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Launch vehicles, satellites and applications

Launch vehicles, satellites and what they are used for: rockets and their engines, Earth observation, communication and navigation satellites, orbits, and the launches of each year. Prelims has asked about the orbits of the Indian Regional Navigation Satellite System (IRNSS) satellites and the uses of Indian Remote Sensing satellites.

UPSC has asked

  • Prelims 2023: countries with their own satellite navigation system
  • Prelims 2018: the orbits of the IRNSS satellites
  • Prelims 2018: India's satellite launch vehicles and the orbits they serve
  • Prelims 2015: uses of Indian Remote Sensing satellites

Showing 1 of 6 subjects, those that changed from 1 to 15 September 2026.Show all

EOS-05

Copy link to EOS-05

Prelims and Mains

Geosynchronous orbit is new ground for Indian Earth observation, and EOS-05 is the first to image from it. Which orbit a satellite is given decides what its pictures can show and how often they arrive, so the choice is made against what the images are for.

  • A Geosynchronous Satellite Launch Vehicle (GSLV-F17) carried EOS-05 to orbit.
  • Also called Geo Imaging Satellite 1A (GISAT-1A), it images chosen areas at frequent intervals for disaster monitoring, agriculture and forestry.
  • It replaces GISAT-1, lost in 2021 when the cryogenic upper stage of its GSLV failed to ignite.
  • A satellite in low Earth orbit sees fine detail, but its revisit time runs to days.
  • A satellite in geosynchronous orbit watches one large region continuously, in coarser detail, and spends fuel on station keeping.
  • Only a satellite in geostationary orbit appears fixed in the sky, while other geosynchronous orbits trace a path across it over the day.
  • What these satellites see feeds the Landslide Atlas of India, the monitoring of glacial lake outburst floods, and the National Database for Emergency Management 5.0.
Satellite orbit bands, not to scaleLow Earth orbit from 160 to 2,000 km, medium Earth orbit from 2,000 to 35,786 km, and geosynchronous orbit at about 35,786 km, where EOS-05 operates.Geosynchronous orbitAbout 35,786 km upOne orbit a day, matching Earth's spinCommunication, weather, now EOS-05Medium Earth orbit2,000 to 35,786 km upNavigation constellations,such as GalileoLow Earth orbit160 to 2,000 km upOne orbit every 90 to 120 minutesMost imaging satellites, the ISSEOS-05Earth

Closer to Earth. Finer detail, but a satellite races past and sees a place only briefly.

Farther from Earth. A wide region watched continuously, in coarser detail.

Not to scale. Altitudes as given in The Indian Express, 5 September 2026.

What changed

  1. 4 Sep 2026

    PIB, 4 Sep 2026: Prime Minister hails the launch of GSLV-F17 carrying EOS-05 (opens in a new tab)

Background reading: The Indian Express, 5 Sep 2026: ISRO launches EOS-05: What are the different types of satellite orbits, and why do they matter? (opens in a new tab)

Also filed elsewhere