  Orbit-use management efforts can be structured as binding national regulatory
policies or as self-enforcing international treaties. New treaties to control
space debris growth appear unlikely in the near future. Spacefaring nations can
pursue national regulatory policies, though regulatory competition and open
access to orbit make their effectiveness unclear. We develop a game-theoretic
model of national regulatory policies and self-enforcing international treaties
for orbit-use management in the face of open access, regulatory competition,
and catastrophe. While open access limits the effectiveness of national
policies, market-access control ensures the policies can improve environmental
quality. A large enough stock of legacy debris ensures existence of a global
regulatory equilibrium where all nations choose to levy environmental
regulations on all satellites. The global regulatory equilibrium supports a
self-enforcing treaty to avert catastrophe by making it costlier to leave the
treaty and free ride.
