The EDRS-C satellite is specifically designed for optical communications. It has been developed, manufactured and tested by OHB on the basis of the SmallGEO platform. © OHB

OHB’s second SmallGEO satellite in orbit

EDRS-C enhances European SpaceDataHighway


Bremen/ Kourou, August 06, 2019. Yesterday evening, the telecommunications satellite EDRS-C, which is the second node of the SpaceDataHighway system (also known as European Data Relay System, EDRS), embarked on its voyage to its destination in space 36,000 kilometres above the surface of the Earth. The SpaceDataHighway is a public-private partnership between the European Space Agency (ESA) and Airbus. EDRS-C was developed and engineered by space systems specialist OHB System AG, a subsidiary of listed company OHB SE.

The 3.2 ton satellite took off from the European spaceport in Kourou, French Guiana at 21:30 CEST on July 06, 2019 on board an Ariane 5 launch vehicle. The satellite separated from the launcher after about 30 minutes when it reached its designated geostationary transfer orbit. Just a few minutes later, the EDRS-C satellite transmitted its first “signs of life” from space. “This was a very special moment because it confirmed that the satellite had withstood the intense stresses and strains to which it had been exposed during the launch process and its rapid ascent into space,” says a delighted Guy Perez, company CTO and member of OHB System AG’s Management Board responsible for telecommunications, who witnessed the launch in Kourou. “I would like to thank Airbus and ESA for the trust they have placed in OHB and all those involved at OHB as well as our many subcontractors for their valuable contributions. I am now eagerly awaiting the day on which our satellite goes into operation and supplements the SpaceDataHighway.”

Mission: to enhance EDRS

Europe’s laser-based data relay system is the world’s first “optical fibre in the sky". The EDRS-C geostationary satellite ordered by Airbus from OHB System AG forms the second node of the SpaceDataHighway.

In the SpaceDataHighway project, a fleet of satellites is to be linked via a network of ground stations. Using innovative laser communication technology, these geostationary satellites will receive data from Earth observation satellites in lower near-Earth orbits, as well as intelligence UAVs (unmanned aerial vehicles) or mission aircraft and transmit it to ground stations in Europe in near real-time and at a rate of 1.8 Gbit/s (giga bits per second). The SpaceDataHighway will give rescue and emergency teams as well as security forces much swifter access to Earth observation data. The system is used by the European Copernicus programme, which provides environmental monitoring and climate change services as well as government security services, maritime surveillance teams and weather forecasting authorities.

Step by step towards the destined position in space

“After it has separated from the launch vehicle, our satellite must manoeuvre itself into its geostationary orbit on its own by using its own chemical propulsion system. EDRS-C will initially head for an assigned test position, which it will reach after about 2 weeks. There it will be calibrated over a period of several weeks and gradually put into operation,” explains Dr. Stefan Voegt, EDRS-C Project Manager at OHB System AG.

Subsequent to the in-orbit testing the satellite will be manoeuvred to its final position located at 31° east about 36,000 kilometres above the equator. This is an ideal position allowing permanent contact for data transmission links with the ground stations. Here, the satellite will undergo commissioning while being gradually integrated in the system. All this will be done from the satellite control centre operated by the German Aerospace Center (DLR), which is located in Oberpfaffenhofen, Bavaria. “Over the coming weeks and months, we will be providing support at the satellite control center in connection with the satellite start-up and mission control. This is a 24/7 task that is organied in shifts,” adds Voegt.

The second of its kind and yet very special...

The EDRS-C telecommunications satellite is not only the second node in the SpaceDataHighway space segment but also the second SmallGEO satellite in orbit. Developed by OHB as part of the ESA ARTES programme (Advanced Research in Telecommunications Systems), SmallGEO is a flexible geostationary satellite platform which can be tailored to different mission goals. The list of possible applications includes telecommunications, Earth observation and technology testing. With its modular structure, the SmallGEO satellite platform can be modified to meet specific customer requirements. There is a choice between classic (i.e. chemical), electric or hybrid satellite propulsion systems. Depending on the type, SmallGEO satellites have a launch mass of between 2,500 and 3,500 kg, with a permitted payload mass of between 300 and 900 kg.

