New ‘eye in the sky’: Isro’s EOS-05 satellite settles into geosynchronous orbit

The Indian Space Research Organisation’s (Isro) Earth Observation Satellite, EOS-05, launched on September 4, has settled into a geosynchronous orbit that will allow continuous observation of the subcontinent from an altitude ranging between 34,903 km and 35,884 km.

“The third and final orbit-raising manoeuvre to increase the perigee of EOS-05 completed successfully at 8.57 pm on September 07, 2026. The LAM engine fired for 1247 seconds and the estimated orbit after manoeuvre is 34,903 km x 35,884 km,” Isro said on Monday night.

“The satellite health is normal,” it added. Over the next few days, the satellite is expected to undergo health and systems checks before its imaging systems are activated and the first Earth observation images are beamed back from its nearly stationary perch along the equator.

“Once the EOS 05 is operationalised in orbit, it will become India’s first dedicated imaging satellite from the geo orbit providing important strategic data for our country,” Isro chairman V Narayanan said after the launch on September 4.

While weather forecasting is one of the intended uses of EOS-5, it is also set to service the imaging requirements of the Indian Navy in a strategic capacity. The EOS-05 satellite was launched by ISRO's GSLV F17 rocket—the heaviest mission for the GSLV class of rockets—and was placed in a sub-geostationary transfer orbit of 171 km perigee (nearest distance to Earth) and 31,000 km apogee (furthest distance from Earth).

On September 5 and 6, orbit-raising manoeuvres put EOS-05 in a more circular orbit with a 20,000 km perigee and 35,786 km apogee. “Each orbit is selected for different purposes. Here we have chosen geosynchronous orbit,” an Isro scientist associated with the satellite programme said.

While the geostationary orbit is a subset of the geosynchronous orbit, the former is considered optimum for Earth observation as the satellite is permanently positioned over one location to collect data in the form of satellite imagery.