Development of a miniature atomic accelerometer for spacecraft drag-free force measurement*

Atom interferometers demonstrate state-of-the-art performance in inertial sensors. This technology can be used as an onboard three-axis absolute accelerometer in spacecraft for planetary science measurements. Such an instrument would allow us to measure non-gravitational forces on spacecraft such as atmospheric drag and solar radiation in order to obtain drag-free measurements, opening new possibilities for exploring diverse planetary environments.

 

Our instrument is designed to meet the constraints of a deep space planetary orbiter mission, with a low size, weight and power consumption, while reaching a sensitivity of 3×10^-8 m/s²/√Hz with a sequential measurement of 3 Hz per axis to match the expected state-of-the-art radio link precision. To achieve this, the atomic vacuum chamber is made of a single block of titanium with brazed sapphire windows, which is fully sealed under ultra-high vacuum without active pump. The atomic physical package will be of 2 L and 2 kg. The laser is designed to be agile and compact with a fully fibred laser and optics system and expected to fit in a 1 L and 1 kg package. We also discuss the microgravity environment requirements and schemes for lifting the velocity degeneracy. We will describe the design concept and progresses toward realization of the atomic device.