposition round begins. There are several other interesting methods, and some seem ideal for work in space. Desktops most commonly extrude and depositing layers of plastic on a bed or platform (the term Fusion Deposited Modeling or FDM, refers to this method). The most common materials used include ABS and PLA, the later of which will biodegrade after some reasonable amount of time. There has been a sub-revolution in printing materials, and while a decade ago the material options for FDM were essentially limited to ABS plastic, ten years on there is a wide gamut of materials available.
The Desktop scene has become an incredibly crowded market, this has greatly driven the prices down and the list of options up. While printers in this realm are accessible and moderately affordable, lower precision and strength of printed results (due to less quality and environmental controls, and reduced operational expertise), along with the fairly slow output speed of these printers, relegate them to hobbyists, primary schools, and maker-spaces. None of this should be confused with a lack of appreciation for desktop 3D printing: It has come a LONG way in a short period of time, and it is getting significantly better at a crazy-impressive rate. Indeed, if you want to enter the world of 3D printing, this is where you start. A great overview of the technologies now available is over at 3dPrintingFromScratch.com.
One area not yet common to desktop printing, which will need to converge with it, is 3D Metal Printing. Think of this as Metallic Frosting, basically a paste of [pick your favorite] metal powder mixed with a resinous liquid to form a heavy viscous paste. To build items or parts, the paste is typically extruded (essentially in the same manner as one would extrude its namesake onto a cake) by depositing a single layer at a time, with fairly high precision. The resinous material, which allows the matrix to flow, is then hit with an ultraviolet light to cure (harden) the resin, thus locking in the shape of the part. Then, the entire part is baked at a temperature high enough to fuse the [pick your favorite] metal powder… this temperature is high enough to burn off the resin. The result is a metal item with a structural integrity/strength of a “sintered” metal component (gear heads might recognize these parts as being very similar to sintered bronze fuel filters). These items are not especially strong, though they are very strong in comparison to other 3d printed items… However, I have yet to see a production or race car with sintered crankshafts (though powered connecting rods and camshaft lobes are very common). While the best engine crankshafts and helicopter swashplates are made of machine milled/turned high grade billet metals, or non-twist forgings of those same metals, some great things have been done with 3D printed metals, such as jawbone replacements and other really amazing medical uses (including printing actual bone).
Industrial Design, Production, Multi-Material, Exotic and Organic Material, and Structural (and Fiber) printing are evolving at a rapid pace. As they do, we will continue to see elements of them trickle down into the Desktop printing market. This is compelling because printing in space will require compact, highly flexible systems, which provide the ultimate in durable reliability, and on-site repairability by its operator(s). Interestingly, the desktop 3D printing category is being tested, optimized, and refined at a much greater rate that more expensive and exotic production printing systems. Think about the giant laboratory which Desktop 3D Printing represents: Thousands (and soon millions) of people, not restricted to industrial utility, age, or profession, are banging on these small inexpensive machines in an unstructured and/or self organizing matrix. This is improving the breed at a rate difficult to match with a structure development plan. And the cool thing is: Desktop, as indicated above, benefits from structured development as well, be they government (DARPA) or corporate (3DSystems, medical/aero/automotive industries) efforts. NASA has already added a desktop printer to the ISS toolbox, and while it is experimental at this point, printing significant portions of Space-station or Spaceship Components in space will surely happen, and it will likely happen within the next 10 years. NASA has also printed copper rocket engine components, and while this was done with highly specialized equipment, it is a big step toward demonstrating the ability to manufacture critical components in the isolated confines of deep space.