Gaganyaan mission: ISRO launches test vehicle minutes after 'anomaly' delay

Sriharikota, (Andhra Pradesh): ISRO has launched the test Vehicle carrying payloads related to the Gaganyaan human space flight programme on Saturday at 10 am. The mission was on hold due to unidentified technical fault.

Following a two hour delay and nerve-wracking moments after the engine of TV-D1 failed to ignite initially, ISRO scientists put the mission on course 75 minutes later when they launched the rocket with precision and achieved the goal of Crew Module and Crew Escape separation that was welcomed with loud cheers at the Mission Control Center here.

TV D1 Mission was fully achieved, ISRO announced.

"I am very happy to announce the successful accomplishment of the TV-D1 mission. The purpose of this mission was to demonstrate the crew escape system for the Gaganyaan program through a test vehicle demonstration in which the vehicle went up to a Mach number, which is slightly above the speed of sound and initiated an abort condition for the crew escape system to function. The crew escape system took the crew module away from the vehicle and subsequent operations including the touch-down at the sea have been very well accomplished. and we have a confirmation of the data for all of this," said ISRO chief S Somanath.

The test Vehicle D1 mission was scheduled for a lift-off from the first launch pad at 8 am which was revised to 8.30 am and later to 8.45 am. However, the space agency confirmed that the liftoff of the test vehicle with crew safety-related payloads in the Gaganyaan mission at Sriharikota is on "hold".

What is TV-D1 mission?

The Saturday morning mission called Flight Test Vehicle Abort Mission-1 (TV-D1) will demonstrate the crew escape system and Saturday’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.

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, the Saturday flight is for flight demonstration and evaluation of test vehicle sub systems; flight demonstration and evaluation of crew escape system 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 tonne, 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.

This Test Vehicle mission with this crew module is 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 will set the stage for the remaining qualification tests and unmanned missions, leading to the first Gaganyaan mission with Indian astronauts, ISRO said.

(With PTI/ IANS inputs)