ISRO Earth Observation Satellite-04 (RISAT-1A) Mission Overview – Timeline, Progress & Scientific Aims

India’s space programme, led by the Indian Space Research Organisation (ISRO), has evolved from modest beginnings into one of the most respected space agencies in the world. Over the years, ISRO has designed and executed a range of missions—from satellite navigation, Earth observation, interplanetary exploration, to solar studies—that have not only enhanced India’s technological self-reliance but also contributed to global scientific collaboration. Its cost-effective approaches and mission diversity—from Chandrayaan and Mangalyaan to Aditya-L1 and the upcoming Gaganyaan—have become case studies in innovation.

For UPSC aspirants, ISROs journey is more than current affairs—it directly intersects with the syllabus of General Studies Paper 3 (Science & Technology), provides examples for GS Paper 2 (International Relations, Governance), and can enrich perspectives in the Essay Paper, Ethics, and even Optional subjects like Geography or PSIR. In this article, we will explore detailed insights about ISRO Earth Observation Satellite-04 (RISAT-1A) Mission —its objectives, timelines, key technologies, and strategic implications.

ISRO Earth Observation Satellite-04 (RISAT-1A) Mission Overview

The Earth Observation (Radar Imaging) mission, ISROs Earth Observation Satellite-04 (RISAT-1A), was planned to address specific operational and technological goals.The trajectory and configuration of Earth Observation Satellite-04 (RISAT-1A) were optimized for operations in Sun-synchronous Polar Orbit.

• The launch of Earth Observation Satellite-04 (RISAT-1A) was carried out by the PSLV-C52.
• Liftoff occurred at Satish Dhawan Space Centre, Sriharikota, as per mission scheduling.
• The main aim of Earth Observation Satellite-04 (RISAT-1A) centered on the need to High-quality all-weather radar imaging for various applications.
• As a secondary focus, Earth Observation Satellite-04 (RISAT-1A) was intended to Agriculture, forestry, soil moisture, flood mapping.
• Operational describes the current phase of the mission.

Earth Observation Satellite-04 (RISAT-1A) Space Mission Overview for UPSC
Mission Name	Earth Observation Satellite-04 (RISAT-1A)
Mission Abbreviation	EOS-04
Mission Type	Earth Observation (Radar Imaging)
Target Celestial Body or Orbit	Sun-synchronous Polar Orbit
Primary Objective	High-quality all-weather radar imaging for various applications
Secondary Objectives	Agriculture, forestry, soil moisture, flood mapping
Mission Status	Operational

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Timeline & Milestones of ISRO Earth Observation Satellite-04 (RISAT-1A) Mission

• ISRO conducted the launch of Earth Observation Satellite-04 (RISAT-1A) on February 14, 2022, as per mission planning.
• 10 years planned was set as the end-of-life marker for the mission’s primary phase.

Timeline & Milestones
Proposal Date	N/A
Critical Design Review (CDR) Date	N/A
Assembly Complete Date	N/A
Launch Date	February 14, 2022
Landing / Flyby Date	N/A
End of Primary Mission Date	10 years planned

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ISRO Earth Observation Satellite-04 (RISAT-1A) Mission Technical Specifications

The EOS-04 mission relied on 1710 kg mass, 2280 W power to meet its mass, power, and structural needs.The mission trajectory for EOS-04 was designed around Sun-synchronous polar orbit, ~529 km altitude, aligned with its objectives.

• The payload configuration of Earth Observation Satellite-04 (RISAT-1A) featured C-band Synthetic Aperture Radar (SAR), tailored to meet mission-specific technical requirements.
• For data relay and payload monitoring, C-band (SAR), X-band (Data transmission) formed the backbone of the missions communication suite.
• ISRO employed Synthetic Aperture Radar (SAR) technology to carry out the mission’s objectives in Sun-synchronous Polar Orbit.

Technical Specifications
Spacecraft Technical Specifications	1710 kg mass, 2280 W power
Scientific Payloads	C-band Synthetic Aperture Radar (SAR)
Orbit Details	Sun-synchronous polar orbit, ~529 km altitude
Communication Frequencies / Band	C-band (SAR), X-band (Data transmission)
Key Technologies Used	Synthetic Aperture Radar (SAR) technology

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Earth Observation Satellite-04 (RISAT-1A) Launch Information

• On February 14, 2022, Earth Observation Satellite-04 (RISAT-1A) was sent into its designated orbit.
• Earth Observation Satellite-04 (RISAT-1A) was launched aboard the PSLV-C52.
• Satish Dhawan Space Centre, Sriharikota hosted the missions launch activities.

