Gauteng Province's proposal to create large new settlements mainly on the spatial periphery of the city-region is intended both to address the inefficiencies of scattered small-scale developments and to respond to economic decline outside the urban core. An ambition to create self-sufficient satellite towns or cities is, of course, not new. In this paper we assess experience internationally and in South Africa, exploring the extent to which sustainable economies have been created in satellite settlements. Internationally, there is a mixed story. There are instances of success but many more cases of failure, or of initial success with later decline. The frequent consequence of a well-intentioned satellite development internationally is extensive commuting. In Gauteng there is a long history of state- and private-sector led satellite town development. This has included the initial expansion of the mining sector; the later development of towns focused on heavy industry; and the displaced urban settlements around the apartheid-era industrial decentralisation points. While there was success in building economies for periods of time, the developments have proven vulnerable to changing global conditions, shifts in policy, and new local dynamics. In recent years, the Gauteng periphery has declined relative to the core, leaving large numbers of people in poverty traps or dependent on commuting. International and Gauteng experiences offer a sobering lesson for present day attempts to create large new settlements on the spatial periphery where economic prospects are, at best, highly uncertain.