  The idea behind FIRST (Fibered Imager foR a Single Telescope) is to use
single-mode fibers to combine multiple apertures in a pupil plane as such as to
synthesize a bigger aperture. The advantages with respect to a pure imager are
i) relaxed tolerance on the pointing and cophasing, ii) higher accuracy in
phase measurement, and iii) availability of compact, precise, and active
single-mode optics like Lithium Niobate. The latter point being a huge asset in
the context of a space mission. One of the problems of DARWIN or SIM-like
projects was the difficulty to find low cost pathfinders missions. But the fact
that Lithium Niobate optic is small and compact makes it easy to test through
small nanosats missions. Moreover, they are commonly used in the telecom
industry, and have already been tested on communication satellites. The idea of
the FIRST-S demonstrator is to spatialize a 3U CubeSat with a Lithium Niobate
nulling interferometer. The technical challenges of the project are: star
tracking, beam combination, and nulling capabilities. The optical baseline of
the interferometer would be 30 cm, giving a 2.2 AU spatial resolution at
distance of 10 pc. The scientific objective of this mission would be to study
the visible emission of exozodiacal light in the habitable zone around the
closest stars.
