An atom interferometer for inertial sensing in microgravity is under
construction, as part of the I.C.E. (Interférométrie Cohérente pour
l'Espace) collaboration. On-board laser systems have been developed
based on fibre-optic components, which are insensitive to mechanical
vibrations and acoustic noise, have sub-MHz line width, and remain
frequency stabilised for weeks at a time. A compact, transportable
vacuum system has been built, and used for laser cooling and
magneto-optical trapping.

A mixture of quantum degenerate gases, bosonic 87Rb and fermionic 40K,
will be used in order to find the optimal conditions for precision and
sensitivity of inertial measurements. Quantum degeneracy will be
achieved by an all-optical route, using a compressible crossed-beam
design. Microgravity will be realised in parabolic flights lasting up
to 20s in an Airbus. The factors limiting the ultimate sensitivity of
a long-interrogation-time atomic inertial sensor are the phase noise
in reference-frequency generation for Raman-pulse atomic beam
splitters and acceleration fluctuations during free fall.