ExplainedSpace
Gaganyaan G1 explained: what India's first uncrewed flight with Vyommitra has to prove
ISRO chairman V Narayanan says the first Gaganyaan test flight is about two months away. Why a robot is going before the astronauts, what the capsule must survive, and how many steps remain before Indians fly.
The short answer
G1 is the first orbital flight of the Gaganyaan crew capsule, carrying no astronauts but a half-humanoid robot, Vyommitra, and a small biology experiment. Launched on the human-rated HLVM3 rocket from Sriharikota, it must show that the capsule can reach low Earth orbit, keep its cabin systems working, come back through the atmosphere, open its parachutes in sequence and splash down safely to be recovered. ISRO chairman V Narayanan said on 24 October that it would fly in about two months. More uncrewed tests are planned before the first crewed flight, which is targeted for 2027.
What is G1?
It is the first time the Gaganyaan crew capsule will go into orbit, with a robot in place of a crew.
Gaganyaan is ISRO’s programme to fly Indian astronauts on an Indian rocket. Before anyone climbs aboard, the agency wants to fly the complete system, rocket, capsule and recovery, without people and see it work. G1 is that rehearsal.
“G1 flight is an uncrewed test mission that will carry the half-humanoid robot Vyommitra into a low Earth orbit,” ISRO chairman V Narayanan said in Chennai on Saturday, adding that it would take place in about two months. It will lift off from Sriharikota on the HLVM3, the human-rated version of ISRO’s heaviest rocket, the LVM3.
Why send a robot?
To check the cabin from the inside, the way an astronaut would experience it.
Vyommitra has a head, arms and a torso but no legs. Narayanan has said it will monitor the module’s parameters, raise alerts and carry out life support operations. Its sensors will record what the cabin goes through, from launch vibration to the heat and deceleration of re-entry, so that engineers can judge whether a human crew would be safe.
The flight is also reported to carry a small biology experiment with fruit flies, planned with researchers from TIFR, the University of Agricultural Sciences in Dharwad and IIST, to study how living organisms respond to spaceflight.
What does the flight have to prove?
That every step from lift-off to splashdown works in the right order.
The HLVM3 must place the capsule and its service module in a low orbit, planned at about 170 by 408 km. In orbit, the crew module’s own thrusters, 12 of them of 100 newtons each, must hold its orientation. Before coming home, the crew module separates from the service module, a step ISRO rehearsed on the ground at the Vikram Sarabhai Space Centre this month, when it said the capsule’s avionics and heat shields came through the shock of separation intact.
Then comes the hardest part. The capsule must survive re-entry and slow down through a chain of 10 parachutes: two to pull away the protective apex cover, two drogues to steady and brake it, three pilot chutes and finally three main parachutes. It must then splash down in the sea and be recovered. Chartered ships stationed in the Pacific and the North Atlantic are expected to help track the flight.
The road to G1
- Oct 2023TV-D1 tests the crew escape system on a single-stage rocket off Sriharikota.
- Apr 2026Crew module dropped from an IAF Chinook to test its parachutes over the Bay of Bengal.
- Oct 2026Crew module and service module separation tests completed at VSSC.
- About Dec 2026G1 flies with Vyommitra on HLVM3, about two months after Narayanan's 24 October remark.
- 2027Target for India's first crewed Gaganyaan flight.
Why has it taken so long?
Because human-rating a rocket and a capsule leaves little room for shortcuts.
The first uncrewed flight was originally targeted for December 2020. The pandemic pushed it back, and every rocket stage, parachute and escape system then had to be qualified to a far stricter standard than an ordinary satellite launch. The date has moved several times since, most recently from 2025 into the last part of 2026.
What comes after G1?
More uncrewed flights, then astronauts. G1 is the first of several uncrewed missions planned before a crew flies, and Vyommitra is expected to fly again. If those go well, ISRO’s target for the first crewed flight is 2027, carrying Indian Air Force test pilots who have been training as astronaut-designates. A clean G1 would be the clearest sign yet that the target is realistic; a problem would very likely push it back.