  We investigate how ideas from the International Environmental Agreement (IEA)
literature can be applied to the problem of space debris mitigation. The
problem of space debris is similar to other international environmental
problems in that there is a potential for a tragedy of the commons
effect--individual nations bear all the cost of their mitigation measures but
share only a fraction of the benefit. Consequently, nations have a tendency to
underinvest in mitigation. Coalitions of nations, brought together by IEAs,
have the potential to lessen the tragedy of the commons effect by pooling the
costs and benefits of mitigation. This work brings together two recent modeling
advances: i) a game theoretic model for studying the potential gains from IEA
cooperation between nations with asymmetric costs and benefits, ii) an orbital
debris model that gives the societal cost that specific actions, such as
failing to deorbit an inactive satellite, have on the environment. We combine
these two models with empirical launch share data for a "proof of concept" of
an IEA for a single mitigation measure, deorbiting spacecraft at the end of
operational lifetime. Simulations of all possible coalitions for a proxy set of
12 asymmetric nations suggest the possibility that stable coalitions can
provide significant deorbiting gains relative to nations acting in the absence
of an IEA coalition.
