French aerospace company Gama has launched its first solar sail to space, with the support of the National Centre for Space Studies (CNES, France) and private companies including CMA CGM, a global logistics company. The satellite containing the solar sail was successfully placed in orbit by a SpaceX Falcon 9 on Jan. 3. The mission aims to test the deployment and control of the sail, a decisive step for the democratization of this new means of space propulsion. Solar sails use only sunlight for propulsion, removing the need to carry fuel. The sails rely on photonic propulsion, using the pressure produced by photons when they bounce off a reflective surface. Though the force is weak, when applied to a large surface and in the void of space, the spacecraft can continuously accelerate. With continuous acceleration, a solar sail could theoretically become the fastest spacecraft made by humans. The result of this continuous acceleration, Gama co-founder Andrew Nutter said, is missions that are 10 to 20× less expensive. The technology also opens possibilities for missions in deep space or in unstable orbits, he said. Gama’s first demonstrator mission, Gama Alpha, is a satellite placed in orbit at an altitude of 550 km by a SpaceX Falcon 9 rocket. The 6U cubesat (the size of a large shoebox) weighs 12 kg, including the packed 73.3-m2 sail. “The first phase will be commissioning the satellite, establishing communications, and checking that all the vital signs are good. The second phase will be the sail deployment,” said Jordan Culeux, Gama lead system engineer. “The satellite will be put in slow rotation, initiating the release of four tungsten masses at the tip of each sail petal. The centrifugal force generated by the rotation is enough to ensure the deployment and the structural shape of the sail.” The primary objective of Gama Alpha is to deploy and control the sail, demonstrating that a very large sail can be controlled from a cubesat and receiving flight data to improve simulations and control algorithms. Demonstrating sustained navigation will be the objective of Gama’s second mission, Gama Beta. The final phase for Alpha will be deorbiting the satellite, benefiting from Earth’s remnant atmosphere at mission altitude. The large surface area and small mass will cause the satellite to rapidly deorbit, minimizing the risk of debris and also demonstrating that a sail can be used to deorbit satellites at end of life. Gama Beta will demonstrate sail propulsion and navigation. Whereas Alpha is about the sail deployment, Beta will be launched at twice the altitude and focus on “navigation” going from A to B using only photonic propulsion and proving all key elements of the technology. In the future, Gama intends to partner with space agencies and commercial players to unlock access to deep space.
