The accumulation of space debris in low Earth orbits poses an increasing threat of collisions and damage to spacecraft. As a low-cost solution to the space debris problem the Gossamer Deorbiter proposed herein is designed as a scalable stand-alone system that can be attached to a low-to-medium mass host satellite for end-of-life disposal from low Earth orbit. It consists of a 5m by 5m square solar/drag sail that uses four bistable carbon fiber booms for deployment and support. Prior to deployment of the gossamer structure, a telescopic enclosure system is used to displace the sail from the host craft in order to extend the sail without hindrance from the host peripherals, and also provide passive stabilization. The principal advantage of an entirely passive operational mode allows the drag augmentation system to act as a “fail-safe” device that would activate if the spacecraft suffers a catastrophic failure. Several scenarios are analyzed to study the potential application and performance of the system to current and future missions. A detailed breakdown of the mechanical subsystems of the Gossamer Deorbiter is presented, as well as the characterization process of the deployable booms and sail membrane and the full qualification testing campaign at component and system levels. Finally, the performance scalability of the concept is analyzed. •We present a detailed overview of the ESA funded project “Deployable Gossamer Sail for Deorbiting” with the purpose of assisting development efforts of similar programs aimed at tackling the problem of space debris in LEO using gossamer sails. The objective has been to give an overall picture of the usefulness and needs of these gossamer structures, show some of the different analyses carried out to established mission requirements, and present the system design, characterization of structural components and qualification testing process to comply with these requirements.•To identify specific use cases for orbit type and host craft, a number of reference mission scenarios were selected. These include the Orbcomm and Iridium replacement constellation satellites and Vega׳s AVUM upper stage.•Deorbiting under drag conditions using a gossamer sail is effective in raising the ceiling altitude from which objects would naturally decay in 25 years. The addition of a large gossamer sail can also decrease the risk of in-orbit debris generating collisions.•Preliminary analysis showed that the sail system is not expected to increase the ground casualty risk of any mission. However, as this system does provide a parachute-like effect, future fragmentation analysis needs to investigate whether there is any risk of the sail system providing enough deceleration to allow the satellite to survive to the ground. As a safety measure, the booms are not designed to withstand the structural loads at altitudes below 300km.•The static and dynamic structural characterization of the CFRP booms demonstrated the complexity of modeling and testing these slender open-section structures, which are very imperfection sensitive as well as dependent on boundary conditions. Nonetheless, reliable FEA models of the booms were built and these were used to correlate with full-scale modal tests and gravity compensated boom loading tests under flight-like conditions.•The scalability analysis showed that system performance in terms of mass saving with respect to a chemical propulsion deorbiting option can be maintained, as the gossamer sail is scaled to achieve more surface area demanding targets.