This proposal is for an Airspace Trial, for which a scaled airspace change process applies and a change level is not applicable.
DSTL is commissioning an Optical Ground Station (OGS) for Space Command, at the western perimeter of their Portsdown West site (50° 51.64'N, 001° 07.79'W. Elevation ~320ft AMSL). This will be used to explore and develop the technology for optical communications from Low Earth Orbiting (LEO) Satellites to the ground station (downlink) but also sending communications from the OGS to the satellites (uplink).
The OGS intends to use laser beacons to establish the line of sight communication channel between itself and LEO satellites. The beacon lasers are used, similar to a lighthouse or floodlight to illuminate the satellite whose position is known. Once this laser beam is detected by the satellite, the satellite broadcasts the information along the same path thus establishing an optical communication link between the OGS and satellite. The uplink is achieved using the laser beacons of the OGS.
The beacons could be pointed in any direction above the OGS from 5 degrees to 85 degrees and along any bearing. The pointing direction depends on the transits of the LEO satellite. Transit of a LEO satellite is typically 10 minutes so the laser beacons will only be operational during this time i.e. not continually but could be several times per day. There are two laser beacons on the OGS telescope which are invisible to the human eye, with a Nominal Ocular Hazard Distance (NOHD) of 300 m. A suitable airspace structure or annotation of the site in the UK AIP is required, to ensure airspace users are aware of the activity. DSTL has identified several mitigations to allow airspace users to be unaffected from the ocular hazard.
