Spacecraft that can repair themselves in the vacuum of space: this idea is now becoming tangible thanks to work by the Swiss company CompPair, supported by the European Space Agency. Such an advance would profoundly change long-term missions and reusable launchers.
This innovative project, named Cassandra, is developing a composite material capable of identifying and correcting its own damage without external assistance.
A demonstration sample from the Cassandra project. The technology integrates sensors and a heating element into a composite material to enable autonomous repair of early-stage damage.
Credit: CompPair
The device's operation relies on a particular composite called HealTech. A healing compound is encapsulated between its layers of carbon fiber. As soon as tiny cracks form, often caused by launch vibrations or temperature variations, the material can trigger a regeneration mechanism. Targeted, moderate heat is then enough for the agent to spread and seal these microcracks.
Damage identification is handled by a mesh of optical fiber sensors embedded in the structure. These sensors constantly monitor the material's condition and pinpoint the exact location where a crack appears. After locating the anomaly, 3D-printed aluminum heating grids come into play to precisely warm the affected area.
Tests conducted on panels measuring about 16 inches (40 cm) have confirmed the system's effectiveness. It correctly detects cracks, distributes heat in a targeted manner, and allows the material to recover its initial strength after the operation. Teams are now focusing on adapting this technology to larger components, such as cryogenic fuel tanks.
Infrared images of the repair process via heating on a test sample from the Cassandra project.
Credit: CompPair
This self-healing capability holds obvious appeal for reusable space transportation systems. Vehicles performing numerous launch and return cycles endure repeated stresses. The ability to automatically correct certain types of damage between flights would limit inspection times and maintenance costs, while extending the lifespan of parts.
A representative of the European Space Agency indicated that this novelty could offer major benefits to the European space sector, particularly by facilitating the design of reusable infrastructure. For her part, the Head of Research and Development at CompPair expressed satisfaction with the performance exhibited by these composites, deeming them compliant with the strict requirements of reusable space tanks and structures.