Assessing the Science Benefit of Space Mission Concepts in the Formulation Phase

Abstract

The formulation of science-driven space mission concepts is challenging – possibly even more so than the development and production of the space systems themselves. The formulation of these missions involves defining science objectives, surveying the state of the art of instrument capabilities, documenting the Program of Record and forecasting satellite lifetimes, defining feasible alternatives for spacecraft platforms and access to space, and identifying potentially enabled applications to cite only some of the tasks faced by mission design teams. The trade space is vast, especially in an era of novel platform concepts where constellations of SmallSats are changing the current paradigm of spaceborne observations. A crucial component of the formulation of science mission concepts is the assessment of the alternatives defined in this trade space. The assessment of the concepts is so complex that a heuristic approach does not sufficiently articulates the benefits of the alternatives under consideration. This complexity can be attributed to several factors. Science missions have to satisfy multiple science goals and their associated science objectives, therefore entering the realm of multi-criteria decision problems. In addition, multiple instruments, platforms, launchers, and ground system options are combined to define the architectures. The alternatives under assessment in these multi-criteria decision problems are numerous, as are the possible components of the segments that make up the architectures. Finally, stakeholders involved in the design and assessment of these science mission concepts have varying value systems: priorities relevant to stakeholders vary from group to group based on interests, objectives, and experiences. The complexity is such that the assessment requires a deliberate and structured approach to provide a comprehensive assessment of the mission concepts. This paper presents an approach that enables the assessment of the science benefits achieved by a space mission concept in the formulation phase. The approach combines Utility and Quality assessments provided by Subject Matter Experts to produce a Science Benefit score for each identified science objective. The paper discusses how this approach was tailored for the assessment of Observing Systems in the Aerosols, Cloud, Convection, and Precipitation (ACCP) study. In this Earth Science application, Utility quantifies how important a given geophysical variable is to addressing an identified science objective, while Quality quantifies how well an architecture obtains a geophysical variable with respect to Minimum levels listed in the Science Traceability Matrix. The resulting Benefit score articulates the science capability of a given architecture to address a given objective. This paper also presents the processes implemented to obtain the assessments from Subject Matter Experts in the ACCP study.