India's space agency is set to launch its next navigation satellite late on Friday night, in a mission that will test both a new spacecraft and a fix for the fault that crippled its predecessor. The Indian Space Research Organisation (ISRO) has scheduled the GSLV-F18 rocket carrying the NVS-03 satellite to lift off at 11:51 pm IST on October 30 from the Satish Dhawan Space Centre at Sriharikota in Andhra Pradesh.

The 24-hour countdown began at 11:51 pm on Thursday, ISRO said, and the agency will webcast the launch from 11:20 pm on Friday. The mission will lift off from the space centre's Second Launch Pad, with the rocket — the 20th flight of India's Geosynchronous Satellite Launch Vehicle (GSLV) — standing about 50 metres tall and weighing around 420 tonnes at lift-off.

What NVS-03 will do

NVS-03 is the third satellite in the second generation of NavIC, short for Navigation with Indian Constellation, India's own regional satellite navigation system. Weighing around 2,250 kilograms, it will be placed first into a geosynchronous transfer orbit — a stretched loop with a lowest point of 170 kilometres and a highest point of 37,023 kilometres — before orbit-raising manoeuvres take it to its final geosynchronous slot.

The satellite carries an indigenous atomic clock, the third such clock India has placed in space, and is designed to ensure continuity of navigation services. NavIC provides positioning, navigation and timing services across India and up to 1,500 kilometres beyond its borders, supporting civilian uses as well as an encrypted service for authorised users, including timing, marine navigation and disaster alerts.

Why this launch matters

The mission comes at a moment when the constellation needs reinforcement. In a written reply to Parliament in July, Space Minister Jitendra Singh disclosed that only three of the seven planned NavIC satellites were providing navigation services, while at least four are required for basic positioning. NVS-03 would take the working fleet to that minimum threshold, though still short of the system's full design capacity.

There is also a technical score to settle. NVS-02, launched in January 2025, reached its intended transfer orbit but its orbit-raising engine could not be operated as planned. An ISRO review published in February 2026 identified a disconnected connector in the drive signal to a pyro valve in the oxidizer line as the most likely cause, affecting both the primary and redundant paths.

For NVS-03, ISRO is flying the satellite with those pyro valves already activated and open, a break from its usual practice intended to ensure the same fault cannot stop the engine again. That means Friday night's lift-off, however clean, is only the first half of the test: the satellite must still complete its orbit-raising and commissioning before it enters navigation service, and ISRO has not yet announced when that will happen.

What to watch tonight

All eyes are now on Sriharikota shortly before midnight.