EDRS, a new dimension for Earth Observation by satellite Under the European Data Relay System (EDRS), data collected by Earth observation instruments will be relayed not directly to ground stations but via one of two geostationary EDRS satellites located 36,000 kilometres above the Earth, which will transmit at very high speed. This will for the first time allow near-constant communication between Earth observation satellites and users on the ground
The European Data Relay System (EDRS) – which will for the first time allow near-constant communication between Earth observation satellites and users on the ground – is calling for new approaches in numerous areas: in devising such a complex system, developing innovative equipment and setting up a dense network of partners within both Airbus Defence and Space and the European space industry. With the contract signed with the European Space Agency (ESA) in early October, forum looks at how this system got off the ground.
We’re seeing what could be described as a ‘bottle neck’ in space,” says Akos Hegyi, EDRS Service Development Manager at Airbus Defence and Space. “There’s a growing flow of data created by an increasing number of more powerful Earth observation (EO) satellites. But right now a communication link can only be established with these satellites for the few minutes that they pass over a ground station. Real-time observation is just not possible.” Under EDRS, however, data collected by EO instruments will be relayed not directly to ground stations but via one of two geostationary EDRS satellites located 36,000 kilometres above the Earth, which will transmit at very high speed. As a result, operators will be able to rapidly task their EO satellites with surveillance or mapping work, and users who have requested the image will be able to rapidly download the acquired data.
The European Commission is the relay service’s anchor customer. EDRS will be used to transmit 50% of the data generated by the Commission’s Global Monitoring for Environment and Security (GMES) Sentinel satellites over Europe. They will be used by European Member States, regional and local authorities, and commercial and private entities in various sectors such as maritime and agriculture, infrastructure and utilities, and emergency services and security. Additional capacity on the system will be marketed by Airbus Defence and Space to third-party users, which could include commercial satellite operators, security and defence organisations, and national or international space agencies that are operating low-earth orbit satellites for EO, meteorology or Research & Development purposes like the German Aerospace Center (DLR), Eumetsat, NASA and the National Oceanic and Atmospheric Administration in the US. The extremely high data rates offered by system are also of interest to the users of High Altitude Long Endurance (HALE) UAVs.
45,000 pages a second
Industrial work has already started across Airbus Defence and Space to meet the ambitious launch date of the first EDRS satellite and the in-service date in 2014. One of the main technological challenges will be posed by the Laser Communication Terminals (LCT), through which the geostationary and EO satellites will ‘talk to each other’ and which are still under development. “The EO and EDRS satellites are up to 40,000 kilometres apart, and the former is circling the Earth at about 28,000 km/h, so achieving these links will be an impressive technical feat,” Akos explains. What’s more, the system will transmit up to 1.8 gigabits of data per second – equivalent to 45,000 A4 pages – to the ground. Next to the inter-satellite laser links, EDRS will also offer a relay service in Ka-band to cater for all types of EO satellites and UAVs. Although there are technological ‘firsts’ involved, Airbus Defence and Space already possesses end-to-end expertise for the entire system. “We were selected by ESA because we’re the leading provider worldwide for both satellite-based telecoms services and EO services to institutional customers,” he summarises. “EDRS is a new telecoms service for EO satellites, so we’re at the frontier of both domains.”
When it comes to cooperating across the space industry, EDRS is a prime example of making a network function. Not only is it run under a public-private partnership with ESA so as to share financing and risks, but it also involves all divisions of Airbus Defence and Space. Airbus Defence and Space will be the programme prime, while Airbus Defence and Space will build the first EDRS satellite, based on its E3000 platform, and Airbus Defence and Space will produce propulsion equipment for the second satellite. The company will also contract OHB-System, Germany, to build this second satellite (for launch in 2015) while the EDRS payloads of both satellites will be manufactured by TESAT, a 100% subsidiary of Airbus Defence and Space, which is also developing the LCTs, along with the DLR. “From this complexity of commercial partners, service customers, agencies and institutions, we created a viable structure and got all the partners to come to the table,” recalls Akos with satisfaction.
He also notes that this arrangement requires colleagues from across the company to work together on a day-to-day basis – by no means a first for Airbus Defence and Space but an approach which was necessary just to get the programme to this stage. “I’m happy to be working with people who understand the complex, transversal, international and very political playing field that is EDRS and who don’t give up before they find a solution to a challenge. They are willing to learn from each other and I am sure this will continue throughout the programme, because they know that there could be bigger and as yet unclimbed peaks around the corner!”
Joanne Foster, forum, the AIRBUS Group internal magazine