  This paper serves as one of the first efforts to enable large-scale and
long-duration autonomy using the Boston Dynamics Spot robot. Motivated by
exploring extreme environments, particularly those involved in the DARPA
Subterranean Challenge, this paper pushes the boundaries of the
state-of-practice in enabling legged robotic systems to accomplish real-world
complex missions in relevant scenarios. In particular, we discuss the behaviors
and capabilities which emerge from the integration of the autonomy architecture
NeBula (Networked Belief-aware Perceptual Autonomy) with next-generation
mobility systems. We will discuss the hardware and software challenges, and
solutions in mobility, perception, autonomy, and very briefly, wireless
networking, as well as lessons learned and future directions. We demonstrate
the performance of the proposed solutions on physical systems in real-world
scenarios.
