A single memory array has an isolation circuit for isolating segments of a same bit line from each other. The light source faces a window element of the closed optics compartment with a first light guide part and directs light further into the optics compartment by means of a second light guide part located on the other side of the window element and aligned with the first light guide part. A cushion is affixed medially of the tube for contact with the user’s body during use of the device. Thus, two wire-side contact pieces at the upper and lower stages can be arranged side by side at substantially the same height in a width area taken up by one wire connecting portion. The orientation of the electric thruster is controlled to activate the electric thruster with a thrust direction deliberately not aligned with a center of mass of the satellite to create desaturation torques in the storage device along axis Y.