ORWELL Demonstrator, the group design project for the MSc in Astronautics and Space Engineering 1998/99, is a demonstrator for an Earth observation (EO) system whose objective is to provide a commercial service complementing current and planned EO systems. Rapid response and low cost are the main mission drivers. The baseline developed uses a constellation of twelve satellites in four planes for the full system, and one of these four planes (with three satellites) for the demonstrator. The payload proposed is a lightweight low- power synthetic aperture radar (SAR). The SAR is technologically demanding but offers the possibility of all-weather 24-hour imaging which is critical for fast-response imaging. A standard minisatellite bus (the SpectrumAstro SA200) is proposed for use in the mission. The report summarises the results of the project and includes executive summaries from all team members. Further information and summaries of the full reports are available from the College of Aeronautics, Cranfield University.