Off-The-Shelf and Free Software Technologies for Spacecraft Control & Command: An Example, Balloon-Borne Stabilised Gondolas

摘要

Balloons are low-cost, short development time space vehicles for science missions and technology in-flight experiments that need out-of- atmosphere or in-situ measurements, thus being complementary to the satellite. CNES stabilised gondolas are versatile space platforms used to fly science instruments mainly for aeronomy and astrophysics that need stabilisation and pointing capabilities, analogous to satellite attitude control subsystems. In order to increase gondola flexibility to new missions, promoted control & command technologies are those of industrial computers, ground networks, free software and, over all, Ada language, for they are open, standard, powerful, low-cost and longlasting solutions. After a brief description of domain- oriented characteristics of stabilised gondola control & command, this paper introduces the various technologies and main design principles proposed to meet system-level goals. Then focus is put on on-board architectures (Ada95 real-time distributed applications), and describes the prototyping work and preliminary development done to ensure feasibility. The paper then discusses the applicability of such solutions to global, ground-toboard, distributed control & command applications, through an IP-based telemetry & telecommand link, such as the one under development in CNES for balloon systems. As a conclusion, this paper shows how adoption of the above technologies for other space programs such as satellite platforms and payloads may change design, development costs, duration and organisation, as well as it may open new ways in ground-to-board communication and spacecraft operation.