Assembled, Modular Hardware Architectures - What Price Reconfigurability?

Recent robotic technology advances have motivated increased interest in the potential of on-orbit assembly to significantly enhance mission capability and scope. Re-usability of space exploration hardware in general is often discussed for its potential to vastly reduce the cost of space operations, and is cited as a potential benefit of on-orbit robotics. But does reconfigurability come at the cost of assembly or performance efficiency? This article specifically evaluates the potential use of highly modular material systems - such as reversibly assembled cellular composite materials - as the basis for re-configurable exploration hardware. First, a dimensional scaling argument is presented to suggest that systems of all sizes can benefit from mass savings associated on-orbit assembly. Next, we examine the relative energetic cost of various strategies for on-orbit manufacturing (reconfiguration, reuse/recycling, deposition based additive manufacturing, or conventional forming processes) and conclude that investment in mechanically assembled reconfigurable material systems holds the potential for orders of magnitude reduction of energy required for long-term on-orbit manufacturing activities. We propose that discretely assembled cellular materials are strong candidate systems, and show that the parasitic mass penalty associated with reversible mechanical connection hardware can be characterized and is well-bounded. Finally, we discuss notional missions at a high level to motivate future detailed analysis and evaluation of various mission architectures.