Launch Information
Launch Vehicle	PSLV-C52
Launch Site	Satish Dhawan Space Centre, Sriharikota

Who are the Stakeholders & Collaborators?

Key roles in the mission were handled by Indian Space Research Organisation (ISRO).Commercial participation in the mission came from Alpha Design Technologies Ltd (Assembly, Integration, Testing).

• The communication and storage protocols for data collected during EOS-04 are aligned with Data distributed by NRSC.

Stakeholders & Collaboration
Agencies Involved	Indian Space Research Organisation (ISRO)
Commercial Partners	Alpha Design Technologies Ltd (Assembly, Integration, Testing)
International Partners	N/A
Payload Contributions by Partners	N/A
Data Sharing Policy	Data distributed by NRSC

Outputs, Applications & Impact of ISRO Earth Observation Satellite-04 (RISAT-1A) Mission

The success of Earth Observation Satellite-04 (RISAT-1A) is often associated with Advanced all-weather Earth observation capability.The data gathered from Earth Observation Satellite-04 (RISAT-1A) included Radar imagery for agriculture, disaster management, surveillance, supporting multiple domains.

• The mission supports strategic developments by Enhances national resource management and disaster response.
• Supports environmental monitoring was taken into account during the missions planning and execution.
• Outputs from Earth Observation Satellite-04 (RISAT-1A) are used in civilian domains, particularly in All-weather imaging for agriculture, forestry, flood mapping.
• Radar imaging capability, vital for disaster management reflects the larger purpose behind EOS-04.
• Post-mission phases for Earth Observation Satellite-04 (RISAT-1A) may involve scaling up efforts through advanced programs such as RISAT series continuity, advanced SAR satellites, ensuring sustained benefits and impact.

Outputs, Applications & Impact of Earth Observation Satellite-04 (RISAT-1A) Mission
Data Outputs and Applications	Radar imagery for agriculture, disaster management, surveillance
Major Achievements	Advanced all-weather Earth observation capability
Applications in Civilian Life	All-weather imaging for agriculture, forestry, flood mapping
Impact on Policy & Global Collaboration	Enhances national resource management and disaster response
Environmental Impact & Sustainability	Supports environmental monitoring
Strategic Significance & Policy Alignment	Radar imaging capability, vital for disaster management
Follow-up Missions or Extensions	RISAT series continuity, advanced SAR satellites
Cost Estimate	N/A

ISRO Earth Observation Satellite-04 (RISAT-1A) Space Mission Risks, Failures & Mitigation

Risks, Failures & Mitigation
Challenges Faced	N/A
Risk Mitigation Measures	N/A
Failures or Anomalies	N/A
Corrective Actions Taken	N/A
Lessons Learned	N/A

UPSC Relevance of ISRO Earth Observation Satellite-04 (RISAT-1A) Space Mission

• Understanding the basic structure of ISRO, its launch centres, and satellite series (such as GSAT, INSAT, or CARTOSAT) is crucial for tackling Prelims questions with precision.
• UPSC often expects candidates to critically evaluate the gaps or opportunities in India’s space sector, where ISROs mission track record provides factual backing.
• ISRO’s space missions offer rich content for UPSC essays on themes like innovation, scientific temper, national self-reliance, or institutional excellence.
• In International Relations, India’s space diplomacy — including satellite launches for SAARC nations or bilateral cooperation with ESA and NASA — provides a solid example.

Past UPSC Mains PYQs on ISRO Space Missions

Q1. Discuss the role of the private sector in the growth of the space industry in India. How has the governments policy of 2023 affected it? (2023, GS Paper 3 - Science & Technology)

Q2. What is India’s plan to have its own space station and how will it benefit our space programme? (2022 & 2019, GS Paper 3 - Science & Technology)

Q3. Space has been the next big frontier for mankind after sea and land. In this context, discuss Indias policy and preparedness for space wars. (2019, GS Paper 3 - Science & Technology)

Q4. Discuss the utility of the Mars Orbiter Mission (MOM) for India. (2016, GS Paper 3 - Science & Technology)

Q5. What do you understand by Standard Positioning Systems and Precision Positioning Systems in the GPS era? Discuss the advantages India perceives from its ambitious IRNSS programme employing just seven satellites. (2015, GS Paper 3 - Science & Technology)

Past UPSC Prelims PYQs on ISRO Space Missions

Q1 [2025]: GPS-Aided Geo Augmented Navigation (GAGAN) uses a system of ground stations to provide necessary augmentation. Which of the following statements is/are correct in respect of GAGAN?

