  The future GAMMA-400 space mission is aimed for the study of gamma rays in
the energy range from ~20 MeV up to ~1 TeV. The observations will carry out
with GAMMA-400 gamma-ray telescope installed on-board the Russian Space
Observatory. We present the detailed description of the architecture and
performances of scientific data acquisition system (SDAQ) developing by SRISA
for the GAMMA-400 instrument. SDAQ provides the collection of the data from
telescope detector subsystems (up to 100 GB per day), the preliminary
processing of scientific information and its accumulation in mass memory,
transferring the information from mass memory to the satellite high-speed radio
line for its transmission to the ground station, the control and monitoring of
the telescope subsystems. SDAQ includes special space qualified chipset
designed by SRISA and has scalable modular net structure based on fast and
high-reliable serial interfaces.
