ISRO has reached a significant milestone in its Gaganyaan program by successfully transferring the first solid motor segment from the production facility to the launch complex. This transfer is a crucial step towards preparing for the upcoming HLVM3 G1 flight, which is part of India's ambitious human spaceflight initiative. The agency announced this achievement on social media, emphasizing that it marks a pivotal moment in realizing India's human spaceflight aspirations.

The announcement came days after the space agency conducted 'well deck' recovery trials of the Gaganyaan with the Indian Navy on December 6.

The Gaganyaan mission aims to demonstrate India's capability for human spaceflight by sending a crew of three astronauts into low Earth orbit at an altitude of 400 kilometers for a three-day mission. The crew will return safely to Earth, landing in Indian waters.

Taking to the social media platform ’X,’ the space agency stated, "A significant milestone for the Gaganyaan Program! The first solid motor segment has been moved from the production plant to the launch complex, marking a key step towards the HLVM3 G1 flight. India’s human spaceflight dreams are taking shape!" Gaganyaan, India’s first human space mission, is one of the projects approved by the Union Cabinet.

Key Components And Developments

Solid Motor Segment: The solid motor segment is integral to the Human Rated LVM3 (HLVM-3) rocket, which has been specifically designed to meet human rating requirements for safety and reliability during manned missions.

Launch Vehicle: The HLVM-3 will utilize various propulsion stages, including solid, liquid, and cryogenic stages, with enhancements made for human safety.

Testing Milestones: Prior milestones include successful tests of the Gaganyaan Service Module Propulsion System and the HS200 solid rocket booster, which is among the largest operational boosters globally. These tests have confirmed the performance and reliability necessary for human spaceflight.

CE-20 Cryogenic Engine: ISRO has successfully carried out the sea level hot test of its CE20 Cryogenic Engine featuring a nozzle area ratio of 100 at ISRO Propulsion Complex, Mahendragiri, Tamil Nadu on November 29, 2024. Performance of a multi-element igniter that is required for engine restart capability was also demonstrated during this test.

Testing the CE20 engine at sea level poses considerable challenges, primarily due to the high area ratio nozzle which has an exit pressure of approximately 50 mbar. The main concern during testing at sea level include flow separation inside the nozzle, which leads to severe vibrations and thermal problems at the flow separation plane leading to possible mechanical damage of the nozzle. In order to mitigate this issue, the flight acceptance tests for CE20 engines are currently being performed at the High-Altitude Test (HAT) facility, thereby adding complexity to the acceptance testing procedure.

Gaganyaan project envisages demonstration of human spaceflight capability by launching crew of three members to an orbit of 400 km for a three-day mission and bringing them back safely to Earth, by landing in Indian sea waters.