ISRO has launched numerous operational remote sensing satellites since IRS-1A in 1988. India now operates one of the largest constellations of remote sensing satellites. Various instruments have been flown onboard these satellites to provide necessary data in a variety of spatial, spectral, and temporal resolutions to meet the needs of different users in the country and globally. These satellites' data is used in a variety of applications, including agriculture, water resources, urban planning, rural development, mineral prospecting, the environment, forestry, ocean resources, and disaster management. In this article, we will discuss in detail regarding Earth Observation Systems which will be helpful for UPSC exam preparation.

Earth Observation System

• The Earth Observing System (EOS) is a network of polar-orbiting and low-inclination satellites designed to provide long-term global observations of the land surface, biosphere, solid Earth, atmosphere, and oceans.
• The fundamental physical, chemical, and biological phenomena that govern and integrate the Earth system are addressed by EOS science objectives.
• EOS observations will allow for evaluation of a variety of Earth system processes, including the following:
  • Hydrologic processes govern the interactions of land and ocean surfaces with the atmosphere via heat, mass, and momentum transport.
  • Biogeochemical processes that contribute to trace gas and aerosol formation, dissipation, and transport, as well as their global distributions.
  • Climatological processes that govern cloud formation and dissipation, as well as their interactions with solar radiation.
  • Ecological processes that are affected by and/or will be affected by global change, as well as their adaptation to such changes.
  • Geophysical processes that have shaped or continue to shape the Earth's surface, such as tectonics, volcanism, and glacier and sea ice melting.
• The EOS mission's goal is to advance scientific understanding of the entire Earth system by developing a deeper understanding of its components and their interactions.
• EOS will provide systematic, continuous observations from low Earth orbit to quantify changes in the Earth system.

What is an Earth Observation Satellite?

• An EOS satellite, also known as an Earth remote sensing satellite, is a satellite that is used or designed for Earth observation (EO) from orbit.
• It includes spy satellites and others with non-military applications such as environmental monitoring, meteorology, cartography, and others.
• Earth-imaging satellites, which take satellite images similar to aerial photographs, are the most common type.
• Some EOS, such as GNSS radio occultation, can perform remote sensing without forming images.

Major Earth Observation (EO) Satellites

1) EOS Series

• EOS-01 is an earth observation satellite designed for agricultural, forestry, and disaster management applications.
• EOS-03 is a cutting-edge Earth observation satellite that will be launched into a Geosynchronous Transfer Orbit by GSLV-F10. Following that, the satellite will use its onboard propulsion system to reach the final geostationary orbit.
• EOS-04 is a Radar Imaging Satellite designed to provide high-quality images in all weather conditions for applications such as agriculture, forestry, and plantation management, as well as soil moisture and hydrology and flood mapping.

2) RISAT Series

• Radar Satellite-1 (RISAT-1) is a cutting-edge Microwave Remote Sensing Satellite carrying a Synthetic Aperture Radar (SAR) Payload operating in C-band (5.35 GHz), allowing imaging of surface features at all times of day and night.
  • Cloud penetration and day-night imaging capability are provided by Active Microwave Remote Sensing.
  • It also has applications in agriculture, particularly paddy monitoring during the kharif season and natural disaster management such as flood and cyclone.
• RISAT-2 is a Radar Imaging Satellite that can take images of the Earth in all weather conditions. This satellite improves ISRO's disaster management capabilities.
• ISRO developed the RISAT-2B radar imaging earth observation satellite.
• RISAT-2BR1 is an earth observation satellite with radar imaging capabilities. The satellite will offer services in agriculture, forestry, and disaster management.

3) CARTOSAT Series

• CARTOSAT-1 is India's first remote sensing satellite capable of providing stereo images in orbit. The images were used for Cartographic applications that met global standards.
• The Cartosat-1 provided the stereo pairs needed to generate Digital Elevation Models, Ortho Image products, and Value Added Products for various Geographical Information System (GIS) applications.
• Cartosat-2 is a high-technology remote sensing satellite.
• The thirteenth satellite in the Indian Remote Sensing Satellite series (IRS) is CARTOSAT - 2A.
  • It is an advanced and tough remote sensing satellite capable of providing scene-specific spot imagery. This satellite was equipped with a Panchromatic Camera (PAN).
  • Images from this satellite were used for cartographic applications such as mapping, urban and rural infrastructure development and management, and applications in Land Information System (LIS) and Geographical Information System (GIS).
• The Cartosat-3 satellite is a third generation agile advanced satellite capable of high resolution imaging.
• Cartosat-3 will meet the growing user demand for large-scale urban planning, rural resource and infrastructure development, coastal land use and land cover, and so on.

