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 INSAT-4A Mission —its objectives, timelines, key technologies, and strategic implications.

ISRO INSAT-4A Mission Overview

INSAT-4A was developed by ISRO as part of its efforts in the field of Communication.The intended zone of activity for INSAT-4A was Geostationary Orbit.

• To execute the launch of INSAT-4A, the Ariane-5GS V169 was deployed.
• Kourou, French Guiana hosted the missions launch activities.
• The primary objective of INSAT-4A was to Provide DTH television services.
• The mission also targeted supporting objectives like Other communication services.
• At this point, the mission remains Decommissioned.

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Timeline & Milestones of ISRO INSAT-4A Mission

• The mission timeline of INSAT-4A began with its launch on December 21, 2005.
• Mission planning documents suggest an operational window lasting until October 21, 2019 (decommissioned).

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ISRO INSAT-4A Mission Technical Specifications

INSAT-4A adopted a design featuring 3081 kg lift-off mass, I-3K bus, launched successfully via Ariane-5GS V169.The choice of Geosynchronous Orbit, 83° East longitude aligned with the mission’s overall strategy for scientific observation and technical validation.

• C-band, Ku-band were utilized as the primary communication channels for INSAT-4A, ensuring connectivity in Geostationary Orbit.

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INSAT-4A Launch Information

• ISRO conducted the launch of INSAT-4A on December 21, 2005, as per mission planning.
• The Ariane-5GS V169 was used to deploy INSAT-4A into space.
• The launch took place at Kourou, French Guiana.

Who are the Stakeholders & Collaborators?

The mission team was composed of personnel from ISRO.Arianespace (Launch) contributed to certain aspects of the mission.

• Launch by European company participated in INSAT-4A to support specific components related to Communication objectives.

Outputs, Applications & Impact of ISRO INSAT-4A Mission

INSAT-4A, launched from Kourou, French Guiana, accomplished First satellite in INSAT-4 series, boosted DTH services.

• The planning of INSAT-4A involved efforts to manage Moved to graveyard orbit.
• The technologies developed under Communication are relevant for DTH, communication services.
• The mission was conceptualized in line with broader policy directions, including High power Ku-band, DTH boom.
• To ensure continuity in the missions goals, ISRO has proposed follow-up programs such as INSAT/GSAT series, which will expand the operational scope of the original initiative.

ISRO INSAT-4A Space Mission Risks, Failures & Mitigation

UPSC Relevance of ISRO INSAT-4A Space Mission

• ISRO’s space-based support to agriculture, weather forecasting, navigation, and defence can be potential UPSC Prelims topics under Science and Economy.
• Questions involving disaster Management, like flood or cyclone monitoring, can be strengthened by citing ISRO’s satellite imagery and forecasting support systems.
• UPSC Essays focused on resilience, long-term vision, or Indias journey in science and technology can be powerfully anchored in examples like Chandrayaan-2’s setback and the recovery through Chandrayaan-3.
• Missions like Cartosat or Resourcesat allow candidates to bring satellite-based data into answers dealing with urban planning, hydrology, and land-use studies.

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. The Diamond Jubilee of Indias first sounding rocket launch was commemorated in which state?
1. Odisha
2. Andhra Pradesh
3. Kerala
4. Tamil Nadu
Answer: Kerala
Solution: The Diamond Jubilee of Indias first sounding rocket launch from Thumba in Kerala providentially coincides with the year 2023 which saw the historic twin feats of Chandrayaan-3 and Aditya-L1 mission. Union Minister of State for Space, Dr. Jitendra Singh, commemorated the 60th year of the First Sounding Rocket Launch at a function held at the Thumba Equatorial Rocket Launch Station, Kerala. Dr. Jitendra Singh observed the ceremonial launch of a sounding rocket from the same location as the original launch that took place on November 21, 1963. Dr. Jitendra Singh described the successful Chandrayaan-3 and Aditya-L1 missions as demonstration of Indias indigenous capabilities and a realization of Dr Vikram Sarabhais dream.

