A software engineering environment (SEE) has been designed, developed, and used for the life-cycle support of weapon system software. This SEE consists of two types of facilities: software production and integration. The software production facility consists of a software system that runs on a commercial multicomputer configuration. The approach features increased management visibility of the software development process, increased programmer productivity through automation, reducing the cost-of-change during maintenance, and the use of automated regression testing to improve software quality. These facilities have been used for eight years to develop and maintain weapon system software for several projects. This paper describes accomplishments, refinements to the code and test functions, and a general approach to extend the capabilities into the requirements and design phases. Techniques are described that simultaneously allow different methodologies, programming languages, and target computers to be implemented on the same host computer. Also discussed is the Implementation of a SEE in a distributed computer network.