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ISRO's GSLV-F17 launched EOS-05, described by the Prime Minister as India's first-ever imaging satellite from geosynchronous orbit.
The mission lifted off on 4 September 2026 from the Second Launch Pad at the Satish Dhawan Space Centre SHAR, Sriharikota - the 19th flight of the GSLV programme.
EOS-05, also designated GISAT-1A, was placed in a Sub-Geosynchronous Transfer Orbit and raised towards the geostationary altitude of about 35,786 km by onboard apogee-motor firings.
From that altitude it can revisit a chosen area in minutes rather than days, supporting cyclone and flood monitoring, agriculture and surveillance.
The Prime Minister linked the achievement to the deepening ISRO-industry partnership across the space ecosystem.
A geosynchronous orbit has an orbital period equal to Earth's rotation, so the satellite returns to the same point in the sky each day. A geostationary orbit is the special case that is also circular and directly above the equator, so the satellite appears fixed. Both sit near 35,786 km.
Simple Analogy: Geosynchronous keeps time with the Earth; geostationary also keeps position.
| Aspect | Low Earth / Sun-synchronous imaging | Geosynchronous imaging (EOS-05) |
|---|---|---|
| Altitude | A few hundred kilometres | About 35,786 km |
| Revisit over one area | Minutes of visibility per pass, days between passes | Continuous view of the same broad region |
| Spatial resolution | Finer, down to sub-metre on some satellites | Coarser - about 42 m multispectral on EOS-05 |
| Best suited to | Detailed mapping and change detection | Rapidly evolving events: cyclones, floods, fires |
Developed the GSLV and EOS-05 and conducted the launch.
ISRO's launch complex; EOS-05 flew from its Second Launch Pad.
Commercial arm of the Department of Space, set up to transfer ISRO technology to industry and market space products and services.
ISRO's Earth Observation Satellite naming convention, which replaced mission-specific names such as RISAT and Cartosat. EOS-09, a C-band synthetic aperture radar satellite also called RISAT-1B, was lost when the third stage of PSLV-C61 malfunctioned on 18 May 2025.
SAR images through cloud and darkness using radar rather than reflected sunlight. EOS-05 is an optical hyperspectral and multispectral imager, so India's radar imaging rests on the RISAT/EOS SAR line, not on this satellite.
The CE-7.5 upper stage is what made the GSLV an indigenous launcher for heavier payloads; cryogenic engines burn liquid hydrogen with liquid oxygen for higher efficiency than storable propellants.
GS Paper 3 > Science and Technology > Space Programme
General Awareness > Science and Current Affairs
When did India successfully complete the SpaDeX docking operation?
Answer: 30th December 2024
With reference to India's satellite launch vehicles, consider the following statements: 1. PSLVs launch the satellites useful for Earth resources monitoring whereas GSLVs are designed mainly to launch communication satellites. 2. Satellites launched by PSLV appear to remain permanently fixed in the same position in the sky, as viewed from a particular location on Earth. 3. GSLV Mk III is a four-staged launch vehicle with the first and third stages using solid rocket motors; and the second and fourth stages using liquid rocket engines. Which of the statements given above is/are correct?
Answer: 1 only
An orbit whose period matches Earth's rotation, near 35,786 km altitude; the equatorial circular case is geostationary.
An elliptical intermediate orbit into which the launcher injects the satellite, from which onboard motors raise it to its final orbit.
Imaging across many narrow, contiguous spectral bands, allowing materials, crops and pollutants to be distinguished by their spectral signature.