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PicSat was a three unit CubeSat (measuring 30 cm x 10 cm x 10 cm) which was developed to monitor the beta Pictoris system. The main science objective was the detection of a possible transit of the giant planet beta Pictoris b's Hill sphere. Secondary objectives included studying the circumstellar disk, and detecting exocomets in the visible band. The mission also had a technical objective: demonstrate our ability to inject starlight in a single mode fiber, on a small satellite platform. To answer all those objectives, a dedicated opto-mechanical payload was built, and integrated in a commercial 3U platform, along with a commercial ADCS (Attitude Determination and Control System). The satellite successfully reached Low Earth Orbit on the PSLV-C40 rocket, on January, 12, 2018. Unfortunately, on March, 20, 2018, after 10 weeks of operations, the satellite fell silent, and the mission came to an early end. Furthermore, due to a failure of the ADCS, the satellite never actually pointed toward its target star during the 10 weeks of operations. In this paper, we report on the PicSat mission development process, and on the reasons why it did not deliver any useful astronomical data., Comment: 11 pages, 11 figures

The FIRST-S project is an astronomical project in the context of exoplanet detection. The scientific objective of this mission would be to study the visible emission of exozodiacal light in the habitable zone around the closest stars. It requires high dynamic range (103) at moderate resolution (arcsec). The proposed instrument is 60 cm baseline stellar interferometer with nulling capabilities based on single-mode fibers and LiNbO3 (Lithium niobate) photonic ship on a 6U CubeSat. This nulling technique is currently developed in the context of FIRST project (Fibered Imager foR a Single Telescope), and is suitable for a nanosatellite application. The first part of this challenge – controlling the injection of the star light in a single-mode fiber with a accuracy of 1 arcsecond – is addressed by the PicSat mission. PicSat is using a 2 stages pointing system: the Attitude Determination and Control System (ADCS) of the platform, and the control of a 2 axis piezo stage. The design is based on two 9cm aperture telescope, inspired by the PicSat payload. The light collected by these two telescopes is guided with the single mode fibers to the integrated active optics. The active part of this ship controls the optical phase difference to a nanometer accuracy over few microns and allow to scan the null fringe. The interferometer itself is used as an OPD sensor and interacts with the ADCS of the platform to maintain this OPD lower to few microns. In this presentation I will present the performances of PicSat on which be can base this design. The satellite design will then be described including the telescopes and injection into fibers and the recombination system. Finally the first results on a lab demonstrator with these parts will be shown.