Operation of solid rockets in comparison with hybrid rockets during the STERN project

In April 2012, the German Aerospace Center DLR launched a support program for students to develop, build and launch their own rockets over a period of three years. The program goes by the acronym STERN (STudentische Experimental-RaketeN). The primary goal of the STERN program is to inspire students in the subject of space transportation through hands-on activities within a project structure, to motivate universities to supervise and support the student projects with the help of financial support and to increase the lecture activities in the field of launcher and propulsion systems. The program is supported by funds from the German Federal Ministry of Economics and Technology (BMWi) and managed by the DLR Space Administration. There are no limits regarding flight altitude or the propulsion systems used by the student teams. The students are free to develop, test and launch their own rocket, or purchase a commercial propulsion system. The main demands for each student project are that (1) the rocket shall reach a velocity of at least Mach 1. Moreover (2) the rocket must have a telemetry system to transmit key trajectory and housekeeping data back to earth during flight and provide information to the students including the rocket altitude. (3) It must have a recovery system. Currently, eight German universities are participating in the STERN-program. In October 2015, the first launch campaign was scheduled in ESRANGE, Sweden. Two solid and two hybrid rockets were launched. Ground and mission operation processes are highly complex and involve a wide variety of technologies. The operation of hybrid rocket motors requires a different kind of care and supervision in comparison to the procedures for a solid rocket motor. This paper describes launch procedures and shows that the vehicle design has a major impact on ground facilities, ground safety and operations