Earth Observation Satellites

News: After a disappointing 2021 which saw just one successful launch, ISRO is getting back to business with the EOS-04, an earth observation satellite.


  • An EOS or Earth remote sensing satellite is a satellite used or designed for Earth observation (EO) from orbit.
  • It includes spy satellites and similar ones intended for non-military uses such as environmental monitoring, meteorology, cartography and others. The most common type are Earth-imaging satellites that take satellite images, analogous to aerial photographs.
  • Some EOS may perform remote sensing without forming pictures, such as in GNSS radio occultation.
  • The EOS-04 is fourth in a series of earth observation satellites that are being launched under a new generic name. It is designed to provide high-quality images for applications such as agriculture, forestry and plantations, flood mapping, soil moisture and hydrology. It will complement the data from Resourcesat, Cartosat and RISAT-2B series of satellites that are already in orbit.
  • Two years ago, ISRO had moved to a new naming system for its earth observation satellites which till then had been named thematically, according to the purpose they were meant for.
  • The Cartosat series of satellites were meant to provide data for land topography and mapping, while the Oceansat satellites were meant for observations over sea.
  • Some INSAT-series, Resourcesat series, GISAT, Scatsat, and a few other earth observation satellites were named differently for the specific jobs they were assigned to do, or the different instruments that they.
  • All these would now become part of the new EOS series of satellites.

Other Satellites:

  • Besides EOS-04, two other small satellites —INSPIREsat-1 and INS-2TD — will ride on the heaviest version of the PSLV rocket in the early hours from the Sriharikota launch range.
  • The other co-passenger, INS-2TD, is a technology demonstrator for the first India-Bhutan joint satellite that is scheduled to be launched next month. The two countries had signed a space agreement last year, and its first outcome would be the launch of Bhutan-Sat, or INS-2B, on a PSLV rocket.
  • India currently has 53 operational satellites, of which 21 are earth observation ones and another 21 are communication-based. EOS-4 launch would be the 54th flight of the PSLV rocket, and the 23rd of its most powerful XL-version that has six strap-on boosters.