Electric Orbit Raising: a premiere for Europe

Artist rendition of EUTELSAT 172B. Credit: Airbus

Launched on 1 June, EUTELSAT172B is the first European-built satellite to use Electric Orbit Raising and has now reached geostationary orbit, breaking the record for the fastest satellite electric orbit raising. This use of electric propulsion to raise its orbit to an In Obit Test (IOT) position means that the satellite is on track to reach its 172° East operational longitude by mid-November. Once at that location, it will continue to use electric propulsion for station-keeping, to maintain its geostationary position.

The EUTELSAT172B launch on 1 June.  Credit Arianespace

Electric propulsion has been used for station-keeping on E3000-based satellites since 2004. Eutelsat 172B is the first E3000 to use it for orbit raising as well.

EUTELSAT 172B is scheduled to enter into service in the fourth quarter of this year, whereupon it will commence operation of its advanced communications payload. It is flying fourteen C-band and thirty-six Ku-band transponders, including a special high-throughput Ku-band payload designed specifically for in-flight broadband, with multiple spot beams targeting busy Asian and trans-Pacific flight paths.

EUTELSAT 172B was built by Airbus based on the company’s E3000 EOR platform.

The role of ARTES

The European Space Agency, through the Competitiveness & Growth (ARTES C&G) element of the ARTES programme, supported the development of a number of key technologies that made this innovative mission possible. These encompassed both the Airbus E3000 platform as well as the satellite’s payload.

The mechanical platform, including the core spacecraft structure and equipment, was developed with the support of ARTES C&G, integrated and tested at the company’s Stevenage site in the UK.

The spacecraft’s electric propulsion thrusters are mounted on a pair of fully-articulated robotic arms, another new technology being used for the first time on a European mission. They were designed and qualified by Airbus and Euro Heat Pipes (BE) also with the support of ARTES C&G.

By mounting the thrusters on deployable arms, they can be aligned tangentially to the optimal orbital path for maximum possible thrust during the Electric Orbit Raising stage. For subsequent station-keeping operations, they can then be re-orientated to optimise North-South station-keeping efficiency and are also able to perform East-West station-keeping and angular momentum control.

Positioning the high-powered thrusters at some distance from the body of the spacecraft also minimises electrical interference to the payload and reduces the impact of thruster plumes on antennas and solar arrays.

To power the thrusters, EUTELSAT 172B is also flying for the first time the PPU Mk3 power supplies manufactured by Thales Alenia Space (Belgium), developed and space-qualified with the support of the Belgian government and ARTES C&G. The new unit is specifically designed to power Hall Effect thrusters in the 5 kW class.

In another ARTES C&G activity, prime contractor Airbus (France) extended the Attitude and Orbit Control System (AOCS) capabilities of the E3000 platform to make it compatible with all-electric missions. This Star-Tracker-based AOCS is now suitable for chemical satellites, hybrid satellites, and all-electric missions.

One of the AOCS actuators is a new 100 Volt electronic Reaction Wheel Assembly, manufactured by Rockwell Collins Deutschland. It was also designed and space-qualified with ARTES C&G support.

As part of its payload, EUTELSAT 172B is flying a new flexible multi-port amplifier. The engineering model for the unit was developed and qualified by Airbus with ARTES C&G support. The new MPA has been aligned for wideband operation, allowing performance to be maintained over the entire Ku-band 10.7 to 12.75GHz downlink band for all beams and redundant configurations, without the need for adjustment, calibration, or operator intervention.

LAUNCH MASS

Because EUTELSAT 172B uses electric propulsion for both orbit raising and long-term station keeping, it had a launch mass of only 3,551 kg. As a result, it could be launched last June using the Ariane-5ECA lower position, resulting in significantly lower launch costs.

“Thanks to significant improvement in the ratio of payload mass to platform mass, all-electric satellites are becoming economically very attractive,” says Michael Harverson, Head of the Payload Technologies and Products Section of ESA’s Telecommunications Directorate. “This is a critical advantage in the highly competitive commercial telecoms market, hence we expect to see an increasing number of all-electric missions in the future.”

Published 03 October 2017
Last updated at 13 October 2017 - 10:01