ISRO chairman S Somanath said the success gave the space agency "greater confidence," as the GSLV will be next deployed in the NISAR mission, a collaborative effort with the US' NASA.
The mission is targeted for launch in the fourth quarter of 2024.
The COVID-19 lockdown has hit several projects of the ISRO including Chandrayaan-3, which was scheduled to be launched in late 2020, and Gaganyaan, the country's first manned space mission.
'When a Project Director is appointed, the whole organization -- including the Chairman ISRO -- works for his success. It is a lesson that has been of abiding value all through the other projects I have worked on,' recalls the late President, one of the earliest pioneers at ISRO.
Swapnila said they saw the GSLV Mk-III rocket that will launch the mission into space. "It was so huge," she added.
Indian Space Research Organisation will announce a revised launch date later.
The mission life of the 2,250kg GSAT-7A, built by ISRO, is eight years. It will provide communication capability to users in Ku-band over the Indian region.
PSLV C-29 blasted off from the Satish Dhawan Space Centre, about 110 km from Chennai, at 6 pm and released the six satellites one by one into a 550 km circular orbit.
It is important for India to develop multiple launch sites and become capable of undertaking more launches in a year's time, says Ajey Lele.