ACES Platform carrying the PHARAO instrument

ACES (Atomic Clock Ensemble System) is an ESA project including two atomic clocks:

• PHARAO: (horloge atomique par refroidissement d'atomes de césium) caesium cold atom clock developed by CNES,
• SHM: Space Hydrogen Maser developed in Switzerland.

The size of ACES is about 1 m³, it weighs 225 Kg and needs 450 W of electrical power.