Active debris removal of a Cosmos-3M second stage by hybrid rocket module

The active debris removal of a large object, such as the second stage of Cosmos-3M, is a complex mission which requires the combination of several advanced technologies. A very crucial aspect is the selection of propulsion system, since it must allow the safe removing of the target from a LEO orbit and its controlled reentry in the atmosphere. Hybrid rocket technology seems to be a valuable option due to its high performance and flexible functioning. In particular the use of hydrogen peroxide as oxidizer, provides several advantages: high density, high performance with HTPB and easy reignition capability, monopropellant for attitude control system (RCS). From the preliminary sizing of the Hybrid Engine Module results a propulsion system with a wet weight of approximately 520 kg, a specific impulse of 305 s and thrusts of the order of 12-15 kN. Several tests on non-classical hybrid engines have demonstrated the possibility to obtain higher combustion efficiency and performance than typical hybrid rockets, keeping, in addition, very compact sizes. Nevertheless the hybrid vortex combustion has still to be tested at high ranges of specific oxidizer mass flow rate, typically classic hybrid operative conditions. For the considered mission the diameter of a VFP hybrid engine results of 53 cm, with a total engine length of 91 cm (including nozzle). Such little dimensions make easier the realization of a full-scale engine demonstrator, starting from lab-scale experimental tests, thanks to the small jump of scale. The resulting sizes of HEM as well its weight allow to use low-cost space launchers, such as VEGA or Dnepr-1 and, considering the total launcher carrying capacity (for example VEGA carries about 1500 kg to LEO), multiple ADR missions can be performed by a single launch.