I. It is designed to provide additional accuracy and integrity.
II. It will allow more uniform and high quality air traffic management.
III. It will provide benefits only in aviation but not in other modes of transportation.

Select the correct answer using the code given below.

(a) I, II and III
(b) II and III only
(c) I only
(d) I and II only

Correct Answer: (d) I and II only

Explanation: Statements I and II correctly describe the core purpose and benefit of the GAGAN system. (I) GAGAN is designed to augment GPS signals by correcting for errors, which provides much greater accuracy and guarantees the integrity (reliability) of the positioning information. (II) This enhanced accuracy and reliability directly enables more precise aircraft routing and landing procedures, thus improving the uniformity and quality of air traffic management.

Q2 [2022]: 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 fail.
2. Tsunamis could occur at equatorial regions.
3. Power grids could be damaged.
4. Intense auroras could occur over much of the Earth.
5. Forest fires could take place over much of the planet.
6. Orbits of the satellites could be disturbed.
7. Shortwave radio communication of the aircraft flying over polar regions could be interrupted.

Select the correct answer using the code given below:

(a) 1, 2, 4 and 5 only
(b) 2, 3, 5, 6 and 7 only
(c) 1, 3, 4, 6 and 7 only
(d) 1, 2, 3, 4, 5, 6 and 7

Answer: The correct answer is (c).

Explanation: A major solar storm can disrupt GPS, power grids, satellite orbits, polar radio communication, and cause auroras, but cannot trigger tsunamis or forest fires.

Q3 [2020]: The experiment will employ a trio of spacecraft flying in formation in the shape of an equilateral triangle that has sides one million kilometres long, with lasers shining between the craft.” The experiment in question refers to

(a) Voyager-2
(b) New horizons
(c) Lisa Pathfinder
(d) Evolved LISA

Answer: The correct answer is (d) Evolved LISA.

Explanation: Evolved LISA (Laser Interferometer Space Antenna) is a planned space-based gravitational wave observatory by ESA and NASA, using three spacecraft in a triangular formation with laser beams to detect cosmic gravitational waves.

Q4 [2016]: Consider the following statements:

The Mangalyaan launched by ISRO

1. is also called the Mars Orbiter Mission
2. made India the second country to have a spacecraft orbit the Mars after USA
3. made India the only country to be successful in making its spacecraft orbit the Mars in its very first attempt

Which of the statement(s) given above is/are correct?

(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Answer: c) 1 and 3 only

Explanation: Mangalyaan is the informal name of Mars Orbiter Mission (MOM), launched by ISRO on 5 November 2013 and India is the only nation to date to have succeeded on its maiden attempt.

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UPSC Practice Questions on ISRO Space Missions

Q1. Recently the XPoSat Mission was in news, it is related to which of the following?
1. India’s first Saturn mission
2. India’s first polarimetry mission
3. India’s first Sun mission
4. Earth Observation Satellite

Answer: Option 2
Solution: The correct answer is Option 2. According to ISRO, XPoSat will study various dynamics of bright astronomical X-ray sources in extreme conditions and will carry two payloads. XPoSat is India’s first, and only the world’s second polarimetry mission that is meant to study various dynamics of bright astronomical X-ray sources in extreme conditions. Hence option 2 is correct. The other such major mission is NASA’s Imaging X-ray Polarimetry Explorer which was launched in 2021. IXPE carries three state-of-the-art space telescopes. Each of the three identical telescopes hosts one lightweight X-ray mirror and one detector unit. These will help observe polarized X-rays from neutron stars and supermassive black holes. By measuring the polarisation of these X-rays, we can study where the light came from and understand the geometry and inner workings of the light source. The spacecraft will carry two scientific payloads in a low earth orbit. The primary payload POLIX (Polarimeter Instrument in X-rays) will measure the polarimetry parameters (degree and angle of polarisation).

Q2. The spacecraft of Chandrayaan 2 was launched from
1. Thumba Equatorial Rocket Launching Station
2. Satish Dhawan Space Centre
3. U. R. Rao Space Centre
4. Vikram Sarabhai Space Centre

Answer: Satish Dhawan Space Centre
Solution: The correct answer is Satish Dhawan Space Centre. Chandrayaan-2 was launched on 22 July 2019 from the Satish Dhawan Space Centre in Andhra Pradesh. The mission of Chandrayaan-2 was lunar exploration. The launch vehicle used was GSLV Mark III-M1. It had:
- Orbiter
- Lander: Vikram
- Rover: Pragyan

Chandrayaan-1 was launched in October 2008. It was India’s first lunar mission. It was launched from the Satish Dhawan Space Centre in Andhra Pradesh. The Satellite launching station, Sriharikota, is a Satellite launching station of the Indian Space Research Organisation. It was renamed the Satish Dhawan Space Centre in the year 2002. Satish Dhawan was the former Chairman of the ISRO. The first satellite launched from the Satish Dhawan Space Centre was the Rohini 1A in 1979.

