Updated on Oct 21, 10.50 a.m.

ISRO successfully launched the TV-D1 test vehicle in second attempt from Sriharikota at 10 am today.

After the lift-off couldn't happen at the scheduled time following an anomaly, the ISRO identified and corrected the errors and launched the TV-D1 test vehicle at 10 a.m. today.

ISRO chief S Somanth said, "I am very happy to announce the successful accomplishment of the Gaganyaan TV-D1 mission".

After rescheduling the test flight at 8.45 a.m. from 8 a.m., ISRO chairman S Somanath has declared that the lift-off system, due to some issue, was put on hold and it could not be launched today.

S Somanath addressed the viewers shortly after the lift-off was put on hold five seconds left into the countdown.

According to S Somanath, the engine ignition in the nominal cause could not happen, putting the launch on hold. However, the vehicle is safe, and ISRO will analyse the vehicle for the issue, and once it is mitigated, the new test date will be announced soon. In the end, Somanath thanked everyone who had joined to witness the test launch.

The scheduled launch of the Gaganyaan test flight

ISRO’s crucial first test flight slated for today at 8.45 a.m. to check the crucial crew escape system of its rocket that would carry the country’s astronauts into space sometime in 2025, could not lift-off today. 

This Test Vehicle mission with this crew module was a significant milestone for the overall Gaganyaan programme as a near-complete system is integrated for a flight test. 

The success of this test flight would have set the stage for the remaining qualification tests and unmanned missions, leading to the first Gaganyaan mission with Indian astronauts, ISRO said. 

What is the TV-D1 test of ISRO for Gaganyaan?

The mission called Flight Test Vehicle Abort Mission-1 (TV-D1) demonstrates the crew escape system and today’s mission is the first of the four such test flights planned by Indian Space Research Organisation (ISRO), said chairman S Somanath. 

In other words, if something goes wrong with the rocket carrying the astronauts in the crew module, then they have to be saved as their lives are at risk. 

The crew escape system is designed to protect the astronauts lives by bringing them safely down to splash on the sea. 

Like a fighter pilot ejecting from a fighter plane, the crew module with the astronauts will get separated and splash down on the sea with the help of parachutes. 

What is Gaganyaan mission?

As per plans, India’s first human space mission or Gaganyaan is expected to happen in 2025 and testing the crew escape system is part of that. 

According to ISRO, today’s flight is for flight demonstration and evaluation of test vehicle subsystems; flight demonstration and evaluation of crew escape systems including various separation systems and crew module characteristics and deceleration systems demonstration at higher altitude and its recovery. 

Measuring about 35 tall and weighing about 44 tonnes, the test vehicle/rocket uses a modified Vikas engine which is powered by liquid fuel.

The crew module and crew escape system are mounted at the fore end of the rocket. 

The entire flight sequence -- from the test rocket’s lift off to the crew module touchdown at the sea with the deployment of parachutes -- will take about 531 seconds or about nine minutes. 

According to ISRO, the mass of the crew module is 4,520 kg and is a single walled unpressurised aluminium structure. At about 61 seconds into the flight and at an altitude of 11.9 km, the test vehicle/rocket and the crew escape system will get separated.

And 91 seconds after the lift off and at an altitude of 16.9 km, the crew module and crew escape system will get separated. 

Subsequently, the abort sequence will be executed autonomously commencing with the separation of crew escape system and deployment of the series of parachutes, finally culminating in the safe touchdown of the crew module in the sea, about 10 km from the coast of Sriharikota, ISRO said. 

The crew module will house the astronauts in a pressurised earthlike atmospheric condition during the real human space mission. 

Currently the crew module for the Gaganyaan mission is in different stages of development. The TV-D1 is an unpressurised version but has an overall size and mass of actual Gaganyaan crew module and would house all the systems for the deceleration and recovery. 

The avionics systems in the crew module are in a dual redundant mode configuration for navigation, sequencing, telemetry, instrumentation and power. 

According to ISRO, the crew module in this mission is extensively instrumented to capture the flight data for evaluation of the performance of various systems. 

The deceleration of the crew module will be done with parachutes with pyro systems. The parachute deployment initiation will be done when the crew module is at about 17 km altitude. 

The crew module will splash down on the sea at about 10 km from the launch pad at Sriharikota at about 531 seconds after the rocket’s lift off and would float till it was recovered by the Indian Navy. 

Recovery ships will approach the crew module and a team of divers will attach a buoy, hoist it using a ship crane and bring it to the shore. The crew escape system will hit the sea at about 14 km from Sriharikota.

(With inputs from IANS)

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