ThispublicationpresentstheproceedingsofICPMSE-7,theSeventhInternational Conference on Protection of Materials and Structures from Space Environment, held in Toronto May 10–13, 2004. The ICPMSE series of meetings became an important part of the LEO space communitysinceitwasstartedin1991.Sincethen,themeetinghasgrownsteadily, establishing itself as the only North American event covering the various aspects of materials protection in LEO and attracting a large number of engineers, - searchers, managers, and scientists from industrial companies, scienti?c insti- tionsandgovernmentagenciesinCanada,USA,Asia,andEurope,thusbecoming a true international event. The ICPMSE-7 meeting continued the tradition of the previous meetings including in the program the topics on protection of materials in GEO and Deep Space. The conference was organized by Integrity Testing Laboratory Inc. (ITL), and hosted by the University of Toronto's Institute for Aerospace Studies (UTIAS). The meeting was sponsored by: a) The Materials and Manufacturing Ontario (MMO) and the CRESTech, two Ontario Centres of Excellence that from April 1, 2004 joined under the - tario Centres of Excellence Inc. (OCE Inc) a not-for-pro?t, member-based corporation dedicated to establishing Ontario as the place to be for innovation; b) MD Robotics; c) The Integrity Testing Laboratory (ITL) and d) The University of Toronto Institute for Aerospace Studies (UTIAS). Over 80 people from countries covering the American, European and Asian continents registered for the conference representing the major space agencies and the major companies, institutions and government organizations involved in space activities, indicating a further increase in international co-operation in this critical area of protection of materials inspace.