European Space Agency

Astrium Services EDRS phase 0 study


Astrium Services (ASV), a company dedicated to the development and promotion of satellite services, has been awarded a Phase 0 contract by ESA for a study related to the development of a European Data Relay Service (DRS) capability.

The DRS capability is based on Geostationary Telecommunication Satellites. They allow to establish two-way large bandwidth telecommunication links between User Platforms in space and the End User on the ground. DRS services have particular additional advantages for a number of User Platforms such as LEO Earth Observation Satellites and Manned or Unmanned Scientific Missions in near-earth orbit or in deep space.

Those advantages are the longer visibility period of the User Platform from the GEO orbital position compared to an Earth Station and the related improved performance of the relay capability. Equally, problems of congestion of the X-band relay links to and from the User Platforms over polar Earth Stations can be avoided.

Therefore, DRS is an essential future capability to enhance or enable European programs that build on those User Platforms. In particular, it is assumed that a DRS capability serving GMES and next generation reconnaissance Earth Observation Satellite systems would be of particular interest: DRS will fulfil their more and more stringent requirement, particularly stemming from such applications as Crisis Management, Security, Humanitarian Aid but also from system effectiveness and efficiency requirements, for delivery of the freshest information to the end-users and for (nearly) real time tasking services

To substantiate the assumptions made so far by various stakeholders and investigate the technical feasibility of such a system, the Study has undertaken to:

  • Identify prospective User Groups of a DRS Capability; Map potential capability gaps and user needs,
  • Outline overall capability scenarios and deployment milestones,
  • Provide budgetary estimates for the infrastructure as well as operations and services,
  • Give indications of possible funding and revenues,
  • Indicate the viability of a Business Case.

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Some investigations of DRS-related business- and financial issues as well as certain technical feasibility have already been carried out by various Stakeholders. The present Phase 0 Study undertakes to substantiate the assumptions made in the course of those investigations in terms of business- and technical aspects.

In particular, the study investigates in detail the potential users of a DRS system, gives possible system architecture, identifies key operational aspects related to the provision of DRS services to the users of interest and establishes some first assumptions and propositions for a business model. The main benefit of this study is therefore to establish the feasibility of a Data Relay Satellite system and to pave the way for a following Phase A.


We found that in order to fulfill the core Earth Observation Satellite user requirements and to provide sufficient redundancy, a minimum of four inter satellite communication terminals would need to be deployed in geostationary orbit in the period for which we have sufficient planning visibility. For cost efficiency reasons, the terminals could be deployed in two groups in order to cater for the two waves of EO user platforms, GMES/Sentinel and MUSIS. For redundancy reasons, the four communication terminals shall be implemented on a minimum of two orbital platforms.

For the user terminals, we have investigated optical as well as Ka-band technologies. Optical terminals have advantaged over RF technology in terms of User Platform power requirement and data growth capacity. On the GEO side, the optical terminal has advantages in terms of accommodation and for feeder link sizing. Ka-band has backward interoperability capability with TDRSS, whilst optical terminals are being increasingly established on various EO satellite programs in Europe.

With the total number of user terminals and GEO platforms set, we have investigated a total of 3 different overall solutions:

  • A reduced scenario caters only for EO Satellite User Platforms. This scenario can be implemented on very small dedicated platforms or as a piggy-back mission on larger GEO (Telecom) satellites.
  • A nominal scenario. The nominal scenario serves the same EO Satellite User Platforms as the reduced scenario. However, it also carries one 3rd party payload serving UAVs and other military users. This payload has technical synergies with the EO mission and the overall scenario can be implemented e.g. on a very small platform plus a small Geo platform such as SmallSat.
  • An extended scenario. In this scenario, the optical terminals are augmented by a Ka-band inter satellite link and an S-band inters satellite link on each DRS platform to serve secondary users such as ATV, ISS and Launchers. This scenario calls for two larger dedicated GEO platforms, but, despite the added overall complexity, cannot fulfill all secondary user requirements e.g. for global coverage and deployment schedule. An even more comprehensive scenario was not pursued due to assumed lack of funding for such a program.


The study aims to focus on key open questions related to the technical and business feasibility of a European DRS capability, with particular emphasis on GMES- and next generation reconnaissance Earth Observation satellites. In order to obtain relevant results within the envisaged short study period, an approach with a close direct contact between the contributors working in parallel and without formal intermediate reviews was chosen. The chart below indicates the Work Break Down structure (WBS), key tasks within each WBS.

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Current status

The project final presentation was held in October 2008. The study is completed.

Status date

Wednesday, November 16, 2011 - 12:27