Earth Observation Satellite EOS-05 (GISAT-1A)
Science & Technology · Thursday, 3 September 2026
ISRO has slated the launch of EOS-05 (formerly GISAT-1A) aboard GSLV-F17 from Sriharikota to place a continuous geo-imaging satellite in Geosynchronous Orbit over the Indian subcontinent. It serves as the operational replacement for the lost GISAT-1 mission with advanced hyperspectral and rapid-revisit capabilities.
Quick highlights
- EOS-05 (formerly GISAT-1A) is built on the I-2K platform and will be placed in Geosynchronous Orbit (~35,786 km) via GSLV-F17.
- Carries a 700 mm Ritchey–Chrétien optical telescope achieving 42 m spatial resolution in VNIR from ~36,000 km altitude.
- Houses hyperspectral sensors: HyS-VNIR (158 bands), HyS-SWIR (256 bands), and Long-Wave Infrared (MX-LWIR).
- Capable of imaging disaster spots every 5–10 minutes and scanning the entire Indian landmass every 30 minutes.
- Provides continuous surveillance over LAC, LoC, and key maritime passages in the northern Indian Ocean.
Context
ISRO has scheduled the launch of EOS-05 (formerly GISAT-1A) aboard the GSLV-F17 rocket from Sriharikota. The mission serves as the operational replacement for the lost GISAT-1 mission, aiming to place a continuous geo-imaging satellite over the Indian subcontinent in Geosynchronous Orbit.
Key Facts
EOS-05 is built on the I-2K spacecraft platform and will operate in Geosynchronous Orbit at ~35,786 km, matching Earth's rotation to overcome multi-day revisit gaps of LEO satellites. It carries a 700 mm Ritchey–Chrétien optical telescope achieving 42 m spatial resolution in VNIR. Advanced hyperspectral sensors include HyS-VNIR (158 spectral bands), HyS-SWIR (256 spectral bands), and MX-LWIR for detailed vegetation, soil health, and atmospheric aerosol analysis. It features electronically steerable phased array antennas and low-jitter reaction wheels for quick repointing.
Significance
EOS-05 can image critical disaster spots every 5–10 minutes and complete a full scan of the Indian landmass every 30 minutes under clear skies. It functions as an 'Eye in the Sky' maintaining uninterrupted coverage over the LAC, LoC, and key maritime passages across the northern Indian Ocean. It drastically cuts emergency warning and reaction times by continuously tracking cyclones, cloudbursts, forest fires, and glacial lake outbursts in the Himalayas.
Challenges / Way Forward
The mission must overcome the challenges that led to the loss of the original GISAT-1 mission. Ensuring reliable GSLV Mk II performance and successful orbital insertion at geosynchronous altitude is critical. Integration of EOS-05 data with existing disaster management and defence surveillance systems will be key to maximizing operational benefits.
Exam Angle
Prelims: EOS-05 orbit type (Geosynchronous), launch vehicle (GSLV-F17), platform (I-2K), predecessor (GISAT-1). Mains (GS III – Science & Tech): Role of geo-imaging satellites in disaster management and border surveillance. Compare LEO vs GEO earth observation satellite capabilities.
Remember this
- EOS-05 (formerly GISAT-1A) replaces the lost GISAT-1; launches via GSLV-F17 from Sriharikota.
- Built on I-2K platform; operates in Geosynchronous Orbit at ~35,786 km.
- 700 mm Ritchey–Chrétien telescope; 42 m resolution in VNIR from ~36,000 km.
- Hyperspectral sensors: HyS-VNIR (158 bands), HyS-SWIR (256 bands), MX-LWIR.
- Can image disaster spots every 5–10 minutes; full India scan every 30 minutes.
- Covers LAC, LoC, and northern Indian Ocean maritime passages continuously.
- GSLV Mk II is the launch vehicle; uses cryogenic upper stage.
Background reading
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