This research aims to develop a web application to realize open model-based collaboration (Open MBC), which is a framework to support efficient and collaborative development of complex systems. We describe the concept of Open MBC and the features of the web application. Furthermore, we introduce an actual case, presenting requirements analysis and management to use the application in the CubeSat project at Osaka Prefecture University. Feedback from students described the difficulty of systems engineering and functional weaknesses prevented the use of our application. Based on this feedback, the paper proposes improvements to functions and operation methods.