UPSC PracticeUPSC Practice
UPSC Notes

Earth Observation Satellites (EOS)

PYQs

8

Articles

2

Momentum

26

Phase IFoundation

Background

Overview

EOS are critical for India's disaster management, environmental protection, resource planning, and national security, directly aligning with GS3 syllabus topics on Science & Technology, Environment, and Disaster Management.

Earth Observation Satellites (EOS), also known as remote sensing satellites, are spacecraft designed to collect information about Earth's physical, chemical, and biological systems. They play a crucial role in monitoring environmental changes, managing natural resources, and aiding disaster response.

Phase IIStatic core

Facts & tables

Key facts

Purpose

Provide real-time imagery and data for various applications.

Applications

Agriculture, environment monitoring, disaster management, strategic data.

Orbit

Can operate from various orbits, including Geosynchronous orbit (as with EOS-05).

Technology

Utilize advanced imaging sensors and data transmission systems.

EOS-05 Significance

India's first dedicated earth-imaging satellite designed for geosynchronous orbit.

Geosynchronous Orbit

Allows continuous observation of the same broad location from approximately 36,000 km altitude.

Low Earth Orbits (LEO)

Provide finer detail but cover different strips of territory on successive passes, taking days to return to the same spot.

Reference table

Key Applications of Earth Observation Satellites

Application AreaBenefit
AgricultureCrop monitoring, yield estimation, soil health assessment
EnvironmentPollution monitoring, forest cover mapping, climate change studies
Disaster ManagementFlood mapping, cyclone tracking, earthquake damage assessment
Strategic DataBorder surveillance, maritime domain awareness

Reference table

Comparison of Satellite Orbits for Earth Observation

Orbit TypeCharacteristics & Applications
Geosynchronous OrbitHigh altitude (~36,000 km), continuous observation of a fixed region, suitable for tracking fast-changing events.
Low Earth Orbit (Polar/Sun-synchronous)Lower altitude (few hundred km), provides finer detail, covers different areas on successive passes, takes days to revisit.

Reference table

Static syllabus anchors

TypeReference
Conceptual areaSpace Science & Exploration
Conceptual areaEnvironmental Law & Policy
Conceptual areaWelfare Schemes & Social Policies

Reference table

Institutions & roles

BodyRole
Indian Space Research Organisation (ISRO)Develops and launches
Phase IIIExam lens

Prelims angle

Overview

Prelims angle: Multi-statement analysis

Prelims angle: Conceptual understanding

Quick revision

  • Satellites for monitoring Earth's surface and atmosphere.
  • Applications: agriculture, environment, disaster management, strategic data.
  • Operate from various orbits, including Geosynchronous.
  • ISRO is a key developer and launcher of EOS.
  • EOS-05 is India's first dedicated imaging satellite from Geo Orbit.

High-confidence PYQs

2026Multi-statement analysis, Factual recall

Which of the following statements about Rare Earth Elements (REEs) and Critical Minerals is/are correct ? 1. Modern technological innovations including Arti...

GeographyOpen question
2022Multi-statement analysis, Conceptual understanding

If a major solar storm (solar-flare) reaches the Earth, which of the following are the possible effects on the Earth? 1. GPS and navigation systems could fai...

Science & TechnologyOpen question
2019Multi-statement analysis, Conceptual understanding

For the measurement/estimation of which of the following are satellite images/remote sensing data used? 1. Chlorophyll content in the vegetation of a specifi...

Science & TechnologyOpen question
2018Multi-statement analysis, Factual recall

With reference to India’s satellite launch vehicles, consider the following statements: 1. PSLVs launch the satellites useful for Earth resources monitoring...

Science & TechnologyOpen question

With reference to the Indian Regional Navigation Satellite System (IRNSS), consider the following statements : 1. IRNSS has three satellites in geostationar...

Science & TechnologyOpen question
2018Statement-based questions, Factual recall

With reference to India’s satellite launch vehicles, consider the following statements: 1. PSLVs launch the satellites useful for Earth resources monitoring...

Science & TechnologyOpen question

With reference to the Indian Regional Navigation Satellite System (IRNSS), consider the following statements : 1. IRNSS has three satellites in geostationar...

Science & TechnologyOpen question
2016Statement-based questions, Factual recall

With reference to ‘Astrosat’, the astronomical observatory launched by India, which of the following statements is/are correct? 1. Other than the USA and Rus...

Science & TechnologyOpen question
2015Multi-statement analysis, Factual recall

In which of the following activities are Indian Remote Sensing (IRS) satellites used? 1. Assessment of crop productivity 2. Locating groundwater resources 3...

Science & TechnologyOpen question
2014Multi-statement analysis, Factual recall

Which of the following pair is/are correctly matched? |Spacecraft|Purpose| |-- |--| |1. Cassini-Huygens | Orbiting Venus and transmitting data to the Earth| ...

