New Delhi: Following the successful deployment of the CMS-03 communications satellite for the Indian Navy, there was an extended silence before the Mission Director Victor Joseph announced the success of the mission. This was because ISRO conducted an additional ‘experiment’ that was not disclosed ahead of the mission, or informed to the viewers of the live programming. ISRO Chairman V Narayanan explained, “Generally, immediately after the end of the third stage, we clap and get up, you have observed. Today, we were waiting, because, we had planned an experiment. After the satellite is injected, we wanted to reorient the cryo stage, and after something around 120 seconds, we have targeted a restart experiment. So for two minutes of pin drop silence, we were all waiting for that result to come. Probably you have misunderstood that why we people were so silent. We wanted to get that experiment data to declare as a great success, first time success. For that, we were waiting.”
ISRO has used the LVM3 mission to place multiple satellites in orbit, but these were in similar orbits, all belonging to the OneWeb constellation. The LVM3 is the mightiest operational rocket in ISRO’s fleet, and is used for heavy geosynchronous satellites, or flagship interplanetary missions. To deploy constellations of small satellites, the upper stage of the rocket has to cut off its engines, coast, and refire the engines to inject the payloads in multiple target regimes. The PSLV, ISRO’s workhorse rocket does this routinely, but uses a liquid upper stage. The LVM3 uses an indigenously developed cryogenic upper stage that is not as easy to restart as a liquid stage. With the experiment, ISRO has demonstrated the capabilities of the LVM3 upper stage of injecting multiple satellites into different orbits.
Flexibility for future missions
The advanced capabilities of the upper stage now enables debris mitigation strategies to ensure the sustainable use of outer space, in addition to deploying satellites in a variety of orbits. ISRO Chairman V Narayanan went on to explain, “Suppose if you want to place two satellites, one in one orbit and another in another orbit, what is required is you stop the system then inject the satellite, then of course you can restart. Even as part of debris management also, if you want to push the cryogenic stage to some areas, here also, this will be really helping. This is a very important experiment which has been carried out, and further studies have to be done. We have to analyse the data and this will help in a very big way for the future flexible mission management.”