EDRS will be an independent European satellite system that reduces time delays in the transmission of large quantities of data. It will contribute to a telecom network that is fast, reliable and seamless, thereby enhancing Europe's self-reliance. The EDRS will make on-demand data available at the right place at the right time.
Why is it needed now?
Despite the present telecommunication capabilities, there are still a number of limitations that delay the delivery of time-critical data to users. With the implementation of the joint ESA/European Commission Copernicus programme, it is estimated that European space telecommunication infrastructure will need to transmit 6 terabytes of data every day from space to ground.
Our present telecom infrastructure is challenged to deliver such large data quantities without significant delays, and conventional means of communication may not be sufficient to satisfy the quality of service required by users of Earth observation data. In addition, Europe currently relies on the availability of non-European ground station antennas to receive data from Earth observation satellites. This poses a potential threat to the strategic independence of Europe, as these crucial space assets may effectively not be under European control. EDRS offers a solution to these issues.
EDRS overview (click to enlarge)
How will it be done?
The EDRS infrastructure will consist of two geostationary payloads, a ground system consisting of a satellite control centre, a mission operations centre, a payload control center, and a dedicated network of ground station antennas.
User data will be transmitted from low earth orbit satellites to either of the EDRS payloads and relayed to the feeder link and data ground stations, from where it will be made available to users.
The EDRS payloads
The first EDRS payload, EDRS-A, comprising of an optical inter-satellite link and a Ka-band inter-satellite link will be hosted on a host satellite operated by Eutelsat (FR) known as EUTELSAT 9B EAST. Anticipated launch date is the first half of 2016. Its orbital position will be 9 degrees East.
The second EDRS payload, EDRS-C, also comprising of an optical inter-satellite link, will be a hosted on a satellite under development on the basis of the SmallGEO platform, which began as a public private partnership (PPP) scheme between OHB (DE) and ESA as part of the ARTES programme. OHB anticipates launching the satellite in 2016. Its orbital position will be 31 degrees East.
The EDRS-C mission will also carry a commercial payload, Hylas-3, developed by Avanti Communications of the UK. Through this arrangement, the cost of satellite resources and the launch will be shared. This contributes to the funding of the EDRS programme while providing access to space at a lower cost for the hosted payload.
Avanti and ESA previously worked together to launch the Hylas-1 satellite in 2010. Hylas-3 includes a steerable multibeam antenna to provide communications for institutional and commercial Avanti customers independent of EDRS.
Once fixed in geostationary orbit, the two satellites will serve as a data relay backbone. The inter-satellite communication terminals (optical and Ka-band inter-satellite links) will offer speeds up to 1.8Gbit/s (optical) and up to 300Mbits/s (Ka-band), while the Ka-band feeder link will offer speeds up to 300Mbits/ to the ground. The data will be received either at dedicated EDRS ground stations or potentially at future user ground stations which would provide direct access to the data. The EDRS ground stations will all be based in Europe.
The most innovative part of the inter-satellite service is the laser communication terminal. It has been developed by TESAT Spacecom GmbH (D) under contract by the German Aerospace Center (D). The new terminal has been validated in orbit on-board the German Terrasar-X satellite and on-board the US NFIRE satellite.
The first optical inter-satellite link between these two satellites was tested in 2008 and resulted in a 5.6 Gbit/s data rate transmission for distances up to 5,000km. The newer second-generation terminal can transmit distances up to 45,000 km at a data rate of 1.8 GBit/s.
Both optical and Ka-band inter-satellite services are transparent to the data routed via the system. No data will be stored on-board; however encryption services are available on request by the user.
The EDRS ground services
Offering data relay services on a commercial basis is complex and requires a substantial investment in ground services.
The EDRS Mission Operation Center is located in Ottobrunn (D) with Redu (B) serving as a backup.
The planning details may vary from user to user, but basically service requests will contain information on the orbital position of the communicating satellite, the planed duration of the link, and the handling of the data on-ground.
Such information, together with the planning constrains of the EDRS system and the user satellite are defining the overall service schedule.
Based on the information described above, the mission operations centre will task the corresponding ground segment elements – either the one related to EDRS-A or the one related to EDRS-C.
Due to the high data rate requirement for the down load of 1.8 Gbit/s, the Ka-band frequency used for the feeder link and required reliability of EDRS (99.6 % uptime), the system is equipped with a data consolidation network.
In addition to the EDRS data receiving stations, users may chose to receive the data at their own ground stations to to have direct access to it.
Who will implement it?
In order to achieve a cost efficient EDRS programme and minimise ESA investment and operation costs, EDRS is being implemented as a Public Private Partnership (PPP) through ESA’s ARTES programme.
Airbus Defense and Space (formerly Astrium) (D) is serving as prime contractor. It won a competitive tender issued in 2010 and will carry the overall responsibility for the implementation of the space segment (including launch) as well as the ground segment.
Airbus has commited to operating the EDRS for 15 years and provide services to ESA, in particular for the Copernicus programme. Sentinel-1A (launched in April 2014) and Sentintel-2A will be two key Copernicus users.
EDRS Copernicus Sentinel services (click to enlarge)
What are the benefits?
EDRS will provide:
- Real time access to Earth observation data
- High data rates
- Encrypted data down link
- Fast forward commanding capability
There are a number of key services that will benefit from this system's infrastructure right from the start:
- Earth observation applications in support of a multitude of time-critical services, e.g. monitoring of land-surface motion risks, forest fires, floods and sea ice zones
- Government and security services that need images from key European space systems such as Copernicus.
- Rescue teams that need Earth observation data within disaster-struck areas
- Security forces that transmit data to Earth observation satellites, aircraft and unmanned aerial observation vehicles, to reconfigure such systems in real time
- Relief forces operating in cut-off areas that require telecommunication support
What are the future plans?
ESA and its partner Airbus Defense and Space are already planning to extent the system by adding additional geostationary satellites and by adding additional features to its service. Called Globnet, the extension programme first step will be to add an additional satellite, most likely as a hosted payload. Plans will be finalised in 2015/16, but should contain two laser communication terminals and two Ka-inter-satellite link terminals, with the launch envisaged for 2020. The service will consider the demand for increased security requirements, increased redundancy requirements and the requirements to serve unmanned aerial vehicles. As an option, the possibility for optical links between two geostationary satellites is also being considered.