Large-scale software projects place special demands on the developing organization and can require much greater participation by outside companies. The IRIDIUM project is one of the most ambitious engineering projects of the past few decades and certainly one of the largest commercial engineering projects ever undertaken. When project planners first conceptualized the IRIDIUM system, they realized that much of the domain expertise for it lay within the US defense and space industry and in other major suppliers around the world. Motorola's Satellite Communications Division began as a brokerage organization, managing many suppliers who were contracted to develop the software. We have learned that suppliers of all sizes can have mature software processes and that mature processes exist among suppliers of every geographic distribution. The most important lesson we have learned is to follow up with suppliers so that they know the importance we place on quality and process improvement.