Science & TechnologyOpen question

Topic timeline

Space Science & ExplorationEnvironmental Law & PolicyWelfare Schemes & Social Policies
Prelims 2014· Multi-statement analysis, Factual recall

Which of the following pair is/are correctly matched? |Spacecraft|Purpose| |-- |--| |1. Cassini-Huygens | Orbiting Venus and transmitting data to the Earth| ...

Open question
Prelims 2015· Multi-statement analysis, Factual recall

In which of the following activities are Indian Remote Sensing (IRS) satellites used? 1. Assessment of crop productivity 2. Locating groundwater resources 3...

Open question
Prelims 2016· Statement-based questions, Factual recall

With reference to ‘Astrosat’, the astronomical observatory launched by India, which of the following statements is/are correct? 1. Other than the USA and Rus...

Open question
Prelims 2018· Multi-statement analysis, Factual recall

With reference to India’s satellite launch vehicles, consider the following statements: 1. PSLVs launch the satellites useful for Earth resources monitoring...

Open question

With reference to the Indian Regional Navigation Satellite System (IRNSS), consider the following statements : 1. IRNSS has three satellites in geostationar...

Open question
Prelims 2018· Statement-based questions, Factual recall

With reference to India’s satellite launch vehicles, consider the following statements: 1. PSLVs launch the satellites useful for Earth resources monitoring...

Open question

With reference to the Indian Regional Navigation Satellite System (IRNSS), consider the following statements : 1. IRNSS has three satellites in geostationar...

Open question
Prelims 2019· Multi-statement analysis, Conceptual understanding

For the measurement/estimation of which of the following are satellite images/remote sensing data used? 1. Chlorophyll content in the vegetation of a specifi...

Open question
Prelims 2022· Multi-statement analysis, Conceptual understanding

If a major solar storm (solar-flare) reaches the Earth, which of the following are the possible effects on the Earth? 1. GPS and navigation systems could fai...

Open question
Prelims 2026· Multi-statement analysis, Factual recall

Which of the following statements about Rare Earth Elements (REEs) and Critical Minerals is/are correct ? 1. Modern technological innovations including Arti...

Open question

ISRO successfully launches Earth observation satellite EOS-05

04 Sep 2026 · EOS are satellites providing data for Earth's systems, crucial for agriculture, environment, and disaster management, exemplified by ISRO's EOS-05.

Read article

Steady gaze: On the launch of the ISRO’s EOS-05 satellite

07 Sep 2026 · Earth Observation Satellites, like India's new EOS-05 in geosynchronous orbit, are vital technological assets providing continuous or high-resolution data for diverse applications from disaster warning and environmental monitoring to resource mapping and strategic intelligence.

Read article

Related topics

Current topic

Earth Observation Satellites (EOS)

Often confused with

Geosynchronous Satellite Launch Vehicle (GSLV)

Open notesOften confused with

India's Space Program

Open notes

Practice writing on this topic

UPSC has asked 8 linked questions on Earth Observation Satellites (EOS) in Mains. Write an answer to one — and get it evaluated.

See Mains PYQsEvaluate an answer

UPSC Prelims PYQs on Earth Observation Satellites (EOS)

Practice official previous year questions asked by UPSC related to this concept.

For the measurement/estimation of which of the following are satellite images/remote sensing data used? 1. Chlorophyll content in the vegetation of a specifi...

2019·Science & Technology
Solve

With reference to India’s satellite launch vehicles, consider the following statements: 1. PSLVs launch the satellites useful for Earth resources monitoring...

2018·Science & Technology
Solve

Which of the following pair is/are correctly matched? |Spacecraft|Purpose| |-- |--| |1. Cassini-Huygens | Orbiting Venus and transmitting data to the Earth| ...

2014·Science & Technology
Solve

In which of the following activities are Indian Remote Sensing (IRS) satellites used? 1. Assessment of crop productivity 2. Locating groundwater resources 3...

2015·Science & Technology
Solve

If a major solar storm (solar-flare) reaches the Earth, which of the following are the possible effects on the Earth? 1. GPS and navigation systems could fai...

2022·Science & Technology
Solve

With reference to ‘Astrosat’, the astronomical observatory launched by India, which of the following statements is/are correct? 1. Other than the USA and Rus...

2016·Science & Technology
Solve

With reference to the Indian Regional Navigation Satellite System (IRNSS), consider the following statements : 1. IRNSS has three satellites in geostationar...

2018·Science & Technology
Solve

Which of the following statements about Rare Earth Elements (REEs) and Critical Minerals is/are correct ? 1. Modern technological innovations including Arti...

2026·Geography
Solve

Editorial & Review Process

Every revision note and practice question on UPSC Practice is researched using authoritative primary sources and reviewed for factual accuracy, syllabus relevance, and exam value. Read our Editorial Policy.

Verified Quality
Browse all topics