Indian Space Agency ISRO has Commenced Assembly of the Human Rated Launch Vehicle Mark 3 (HLVM3) Rocket that will Eventually Carry Indian Astronauts to space as part of the Country Ganganyaan Human Spaceflight Programme

Indian Space agency ISRO has commenced assembly of the Human-rated Launch Vehicle Mark 3 (HLVM3) rocket that will eventually carry Indian astronauts to space as part of the country's Gaganyaan human spaceflight programme.

Presently, the rocket is being assembled at the Indian Spaceport in Sriharikota, in preparation for a maiden mission where the rocket will be carrying a humanoid robot 'Vyommitra' to space, instead of astronauts.

Vyommitra will fly on three test missions to space, and once all these missions are successfully accomplished, ISRO will carry out the astronaut mission.

The data gained through the uncrewed flights will be instrumental for the success of the crewed missions.

HLVM3 is a three-stage rocket with a payload capacity of about 10 tonnes to Low Earth Orbit. The vehicle is 53 metres tall and weighs 640 tonnes.

"At 8:45 Hrs on 18th December, 2024 at SDSC, the stacking of the nozzle end segment with full flex seal nozzle of the S200 motor took place, thus commencing the official launch campaign of the HLVM3-G1 / OM-1 mission," ISRO said.

Twin S200 motors powered by solid fuel comprise the first stage of the rocket. L110 (liquid stage) and C32 (cryogenic) stages for the HLVM3, which serve as the second and final stage of the rocket, are also ready at the spaceport, ISRO added.

HLVM3 is a modified version of India's heaviest rocket, the LVM3. Simply put, ISRO has enhanced the satellite-carrying LVM3 rocket to carry astronauts to space.

Further, the crew escape systems elements are also at the spaceport.

The Crew Escape System is what ejects the astronaut-carrying capsule to safety when there is an anomaly detected in the rocket mid-flight.

The integration of Crew Module (the capsule that will house astronauts) is happening at ISRO's Vikram Sarabhai Space Centre (VSSC) in Thiruvananthapuram, and the integration of Service Module (which contains critical systems that support the mission) is taking place at UR Satellite Centre (URSC), Bengaluru. 

Subsequently, the Crew Module and the Service Module will be integrated and tested at URSC, Bengaluru.

Significance of Dec 18 and ISRO's LVM3-X/CARE mission
It was on December 18th, 2014, that ISRO carried out the maiden flight of the LVM3 rocket. In a mission dubbed 'LVM3-X/CARE', the LVM3-X rocket had lifted a 3775 kg Crew Module to an altitude of 126 km above the earth. 

From that sub-orbital altitude, it was controlled using thrusters to orient it for a favourable re-entry. The Crew Module descended using parachutes to have a smooth splashdown at the designated location off India's East Coast.

The Indian Coast Guard recovered the Crew Module from the turbulent seas of the Bay of Bengal, approximately 1600 km from the Indian spaceport.

Conducted exactly a decade ago, that mission was developed as part of pre-project activities of the Human Spaceflight Project, well before the official Gaganyaan project was approved in 2019.

It is a fitting coincidence that ten years later, on the same day, ISRO is gearing up for the first uncrewed mission of Gaganyaan by commencing the stacking of human-rated LVM3, christened HLVM3, at the spaceport.

The primary objective of the LVM3-X/CARE mission was to validate the then new rocket's flight through the atmospheric regime and demonstrate the re-entry of a full-scale Crew Module into Earth's atmosphere. 

The mission achieved several critical technical milestones, including the flight validation of the LVM3 rocket, synchronized performance of the paired S200 solid rocket boosters, twin-engine operation of the Vikas engines in L110 stage, algorithms across the rocket's first two stages, and complex stage separation mechanisms.

That success also validated the entire integration, assembly, testing, and launch servicing processes, as well as the mission design and simulation cycles, ensuring readiness for future missions. 

The CARE experiment itself served as a platform to evaluate the aerothermal performance of the Crew Module and validate critical re-entry technologies. 

It successfully demonstrated blunt-body re-entry aerodynamics, thermal protection systems, parachute-based deceleration mechanisms, and recovery logistics, providing invaluable insights for further developments, ISRO said.

ISRO has come a long way from the experimental mission of LVM3-X/CARE mission.

The human-rated launch vehicle, HLVM3, is derived from LVM3 and designed with enhanced reliability to meet human safety considerations.

Additionally, a Crew Escape System (CES) is implemented to ensure crew safety by safe ejection of Crew Module (CM) in a potentially adverse situation.

The CES is operational from the launch pad till its separation after the atmospheric flight regime.

The success of the LVM3-X/CARE mission was instrumental in ISRO's journey toward self-reliance in launching heavier satellites. LVM3 has since completed seven successive successful launches.

The insights gained from the CARE mission have also been pivotal in shaping ISRO's human spaceflight program.

Iterations in the Crew Module design, along with subsequent pad abort tests, air-drop tests, and test vehicle flights, are built on the foundational data provided by CARE.

Dr. S Somanath, Mission Director of the LVM3-X/CARE mission, now serves as the Secretary of the Department of Space and Chairman of ISRO, while Dr. S Unnikrishnan Nair, the Payload Director of the LVM3-X/ CARE mission, became the founding Director of the Human Space Flight Centre (HSFC), Bengaluru, and now leads the Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram.