Gaganyaan TV-D1: Crew Module Of First Uncrewed Flight Successfully Splashes Down In Bay Of Bengal

Gaganyaan TV-D1: The first developmental flight test, known as the TV-D1 mission, was launched on October 21, 2023, at 10:00 am IST. It demonstrated the performance of the Crew Escape System. 

Gaganyaan TV-D1: The Crew Module of the first developmental flight test of the Indian Space Research Organisation's (ISRO's) Gaganyaan programme has successfully splashed down in the Bay of Bengal. The first developmental flight test, known as the TV-D1 mission, was launched on October 21, 2023, at 10:00 am IST. Gaganyaan's TV-D1 mission is important because it demonstrated the performance of the Crew Escape System. 

ISRO said in a mission update on X (formerly Twitter) that the Crew Escape System performed as intended, and that the Gaganyaan mission has started on a successful note. 

An in-flight abort of the Crew Escape System was demonstrated, which means that while the Crew Module was in the air, the Crew Escape System was jettisoned. This allowed ISRO to check certain flight parameters, and whether the Crew Escape System can be effectively separated from the Crew Module to save the lives of astronauts in case a mishap occurs. ISRO aims to conduct more test flight missions in the future. 

ISRO aborted the TV-D1 mission at Mach number 1.2, which means that at the time of abort, the speed of the Crew Module was 1.2 times the speed of the sound in air.

The reason why ISRO aborted the TV-D1 mission at Mach number 1.2 is that it is at this stage that the spacecraft is expected to experience the greatest challenge, in terms of vibration and other parameters. Therefore, if any anomalies are likely to occur, they will probably occur at this stage. Mach number 1.2 is about 360 metres per second. Once the Crew Module achieved this speed, the abort command was given. The role of the Crew Escape System was to safely pull out the Crew Module from the launch vehicle, so that the Crew Module and the Crew Escape System could go in a direction different from that of the launch vehicle.

As part of the TV-D1 mission, the subsystems of the test vehicle were also evaluated. The deceleration systems of the Crew Module were tested at higher altitudes. 

For this mission, an unpressurised Crew Module was used, unlike the crewed mission of the Gaganyaan programme, in which a pressurised crew module will be used. Both the pressurised and unpressurised versions have the same mass and size, and are equipped with the same systems for deceleration and recovery, including complete sets of parachutes. 

In the crewed flight test of Gaganyaan, Earth-like atmospheric pressure conditions will be simulated.