The PSLV-C56 vehicle successfully injected DS-SAR and six other satellites into their intended 536km circular LEO. The vehicle achieved the precise target orbit conditions in 20 minutes after lift-off using the onboard Navigation, Guidance and Control (NCG) system and completed its mission.
“Left alone in a 536km circular orbit, the PS4 would orbit Earth for more than 25 years. As the number of satellites in LEO is growing and the space around this orbit is of particular interest, the orbit of the spent PS4 was reduced to 300km circular,” Isro said.
Stating that this was in line with India’s commitment to supporting worldwide space debris mitigation efforts, the space agency said: “The onboard guidance algorithm was modified to achieve this orbit-change manoeuvre. The orbit change thrusters (low thrust engines) were fired twice for orbit change.
Further, in line with standard launch practices, the PS4 was passivated after the de-orbiting process, as no further active propulsion needed was anticipated.
“This passivation involved venting of all pressurised compartments (tanks/gas bottles) to release any stored energy or potential hazardous substances. By mitigating the possibility of pressurised compartment failures, the chance of fragmentation of the spent stage in orbit is minimised, thereby further reducing the creation of space debris,” Isro said.