Miniature Swiss clock to make telling time in space easier

A tiny atomic clock, just five millimetres across, that requires very little power to run has been developed by a Swiss company to improve the sensitivity of sensors and instruments in space.

The company, Spectratime, developed the clock as part of a GSTP contract to build a timing source that is incredibly precise but uses as little power as possible. A timing source with very low power consumption could drastically reduce battery size, weight and cost for any battery-powered operation that requires precise timing but might not be able to access navigation signals or other external synchronisation sources, e.g. mobile phone networks during GPS outages, sub-marine geological research and Earth Observation sensors and instruments.

The clock was developed using commercially available, off-the-shelf parts. The team also built software to monitor and control the clock before testing the prototype at ESTEC to see how it withstood radiation and changes in temperature 

After spending three months in a vacuum, the clock had drifted negligibly from the accurate time and was unaffected by changes in radiation but improvements are still needed to reduce the magnetic sensitivity of the timepiece. It used just 450 mW (about half the power used by a standard clock radio) in the vacuum at -20°C.

Next, the team will rebuild the miniature clock using parts that have already been qualified for space and test how well it can withstand vibrations and shocks. They also hope to use a CSEM ASIC chip that is just 2x2 mm² to enable the tiny clock to run on even less power – under 30mW.