4) RESOURCESAT Series

• RESOURCESAT-1 is ISRO's tenth satellite in the IRS series, and it is designed to not only continue the remote sensing data services provided by IRS-1C and IRS-1D, both of which have far outlived their designed mission lives, but also to vastly improve data quality.
• RESOURCESAT-1 is ISRO's most advanced remote sensing satellite as of 2003.
• RESOURCESAT-2 is a follow-up mission to RESOURCESAT-1 and ISRO's eighteenth Remote Sensing satellite.
• RESOURCESAT-2 is designed to continue the remote sensing data services provided by RESOURCESAT-1 to global users while also providing data with enhanced multispectral and spatial coverage.
• RESOURCESAT-2 also carries an AIS (Automatic Identification System) payload from COMDEV, Canada as an experimental payload for ship surveillance in the VHF band to determine ship position, speed, and other information.
• RESOURCESAT-2 carries two Solid State Recorders, each with a capacity of 200 Giga Bytes, to store images captured by its cameras and later read out to ground stations.

5) OCEANSAT Series

• IRS-P4 (OCEANSAT-1) is the first satellite primarily designed for ocean applications.
• For oceanographic studies, this satellite carries an Ocean Colour Monitor (OCM) and a Multi-frequency Scanning Microwave Radiometer (MSMR).
• Oceansat-2 is designed to maintain the operational services of Oceansat-1 (IRS-P4) while expanding its application potential.
• It carried three payloads, including:
  • Ocean Colour Monitor (OCM)
  • ISRO developed the Ku-band Pencil Beam Scatterometer (SCAT)
  • The Italian Space Agency developed the Radio Occultation Sounder for Atmosphere (ROSA)

6) IRS Series

• IRS-1A, the first of a series of indigenous state-of-the-art remote sensing satellites, was successfully launched into a polar sun-synchronous orbit from the Soviet Cosmodrome at Baikonur on March 17, 1988.
• Improved features over its predecessor include gyro referencing for improved orientation sensing, time tagged commanding (IRS-1A) for greater flexibility in camera operation, and line count information for improved data product generation.

List of Earth Observation Satellites

Need for Earth Observation Satellites

• To counter China: The main reason for having them is that the People's Republic of China (PRC) has a large number of these EOS. Because of a lack of EOS, the People's Republic of China's (PRC) troop movement in the Ladakh region went largely undetected in 2020.
• Surveillance in the Indian Ocean Region: Aside from the threat on its Himalayan borders with China, there has been a significant increase in its influence in the Indian Ocean Region. This must be addressed through the use of advanced surveillance systems.
• To overcome drone and UAV limitations: Using UAVs (unmanned aerial vehicles) and drones has drawbacks because they can be shot down if the reconnaissance mission requires flying over the adversary's military installations.
  • In contrast, satellite imagery will be able to zoom into the most remote corners, allowing our security forces to take timely action and track suspicious movements.
• For border management: India must also strengthen its anti-infiltration grid along the Pakistan-Bangladesh border, as infiltration and smuggling along the line of control have long posed a threat to national security.
• Post-attack damage assessment: This is critical for assessing post-attack damage and will allow us to create opportunities to refine our attacks against enemy targets in the future.

Technology Used in Earth Observation Satellites

• Imagery Intelligence (IMINT): This is an intelligence-gathering system in which aerial images are analysed to identify intelligence-valued information.
• SAR (Synthetic Aperture Radar): It is used to create two-dimensional or three-dimensional images of objects and landscapes. It is critical for aerial surveillance and precision targeting. It is a day/night, all-weather imaging system that is essential for military applications.
• Electro-Optical Functions: Images are provided by this system to military and law enforcement agencies. It can detect and track flying objects automatically. The system's functionality can be improved by incorporating an infrared sensor.
• Photo reconnaissance: It can be used for a variety of purposes, including artillery spotting and military manoeuvring.

Conclusion

In contrast to morality and sovereignty in the 1980s and 1990s, our approach to space policy is now driven by national security concerns. Geopolitics is the new motivator for India to prioritise the military component of its space programme. To meet the challenges posed by our neighbouring countries, our military requires Earth Observation (EO) satellites and should consider it a strategic investment.

