ESA Atomic Clock in Space Experiment on the ISS: Getting Ready for Flight

Paper number

IAC-09.A2.1.3

Author

Mr. Giuseppe Reibaldi, European Space Agency (ESA), The Netherlands

Coauthor

Mr. Rosario Nasca, European Space Agency (ESA), The Netherlands

Coauthor

Mrs. Elena Daganzo, European Space Agency (ESA), The Netherlands

Coauthor

Mr. Stephen Feltham, European Space Agency, The Netherlands

Coauthor

Dr. L. Cacciapuoti, European Space Agency (ESA), The Netherlands

Coauthor

Mr. Rudolf Much, European Space Agency (ESA), The Netherlands

Coauthor

Dr. Didier Massonnet, Centre National d'Etudes Spatiales (CNES), France

Coauthor

Mr. Christophe Delaroche, CNES, France

Coauthor

Mr. Pascal Rochat, SpectraTime, Switzerland

Coauthor

Mr. Marc Peter Hess, Astrium UK, Germany

Coauthor

Mr. Roland Stalford, Astrium UK, Germany

Coauthor

Mr. Sylvere Froidevaux, T4Science, Switzerland

Coauthor

Mr. Luca Stringhetti, Astrium UK, Germany

Year

2009

Abstract

The Atomic Clock Ensemble in Space (ACES) is a European Space Agency (ESA) payload to be deployed externally to the Columbus Laboratory on the International Space Station (ISS). ACES is one of the most challenging ISS experiments under development. 

It consists of two high precision atomic clocks, namely the Cs cold atom clock PHARAO (Projet d'Horloge Atomique par Refroidissement d'Atomes en Orbit) and the active Space Hydrogen Maser (SHM). PHARAO is developed by the French National Space Agency (CNES) and the SHM is developed in Switzerland by Spectratime.  The excellent short-term performance of SHM is combined with the long-term stability and accuracy of the PHARAO clock to generate an on-board ACES time scale with fractional frequency instability and inaccuracy of a few parts in 1016. 

A MicroWave Link (MWL) ensures stable and accurate time and frequency transfer for direct comparison of atomic clocks both space-to-ground and ground-to-ground. In particular, comparisons of ground clocks down to the 10-17 frequency uncertainty level will be possible using both common view and non-common view techniques. The MWL Ground Terminals (GTs) will interface with the ACES payload, ground segment and a world-wide network of ground clocks operated by cooperating research institutes. 

The ACES Ground Segment (GS) will be integrated into the overall ISS ground architecture providing the communication links between ground and space through the Columbus Control Centre and NASA ground segment. 

The funding for the ACES flight model was secured at the recent ESA Council at Ministerial level in November 2008. This included funding for the SHM development. CNES also recently indicated its commitment to deliver a flight model of PHARAO.

This paper will review the status of the ACES payload and ground segment development activities. It will also highlight recent progress and outline the future activities necessary to achieve flight readiness for the ACES payload.
 

Abstract document

IAC-09.A2.1.3.pdf

Manuscript document

IAC-09.A2.1.3.pdf (🔒 authorized access only).

To get the manuscript, please contact IAF Secretariat.