Abstract: Optical communications system (10) and method for transmission of payload data (PD) from a low earth orbit satellite (20) to an optical ground terminal (30), the low earth orbit satellite (20) being connectable with the optical ground terminal (30) via an optical downlink channel (DL), and the optical ground terminal (30) being connectable with the low earth orbit satellite (20) via an uplink channel (UC); wherein said uplink channel (UC) is an acquisition and tracking beacon channel by means of a ground beacon (GB) controlled by a point-acquisition-track subsystem (PAT), the ground beacon (GB) comprising a wide angle beam (W) for acquisition and a guidance beam (G) for tracking; and wherein the ground beacon (GB) for the uplink channel (UC) is a pulse position modulated PPM channel.

Abstract: Optical downlink system (10) and method of optical data transmission between a remote terminal (20) having a number of n optical communication terminals (OT1-OTn), and a ground terminal (30) comprising a cluster of n optical ground stations (OGS1-OGSn) connected by n optical downlink channels (DL1-DLn) respectively n optical uplink channels (UC1-UCn) characterised by a spatial separation of the optical downlink channels (DL1-DLn) and a temporal separation of the optical uplink channels (UC1-UCn).

Abstract: A system and corresponding method for a launch vehicle or spacecraft for releasably connecting a first body (100) with a first interface (101) and a second body (200) with a second matching interface (201), said system comprising: a belt (300) for releasably securing said first body (100) to said second body (200); a circumferential trench (203) at said second interface (201) for receiving said belt (300) in order to provide for a fixation of said belt (300) with relation to said second body (200); mechanical fixation means (301) attaching said belt (300) to said first body (100), said mechanical fixation means (301) being provided to enable a circumferential shifting movement of said belt (300) with respect to said circumference of said first body (100) in order to initiate a separation of the first body (100) from the second body (200), wherein said circumferential shifting movement induces a relative movement of said belt (300) with respect to said circumference of said first body (100) in order to remove