Application of additional inflatable aerodynamic device to ensure the required degradation of the disposal orbit of large-size space debris

Abstract

The paper studies the effectiveness of joint application of active and passive space debris removal technologies in low-Earth orbits.An active spacecraft-collector (SC), equipped with several detachable thruster deorbiting kits (TDKs), ensures the capture of the rocket stage. The TDK of dry mass about 90 kg should be fixed in the stage nozzle. After undocking from the SC, the TDK executes a deorbiting velocity impulse in order to form an elliptical disposal orbit with a predicted lifetime of 25 years in compliance with ISO standard requirements. However, many experts have recently called for a significant enhancement of these requirements.One of the ways to reduce the lifetime of the resulting disposal orbit is to equip the TDK with an aerodynamic decelerator, which has a shape of a spherical balloon. After the deorbiting impulse is applied, the balloon is supercharged by the gas remaining in the pressurized-propellant feed system of the TDK. Rigidization of the balloon shell is carried out by supercharging it above the yield point. The most rational balloon diameters are chosen based on the analysis of its effect on the lifetime of the disposal orbit.If the detachable TDK is equipped with an inflatable balloon, one can consider the combined and hybrid braking schemes. According to the first scenario, the balloon of diameter 12–14 m (“Zenith-2” case) or 7–8 m (“Kosmos-3M” case) is inflated in the already formed 25-year disposal orbit reducing its lifetime to about 5 years, while the dry mass of each TDK increases by 28 kg and 10 kg, respectively. Within the second scenario, a noticeably smaller deorbiting impulse results in a hybrid disposal orbit, which exists for 25 years due to subsequent inflation of the balloon of almost the same size. An analysis shows that the combined braking scheme is more preferable: with an insignificant increase in the SC launch mass, it does not create additional risks of failure and quickly deorbits the object from the most populated altitudes.