Chennai, Sept 8:
The Indian Space Research Organisation (ISRO) has successfully completed the third orbit-raising manoeuvre of its advanced Earth observation satellite EOS-05, moving the 2,367-kg spacecraft closer to its planned operational orbit.
The manoeuvre was completed at 8.57 pm on September 7, with the satellite’s Liquid Apogee Motor (LAM) engine firing for 1,247 seconds. The estimated orbit after the manoeuvre is 34,903 km x 35,884 km, and the spacecraft remains in normal health, ISRO said.
EOS-05 was launched on September 4 aboard the GSLV-F17, which lifted off from the Second Launch Pad at the Satish Dhawan Space Centre, Sriharikota, in a pre-dawn mission. The satellite was injected into a Sub-Geosynchronous Transfer Orbit about 18 minutes after liftoff, with a perigee of 170 km and an apogee of 28,934 km.
The spacecraft, with a mission life of 10 years, is the heaviest payload carried by a GSLV so far. Its launch also marked ISRO’s first mission from Sriharikota in seven months.
The first orbit-raising manoeuvre was successfully carried out on September 5 at 8.19 pm using the onboard LAM engine. The engine was fired for 5,406.4 seconds, raising the satellite to an estimated orbit of 20,000 km x 31,129 km.
The second and third manoeuvres have since further raised the orbit. Additional manoeuvres are planned in the coming days to place EOS-05 in its final geosynchronous orbit at 85.5 degrees East.
The mission is significant as EOS-05 is designed to become the first imaging satellite to operate from a Sub-Geosynchronous Orbit, a major milestone in India’s Earth-observation capabilities. Traditionally, India’s Earth observation satellites have largely been placed in low Earth orbits.
EOS-05, described as an “Eye in the Sky,” is designed to provide detailed images of the Earth for applications including land and environmental monitoring. The satellite is intended to strengthen India’s remote-sensing and geographic information system capabilities.
The GISAT-class satellite is designed to provide frequent observations over large areas, including selected-field imaging at intervals of around five minutes and imaging of the entire Indian landmass every 30 minutes, with a spatial resolution of about 42 metres.
EOS-05 is also a replacement for GISAT-1, which was lost during an unsuccessful launch attempt in 2021 after a malfunction in the cryogenic upper stage prevented the rocket from achieving the required trajectory.
The successful EOS-05 mission is therefore being closely watched as an important recovery milestone for ISRO following successive launch setbacks involving PSLV missions in 2025 and early 2026.
With the third orbit-raising manoeuvre completed successfully, ISRO is now preparing for the remaining operations to place EOS-05 in its designated orbital slot and begin its planned Earth-observation mission.