The Small Mars Satellite: a European small-size Martian lander

The Small Mars Satellite (SMS) is a proposed mission to Mars. The project is being funded by the General Studies Programme of the European Space Agency and has recently successfully concluded Phase 0 (feasibility study). The prime contractor is ALI S.c.a.r.l. (Naples), and the study team includes the University of Naples “Federico II” (UniNA), the Astronomical Observatory of Capodimonte (INAF-AOC, Naples) and the Space Studies Institute of Catalonia (IEEC, Barcelona). The objectives of the mission are technological and scientific, and consist in delivering to Mars a small lander carrying a dust particle analyser (DPA), developed by INAF-AOC, and an aerial drone (AD), proposed and designed by UniNA. The former shall perform in situ measurements of the size distribution and abundance of the dust particles suspended in the Martian atmosphere, whereas the latter shall execute multiple, low-altitude flights in the rarified environment of the red planet. The mission-enabling technology is an innovative deployable heat shield (DHS), whose original design is known as IRENE (Italian ReEntry NacellE), developed and patented by ALI. The core characteristics of SMS are the low cost (target 120 M€) and the small size (320 kg), features which stand out with respect to previous Mars landers. This target puts strict requirements on the choice of the materials, the sizing of payloads and subsystems, their arrangement inside the spacecraft and the choice of the launcher. Complying with them has been extremely challenging. The reasons for a successful design include the benefits derived from the heritage of previous missions, the implementation of recently developed technology (e.g., the heat shield), and the adoption of COTS hardware and lightweight materials, on the one hand, and a close compliance with system’s engineering (SE) principles, on the other: from the mission objectives to the engineering solutions through requirements formulation and implementation, identification of alternative options, execution of engineering trade-offs and design iterations. Concurrent engineering (CE) has also been applied, not through the use of specialized digital facilities, but by adopting fruitful practices, such as: an efficient project management, frequent team meetings and interactions with the customer, sharing of a common database, and, in general, a constant effort towards critical thinking aiming at identifying weak points and formulating strategies for their improvement. This contribution starts with an illustration of the current state of the project from the mission concept to the design of the spacecraft (Section “Mission description”). The implementation of SE and CE methods is dealt with in specific sections (“Systems Engineering Issues” and “Concurrent Engineering”). A discussion on the experience, the lessons learnt and the future prospects of the project and its design methods closes the paper.