The Human-rated Launch Vehicle Mark-3 (HLVM3) is the launch vehicle specifically adapted by the Indian Space Research Organisation (ISRO) to safely carry astronauts, or Gaganyatris, into space. It is an upgraded version of the operational Launch Vehicle Mark-3 (LVM3), which was previously known as the GSLV Mk III. The LVM3's development began in the early 2000s to create a more powerful launcher capable of placing heavier communication satellites into Geostationary Transfer Orbit (GTO).
The need for the HLVM3 arose from the announcement of the Gaganyaan program on August 15, 2018, which aims to demonstrate India's indigenous human spaceflight capability to Low Earth Orbit (LEO). The core mechanism of the vehicle remains a three-stage design, featuring two S200 solid rocket boosters, an L110 liquid core stage, and a C25 cryogenic upper stage, which uses the indigenously developed CE-20 cryogenic engine. The key difference is the "human-rating," which involves significant modifications to ensure crew safety and reliability.
These modifications include enhanced redundancy in critical systems, robust structural changes, and the integration of a crucial Crew Escape System (CES). The CES is a safety mechanism designed to quickly eject the crew module from the rocket in the event of an emergency during the initial phases of the flight. The HLVM3 is designed to carry a payload of approximately 10 tonnes to LEO, which includes the Crew Module and Service Module. The successful qualification of the HLVM3 is a critical step for the Gaganyaan mission, which will form the backbone for India's future long-term space goals, such as the planned Bharatiya Antariksha Station.