The European Space Agency (ESA) has long been a fan of 3D printing, successfully testing a 3D printed platinum alloy rocket combustion chamber in 2015, announcing on more than one occasion that it planned to use 3D printing to build a human-occupied base on the moon, and opening a new Advanced Manufacturing Laboratory to study 3D printing for future missions to space. Now, as the first test of its new 3D printable electrically conductive hard plastic, the ESA has 3D printed CubeSats with their own electrical lines.
CubeSats are basically mini satellites, and were originally developed as educational tools, based on rugged, stackable electronic boards that are placed in one, or more, standardized 10 cm units. 3D printed CubeSats are not a new concept: they have been the subject of design challenges, aerospace company Aerojet Rocketdyne signed a contract with NASA about a propulsion system for an MPS-130 CubeSat propulsion system, and a 3D printed Russian CubeSat will be placed into orbit from the ISS this July.
The ESA has been working recently with robust PEEK thermoplastic 3D printing material, which is stable, strong, and temperature resistant, with a melting point of around 370°C.
“We started a project with Portuguese company PIEP and, in a technical first, we made this printable PEEK electrically conductive by adding certain nano-fillers to the material,” ESA’s Ugo Lafont explained. “This kind of customising has taken place for as long as the plastic industry has existed. Plastic has been mixed with different materials to tailor their properties as desired, to make them more resistant for instance, or shinier. In this instance, this ‘doped’ PEEK filament can now be used as a standard feedstock in our 3D printing process.”
To demonstrate its breakthrough with the electrically conductive PEEK material, Lafont and ESA intern Stefan Siarov, from TU Delft, chose to 3D print CubeSat bodies.
Siarov said, “The resulting PEEK CubeSat structures would be capable of flying in space. But these bodies are also functional, because they incorporate electrically conductive lines in place of the wire harness normally connecting up the different CubeSat subsystems.”
The ESA’s Materials’ Physics & Chemistry team is working with the ESA’s Directorate of Human Spaceflight and Exploration to develop a space-optimized PEEK printer. The printer will be tested initially on a zero gravity aircraft, and then eventually used by astronauts aboard the International Space Station.
“The vision we have to enable a new maintenance strategy. Rather than just making toys with no added value, PEEK and comparable thermoplastics are robust enough to find a lot of practical uses, plus the added option of electrical functionality,” said Lafont. “Space Station crews end up needing all kinds of items, all of which currently require transport from Earth: everything from screws and water valves to hermetic containers and water valves. All of these could be 3D-printed instead – even toothbrushes – since PEEK is biocompatible. 3D-printing such items in orbit would be cheaper, and would change the equation of recyclability. Because these plastic items can later be recycled, we reduce the scarcity of materials in space and start to make human missions to space more self-sustaining.”
While the Made In Space 3D printing filament for its Zero-Gravity 3D printer aboard the ISS seems to be working just fine, it never hurts to have an electrically conductive material like ESA’s new PEEK material on hand. Siarov is currently working at ESA’s European Astronaut Centre in Cologne, Germany, to determine how recyclable other 3D printed engineering thermoplastics are.
Christopher Semprimoschnig, who leads the ESA’s Materials’ Physics and Chemistry Section, said, “We have been taking a continuing interest into high-performance thermoplastic materials over the last decade. The freedom that new processing options such as 3D printing offer are especially intriguing for ESA.”
Lafont and Siarov’s 3D printed CubeSat bodies could eventually help in making space missions faster and less expensive: the miniature satellites would be ready for launch as soon as the solar panels, circuit boards, and various instruments were slotted in. Additionally, a small structural part made with the PEEK material is set to fly on the Meteosat Third Generation Series of weather satellites at the end of the decade. Discuss in the ESA forum at 3DPB.com.[Source/Images: European Space Agency]