The space year 2023 starts with a bang! SpaceX’s Transporter 6 Falcon 9 rocket lifted off from Cape Canaveral today and sent over 110 satellites into space at once! Among them, the French: there is a satellite from the maritime surveillance fleet of the Breton start-up UnseenLabs, and especially the demonstration nanosatellite Gama Alpha.
Gama Alpha is a 6U cubesat (1U = unit of volume corresponding to a 10 cm side cube), it weighs around ten kilos and is the size of a shoebox. Yet it is in there that the engineers of the French start-up Gama have stored a 73 m² solar sail, an extremely thin and hand-folded sail. The Alpha mission is the first of the program, the purpose of which is above all to test in low orbit the proper functioning of the hyper-detailed device for deploying the sail, and to test its effectiveness.
The Gama Alpha mission. © Gamaspace, YouTube
The principle of the solar sail is quite unusual because even if there is no air in space, there can be wind. It is not air molecules that are charged by this wind but particles coming from the Sun, ejected from its surface. By bouncing on the surface of the sail, these particles push the satellite thanks to the principle of action-reaction. This principle makes it possible to move forward – albeit slowly – without the need for propulsion, an ideal gain in weight and longevity for the satellite.
After the Alpha mission, Gama plans another test mission in higher orbit in 2025, then will follow a mission to Venus and others further, even beyond the Solar System! If Alpha is the first French mission, the principle already has a lot of experience. Several other test missions around the world have already been carried out.