Mars Project Software Systems Engineering Improvements

Increasingly challenging missions are characterizedby an expansion of the mission-critical role of software. In theMars projects, Entry, Descent, and Landing (EDL) are softwarecontrolled. EDL relies on software timing and functionality,leading to such things as second chance flight software operatingas a copilot on the backup flight computer. Therefore, much ofthe project risk lies in robustness of software. Within thelaboratory, the Project Software Systems Engineering (PSSE)has the responsibility of planning, systems engineering, andoverseeing all project software while development organizationsdeliver domain specific software, such as Command & DataHandling (C&DH) software, Sample Recovery Helicopter(SRH), Guidance, Navigation, & Control (GN&C) software,Vision Compute Element (VCE) software, Ground Data System(GDS) software, Simulation Support Equipment (SSE)software, etc. The software lifecycle chosen for Mars projectsoftware development is the incremental lifecycle, wherein thecontent and scope of each software release will be built upon thedelivered capabilities of previous releases to achieveincremental functionality. In this context, the challenge stemsfrom the surge in detail and complexity where current softwaresystems engineering practices will be hard-pressed to keep up.This paper describes an assessment of software systemsengineering processes, specifically in the NASA Mars ScienceLaboratory Curiosity Rover, Mars2020 Perseverance Rover,and Mars Sample Retrieval Lander, and identifies potentialefficiencies and improvements. It also describes the innovationsin Mars project software systems engineering and makesrecommendations as to how these evolved and what newmethods and techniques should be infused into flight projects atthe laboratory.