Q2. Consider the following about Astrosat:
1. It is Indias first dedicated multi-wavelength space observatory.
2. Recently it has successfully detected its 600th Gamma-ray Burst GRB, an event named GRB 231122B.
Which of the above statements is/are correct?
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2
Answer: Option 3
Solution: AstroSat is Indias first dedicated multi-wavelength space observatory. Hence statement 1 is correct. It is the first dedicated Indian astronomy mission aimed at studying celestial sources in X-ray, optical, and UV spectral bands simultaneously. AstroSat, with a lift-off mass of 1515 kg, was launched by the Indian launch vehicle PSLV from Satish Dhawan Space Centre, Sriharikota, on September 28, 2015, into a 650 km orbit inclined at an angle of 6 degrees to the equator. The spacecraft control center at Mission Operations Complex MOX of ISRO Telemetry, Tracking and Command Network ISTRAC, Bengaluru, manages the satellite during its entire mission life. In an astronomical feat, Indias first multi-wavelength space telescope, AstroSat, has successfully detected its 600th Gamma-ray Burst GRB, an event named GRB 231122B. Hence statement 2 is correct.

Q3. Which among the following institutions recently tested CE-20 Cryogenic Engine?
1. PRL Physics Research Laboratory
2. HAL Hindustan Aeronautics Limited
3. ISRO Indian Space Research Organization
4. DRDO Defense Research and Development Organization
Answer: ISRO Indian Space Research Organization
Solution: ISRO has accomplished a major milestone in the human rating of its CE20 cryogenic engine that powers the cryogenic stage of the human-rated LVM3 launch vehicle for Gaganyaan missions, with the completion of the final round of ground qualification tests on February 13, 2024. The final test was the seventh of a series of vacuum ignition tests carried out at the High Altitude Test Facility at ISRO Propulsion Complex, Mahendragiri, to simulate the flight conditions. The ground qualification tests for the human rating of the CE20 engine involved life demonstration tests, endurance tests, and performance assessment under nominal operating conditions as well as off-nominal conditions with respect to thrust, mixture ratio, and propellant tank pressure. All the ground qualification tests of the CE20 engine for the Gaganyaan programme have been successfully completed.

Q4. The new species of deep-sea isopod named after the Indian Space Research Organisation ISRO is ______________.
1. Cirolanidae gagan
2. Oceanisro bharati
3. Isropoda chandrayan
4. Brucethoa isro
Answer: Brucethoa isro
Solution: Brucethoa isro was named in honour of the Indian Space Research Organisation ISRO, reflecting a commendable acknowledgement of the institutions contributions to science and space exploration. The discovery of Brucethoa isro took place off the Kollam coast, where it was found parasitizing the Spinyjaw greeneye fish, showcasing the diverse and often surprising nature of marine life. Researchers P. T. Aneesh, A.K. Helna, and A. Biju Kumar identified Brucethoa isro, adding a significant entry to the marine biological records and emphasizing the importance of exploring and understanding deep-sea ecosystems. The naming of a new genus, Brucethoa, in 2020 by the same team and later dedicating a species within this genus to ISRO highlights the interdisciplinary appreciation and synergy between marine biology and space research fields.

Q5. Indias first lunar mission, Chandrayaan-1, ended on _________ due to loss of communication with the spacecraft.
1. 15 August 2009
2. 29 August 2009
3. 5 September 2009
4. 28 July 2009
Answer: 29 August 2009
Solution: Indias first lunar mission, Chandrayaan-1, ended on August 28, 2009 due to a loss of communication with the spacecraft. It was launched on October 22, 2008. Chandrayaan-1 is Indias first lunar probe developed by the Indian Space Research Organisation ISRO. The spacecraft is a very small cube about 1.5 meters on each side i.e about half the size of a smart car. The spacecraft was orbiting around the Moon at a height of 100 km from the lunar surface for chemical, mineralogical, and photo-geologic mapping of the Moon. The spacecraft carries 11 scientific instruments built in India, the USA, UK, Germany, Sweden, and Bulgaria.

