ISRO set to achieve milestone with its 100th launch from Sriharikota in January 2025

S Somanath, the chief of the Indian Space Research Organization (ISRO), announced on Dec 30 that the space agency is preparing to reach a major milestone: the 100th launch from the Sriharikota space station of Andhra Pradesh will occur in January during a Geosynchronous Launch Vehicle (GSLV) mission.

PSLV-C60, the 99th launch from Sriharikota on Dec. 30, successfully positioned two spacecraft in a circular orbit for the Space Docking Experiment.

"So, all of you have seen the majestic lift-off and the launch of the SpaDeX (Space Docking Experiment) rocket, and for us, this is the 99th launch of any vehicle from Satish Dhawan Space Centre, so that is also a very important number. So, we are going for the 100th launch at the beginning of the next year," said Somnath.

The SpaDeX mission is a low-cost technology demonstrator mission that uses two tiny spacecraft launched by PSLV to demonstrate in-space docking.

The mission's main goal, according to the space agency, is to create the technology required to do in-space docking and undocking with two tiny spacecraft.

"In 2025, we will have many missions to start with the GSLV launching the (navigation satellite) NVS-02 in the month of January," Somanath said in referring to the upcoming launches that ISRO has planned.

The GSLV-F12/NVS-01 rocket was successfully equipped with a navigation satellite by ISRO in May 2023.

The NVS-01 navigation satellite, which weighed roughly 2,232 kg, was successfully launched into a Geosynchronous Transfer Orbit (GTO) by this GSLV rocket.

Of the second-generation satellites planned for the Navigation with Indian Constellation (NavIC) services, the NVS-01 was the first.

Somanath said he hoped the scientists would undertake a lot more space docking experiments in the days ahead on the Dec 30 PSLV-C60 mission.

"It is really an important mission with (India's) space sector reforms and expansion of space activities. There will be many more SpaDeX varieties, including complex missions of docking systems, in the coming days," he said.

According to Somanath, scientists do a conjunction study to see whether a satellite entering an orbit passes very close to another satellite while in the same orbit, which is why the PSLV-C60 rocket was rescheduled from its original 9:58 pm to 10 pm.

"If you find there is any close proximity (between satellites), then we have to move the current satellite a little bit. Either we delay it (the launch) or make it early, so that this proximity condition does not occur," he added.

According to him, scientists spent time determining the optimal moment to launch and liftoff in order to go as far away from the other satellite in orbit as possible.