ISRO gears up for Gaganyaan test vehicle mission launch: Key highlights of India's first human spaceflight program

The Indian Space Research Organization (ISRO) has started the countdown and is all set to embark on a historic journey towards its first human space flight program, Gaganyaan. The initiative will commence with the launch of a single-stage liquid propulsion rocket set to take place on Saturday i.e. October 21, 2023, at 8 am.

Gaganyaan Live

The primary objective of this test mission is to ensure the safety of astronauts, marking a significant milestone in India's expanding space exploration endeavors. ISRO aims to send humans into space on a Low Earth Orbit of 400 km for a three-day mission and bring them safely back to earth.


Unlike previous missions undertaken by ISRO, this launch involves the Test Vehicle (TV-D1), a single-stage liquid propulsion rocket. Interestingly, the duration of the test procedure will merely be 531.8 seconds.

The success of this test flight will pave the way for further qualification tests and unmanned missions, leading up to the actual Gaganyaan program with Indian astronauts, expected to materialize in 2025.

Details of crew module:
The crew module, a vital payload in the rocket, is a habitable space designed to provide an Earth-like environment for the crew. It consists of a pressurized metallic 'inner structure' and an unpressurized 'external structure' with 'thermal protection systems'. The Crew Module houses various critical systems, including crew interfaces, life support systems, avionics, and deceleration mechanisms, ensuring crew safety during descent and landing.

Prior to the October 21 launch, the Crew Module underwent extensive testing at ISRO centers before integration into the launch complex in Sriharikota, located approximately 135 km east of Chennai.

The upcoming test flight is expected to be concise, with the Test Vehicle Abort Mission (TV-D1) launching the Crew Escape Systems and Crew Module at an altitude of 17 km. These components are anticipated to safely touch down in the Bay of Bengal, about 10 km from the eastern coast of Sriharikota, where they will be retrieved by the Navy.

TV-D1 vehicle specifications:
The TV-D1 vehicle is equipped with a modified VIKAS engine, with the Crew Module and Crew Escape System mounted at its fore end. This 34.9-meter-tall vehicle has a lift-off weight of 44 tonnes and features a single-walled unpressurized aluminum structure with a simulated thermal protection system.

The objectives of the Test Vehicle D1 mission include a demonstration of in-flight abort of the Crew Escape System, Crew Module separation, and safe recovery. These tests aim to ensure the safety of the crew who will eventually be sent into space in the Crew Module aboard an LVM-3 rocket during the Gaganyaan mission.

ISRO Chairman S. Somanath recently announced that similar abort missions would be conducted in advance of the human space flight program. The prerequisites for the Gaganyaan mission encompass the development of critical technologies, including human-rated launch vehicles, a life support system, and crew emergency escape provisions.

For the upcoming Test Vehicle Abort Mission 1 (TV-D1), the Crew Module is an unpressurized version, replicating the size and weight of the actual Crew Module to be used in the Gaganyaan mission. This Crew Module is equipped with various systems for deceleration and recovery, including a set of parachutes.
A look at the trajectory:

Objective of the mission:
Some of the mission objectives include flight demonstration and evaluation of test vehicles, Crew Escape Systems, Crew Module characteristics, and deceleration systems demonstration at higher altitude and its recovery.

Through this campaign, scientists aim to ensure the safety of the crew who would be actually sent in the Crew Module on an LVM-3 rocket during the Gaganyaan mission.

The prerequisites for the Gaganyaan mission include the development of many critical technologies, including human-rated launch vehicles for carrying the crew safely into space, a life support system to provide an earth-like environment to crew in space and crew emergency escape provision.

The success of this test flight would set the stage for the remaining qualification tests and unmanned missions, leading to the first Gaganyaan programme with Indian astronauts, which is expected to take shape in 2025.