This paper describes how GNAT Pro for ERC32 and the Ravenscar profile are suitable for designing and implementing complex on-board software using high-level tasking facilities.The static and simple tasking model defined by the Ravenscar profile allows for a streamlined implementation of the run-time system directly on top of bare machines. The reduced size and complexity of the run time, together with its configurability, makes it suitable for mission-critical space applications in which certification or reduced footprint is needed. Software reliability and predictability is also increased by excluding non-deterministic and non analysable tasking features. Product validation has been achieved by means of a comprehensive test suite intended to check compliance with the Ravenscar profile and Ada standards, and correct be- haviour of specialised features and supplemental tools. with the goal of achieving 100% statement coverage.