Gaganyaan Test Flight: The Indian Space Research Organisation (ISRO) is set to launch the first uncrewed flight test of the Gaganyaan programme on October 21, 2023, at 8:00 am IST. The first uncrewed flight is called the Test Vehicle Development Flight Mission-1 (TV-D1), or the Flight Test Vehicle Abort Mission-1. It will be launched from the First Launch Pad at Satish Dhawan Space Centre, Sriharikota, Andhra Pradesh.
The significance of the Gaganyaan TV-D1 mission is that it will demonstrate the performance of the Crew Escape System, and check if it can save the lives of astronauts in case of a mishap.
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When and how to watch the TV-D1 mission online
People can watch the Gaganyaan TV-D1 mission online on the official website of ISRO, the official Facebook account of the space agency, or its official YouTube account. The livestream will start at 7:30 am IST on October 21, which is 30 minutes before the launch.
One can also watch the launch on DD National TV.
More about Gaganyaan's TV-D1 mission
The main objective of the TV-D1 mission is to demonstrate the in-flight abort of the Crew Escape System, which means that while the Crew Module is in the air, the Crew Escape System will be jettisoned. This will allow 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 during crewed missions in case a mishap occurs. ISRO aims to conduct more uncrewed test flight missions in the future.
The TV-D1 mission will be aborted at Mach number 1.2. Mach number is the ratio of the velocity of an object to the velocity of sound in the surrounding medium. Therefore, Mach number 1.2 means that the velocity of the velocity of that object is 1.2 times the speed of sound. The fact that the Crew Escape System will be jettisoned at Mach number 1.2 means that at the time of jettisoning, the velocity of the Crew Module has to be 1.2 times the velocity of sound in air.
Mach numbers 0.8 to 1.2 are considered transonic speed.
The reason why the abort will be carried out at Mach number 1.2 is that this is the stage at which the launch vehicle is expected to experience the greatest challenge, in terms of vibration and other parameters. So, most anomalies are likely to occur during this stage. Mach number 1.2 is 360 metres per second, and at the time of jettisoning, this will be the speed of the Crew Module.
An unpressurised Crew Module will be used to conduct the TV-D1 mission.