FAQs

MCQs

1. What is the main purpose of Earth Observation Systems?

A) Weather forecasting
B) Environmental monitoring and resource management
C) Meteorological data collection
D) Military surveillance

2. Which organization operates Earth Observation Satellites in India?

A) DRDO
B) NASA
C) ISRO
D) ESA

3. Which of the following is an application of Earth Observation Systems?

A) Agricultural monitoring
B) Meteorology
C) Oceanography
D) All of the above

4. What type of data does Earth Observation Systems primarily provide?

A) Atmospheric data
B) Geographic and environmental data
C) Political data
D) Economic data

5. How does remote sensing aid in disaster management through Earth Observation Systems?

A) By providing early warnings of natural disasters
B) By collecting real-time data on environmental hazards
C) By assessing post-disaster damage
D) All of the above

GS Mains Questions and Model Answers

Q1: Discuss the role of Earth Observation Systems in sustainable environmental management.

Answer: Earth Observation Systems (EOS) play a vital role in sustainable environmental management by providing critical data for monitoring environmental changes and managing natural resources. Through satellite imagery and sensor data, EOS helps in assessing land degradation, deforestation, water resource management, and urban sprawl. This information supports policymakers in making informed decisions related to conservation, resource allocation, and environmental sustainability. Moreover, EOS aids in tracking climate change impacts, such as changes in weather patterns, temperature, and sea levels, ensuring proactive measures to mitigate environmental risks. EOS's integration with Geographic Information Systems (GIS) enhances spatial data analysis for effective planning and implementation of sustainable practices.

Q2: Explain the significance of Earth Observation Systems in disaster management and mitigation efforts.

Answer: Earth Observation Systems are crucial in disaster management, providing real-time data on environmental hazards such as floods, cyclones, wildfires, and earthquakes. EOS enables early warning systems, which help in timely evacuations and resource deployment. In the aftermath of a disaster, EOS assists in damage assessment, monitoring recovery progress, and planning rehabilitation efforts. For instance, satellite imagery can be used to assess flooded areas, identify impacted regions, and optimize disaster relief operations. Additionally, by tracking environmental changes such as soil erosion or forest cover loss, EOS contributes to disaster risk reduction strategies. This data-driven approach significantly enhances disaster preparedness, response, and mitigation efforts.

Q3: What are the challenges faced by Earth Observation Systems in India and how can they be addressed?

Answer: While Earth Observation Systems have provided immense benefits, India faces several challenges in leveraging this technology. One major challenge is the lack of data integration, which hinders comprehensive analysis across different sectors like agriculture, disaster management, and urban planning. To address this, India can focus on improving data-sharing mechanisms between governmental agencies, research institutions, and private sector stakeholders. Another challenge is the need for better infrastructure to process and analyze the large volumes of data generated by EOS. Strengthening the technological capabilities, including the use of artificial intelligence and machine learning for data analysis, can help in extracting meaningful insights. Additionally, building local expertise in remote sensing and satellite technology will enable better utilization of Earth Observation Systems in India’s development goals.

Previous Year Questions on Earth Observation Systems

1. UPSC CSE Mains 2021 (GS Paper 3):

Question: "Explain the significance of Earth Observation Systems in monitoring and managing natural resources."

Answer: Earth Observation Systems are essential in monitoring natural resources like water, land, and forests. They provide real-time satellite data for assessing the health of these resources, supporting sustainable management practices. For example, EOS aids in tracking deforestation, monitoring agricultural health, and managing water bodies, thus informing conservation policies and resource allocation decisions. By providing objective and accurate data, EOS ensures that natural resources are utilized efficiently while minimizing environmental degradation.

2. UPSC CSE Mains 2020 (GS Paper 3):

Question: "Discuss the role of satellite-based Earth Observation in disaster management and preparedness."

Answer: Satellite-based Earth Observation plays a pivotal role in disaster management by offering early warning systems, monitoring environmental hazards, and assisting in post-disaster damage assessments. By providing real-time imagery of affected areas, EOS enables quick response and relief efforts. It also contributes to long-term mitigation strategies by identifying disaster-prone areas and monitoring environmental changes that could lead to future disasters. EOS is integral to improving disaster resilience and response, ensuring more effective recovery and minimizing loss of life and property.