Gaganyaan TV-D1: ISRO Postponed Launch Of First Test Development Flight Due To 'Monitoring Anomaly', Says Chief

Gaganyaan TV-D1: ISRO Chairman S Somanath said that the vehicle is safe, and that the space agency will soon return with an update after analysing what went wrong.

Gaganyaan Test Flight: The Indian Space Research Organisation (ISRO) has postponed the launch of the first development flight test of the Gaganyaan programme. The mission, known as the Test Vehicle Development Flight (TV-D1), was scheduled to launch on October 21, 2023, at 8:00 am IST. However, the mission was rescheduled to 8:30 am IST and then to 8:45 am IST. But the mission could not take off on October 21, ISRO Chief S Somanath said in a livestream. 

He also said that the vehicle is safe, and that ISRO will soon return with an update after analysing what went wrong.

The mission will be launched from the First Launch Pad at Satish Dhawan Space Centre, Sriharikota, Andhra Pradesh. Gaganyaan TV-D1 is an important mission because it will demonstrate the performance of the Crew Escape System, and is the first mission of Gaganyaan's uncrewed flight tests.

An in-flight abort of the Crew Escape System will be demonstrated, which means that while the Crew Module is in the air, the Crew Escape System will be jettisoned, so that ISRO will be able 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 will abort the TV-D1 mission at Mach number 1.2, which means that at the time of abort, the speed of the Crew Module will be 1.2 times the speed of the sound in air.

The reason why ISRO will abort 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 achieves this speed, the abort command will be given. The role of the Crew Escape System is to safely pull out the Crew Module from the launch vehicle, so that the Crew Module and the Crew Escape System can go in a direction different from that of the launch vehicle.

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

A single-stage liquid propelled test vehicle equipped with a VIKAS engine will carry the Crew Module and the Crew Escape System to an altitude of 11.7 kilometres in about 60 seconds. At that time, an abort command will be given. As a result, the Crew Escape System will pull the Crew Module out of the launch vehicle, and take the Crew Module to an altitude of 16.7 kilometres. Drogue parachutes will be deployed so that the velocity of the crew module is decreased. The main parachute will be deployed when the Crew Module reaches an altitude of 2.5 kilometres above sea level.

Eventually, the Crew Module will splash down into the Bay of Bengal, and will be recovered by the Indian Navy.