Open Source 3D Printed Satellites: Where Additive Parts Actually Earn Their Place

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  What Open Source 3D Printed Satellites Change, and What They Do Not
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  Printing Processes and the Materials That Survive a Launch
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  Which Parts Still Come Off a CNC Machine
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  Two Traps That Catch First-Time Builders
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  From Open File to Flight Part in Six Steps
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  Printed or Machined: A Part-by-Part Read

A CubeSat is a 10 × 10 × 11.35 cm building block. Stack a few and you have a nanosatellite that fits a rideshare slot instead of buying its own launch. The open source part of the story is the design files: structures, brackets, antenna mounts and deployer interfaces published so any team can cut, print or mill them locally.

Additive manufacturing fits that model because it removes tooling. A printed bracket can carry ribs, cable channels and a standoff in one piece. No mold, no minimum order, and a geometry change costs only a new file. For a student team working to a launch date that moves, that is the whole argument.

What additive does not change is physics. A printed panel still has to survive vibration at launch, hold alignment across a wide temperature swing, and conduct heat away from a radio. Material and process decide that, not the file format.

So the useful question is not whether a satellite can be 3D printed. It is which parts should be. Print the geometry that is hard to machine. Machine the parts that carry load, seal a cavity or set the reference plane for an instrument. Most working nanosatellites use both.

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  Print whenthe shape is complex, the run is one or two units, or the part changes often
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  Machine whenthe part sets alignment, carries launch load, or needs a sealed or grounded face
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  Always verifyprinted flight hardware needs its own test data, not a datasheet assumption

Three processes show up in small satellite work. FDM with PEEK or PEI gives the best strength per gram and handles up to roughly 250 °C, but it prints slowly and needs a hot chamber. SLS with PA12 or glass-filled PA12 is the usual pick for brackets and housings because it needs no support and holds ±0.3 mm on small features. SLA and DLP resins are for mock-ups, jigs and cable routing trials, not for parts that see vacuum.

Outgassing is the first filter, not the last. In vacuum, a polymer releases trapped volatiles that can condense on optics, solar cells and thermal radiators. Printed parts for vacuum service should be baked before integration, and the bake schedule belongs in the build plan. Unbaked PA12 in a sealed volume is a known source of contamination.

Thermal expansion matters as much as strength. Aluminum 6061 sits near 23 × 10⁻⁶ /K. Common print polymers sit several times higher. If a printed bracket holds an optical bench to an aluminum frame, a 60 °C swing moves the two materials by different amounts. Design the joint so it slides, or use a printed part only where alignment is not set.

Radiation is the third limit. Commercial print polymers accumulate total ionizing dose and go brittle. For a one-year low Earth orbit mission the dose is modest and usually tolerable. For a five-year mission in a higher orbit, printed structural parts need shielding or replacement with metal.

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  FDM PEEK / PEIstrongest printed option, roughly 250 °C service, slow, needs a heated chamber
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  SLS PA12best cost per part for brackets and housings, ±0.3 mm, needs a vacuum bake
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  SLA / DLP resinmock-ups, jigs and fit checks only, not vacuum-rated

The structural frame is the clearest case. A CubeSat chassis has to hold a 10 × 10 cm envelope within tight limits so it slides into the deployer, and it carries the launch vibration load into every mounted box. Aluminum 6061-T6 and 7075 are the standard picks because they machine cleanly, anodize well and have published flight heritage.

Any face that sets alignment should be machined. Star tracker mounts, reaction wheel brackets, antenna feed plates and camera boresights all fall into this group. A five-axis cut can hold ±0.005 mm on a bore and keep two faces square to each other in one setup. Printed parts cannot hold that, and shimming a printed mount to fix it adds a joint that can slip.

Thermal hardware is usually machined too. Radiator plates, heat spreaders and cold plates need flat contact and known conductivity. Copper, aluminum and titanium all cut well, and a lapped or bead blasted face gives a predictable interface. A printed spreader has lower conductivity and a rougher mating surface.

Feedthroughs, sealed enclosures and RF cavities round out the list. If a part has to hold helium, carry current or set a resonant dimension, machining is the safer route. GreatLight runs 127 CNC machines across three plants, including 16 simultaneous five-axis centers, which covers this kind of one-off structural work without a tooling charge.

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  Chassis railsmachined 6061-T6 or 7075, anodized, held to the deployer envelope
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  Alignment mountsfive-axis cut to ±0.005 mm, one setup keeps faces square
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  Thermal platesaluminum or copper, flat contact face, Ra 0.8–1.6 μm typical

The first trap is trusting a printed dimension after finishing. Bead blasting, tumbling and dyeing all remove or add material. A printed bore quoted at ±0.3 mm can move another 0.1 mm after blasting. If a printed feature is a locating feature, either mask it during finishing or move the tolerance to a machined insert.

The second trap is forgetting inserts. Threads cut directly into PA12 strip out at low torque. Heat-set brass inserts solve this, but they need a boss with enough wall thickness and a defined depth. Design the boss into the printed model from the start. Retrofitting inserts into a thin printed wall usually means a new print.

A third issue appears at integration: grounding. Printed polymers do not conduct. If a printed housing contains a board that needs a chassis ground, run a machined or plated path to the frame. Conductive plating on printed parts exists, but the conductivity is far below bulk aluminum and the layer can flake at fastener points.

None of this is exotic. It is the same discipline used on any mixed-material assembly. The difference is that the open source files often do not carry the notes that a production drawing would, so the build plan has to supply them. Write the bake schedule, the insert callouts and the grounding path down before the first print.

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  Finish moves dimensionsmask locating features or move the tolerance to a machined insert
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  Use heat-set insertsdesign the boss and depth into the model, not into the assembly step
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  Plan the ground pathprinted polymer does not conduct, so add a metal or plated route