Q3. What is the name of the Reusable Launch Vehicle (RLV) that the Indian Space Research Organisation (ISRO) successfully landed at the Aeronautical Test Range (ATR) in Karnataka's Challakere?
1. Warbird
2. Saraswati
3. Vimaan
4. Pushpak

Answer: Pushpak
Solution: The correct answer is Pushpak. ISRO successfully carried out the landing mission of its Reusable Launch Vehicle (RLV) named Pushpak at Karnataka’s Challakere. The rocket was launched from the Chalakere Runway, marking the third landing mission of the RLV. An Indian Air Force helicopter carried the launch vehicle to an altitude of about 4.5 km and released it after attaining predetermined parameters. The mission is part of ISRO's efforts to develop essential technologies for a fully reusable launch vehicle, enabling low-cost access to space. The Pushpak RLV is designed as an all-rocket, fully reusable single-stage-to-orbit vehicle, incorporating major elements from various advanced technology demonstrators. Pushpak features a fuselage, a nose cap, double delta wings, twin vertical tails, and active control surfaces such as Elevons and Rudder. ISRO aims to minimize space debris with Pushpak and envisions capabilities like refueling of in-orbit satellites or retrieving satellites for refurbishment.

Q4. Which team received the Vigyan Team Award for their contribution to India's space program?
1. Team Mangalyaan
2. Team Gaganyaan
3. Team Chandrayaan-2
4. Team Chandrayaan-3

Answer: Team Chandrayaan-3
Solution: The correct answer is Team Chandrayaan-3. Team Chandrayaan-3 was recognized with the Vigyan Team Award. The award was for their exceptional contribution to India’s space program. The team was particularly noted for the successful moon landing mission. The award highlights the importance of collaborative research in modern scientific endeavors.

Q5. With which space agency has ISRO signed an Implementation Agreement for cooperation in crew and crew module recovery for Gaganyaan missions?
1. NASA
2. European Space Agency
3. Australian Space Agency
4. Roscosmos

Answer: Australian Space Agency
Solution: The correct answer is Australian Space Agency. ISRO signed an Implementation Agreement with the Australian Space Agency on November 20, 2024, to enhance cooperation in space activities. The purpose of the IA enables collaboration on crew and crew module recovery for Gaganyaan, India's first crewed spaceflight program. It ensures search and rescue support for crew and recovery of crew module in contingency situations, especially during the ascent phase near Australian waters. The agreement was signed by D K Singh, Director of ISRO's Human Space Flight Centre, Bengaluru, and Jarrod Powell, General Manager of ASA's Space Capability Branch, Canberra. About the Gaganyaan program, it aims to demonstrate India's capability for Low Earth Orbit missions. Plans to carry up to three crew members in an Indian Crew Module for up to three days. Includes provisions for the safe recovery of the module post-mission.

Q6. What significant milestone will ISRO achieve with the launch of the NVS-02 satellite in January 2025?
1. Its first interplanetary mission
2. Deployment of the heaviest satellite to date
3. Completion of the NavIC satellite constellation
4. The 100th mission of the ISRO Geosynchronous Satellite Launch Vehicle

Answer: The 100th mission of the ISRO Geosynchronous Satellite Launch Vehicle
Solution: The correct answer is The 100th mission of the ISRO Geosynchronous Satellite Launch Vehicle. ISRO is set to launch the NVS-02 satellite in January 2025, marking the 100th mission of ISRO with the Geosynchronous Satellite Launch Vehicle. NVS-02 is part of the Indian Regional Navigation Satellite System, also known as NavIC, which provides accurate position information services to users in India and the surrounding region. The satellite will enhance the capabilities of NavIC by providing signals in the L1, L5, and S bands, improving accuracy and coverage. NVS-02 follows the successful launch of NVS-01 in May 2023, which was the first in the second generation of navigation satellites and featured an indigenous atomic clock. The GSLV Mk II is a three-stage launch vehicle developed by ISRO, capable of placing satellites into geosynchronous transfer orbits; the upcoming launch will be its 100th mission, marking a significant milestone for India's space program.

