In order to achieve mission success with more demanding mission requirements and more complex onboard software, our software independent verification and validation (IV&V) has been applied to various spacecraft software programs, such as software on satellites, ground stations, and the Japanese Experimental Module (JEM) of the International Space Station (ISS). The malfunction procedure in the operations data file for JEM is also the target for applying software IV&V. Suitable software IV&V can be performed for each spacecraft throughout the entire development life cycle. The objectives for software IV&V activity are the following: applying suitable software IV&V to each spacecraft, creating new software IV&V technologies for spacecraft, and spreading new software engineering technologies based on our software IV&V to development teams and contractors. This paper introduces our software IV&V activities and several examples to confirm that our activities are effective and efficient for spacecraft.