Hardware emulation and real-time simulation strategies for the concurrent development of microsatellite hardware and software

In small satellite projects on short schedules, there is often insufficient time to develop new hardware and subsequently write software once the hardware is tested and ready. However, emulating the hardware may be useful if the effort involved in doing so is kept to a minimum. The purpose of the emulation should be to act as a substitute for the missing hardware so that flight code can be developed concurrently with the hardware. The use of the real-time development system RT-Lab(TM) provides a flexible environment to develop flight software early in the development cycle of a small satellite. The degree to which hardware can be emulated is investigated using the development of the attitude control system for the MOST microsatellite as an example. A trade study is presented that indicates when the cost of programming the emulator outweighs the benefits. A level of hardware emulation is recommended that facilitates the early development of flight code.