Gaganyaan-G1 mission to validate critical technologies in the run-up to manned flight: VSSC Director S. Unnikrishnan Nair

Gaganyaan-G1, the first of three un-crewed test missions that will lead up to India’s maiden human spaceflight, is designed to mimic - end to end - the actual flight and validate critical technologies and capabilities including the Human-rated Launch Vehicle Mark-3 (HLVM3), S. Unnikrishnan Nair, Director, Vikram Sarabhai Space Centre (VSSC), has said.

The Indian Space Research Organisation (ISRO) began the ‘stacking,’ or assembly, of HLVM3 at the Satish Dhawan Space Centre, Sriharikota, on December 18, coinciding with the tenth anniversary of the sub-orbital Crew Module Atmospheric Re-entry Experiment (CARE) mission of 2014.

Speaking to The Hindu about the upcoming HLVM3-G1 mission, Dr. Unnikrishnan Nair said the integration of the crew module, which will fly aboard the mission, is progressing at the VSSC, which is ISRO’s lead facility for launch vehicles at Thumba here. Once the crew module is ready, it will be transferred to the U.R. Rao Satellite Centre (URSC), Bengaluru, for integration with the service module.

Orbital module

The service module and the crew module together make up the orbital module. “After a series of tests including thermo-vacuum tests at the URSC, the orbital module will be transported to Sriharikota to be placed aboard the launch vehicle,” said Dr. Unnikrishnan Nair, who was the first Director of the Human Space Flight Centre (HSFC), Bengaluru.

The HLVM3-G1 mission will place the orbital module in an 170 km x 430 km elliptical orbit around the earth. It will subsequently be manoeuvred into a circular orbit. Once the orbital module de-orbits, the crew module, which has enhanced safety margins and multiple redundancies, will separate for controlled re-entry into the earth’s atmosphere and splashdown in the Bay of Bengal.

End-to-end mission

The HLVM3-G1 mission is designed to validate  technologies and abilities needed for a manned mission. “It is designed as an end-to-end mission covering lift-off, injection into orbit,  ‘circularisation’ of orbit, re-entry and splashdown,”  Dr. Unnikrishnan Nair said. The G1 mission will also flight-test the humanoid robot Vyommitra developed by the ISRO Inertial Systems Unit (IISU).

The ISRO recently announced that the human-rating of the LVM3 vehicle has been completed and all systems have been “tested for enhanced reliability.” The related tests had taken close to three years, according to Dr. Unnikrishnan Nair. The launch vehicle components - the S200 solid rocket boosters, the L110 liquid stage and the C32 cryogenic stage - have arrived at Sriharikota after clearing the human-rating process.

Compared to the conventional LVM3 (formerly known as Geosynchronous Satellite Launch Vehicle Mk-III), the HLVM3 has distinct features. “The aerodynamic configuration is different. Normally, you have a bulbous payload fairing atop the vehicle protecting the satellite. Here, we have the crew escape system at the very top. Inside it will be the orbital module. The crew module is connected to the crew escape system. The overall height of the vehicle has increased by around 10 metres to 53 metres,” Dr. Unnikrishnan Nair said.

The ISRO is planning two more uncrewed missions - G2 and G3 - before the actual manned flight. These two test missions will be identical in their parameters, Dr. Unnikrishnan Nair said.