ISRO Raises EOS-05 Apogee to 35,786 Km in Second Successful Orbit Manoeuvre

The Indian Space Research Organisation has successfully carried out the second orbit-raising manoeuvre of its newly launched EOS-05 Earth observation satellite, taking the spacecraft another major step toward its intended geosynchronous orbit.

ISRO confirmed that the manoeuvre was completed successfully at 7:00 PM on September 6, 2026. During the operation, the spacecraft’s Liquid Apogee Motor (LAM) fired for 338.9 seconds, raising the satellite’s estimated apogee to 35,786 km. ISRO also reported that the spacecraft remained in normal health following the operation.

The latest manoeuvre follows a much longer first orbit-raising operation completed on September 5. During that operation, the LAM was fired for 5,406.4 seconds, after which EOS-05 entered an estimated orbit of 20,000 km by 31,129 km. ISRO had said at the time that additional manoeuvres would be conducted over the following days to progressively place the spacecraft in its planned geosynchronous orbit at the 85.5° East orbital slot.

The successful second firing has now lifted the satellite’s apogee to approximately the altitude associated with the geosynchronous belt. Further orbital adjustments will be required to shape and orient the orbit before EOS-05 reaches its intended operational configuration.

EOS-05 was launched aboard GSLV-F17 on September 4, 2026, from the Satish Dhawan Space Centre at Sriharikota. The mission marked the 19th flight of India’s Geosynchronous Satellite Launch Vehicle. GSLV-F17 successfully injected EOS-05 into a sub-geosynchronous transfer orbit, from where the satellite began using its onboard propulsion system to climb toward its final orbit.

EOS-05 is particularly significant because ISRO describes it as India’s first imaging satellite designed to operate from geosynchronous orbit. Unlike many conventional Earth observation satellites that operate in low Earth or polar orbits and pass over particular locations at intervals, a geosynchronous imaging spacecraft can maintain prolonged visibility over a very large geographical region.

That orbital position could provide important advantages for applications where frequent or persistent observation is useful. The mission therefore represents a new capability within India’s expanding Earth observation architecture and complements the country’s existing fleet of remote-sensing satellites operating in other orbital regimes.

Orbit raising is a carefully sequenced part of missions in which a launch vehicle initially places a spacecraft into an elliptical transfer orbit. The spacecraft then uses its own propulsion system at selected points in the orbit to progressively increase altitude and alter orbital parameters. Each engine firing must be accurately timed and controlled because the resulting velocity change determines the satellite’s subsequent trajectory.

For EOS-05, the long-duration first manoeuvre provided a major increase in orbital energy, while the second firing has now carried the apogee to 35,786 km. Subsequent operations will concentrate on bringing the spacecraft into the required geosynchronous configuration and ultimately positioning it around the designated 85.5° East longitude.

The two successful manoeuvres following the GSLV-F17 launch indicate that the spacecraft’s propulsion and associated onboard systems are functioning normally so far. ISRO is expected to continue the planned orbit-raising sequence before EOS-05 enters its operational phase.

With EOS-05, India is adding a new geosynchronous dimension to its Earth observation capabilities while also demonstrating the ability of the GSLV and indigenous spacecraft propulsion systems to support increasingly sophisticated high-orbit missions.