How a Concorde jet chased the Moon's shadow over Mauritania

French astronomer Pierre Léna devised a plan to use a Concorde supersonic jet to observe a total solar eclipse from an altitude of nearly 17 kilometers in the stratosphere. Flying that high offered major advantages for observation, since the lack of humidity allowed infrared light from the Sun to pass through with excellent clarity.

A multinational scientific team

Léna originally intended to study dust particles in the solar corona at infrared wavelengths, but he decided it would be wasteful to dedicate such a large aircraft to a single experiment. He therefore invited other research groups from France, the UK, and the United States to join the flight. The final team included scientists from the Paris Observatory, the French National Centre for Scientific Research, Queen Mary College in London, Kitt Peak Observatory in Arizona, Los Alamos National Laboratory, and the University of Aberdeen.

Studying the corona across wavelengths

The extended period of totality made it possible to study the solar corona — visible in full only during a total eclipse — across multiple wavelengths. The planned experiments covered the corona's infrared-emitting dust, its oscillating hot gas, and the chromosphere.

To fit all the necessary instruments, the Concorde 001 prototype underwent major modifications, including four portholes cut into the ceiling, each assigned to a different experiment. Those portholes remain visible in the aircraft's cabin today.

Two rehearsal flights preceded the actual mission. The historic flight itself departed from Las Palmas in the Canary Islands, heading for a rendezvous with the eclipse shadow over Mauritania.