India's Bharatiya Antariksh Station: What ISRO Has Proposed and What It Will Take to Build

The Bharatiya Antariksh Station, as ISRO has formally described it, is planned to weigh approximately 20 tonnes at initial configuration, about one-thirtieth the mass of the International Space Station at its completion. That number is not a limitation so much as a starting point. The ISS began with a single 20-tonne module, Zarya, launched in 1998, and grew over thirteen years and more than forty assembly flights. India's station is being designed with the same logic: a first module that can sustain a small crew, with docking ports that allow expansion later.
The target orbit is low Earth orbit, between 400 and 450 kilometres in altitude, the same band the ISS occupies, chosen because it keeps radiation exposure manageable for long-duration crews and allows resupply missions without the energy cost of higher orbits. ISRO's current plan calls for a crew of three astronauts at a time, with missions of up to fifteen to twenty days in the initial phase. That is a modest number by ISS standards, where crews of six or seven are routine, but it matches what India's life-support and crew-transport systems can realistically sustain in a first-generation station.
The Bharatiya Antariksh Station cannot exist without Gaganyaan. This is structural, not just sequential. Gaganyaan, India's crewed orbital mission, targeting low Earth orbit, is the vehicle that will carry astronauts to the station once it is built. The crew module being developed for Gaganyaan is also the crew transport vehicle for the station. ISRO is not designing two separate crewed systems; the station is an extension of the Gaganyaan architecture.
Gaganyaan's uncrewed test flights have been underway, with the first crewed mission targeting a date in the mid-2020s. Group Captain Shubhanshu Shukla, one of the four astronaut-designates selected by ISRO and trained in Russia, is among those being prepared for early Gaganyaan missions. His assignment also includes a planned mission to the ISS as part of the AXIOM Space collaboration with NASA, experience that will directly inform how Indian astronauts operate in an orbital environment before India's own station is ready.

The LVM3 rocket, which successfully launched Chandrayaan-3 in 2023, is the current baseline launch vehicle for Gaganyaan. Putting a 20-tonne station module into orbit requires either a significantly upgraded LVM3 or a new heavy-lift vehicle. ISRO has been developing the Next Generation Launch Vehicle (NGLV), designed to carry heavier payloads at lower cost per kilogram, and the station's assembly schedule depends directly on when NGLV reaches operational status.
Three subsystems define whether a space station is liveable or merely habitable on paper: life support, thermal control, and attitude control. Each one is harder than it sounds from a press release.

Life support on a crewed station means closed-loop oxygen generation and carbon dioxide removal running continuously, with no margin for extended failure. The ISS uses electrolysis of water for oxygen and a molecular sieve system for CO2 scrubbing. India has experience with environmental control systems from satellite development, but a crewed station's life-support load is categorically different, it must function for months without a resupply, and any failure is immediately a crew safety event. ISRO will need to develop or procure systems that have flight heritage in crewed applications, not just adapt satellite technology.
Thermal control is equally unforgiving. A station in low Earth orbit passes through sunlight and shadow roughly sixteen times every twenty-four hours. The temperature swing on an unprotected surface can exceed 270 degrees Celsius between the two states. Radiator panels, heat pipes, and fluid loops must manage this cycling continuously. The ISS has a dedicated thermal control system with ammonia coolant loops covering an area larger than a football field. India's first module will be smaller, but the physics do not scale down proportionally, the heat generated by electronics and crew metabolic activity still has to go somewhere.

Attitude control, keeping the station pointed correctly so solar panels face the sun and docking ports align with visiting vehicles, requires gyroscopes and thrusters firing in coordinated sequences. A station that tumbles cannot be docked with. Getting this right on a multi-module structure, where each added module changes the station's moment of inertia, is one of the reasons ISS assembly required such precise sequencing over its construction decade.
ISRO has stated a target of 2035 for the Bharatiya Antariksh Station to be operational. Working backward from that date: the first crewed Gaganyaan mission needs to succeed well before then, the NGLV needs to be operational for heavy module launches, docking technology needs flight validation, and at least one uncrewed station module needs to reach orbit and check out successfully before any astronaut boards it.
Each of those milestones has its own dependency chain. India demonstrated autonomous docking technology with the SpaDeX mission, which successfully tested space docking in early 2025, a capability that is non-negotiable for a multi-module station. That demonstration matters: without proven docking, no station module can be assembled on orbit, and no crew vehicle can reach the station safely.
The risk factors are the usual ones for any long-duration space programme: budget continuity across government cycles, supply chain development for components that India does not yet manufacture domestically, and the technical maturation of life-support systems that have no Indian flight heritage. International partnerships, with agencies that have already built and operated stations, could compress some of these timelines. ISRO has existing cooperation frameworks with NASA, ESA, and Roscosmos, and the Axiom mission gives Indian astronauts direct ISS exposure before their own station exists.
What India has proposed is credible in its ambition and honest in its phasing. The 20-tonne initial module, the Gaganyaan crew vehicle as the transport backbone, the NGLV as the heavy-lift enabler, these are not disconnected announcements. They form a sequence. The station is the destination that gives every upstream programme its long-term justification.
The Chandrayaan and Mangalyaan missions showed that ISRO can reach targets hundreds of millions of kilometres away on budgets that would not fund a single ISS module. A station in low Earth orbit is a different class of challenge, not because of distance, but because it has to keep people alive, indefinitely, in a place that will kill them in seconds if the engineering fails. That is the gap between a mission and a home.