The role of flight software in the spacecraft is becoming more essential if missions are to be considered successful. 1 2 To realize more reliable and continuous independent verification and validation (IV&V) and improve the dependability of flight software, a systems engineering process called Model-based IV&V (MBIVV) was developed and has been applied to flight software for several years. This paper examines the experience of performing MBIVV, a process which augments existing IV&V methods with various potential benefits to improve the dependability of flight software. MBIVV techniques are effective for detecting basic or complex errors and many warnings, all of which may not be identified in existing IV&V processes. Moreover, the techniques can be applied to all or only the critical portions of the target software. The number, level of abstraction, and scope of the models are adjusted to meet the objectives of the IV&V attribute and the complexity of the target flight software. This paper introduces the MBIVV paradigm, activities, and practical applications to demonstrate that this MBIVV is an effective means of ensuring the dependability of flight software.