ETH Zurich is developing the ETHOS research satellite to investigate connections between solar activity, Earth’s upper atmosphere, and satellite motion. Announced on November 2, 2026, the mission is expected to begin observations in 2030. The planned spacecraft weighs 25–30 kilograms and would operate approximately 550 kilometers above Earth.
Solar activity can heat and expand the upper atmosphere, increasing the density encountered by low-orbit spacecraft. Greater atmospheric drag changes their trajectories. ETHOS will combine observations of solar radiation and the ionosphere with precise measurements of its own orbit to investigate those relationships.
The Physical Meteorological Observatory Davos will contribute solar-observation instruments. ETH Zurich’s space-geodesy team is developing a compact navigation-signal receiver, and the University of Bern contributes laser-ranging and space-weather expertise. EPFL is evaluating a sensitive camera for potential testing aboard the mission.
ETH Zurich will oversee the mission from development through operations and retirement, using a commercially supplied spacecraft. The project also provides supervised opportunities for students to participate in assembly, testing, and operations. Its solar observations are intended to contribute to long-term records used in climate research.
