ALE-1, a micro-satellite created for the demonstration of artificial shooting stars, required orbital descent before mission execution due to safety aspects in orbit. ALE-1 utilized a drag sail called SDOM (Separable De-Orbit Mechanism) for a passive de-orbit maneuver, which was successfully completed, lowering the orbit from about 500 km down to about 400 km. This paper summarizes the detailed history of satellite operation and the results of the de-orbit maneuver demonstration during the past three years. Although the SDOM sail faced difficulty in keeping the desired deployed shape of the drag sail due to mechanical troubles, by letting the sail be a drag flag instead, it could still deliver a meaningful de-orbit performance to allow the satellite to successfully lower the orbit as planned. The de-orbit effect of the drag flag was evaluated using comparisons between orbit propagation simulations and the actual orbit transition flight data provided in the form of TLE (Two-Line Element) sets. Through this study, it is demonstrated that the SDOM can provide orbit transfer capabilities for satellites. Furthermore, the de-orbit performance of the drag flag can be evaluated, which could be an important reference for the future implementation of de-orbit devices to solve space debris problems.

Many satellites are currently in orbit around the Earth and will remain so for years, even though they have completed their intended missions owing to their long natural de-orbiting times. Many methods have been proposed to increase the de-orbiting speed of such satellites, of which one uses atmospheric drag sails. The micro-satellite ALE-1 is equipped with a drag sail that is deployed at a distance from the satellite through the use of a boom element to ensure continuous communication and solar charging. The drag sail is also capable of separating itself from the micro-satellite if necessary to decrease the de-orbiting speed. This paper discusses an in-orbit demonstration where the aforementioned boom element is extended, as well as the deployment of the aforementioned drag sail and com-pares the space and ground experiment results.