Airbus Defence and Space

Airbus Defence and Space will develop the Atomic Clock Ensemble in Space (ACES) for the European Space Agency

  • The ACES payload accommodates a new generation of atomic clocks on the International Space Station (ISS) for fundamental physics experiments

  • Contract value for the full development of the ACES is €35 M


Friedrichshafen, July 19th, 2010: Alain Charmeau, CEO of Airbus Defence and Space, Michael Menking, Director of Orbital Systems at Airbus Defence and Space and Simonetta di Pippo, ESA Director for Human Space Flight, have signed  a €35M contract for the full development of the Atomic Clock Ensemble in Space (ACES) for the International Space Station (ISS). This contract follows on from several years of pre-development under the prime contractorship of Airbus Defence and Space.


The contract comprises the development of the ACES Flight Model, up to its integration for launch on the Japanese HTV transport vehicle. Additionally it includes the set-up of the ACES specific ground segment, establishing a network of ground reference clocks, communicating with the ISS based ACES payload and its two atomic clocks via Microwave-Link ground terminals.


The ACES payload will test a new generation of atomic clocks in space. The Caesium cold atom clock PHARAO, developed and provided by CNES, and the Space Hydrogen Maser (SHM), funded through the Swiss contribution to ELIPS( European Life and Physical Sciences (Program), are the heart of the ACES payload. They will be characterised and compared to each other, as well as to ground based national time standards in different countries.


The fact that time and frequency can be measured very precisely, far better than any other physical parameter, is basic for physical measurements on relativistic effects. The ACES mission will improve the accuracy of time measurement and therefore enable the analysis of the predictions of the theory of relativity with a higher resolution of up to two orders of magnitude compared to current experiments. This can be achieved by the manipulation of cold atoms under microgravity conditions, allowing longer interaction between the atoms and the laser radiation, because the perturbation from the Earth’s gravitational force is removed.



In the research community the ACES is considered to be one of the most exciting microgravity physics experiments on the ISS ever conceived, and therefore the ACES project is accredited with the highest scientific merits. The ultimate performance of space based atomic clocks in a microgravity environment will be explored and a number of fundamental physics experiments will be performed. A number of ground based atomic clocks, at research institutes world-wide will also participate in the ACES mission.


Delivery of the ACES Payload for launch to the ISS is planned for autumn 2013 with an on-orbit accommodation on the Columbus External Payload Facility (CEPF). The duration of the mission will be at least two years.


About Airbus Defence and Space

Airbus Defence and Space, a wholly owned subsidiary of AIRBUS Group, is dedicated to providing civil and defence space systems and services. In 2009,Airbus Defence and Space had a turnover of €4.8 billion and more than 15,000 employees in France, Germany, the United Kingdom, Spain and the Netherlands. Its three main areas of activity are Airbus Defence and Space for launchers and orbital infrastructure, Airbus Defence and Space for spacecraft and ground segment and Airbus Defence and Space for the development and provision of secure and commercial satcoms and networks, high security satellite communications equipment, geo-information products and services, and navigation services.


AIRBUS Group is a global leader in aerospace, defence and related services. In 2009, AIRBUS Group generated revenues of €42.8 billion and employed a workforce of more than 119, 000.



Press contacts:

Daniel Mosely (Airbus Defence and Space UK)                                                      Tel.: +44 (0)1 438 77 8180

Matthieu Duvelleroy (Airbus Defence and Space FR)                                              Tel.: +33 (0) 1 77 75 80 32

Ralph Heinrich (Airbus Defence and Space GER)                                                   Tel.: +49 (0) 89 607 33971

Francisco Lechón (Airbus Defence and Space SP)                                                 Tel.: +34 91 586 37 41

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