Bion-M is a new generation of Russian space capsule intended for biological research and capable of returning living organisms to Earth from orbit. The 'M' letter stands for "modified" in Russian. The latest generation received a new propulsion system enabling the increase in weight of scientific instrumentation, maneuverability of spacecraft, and extending the mission's length. The configuration of both spacecraft and the launch vehicle for the Bion missions are similar to the Progress cargo and Soyuz manned missions but the capsule itself derives from older Zenit photoreconnaissance satellites based on Vostok manned capsules.