Aerographite Solar Sails – Photon Pressure Thrust Measurements of Spacecrafts made from Ultra-Lightweight Materials

• Applicant: Professor Dr. Martin Tajmar
• Subject Area: Measurement Systems ; Synthesis and Properties of Functional Materials
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 564795057

In this project, the high-performance material aerographite is to be investigated in detail for use as a passive solar sail. Due to its unique light-matter interaction properties, aerographite has the potential to far surpass current solar sail technologies. Based on previous experiments, these and other properties will be experimentally investigated and comprehensively understood. The material will be exposed to extreme conditions in a space-like environment with laser and light sources in the solar spectrum and the resulting thrust force will be measured. In the project, a suitable test environment is first created and adjustments are made to the shear measuring balance used. In a large vacuum chamber, an ultra-precise shear measuring balance is used to detect sub-nanonewton shear forces. Laser and light sources are then used to exert a defined photon pressure on the aerographite on the balance in order to characterize its impulse response. For comparison, the generated photons are first captured in a beam trap in order to transfer the entire impulse to the balance without reflections. In this way, a variety of sample geometries with varying material parameters and geometries such as spherical or planar samples with density gradients will be tested to demonstrate the potential of aerographite. Previous experiments indicate another property of the material that would be of great advantage for a solar sail - the residual gases stored in the material can be released by targeted heating and thus generate additional thrust. To this end, the aerographite is to be heated to high temperatures on the thrust measuring scale using heaters in order to evaluate this effect. Taking all the results into account, the optimum solar sail will ultimately be developed.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr.-Ing. Bodo Fiedler