Trade space evaluation of multi-mission architectures for the exploration of Europa

Abstract

Recent cuts to NASA's planetary exploration budget have precipitated a debate in the community on whether large flagship missions to planetary bodies in the outer solar system or sequences of smaller missions as part of a long-term exploration program would be more beneficial. The work presented explores the trade between these two approaches as applied to the exploration of Europa and concentrates on identifying combinations of flyby, orbiter and/or lander missions that achieve high value at a lower cost than the Jupiter Europa Orbiter (JEO) flagship mission concept. The effects of the value attributed to the four main science objectives for Europa, which can be broadly classified as investigating the ocean, ice-shell, composition and geology, are demonstrated. The current approach proposed to complete the ocean exploration objective is shown to have conflicting requirements with the other three objectives. For missions that fully address all the science objectives, such as JEO, the ocean goal is therefore found to be the main cost driver. Instrument combinations for low-cost flyby missions are also presented, and simple lander designs able to achieve a wide range of objectives at a low additional cost are identified. Finally, the current designs for the Europa Habitability Mission (EHM) are compared to others in the trade space, based on the prioritization given to the science goals for the exploration of Europa. The current EHM flyby mission (Clipper) is found to be highly promising in terms of providing very high potential science value at a low cost.

Trade space evaluation of ascent and return architectures for a Mars Sample Return mission

“…[17,18] These are typically used to assign additional margins in early cost estimates, but were also shown to help provide more accurate cost correlations when used as mass weightings. The complexity metric defined for this study is therefore an adaptation of the two above-mentioned sets of weightings and the complexity metric presented in [19]. The formula is shown in Equation (4):…”

The Cost of Jointness: Insights from Environmental Monitoring Systems in Low-Earth Orbit

“…Other than noting this relationship, disaggregation literature is largely silent on the topic of cost growth mechanisms-or the specific elements within aggregated technical architectures that increase complexity and contribute to cost growth-and that can be eliminated through disaggregation. Notable exceptions include several authors who note that conflicting performance requirements can induce complexity in aggregated technical architectures [14,50,54,55]. …”

“…Finally, +1 was added to DSM T entries to account for interferences between components. As noted by [41,55,172], components can interfere electromagnetically, mechanically, optically, and through a system's reliability budget. Interferences induce complexity because they must be actively managed and compensated for during the system development process.…”

“…The formula for N cc was derived from a complexity metric that was used to study the disaggregation of spacecraft architectures for planetary exploration [55]; however, by classifying mechanisms in terms of three complexity types-design, process, and architectural-my metric is generalizable to other systems as well.…”

“…Component cost (C i ) can be estimated using system-specific parametric costestimating relationships and corrected for design complexity (C i (DC i )) either by adding a penalty to component mass prior to estimating its cost (as in [41,55]) or by adding a penalty after its costs have been calculated (as in [176]). The weightings that are applied to correct the cost estimate for process and…”