The lift-off of the test vehicle — that was originally scheduled at 8am from the first launch pad at the Satish Dhawan Space Centre in Sriharikota — was postponed to 8.30am and 8.45am due to unfavourable weather conditions. And again, Isro deferred the launch a few minutes before the lift-off as the engine ignition had not happened nominally. The reason for the launch hold was identified and corrected, and the launch happened at 10am.
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One and a half minutes after the test vehicle lifted off, Isro scientists demonstrated an abort condition, wherein the vehicle intentionally caused an anomaly and allowed the crew module to separate when the vehicle was at around 17km altitude. The crew module then performed tumbling manoeuvres, deployed parachutes and landed in a designated spot on the sea before being recovered. The crew module splashed down in the Bay of Bengal 10km off the coast, and the crew escape system splashed down 14km off the coast.
Isro chairman S Somanath congratulated the team on the successful launch. He said, “We initially wanted the launch to happen at 8am, but there was some weather-related issues and we rescheduled. But after going through the nominal loft off process, there was a hold issued by the ground computer which is called automatic launch sequence computer. It detected and sort of non-conformance for allowing the engine to continue to thrust to further go. This happened due to a monitoring anomaly in the system. We could identify it very fast and correct it and make the vehicle ready.”
Isro had said the Indian Navy team would lead the recovery of the TV-sD1 crew module after the touchdown. Recovery ships positioned at a safe range in sea would approach the crew module. A team of divers would attach a buoy, hoist the crew module using a ship crane and bring it to the shore.
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“We will come back with an analysis and more data on the recovery of the crew module happening now,” Somanath said.
The objectives of the mission included flight demonstration and evaluation of test vehicle sub systems, flight demonstration and evaluation of the crew escape system including various separation systems and crew module characteristics and deceleration systems demonstration at higher altitude and its recovery.
Isro has developed a liquid propelled single stage test vehicle, which used a modified Vikas engine, to carry the crew module and the crew escape system on its fore end. The crew module in the launch is a replica of the module that will carry three astronauts to space.
The crew escape system consists of five types of quick acting solid motors namely crew escape system jettisoning motor, high-altitude escape motor, low-altitude escape motor, low –altitude pitch motor and high-altitude pitch motor, which generate required acceleration for varying mission requirements.
The chairman said the first unmanned Gaganyaan vehicle mission would take place in the beginning of 2024.
Watch Gaganyaan mission: ISRO successfully test fires TV-D1 crew module on second attempt