Three Versions, Nine Hours of Printing, One Final Design

Ikarus 3.0, our final chassis design, shown assembled and ready. The white PETG version will fly on launch day.

When Luka first opened Onshape to start designing the CanSat chassis, he drew a cylinder. That is it. A cylinder with a flat bottom and a lid. It looked like a trash can. It basically was a trash can. And that first design, while completely unlovable from an engineering standpoint, taught us more about mechanical design than any textbook probably could have.

Designing the physical body of a CanSat is one of those challenges that looks simple until the moment you try to do it. The constraints are brutal: maximum 66mm in diameter, maximum 115mm in height, and a total system weight of exactly 300 grams including all electronics and the parachute. It has to survive being ejected from a rocket at altitude, descend on a parachute, and then hit the ground. It has to be openable by human hands. It has to have a hole for the antenna, attachment points for the parachute, and now, for our secondary mission, airflow vents large enough for the CO2 sensor to actually measure the air around it rather than just the stale air trapped inside the can.

The Evolution of Ikarus

Version 1.0 January	Three separate parts held together by two M3 screws through 3.2mm holes. Immediately revealed to be too fragile. No parachute attachment points. No antenna hole. The holes were slightly too small which made assembly a nightmare. Scrapped entirely.
Version 2.0 February	Simplified to two parts. Added parachute holes. Still two screws, still no vents, still no nut recesses. The screws bent under landing loads. The lack of vents was only discovered when we realized the CO2 sensor would be measuring a closed bubble of air, not the atmosphere.
Version 3.0 March	A complete redesign. Walls thickened from 1mm to 2mm. Bottom plate increased to 5.4mm to absorb landing impact. Three screws with nut recesses so they cannot spin. Screw holes enlarged to 3.4mm for printing tolerances. Large airflow vents added. EVA foam padding added internally. This is the version we are flying.

The jump from Ikarus 2.0 to Ikarus 3.0 was not a small revision. It was a complete rethink of how the structure distributes force. With two screws, the mechanical load of a landing impact concentrated on those two points and bent them. By moving to three screws placed around the perimeter and adding nut recesses, the forces spread evenly across the whole cross-section of the body. Adding extra thickness to the bottom plate means the structure does not crack on impact. It sounds obvious in retrospect. Most engineering lessons do.

“The vents were something none of us had thought about until we sat down and traced the airflow path to the CO2 sensor. That one conversation changed the entire geometry of the bottom half of the chassis.”

— Team Icarus 6

The design was done entirely in Onshape, a browser-based 3D CAD platform. For some of the more complex geometry we also used Zoo.dev, an AI-assisted 3D modeling tool. The actual printing was done at the Makerspace inside the Forum Geesseknäppchen in Luxembourg, which made the printing entirely free. The full print took nine hours.

The current prototype is white PLA. White specifically because it is easier to spot against ground-level backgrounds after landing. The final flight version will be printed in PETG, which has better impact resistance and does not soften in the heat that builds up inside a sealed enclosure in the sun before launch.

The final Ikarus 3.0 can be fully opened in about ten seconds and closed in around twenty. It sits securely during flight. It can survive a landing at the speeds our parachutes generate. It has four parachute attachment points on the top, a dedicated 5mm hole in the bottom for the antenna, and foam and EVA padding protecting the electronics from shock inside.

It took us three tries and several months of iteration to get there. That is not failure. That is engineering.