The Apollo Command and Service Module served as the ‘mother ship’ for all the flights to the Moon. It consisted of a conical Command Module, where the astronauts were located, and a cylindrical, 7.5-metre-long service module containing fuel, oxygen and the power supply. During the journey to the Moon, the Lunar Module was attached to the tip of the Command Module. This configuration was also used to perform experiments and observations from the open scientific instrument module or SIM bay while in lunar orbit. These included photographs taken using special cameras, alpha particle, X-ray and gamma ray measurements, and gravitational and magnetic field studies.