  On-orbit close proximity operations involve robotic spacecraft maneuvering
and making decisions for a growing number of mission scenarios demanding
autonomy, including on-orbit assembly, repair, and astronaut assistance. Of
these scenarios, on-orbit assembly is an enabling technology that will allow
large space structures to be built in-situ, using smaller building block
modules. However, robotic on-orbit assembly involves a number of technical
hurdles such as changing system models. For instance, grappled modules moved by
a free-flying "assembler" robot can cause significant shifts in system inertial
properties, which has cascading impacts on motion planning and control portions
of the autonomy stack. Further, on-orbit assembly and other scenarios require
collision-avoiding motion planning, particularly when operating in a
"construction site" scenario of multiple assembler robots and structures. These
complicating factors, relevant to many autonomous microgravity robotics use
cases, are tackled in the ReSWARM flight experiments as a set of tests on the
International Space Station using NASA's Astrobee robots. RElative Satellite
sWarming and Robotic Maneuvering, or ReSWARM, demonstrates multiple key
technologies for close proximity operations and on-orbit assembly: (1) global
long-horizon planning, accomplished using offline and online sampling-based
planner options that consider the system dynamics; (2) on-orbit reconfiguration
model learning, using the recently-proposed RATTLE information-aware planning
framework; and (3) robust control tools to provide low-level control robustness
using current system knowledge. These approaches are detailed individually and
in an "on-orbit assembly scenario" of multi-waypoint tracking on-orbit.
Additionally, detail is provided discussing the practicalities of hardware
implementation and unique aspects of working with Astrobee in microgravity.
