When it comes to space missions, even the smallest tools have to be light, tough, and reliable, and one small device is proving just how powerful that combination can be. It’s called MiniFix and it might just be the future of sustainable science in orbit.
Developed by the German Aerospace Center (DLR), MiniFix is the first fully FDM-printed system for preserving biological samples during space missions, like cells or tissue. It works by injecting chemicals (from two tiny syringes) into the sample to stabilize it, preventing it from breaking down over time. This kind of process is essential in space because astronauts can’t do complex lab work the way they do on Earth.
MiniFix hardware for preserving biological samples during space missions. Image courtesy of the German Aerospace Center.
Built on the Desktop, Bound for Space
Built with desktop 3D printers and open-source electronics, MiniFix still met the demands of spaceflight, completing five suborbital missions through the DLR’s MAPHEUS program, short for Materials Physics Experiments under Microgravity. It did so without any structural damage, even under extreme conditions like high acceleration, vibration, and the intense heat changes of re-entry.
The heart of the system is the dual-syringe unit. This allows it to perform programmable chemical fixation, a method used to preserve biological samples in space, where manual processes are not an option. The system also reuses the heat generated by its small stepper motors to keep the device warm, which saves energy and makes the design less complicated. The system’s heat management is impressively efficient, using only 4.6 watt-hours of power to keep samples at the right temperature, even during atmospheric reentry.
The scientific thinking behind these choices is explained in more detail in a peer-reviewed paper the team published in April 2025, titled Pioneering the Future of Experimental Space Hardware: MiniFix – a Fully 3D-Printed and Highly Adaptable System for Biological Fixation in Space, in the journal Microgravity Science and Technology.
Sebastian Feles with MAPHEUS. Image courtesy of the German Aerospace Center.
MiniFix made history as the first piece of space hardware ever flown using a compostable biopolymer called GreenTEC Pro. Made from renewable, plant-based materials, GreenTEC Pro is stronger and more heat-resistant than typical compostable plastics, yet can still break down under industrial composting conditions. Using it in a space mission marks a major step forward for sustainable space tools. In an industry known for its complex and high-cost materials, MiniFix demonstrates that environmentally conscious materials can withstand the harshness of space.
This sets an exciting precedent, since future missions might begin to consider using more recyclable or biodegradable components, especially for single-use instruments or experiments.
What Makes MiniFix Special?
According to Sebastian Feles, who submitted the story proposal and leads the Aeromedical FabLab at DLR, MiniFix represents something rare in space tech, since it’s affordable, scalable, and mission-ready.
Scientist and inventor Sebastian Feles. Image courtesy of Sebastian Feles.
To make the device, Feles’ team used a Prusa MK3+ desktop printer and three standard filaments: PLA, PETG, and the compostable GreenTEC Pro. What’s more, the modular syringe unit can be sterilized and reused. The syringe module is designed to be pre-assembled under sterile conditions, keeping biological samples safe from contamination during launch and flight. The device is also equipped with NEMA (National Electrical Manufacturers Association) 11 stepper motors for precise timing of chemical fixation and doesn’t require a cleanroom or post-processing; simply print and assemble.
Because MiniFix is fully 3D printed, it can be quickly updated for different experiments, such as adding a light source for plant tests, without long delays or expensive redesigns.
MiniFix CAD file. Image courtesy of the German Aerospace Center.
MiniFix was printed with 0.3 mm layer height and 0.4 mm nozzle settings, following a fast, lab-style development approach. Roughly the size of a large smartphone, the device shows that space hardware doesn’t always need to come from high-end, million-dollar systems. The compact system fits into standard 2U CubeSat modules and weighs just 880 grams when made with compostable material. For missions that require extra protection, it can be housed in a sealed pressure vessel, bringing the total weight to around 2.3 kilograms.
“This kind of flexible, low-cost platform could open new doors for space-based research,” the team writes. “MiniFix isn’t just about preserving samples—it’s about making space experiments more accessible, adaptable, and sustainable.”
