Autonomy has proven vital to many aspects of space missions. On crewed spacecraft, it is necessary when the response is needed faster than human reaction time can provide. On robotic (uncrewed) spacecraft, it is necessary when the delay caused by the round-trip light time precludes Earth-controlled operation. Autonomy goes beyond straightforward automation when the dynamics of a spacecraft’s situation cannot be predicted in advance. Verification of autonomy, essential if we are to trust human lives and expensive missions to its control, is particularly challenging when there is a wide range of possible such situations. This chapter provides case studies of several successfully verified autonomous software systems acting in several phases of spacecraft flight (launch, transit, and entry and landing) and can serve as an example to future spacecraft in methods of successfully assuring spacecraft autonomy.