In 1955, the first cesium beam clock paved the way towards high performance atomic clocks and completely changed the impact of time and frequency domain on science and technology. The basic postulate is that atomic properties are invariant in space and time. The technical improvements gave birth to permanently increased performances - roughly by a factor of 10 every 10 years - and, since the beginning of the seventies, to many unexpected applications such as GPS, which associates space and clocks. During the eighties, the development of atom cooling by laser radiation made it possible to obtain a new step in the clock performance by means of atomic fountains. The ultimate improvement to be obtained in microwave atomic clocks with cold atoms will be in microgravity environment with PHARAO, French acronym for 'Project of atomic clock using in orbit atom cooling'. It will be the heart of the ACES - Atomic Clock Ensemble in Space - mission aiming at the test of fundamental theories and of new space technologies, the time and frequency transfer with outstanding accuracy.
Temps et micro-gravite: le projet PHARAO-ACES
Zeitmessung und Mikrogravität: das Projekt PHARAO-ACES
Revue de l'Electricite et de l'Electronique - REE ; 6/7 ; 102-108
2009
7 Seiten, 7 Bilder
Aufsatz (Zeitschrift)
Französisch
Le projet "Greenglow" pour contrôler la gravité
Online Contents | 2000
PHARAO LASER Desing and Performances
British Library Conference Proceedings | 2006
|NTIS | 2011
|NTRS
|Pharao bestimmt die Zeit. Internationale Raumstation
Tema Archiv | 2002
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