Indian Space Research Organisation (ISRO) has successfully decommissioned its communication satellite INSAT-4B. INSAT-4B has undergone post mission disposal (PMD) at the end of its life, followed by decommissioning on 24 January 2022, to comply with the UN and the Inter Agency Space Debris Coordination Committee (IADC) recommended space debris mitigation guidelines.
INSAT-4B is the 21st Indian geostationary (GEO) satellite to undergo post-mission disposal, the required propellant for such re-orbiting was included in the initial fuel budget as a part of standard practice. The finally achieved orbit is about 340 km above GEO altitude in perfect compliance with IADC guidelines for space debris mitigation of GEO objects.
INSAT-4B weighed around 3,025 kilograms. It was launched in 2007 using Arianespace’s rocket Ariane 5. The satellite’s mission life was 12 years. After completing nearly 14 years of on-orbit operations, the C band and Ku band payload services of INSAT-4B were seamlessly migrated to other GSATs before commencement of the post mission disposal.
As per IADC space debris mitigation guidelines, at its end-of-life, a GEO object should be raised to a nearly circular orbit well above the GEO belt to prevent its orbit from coming back into the GEO protected region within 100 years of re-orbiting. As per ISRO, in this case, the minimum orbit raise required was 273 kilometres and this was achieved through 11 re-orbiting manoeuvres executed during January 17-23, 2022.
