  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.
