CubeSats are miniature, lightweight satellites used for space research, earth observation, telecommunications, and a wide array of other purposes. Typically, they have a lifespan of a few years before being decommissioned by letting them burn up in the atmosphere upon re-entry. They are produced in low volumes, are of very high value, and often highly customized to their application. Since CubeSats pose little to no harm to human wellbeing, they are part of an industry that is not highly regulated and therefore allows for a lot of customization and innovation. To ensure CubeSats will not negatively affect other satellites or hardware, both during launch and while in space, quality CubeSats adhere to a strict set of design specifications such as those originally published by Cal Poly SLO. This also limits the size and weight of CubeSats.

Traditionally, the frame enclosing a CubeSat is made from aluminum; one of the lightest materials suitable for space. Weight is a very important factor in the CubeSat industry, as launch costs are determined mostly by weight rather than volume. Compared to polymers, aluminum is relatively heavy, and disintegrates slower and produces more volatile space debris when the CubeSat is decommissioned. 

Frames made from high-performance polymers, such as PEEK are more desirable alternatives to aluminum frames due to their lightweight, low-density properties and high strength-to-weight ratio. However, these polymers are often very expensive, especially when considering the waste produced during traditional manufacturing. Like aluminum frames, these PEEK alternatives are created using CNC milling and machining. These are subtractive processes where a lot of material needs to be removed to cut the desired shape out of a block of raw stock material, creating expensive waste. In addition to wasting resources, these traditional manufacturing methods face other limitations as well: parts can only be completely solid, have limitations when it comes to detail depending on the available tooling, and the process is not ideal for the creation of many variants or small batches, since the machines used need to be reconfigured for every different part.

An alternative method for using high-performance polymers is 3D printing, also known as additive manufacturing. For the production of CubeSats, the “Fused Filament Fabrication” (FFF, also known as FDM) method is the most promising, even though there are a number of other popular additive manufacturing methods available, such as Selective Laser Sintering (SLS). FFF processes can manufacture a variety of parts using a wide range of thermoplastics, including PEEK, ULTEM, or PC, with very little waste. This is an important distinction from SLS, which is often wasteful with raw resources and the material choice is much more limited. 

Until recent technological advancements, using an FFF process to produce high-quality parts out of these high-performance polymers was quite difficult. Many additively manufactured parts, especially those made from PEEK, often suffer from “delamination”. This means that the fused layers that build the final shape are not properly welded together. These faulty PEEK parts behave more like a stack of loosely connected slices than as a continuous whole. These uneven mechanical properties are referred to as “anisotropic properties” and are a common problem in printed parts from many manufacturers. 

In addition to reducing complexity, more weight can also be saved by leaving parts of the component hollow. The material on the outer sides of a part is the most crucial to providing the necessary strength, whereas the inner material merely provides a way for those walls to connect. Removing most of that inner material is a great way to reduce material use and part weight, and is easy to do with FFF processes. Where, for instance, SLS-made components require either one open side to the cavities, or require the parts to be fully dense, FFF processes allow parts to fully enclose hollow shapes. The resulting air pockets do not produce issues when using these parts in space; after all, foams are often used on spacecraft as well. 

To ensure that the printed CubeSat parts would survive in space, parts printed using Orion’s A150 machine were tested at the ESA-ESTEC laboratories. A simulated space environment exposed the printed components to an UV exposure, equivalent to 3,4 times the solar constant, and vacuum, similar to what CubeSats experience every day. This was followed by thermal vacuum cycling, switching between -100°C and +100°C. Even after exposure to these simulated space challenges, there was little to no change in the material properties of the parts, and the components remained functional.

Conclusion

Using a cutting edge additive manufacturing process with Orion’s Thermal Radiation Heating system, it is possible to reduce the mass of a CubeSat’s frame by up to 50%, while maintaining the same strength and adhering to the same tolerances and requirements as more traditionally produced components. Parts manufactured this way have proven to withstand the challenges of space, and can reduce the launch cost per CubeSat by up to €25.000,- or can lead to larger freedom in payload selection and weight without compromising functionality, launch cost, nor safety, because of the highly isotropic properties of components printed using Orion’s Thermal Radiation Heating system.