September 26 Monday, 2016 has to be written in golden letters in the history of India’s space exploration as the scientists of the country proved to the world that the Polar Satellite launch Vehicle, the time tested workhorse of Indian Space Research Organisation (ISRO) could be made to perform as per the needs and requirements of the customers.
The day saw PSlV-C 35, the trusted workhorse of ISRO, deploying eight satellites in two different orbits in a mission described as an ‘exciting and excellent mission’ by K Sivan, director, Vikram Sarabhai Space Centre, Thiruvananthapuram, the nerve centre of India’s space research.
At the stroke of 09.12 hrs, the PSlV blasted off from SDSC, India’s gateway to the skies with eight satellites on board. It deployed SCATSAT-1, a 377 Kg earth observation satellite into an orbit 730 km away from the earth after 17 minutes of its lift off. By the time it reached the first port of call (the orbit 730 km away from earth), the three stages of the rocket had been burnt down and the firing of the fourth stage had begun.
Within seconds, the engine of the fourth stage of the vehicle was shut down and it began its descend to a different orbit , 670 km away from the earth, to deploy the remaining seven satellites into their pre-destined positions. A series of embedded commands programmed into the brain of the spacecraft made the vehicle to shut down the fourth stage of the rocket within seconds of it placing the SCATSAT-I into the destined orbit at 730 km from the earth.
It took the spacecraft two hours and 15 minutes to enter the orbit 670 km away from the earth for deploying the remaining satellites. The motion of the spacecraft between the deployment of SCATSAT-1 and the remaining satellites was being monitored by ISRO’s two tracking stations in the North and South Poles. Once B Jayakumar, mission director, made the announcement that all the satellites have been deployed successfully, a beaming AS Kiran Kumar, chairman, ISRO, who was keenly watching the process from the word go, announced to the world that it was a landmark day in the history of the country’s space agency. “It has been a successful mission. We have deployed all the satellites including the six customer satellites into their respective orbits,” said Kumar.
The seven other satellites deployed by the PSlV-C35 mission include three Algerian satellites, one satellite each from the United States of America and Canada. Two academic satellites fabricated by the students of Indian Institute of Technology-Bombay and PES University, Bangalore too were deployed with this mission.
With this mission, Indian space scientists proved to the world that they could launch multiple satellites into multiple orbits with a single launch vehicle. Jayakumar described PSlV as the most competitive launch vehicle the manoeuvrability of which was in full display during the PSlV-C 35 mission. Though ISRO had deployed multiple satellites in a single mission in the past, this is the first time the satellites were injected into two different orbits.
The SCATSAT-1, according to Kiran Kumar, is a stopgap arrangement to continue the services rendered by the aging OCEANSAT-2, launched in 2009. It has a life period of five years. The satellite will help the country’s meteorologists to forecast with precision the possibility of cyclones and study other ocean parameters.