ISRO's EOS-05 Mission: A Geosynchronous Eye for Continuous Earth Watch
ISRO will launch EOS-05 aboard GSLV-F17 on Sept 4, 2:55 am, enabling continuous Earth observation from geosynchronous orbit.
After a nearly eight-month hiatus and two consecutive PSLV failures, the Indian Space Research Organisation (ISRO) is gearing up for a pivotal launch. At 2:55 am on September 4, the GSLV-F17 rocket will lift off from the second launch pad at Satish Dhawan Space Centre, Sriharikota, carrying the EOS-05 Earth observation satellite.
EOS-05 is India's first imaging satellite to operate from geosynchronous orbit, positioned about 36,000 km above Earth. This vantage point will allow the satellite to maintain a constant watch over the Indian subcontinent, including its territory, coastlines, weather systems, and disaster-prone regions. Equipped with a high-resolution camera, it is also expected to bolster border monitoring.
The satellite, with an estimated launch mass of 2,367 kg, will be placed into a sub-geosynchronous transfer orbit. The GSLV-F17 rocket stands 51.7 metres tall and has a liftoff mass of 420.5 tonnes, making it one of India's largest operational launch vehicles. It uses a three-stage architecture with a 4-metre diameter payload fairing.
The first stage combines a massive S-139 solid motor, carrying 138 tonnes of solid propellant, with four liquid strap-on boosters that together hold about 170 tonnes of UH25 and nitrogen tetroxide. The second stage, powered by liquid propulsion, carries 42 tonnes of the same propellants. The third stage is the indigenous cryogenic upper stage (CUS-5), which uses 15 tonnes of liquid hydrogen and liquid oxygen to perform the final orbital insertion.
Once the cryogenic stage completes its burn, EOS-05 will be deployed from the payload fairing, marking a significant step in India's Earth observation capabilities.