Centralised computation service architecture for the X-Sat micro-satellite

Recent small-satellite developments have been characterised by an increased demand for on-board computational capability. The reasons are manifold and span from the need for autonomy to complete processing of acquired payload data. However, in many cases the needs for all these tasks arise within the same mission and have different, possibly conflicting, requirements in terms of processing resource requests and level of service reliabilities. Due to the design limitations inherent to small-satellites, often a single system is designed that is characterised by a trade-off between the applications and the available resources. Alternatively, multiple dedicated systems are flown which due to their individual designs do not operate in a synergetic manner. To solve the problem this paper proposes a computation service architecture, which almost transparently allocates a given task, a so-called software payload, according to its requirements to an executing unit within the system. Using this concept provides a high degree of resource utilisation, an improved level of reliability, and can cater for changing resource needs during development and mission lifetime without the necessity for a redesign