Instrument testbeds support anomaly resolution and testing of flying instruments (Cassini Imaging Science Subsystem).

System testbed validates analytical modeling approach for predicting flight system dynamics (SIM-PlanetQuest).

Instrument Engineering Model electronics and flight software are tested using spacecraft simulators (Lunar Reconnaissance Orbiter Diviner Instrument).

Software plays a critical role in the science return of an instrument; design decisions for onboard fault protection, commanding and data processing must be made in parallel with those for hardware design. Once those decisions have been finalized, development of Instrument Flight Software (IFSW) and/or Field Programmable Gate Arrays (FPGAs), and the ground instrument testing capability—Ground Support Equipment (GSE)—is begun.

Analysis of the instrument's onboard processing needs determines the trade space between flight software and FPGA. Often, a general-purpose processor and IFSW are the best solution; however, more creative solutions are needed when large amounts of data are processed. Considerable expertise is needed to understand the design possibilities: FPGA alone, combination of FPGA and embedded processor, independent IFSW, or IFSW within the spacecraft bus. Another factor in the IFSW/FPGA decision is the ability to make updates in flight to accommodate hardware behavior changes, new scientific objectives, or instrument anomalies. IFSW updates are straightforward, but this is not the case with the FPGAs currently in use in flight instruments.

Prior to spacecraft integration, instruments undergo extensive testing of the integrated system, subassemblies, IFSW, hardware and software interfaces, and spacecraft interfaces. During mission Assembly Test and Launch Operations (ATLO), the instruments are tested in their flight configuration with the fully integrated spacecraft. GSE software enables instrument testing and calibration, through instrument and spacecraft simulation, data acquisition and analysis, and monitor and control.

Software design and development for these onboard and ground systems require an in depth understanding of the instrument, the interaction of the instrument with the spacecraft, mission science objectives, instrument operations, calibration, data formats and analysis, as well as expertise in the software-related disciplines of real-time embedded programming, FPGA capabilities and limitations, simulation and user interface.