3D Printing

A 3D printed “mothership” used to launch multiple PocketQube satellites into space

As tiny and reliable emerging satellites, PocketQubes are “an exemplar of New Space research and innovation.”

The original idea came from Professor Robert J. Twiggs from Morehead State University (MSU), who proposed the standard of “a satellite that fits in your pocket”. A PocketQube is a type of miniaturized satellite for space research that usually has a size of 5 cm cubed (one eighth the volume of a CubeSat), a mass of no more than 250 grams, and typically uses commercial off-the-shelf components for its electronics.

3D printed AlbaPods 2.0 in Windform® XT 2.0. Courtesy of Alba Orbital

This type of satellite is quite young – started in 2009 – but its importance is increasing as a solution to the rising costs of CubeSat launches to low Earth orbit. Since then, interest for PocketQubes has arisen from the Space industry. The first PocketQube Standard was issued in June 2018, providing a shared platform to the PocketQubes community; one of the contributors (along with GAUSS Srl, TU Delft) is Alba Orbital, a fast growing high-tech SME based in Glasgow, Scotland.

Alba Orbital provided a hub of support for the class of PocketQube satellites, by not only building its own platforms but providing parts and launch to companies, universities and space agencies around the world.

Fully loaded 3D printed AlbaPod 2.0 for flight – Rear cover removed for inspection. Courtesy of Alba Orbital

Recently, Alba Orbital needed to build an updated version of its PocketQube satellite deployer, AlbaPod 2.0. The goal was to improve on previous designs in terms of weight, manufacturability, access and incorporate a number of safety features.

The company’s engineering team turned to CRP Technology for the manufacturing of the deployer. CRP Technology is an Italian-based 3D printing company that offers Windform composite materials. Most of these materials are suitable for space applications and have passed outgassing tests at NASA and ESA.

As with any aerospace part, minimizing weight is a major design goal. Plus, it is essential that the material be approved for flight due to tight rules regarding degassing once in space. It was clear that using a material already approved by the major launch providers would ease the adoption of the launcher by all parties.

Fully loaded 3D printed AlbaPod 2.0 for flight – Rear cover removed for inspection. Courtesy of Alba Orbital Orbital

For CRP Technology’s 3D printing department, the work began with an accurate analysis of the 3D and 2D files. Selective Laser Sintering with Windform XT 2.0 Carbon composite material was chosen.

The team noted that the pod needed to withstand high vibrations, and in the worst scenario, contain any satellite that breaks free internally. Windform XT 2.0’s toughness and strength make it a suitable candidate for this use case.

Windform XT 2.0 features improvements in mechanical properties including +8% increase in tensile strength, +22% in tensile modulus, and a +46% increase in elongation at break.

Once CRP received the final .STP file from Alba Orbital, it created the AlbaPod v2, a light weight flight proven 6P (Up to 6 satellites) 3D printed deployer for PocketQube compatible satellites, with a mass of <500g (60% less than AlbaPod v1).

Professional 3D printing, combined with Windform XT 2.0 Carbon-composite material, proved to be the best choice: the 3D printed deployer has successfully passed the control criteria.

The material combined with the manufacturing technique allowed the design team to design parts that cannot be manufactured with traditional techniques, with thin sections and complex geometry’s, and these parts can be manufactured and delivered in a fraction of the time for a traditional supply chain.

“The most innovative aspect of the project,” said one engineer, “was the sheer number of components we switched over to Windform XT 2.0. Not only was the shell redesigned in the material, but also the moving ejection mechanism and door assembly. Additionally, some parts are critically structural to the assembly as a whole.”

Regarding the mechanical performance of this part, they say that “this is critical.” Not only does the full assembly need to function correctly to facilitate the deployment of the satellites inside, but must also contain the satellites in the event of catastrophic failure of a payload during the launch as anything breaking free could fatally damage other payloads or the launch vehicle itself. This was tested thoroughly with free masses on vibration tables at extremely high loading and the shell held up phenomenally.

3D printed AlbaPod 2.0 on vibration table going through preflight certification. Courtesy of Alba Orbital

Additionally, weight is a concern with anything going into space due to the costs associated, using Windform XT 2.0 reduced the mass of a number of major components.

The Alba Orbital team foresee and hope for an increasing use of professional 3D printing in the field, because, they say, “3D printing allows us to rapidly improve design and customise/create launchers for demanding payloads which may fall outside the PocketQube standards or require special considerations. It will also allow the fast integration of new release mechanisms to switch manufacturers quickly and easily if problems with supply chain arise.

Fully loaded 3D printed AlbaPod 2.0 for flight – Rear cover removed for inspection. Courtesy of Alba Orbital Orbital

The Alba Orbital team performed many tests on the 3D printed AlbaPod v2. On September 9th 2019 the first integration occurred. At the beginning of December 2019, the team launched 6 PocketQube satellites into orbit via the AlbaPod v2 (mission: Alba Cluster 2). Alba Cluster 2 has been on orbit for 100 days. New launch with 3D printed AlbaPod v2 (Alba Cluster 3) is expected for later 2020.

Crptechnology.com
Windform.com