  In this paper we present a trade study-based method to optimize the
architecture of ReachBot, a new robotic concept that uses deployable booms as
prismatic joints for mobility in environments with adverse gravity conditions
and challenging terrain. Specifically, we introduce a design process wherein we
analyze the compatibility of ReachBot's design with its mission. We incorporate
terrain parameters and mission requirements to produce a final design optimized
for mission-specific objectives. ReachBot's design parameters include (1)
number of booms, (2) positions and orientations of the booms on ReachBot's
chassis, (3) boom maximum extension, (4) boom cross-sectional geometry, and (5)
number of active/passive degrees-of-freedom at each joint. Using first-order
approximations, we analyze the relationships between these parameters and
various performance metrics including stability, manipulability, and mechanical
interference. We apply our method to a mission where ReachBot navigates and
gathers data from a martian lava tube. The resulting design is shown in Fig. 1.
