PicSat is a nano-satellite designed to measure exoplanetary transits. The project, conducted within the High Angular Resolution Astronomy group at LESIA, uses interferometric instrumentation, integrated optics and single-mode fibre filtering for the study of stellar environments.
The science instrumentation on-board the PicSat satellite has been specifically designed for the observation of the transit β Pictoris. It is capable of achieving high precision photometric measurements on bright targets, in the visible band (up to 100 ppm/hour on β Pictoris, which has a magnitude of 3.86 in the visible band). To do so, it uses a 5cm optical telescope, coupled to a state-of-the-art single-pixel avalanche photodiode by a single-mode optical fiber.
The photodiode provides extremely precise measurements of the number of photons hitting the telescope at any given time, and the optical fiber, with its very small core, helps to get rid of all the background noises (light coming from the Moon or the Earth, and scattered by the telescope structure, for example).
But because the optical fiber is so small (about 3μm in the focal plane of the telescope, which is equivalent to about 2 arcsec on the sky), a very fine pointing system is required, to ensure that the fiber will always stay centered on the science target. This is achieved by a dedicated algorithm driving a two-axis piezoelectric actuator on which the fiber is mounted.
The ID101 from ID Quantique was chosen for its robustness, ease of integration and compact dimensions.
More about the PicSat Mission