Radar sats and laser comms in orbit

Satellite radar data has been relayed via a 35,000 km, 600 Mbps laser connection.

The European Space Agency (ESA) has unveiled the first Sentinel-1 radar satellite images sent via the European Data Relay System’s (EDRS) laser technology in high orbit.

The images were taken by the radar on the Copernicus Sentinel-1A satellite over La Reunion Island and its coastal area.

Sentinel-1A, sweeping around the globe at 28,000 km/h, transmitted the images to the EDRS-A node in geostationary orbit via a laser beam at 600 Mbps. The laser terminal is capable of working at 1.8 Gbps, enabling EDRS to relay up to 50 TB a day. EDRS immediately beamed the data down to Europe. 

The transfer between the two satellites was fully automated — EDRS connected to Sentinel from more than 35,000 km away, locking onto the laser terminal and holding that link until transmission was completed.

The German Space Operations Centre in Oberpfaffenhofen, tasked by the Mission Operating Centre of Airbus Defence and Space in Ottobrunn, received the raw Sentinel-1A data at its station in Weilheim. The data was then passed to the ESA-managed Sentinel-1 ground segment, where it was processed to generate the final products.

Quick data for disaster relief

EDRS will improve access to more urgent and potentially lifesaving coverage from space than ever before.

Satellites such as the Sentinels can help to survey areas struck by natural disasters. When the situation on the ground is changing rapidly, hours-old satellite information is of little use to rescue teams. EDRS will allow access to time-critical data acquired around the world.

EDRS will help in disaster relief as well as for operational monitoring services, such as maritime surveillance, by relaying the data as quickly as possible to Europe, thanks to its network of ground stations like the one in Oberpfaffenhofen.

Sentinel-1A radar satellite test image taken on 26 May, recorded and relayed to Earth by EDRS-A on 31 May via laser. This is a false-colour composite based on the radar’s two polarisation channels.

Magali Vaissiere, ESA director of telecommunications and integrated applications, said at the Berlin Airshow on 1 June, “With today’s first link, EDRS is close to becoming operational, providing services to the Copernicus Sentinel Satellites for the European Commission.”

“SpaceDataHighway is no longer science fiction,” noted Evert Dudok of Airbus Defence and Space. “It will revolutionise satellite communications and help to keep Europe’s space industry at the forefront of technology and innovative services.”

For Sentinel-1, EDRS adds flexibility, increasing the availability of products to users. It will also enable the fast downlink of data acquired outside of Europe, helping services requiring products in real time as well as in emergency and crisis situations.

Further development

The SpaceDataHighway is a public-private partnership between ESA and Airbus Defence and Space. The DLR German Aerospace Centre funded the development of the cutting-edge laser technology that forms the backbone of the system.

The first node, EDRS-A, was launched on 29 January 2016 as a hosted payload on the Eutelsat-9B satellite. The second, the dedicated EDRS-C satellite, will be launched in 2017.

The European Commission’s Copernicus Sentinel satellites are the first users of the EDRS service.

ESA is planning the GlobeNet program to extend EDRS by 2020, providing additional security services to satellites, aircraft and drones.

The laser communication technology used today will be able to bridge up to 75,000 km, sending data from one node over the Asia–Pacific region (EDRS-D) to another over Europe (either EDRS-A or EDRS-C).

Information courtesy of ESA

Top image: Artist's impression of the GlobeNet system, due for completion by 2020.