Overview of Space Debris Mitigation Activities in ISRO

For several decades orbital debris has been identified as a serious concern by all space-faring agencies and nations as it potentially threatens the current and future space endeavors. The Indian Space Research Organization (ISRO) is well aware of the current space debris scenario and is committed to achieving the goal of preserving outer-space for humanity. ISRO works on different aspects to effectively manage the threats due to space debris. This paper provides an overview of past activities carried out in ISRO towards the implementation of space debris mitigation guidelines. One of the significant step taken is the end of life passivation of the cryogenic upper stage of ISRO’s Geosynchronous Satellite Launch Vehicle (GSLV). Another one is the successful design and development of propellant venting system for the upper stage of ISRO’s Polar Satellite Launch Vehicle (PSLV). ISRO’s constellation of communication satellites orbiting in GSO’s is designed with adequate propellant so that it can re-orbit to the higher graveyard orbit at the end of their operational lifetime. A typical successful re-orbiting and decommissioning operation of INSAT-3E is described in detail here. ISRO has successfully designed and developed the models and software to predict the atmospheric re-entry of satellites and launch vehicle upper stages, also to compute the collision risk between the debris and the operational satellites. ISRO has also developed models to study the evolution of the space debris environment in LEO and GEO. ISRO actively support the efforts of the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS) and Inter-Agency Space Debris Coordination Committee (IADC) to develop and adopt the space debris mitigation guidelines.