When is a satellite not a toaster?

Automobiles are repaired but inexpensive appliances are discarded at the first sign of trouble: they ‘cost too much to fix.’ Comparing $50M satellites with toasters may seem odd, but the analogy can be appropriate. The too-much-to-fix argument can be used in deciding whether to replace or to repair earth satellites. The authors investigated (1) when cost considerations dictate using constellations of expendable satellites to be routinely replaced and discarded on failure, and (2) when circumstances indicate using constellations of satellites to be repaired on-orbit by exchanging failed modules.