In a contract for Airbus, OHB has engineered and manufactured EDRS-C, a satellite specifically designed for optical communications: Laser communication terminals manufactured by Tesat-Spacecom with correspondingly high data rates are used to link the satellites, i.e. to establish a connection between the Earth observation satellites collecting the data, as well as intelligence UAVs or mission aircraft, and the EDRS satellites. The connection between the EDRS satellites and the ground stations necessary for data transmission to Earth will be achieved with a set of Ka-band RF (radio frequency) terminals. Data can be transmitted at rates of up to 1.8 Gbit/s.

EDRS-C meets the specific requirements of the SpaceDataHighway, simultaneously expanding the range of applications for which the SmallGEO platform can be used. “Optical data transmission places high demands on the satellite right from the outset. We were able to meet all requirements through various adaptations and enhancements,” explains Dr. Voegt. “For this second SmallGEO mission, we have also expanded our modular TM/TC (telemetry/telecommand) subsystem to include S- and Ka-band operation. And because time-critical and sensitive information will be transmitted, we use electronic encryption systems to ensure secure communications with the satellite.”

At launch, the satellite had a mass of approximately 3.2 tons and measured 3.2 by 2.3 by 4.0 metres. However, EDRS-C now measures 7.7 by 16.8 by 4.0 metres as its two solar modules and the three antennas did not deploy until the satellite was in space.

Team work

“I am very grateful for being able to depend on experienced and highly motivated colleagues in the development of this satellite. Some of them have been working on the project for several years, going well beyond the call of duty especially during the months in which the testing campaigns were carried out in shifts. This is a great team success, which once again testifies to the famous OHB spirit,” says Project Manager Voegt. “I would also like to thank our client Airbus as well as ESA for the good and constructive way in which we worked together.”

As the industrial prime contractor and system lead, OHB utilised the services of numerous subcontractors. “Our partner Tesat-Spacecom supplied the data relay payload including the laser communications terminal that is required for the inter-satellite link. At times we had to coordinate more than 30 international suppliers and service providers. This was fantastic collaboration that produced a solid satellite, something that was demonstrated not only during the test campaign at IABG, which lasted several months, but also during the prescribed test series at the launch site,” explains Project Manager Voegt. The HYLAS 3 payload was delivered to OHB System AG by ESA on behalf of Avanti Communications as a customer-furnished item.

The contractual partners also included other OHB Group companies: LuxSpace in Luxembourg was responsible for the TT&R (telemetry, telecommand and ranging) subsystem, which enables communications with the satellite, and also made contributions to the satellite simulator. Bavarian subsidiary MT Aerospace AG supplied all the structural panels. OHB Sweden was responsible for the Attitude and Orbit Control System (AOCS) and is actively involved in the “intensive care” for the satellite during its first few weeks in space, sending experts to the satellite control center in Oberpfaffenhofen.

The EDRS programme is being supported by the German Space Administration at DLR, which has received funding from the German Federal Ministry for Economic Affairs and Energy and the Bavaria state government for the development of the system.

First there was one, now there are two ... the SmallGEO family is growing!

The first SmallGEO satellite, the H36W-1, was built in the form of a private-public partnership between ESA, OHB and the Spanish satellite operator HISPASAT. It was integrated within the Hispasat satellite fleet in 2017, providing flexible broadband coverage for Spain, Portugal, the Canary Islands and South America.

Apart from EDRS-C (laser relay), another project in the conventional telecommunications segment being handled by OHB System AG is the national satellite project Heinrich Hertz (in-orbit verification of numerous national scientific and technical innovations as well as satellite communications for the German federal armed forces).

Due to its high-level flexibility and modularity, the SmallGEO platform has also been chosen for Europe’s third-generation weather satellites (Meteosat Third Generation, MTG).

OHB is also developing Electra, a satellite with a fully electric propulsion system, which will be able to carry a substantially larger payload due to the lower mass of the propulsion system and complies with ESA’s clean space policy. “Electra gives our customers full flexibility in terms of selecting the launch vehicle and the position of the satellite on board the launch vehicle, the release of the satellite into the target orbit, the desired communications bands (C, Ku/Ka band, flexible) and also scalability with respect to mass, power consumption and heat dissipation,” says Management Board member Guy Perez. “Since we can carry classical bent-pipe or flexible payloads of up to 900 kg and up to 60 transponders with Electra, we are able to assemble tailor-made packages for each mission.”

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