Q7. The major science objectives of Aditya-L1 mission are
i. Study of Solar upper atmospheric dynamics
ii. To demonstrate Safe and Soft landing on Solar Surface
iii. To demonstrate Rover roving on the sun

1. Only iii
2. Only i and iii
3. Only i
4. All of the above

Answer: Only i
Solution: The correct answer is Only i. Aditya-L1 Mission is India's first solar observatory mission launched by ISRO. The objective is to study the Sun, specifically the dynamics of the solar upper atmosphere including the chromosphere and corona. It will be positioned at the Lagrange point 1, approximately 1.5 million km from Earth, to continuously observe the Sun without interruptions. Scientific Instruments on Aditya-L1 include Visible Emission Line Coronagraph to observe the solar corona, Solar Ultraviolet Imaging Telescope for imaging the Sun in the ultraviolet spectrum, Aditya Solar Wind Particle Experiment to study the solar wind and its interaction with the Earth's magnetosphere, and Plasma Analyser Package for Aditya to understand the composition of solar winds. The mission will enhance understanding of solar activities and their impact on space weather, benefiting satellite communication and navigation systems.

Q8. Which cryogenic engine did ISRO successfully test for the Gaganyaan mission?
1. CE7.5
2. Vikas
3. CUS2
4. CE20

Answer: CE20
Solution: The correct answer is CE20. ISRO successfully conducted a vacuum ignition test of the CE20 cryogenic engine on February 7, 2025, at the ISRO Propulsion Complex, Mahendragiri, Tamil Nadu. CE20 engine is used in the upper stage of the LVM-3 rocket and is critical for ISRO's Gaganyaan human spaceflight program. The test focused on ignition and restart capabilities using a multi-element igniter under vacuum conditions, simulating real space scenarios. The engine demonstrated thrust levels between 19 to 22 tonnes and is now being tested for multiple restart capability to enhance mission flexibility. ISRO is exploring a bootstrap mode for turbopump initiation to improve restart efficiency over conventional stored gas systems. Successful testing is crucial for Gaganyaan, ensuring engine reliability for sending Indian astronauts into space. ISRO's rigorous testing approach reinforces confidence in mission success, advancing India's capabilities in human space exploration.

Q9. RISAT-2BR1 satellite which is related to disaster management, was launched by the Launch Vehicle
1. GSLV-1
2. PSLV-C48
3. GSLV-A1
4. PSLV-C46

Answer: PSLV-C48
Solution: The correct answer is PSLV-C48. RISAT-2BR1 is an Indian radar imaging reconnaissance satellite used for earth observation. It was launched by the Indian Space Research Organisation on 11 December 2019. The launch vehicle used for this mission was PSLV-C48, which is part of the Polar Satellite Launch Vehicle series. PSLV-C48 successfully placed RISAT-2BR1 and nine other customer satellites from various countries into a sun-synchronous orbit.

Q10. Which of the following is true for OHRC with respect to the moon?
1. Orientational High Resolving Camera
2. Orbital Highly Resolution Circle
3. Orbiter High Resolution Camera
4. Orbital Height Round Circle

Answer: Orbiter High Resolution Camera
Solution: The correct answer is Orbiter High Resolution Camera. The Orbiter High Resolution Camera is a scientific payload onboard Chandrayaan-2, India's lunar mission. OHRC is designed to capture high-resolution images of the lunar surface, with a spatial resolution of 0.32 meters, making it ideal for detailed mapping. It focuses on imaging specific areas of scientific interest, such as craters, lunar regolith, and potential landing sites. The OHRC operates in the visible region of the electromagnetic spectrum and is mounted on the Orbiter of Chandrayaan-2. Its primary objective is to assist in identifying and analyzing the terrain for future exploration and lunar landings. Chandrayaan-2 Mission was launched by ISRO on July 22, 2019. It consists of three components: Orbiter, Vikram Lander, and Pragyan Rover. The primary objective is to study the lunar surface, analyze the composition, and map the presence of water ice. High-resolution imaging is crucial for identifying geological features, craters, and potential landing sites. It aids in understanding the Moon's evolution and providing data for future missions. Other Payloads on Chandrayaan-2 Orbiter include Terrain Mapping Camera-2 for large-area mapping of the lunar surface, Solar X-ray Monitor and Large Area Soft X-ray Spectrometer for analyzing the lunar surface composition, and Dual Frequency Synthetic Aperture Radar for detecting water ice in the polar regions. Lunar Exploration Goals include studying the Moon's topography, mineralogy, and elemental abundance, enhancing understanding of the Moon's exosphere and its interaction with solar radiation, and paving the way for future human and robotic missions to the Moon.

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