Bion-M is the next generation of Russian biological research satellites. While retaining the Vostok/Zenit-derived reentry module of the earlier Bion, the propulsion module has been replace by a Yantar type module, which provides maneuvering capabilities and longer mission support. The mission duration has been increased to up to 6 months by using solar cells for energy generation. The weight of scientific equipment has been increased by 100 kilograms.