Q6. What is the primary purpose of Indias GSAT-20 satellite, which is set to be launched by SpaceXs Falcon-9 on November 19?
1. To enhance weather forecasting and Earth observation
2. To improve internet services, especially in remote areas
3. To provide global navigation and positioning services
4. To facilitate high-resolution imaging for defense purposes
Answer: To improve internet services, especially in remote areas
Solution: SpaceX will launch Indias GSAT-N2 communications satellite on November 19, 2024, using the Falcon 9 rocket from Cape Canaveral, Florida. The GSAT-N2 satellite, weighing 4700 kg, will enhance Indias communication infrastructure, featuring a Ka-band high-throughput payload with a 14-year mission lifespan. ISROs heaviest rocket, LVM-3, can carry up to 4000 kg into Geosynchronous Transfer Orbit, making it unable to handle GSAT-N2s weight, necessitating the collaboration with SpaceX. The satellite will provide vital services, including internet connectivity for remote areas and in-flight internet services for Indian airspace. This is the first commercial collaboration between ISRO and SpaceX, marking a shift from relying on European Arianespace and Russian/Chinese launches due to geopolitical issues.

Q7. How many of the following missions to Venus and their corresponding countries are correctly matched?
1. Mariner 2 - European Space Agency ESA
2. Venus Express - United States
3. Akatsuki - Japan
4. Venera-D - Russia
Select the correct answer using the code given below:
1. Only one
2. Only two
3. Only three
4. All four
Answer: Only two
Solution: Mariner 2 - United States: NASA's first spacecraft to fly past Venus in 1962 (not ESA). Venus Express - European Space Agency ESA: Conducted studies on Venus' atmosphere and ionosphere (not the United States). Akatsuki - Japan: Currently studying Venus' atmosphere from orbit. Venera-D - Russia: A planned mission to study Venus' atmosphere and surface. Hence, pairs 3 and 4 are correctly matched.

Q8. Recently, ISRO conducted recovery trials for the Gaganyaan mission. Consider the following statements regarding the Gaganyaan program:
1. The Gaganyaan mission aims to demonstrate Indias interplanetary exploration capability by sending a crew to an orbit of 1000 km for a seven-day mission.
2. One of the preferred options for recovering the crew module involves towing it into the well deck of a ship to ensure crew safety and comfort.
3. The Gaganyaan mission will be launched using ISROs Human-Rated LVM3 rocket.
Which of the statements given above is/are correct?
1. 2 and 3 only
2. 1 and 2 only
3. 1 and 3 only
4. 1, 2, and 3
Answer: Option 1
Solution: The Gaganyaan mission is not focused on interplanetary exploration. Instead, it is designed to demonstrate Indias human spaceflight capability by sending a crew to Earths orbit for a three to five day mission and safely bringing them back to Earth. One of the preferred options for recovering the crew module involves towing it into the well deck of a ship. This procedure ensures crew safety and comfort and has been validated during recovery trials conducted by ISRO and the Indian Navy. The Gaganyaan mission will be launched using ISROs Human-Rated LVM3 rocket, also known as GSLV Mk III, which has been modified to meet human-rating requirements for carrying astronauts safely to space.

Q9. What is the total expenditure approved by the Union Cabinet for the establishment of the Third Launch Pad TLP at ISROs Satish Dhawan Space Centre, and within how many months is the project expected to be completed?
1. ₹3984 crore; 36 months
2. ₹3984 crore; 48 months
3. ₹4450 crore; 48 months
4. ₹3984 crore; 60 months
Answer: ₹3984 crore; 48 months
Solution: The Union Cabinet has approved the establishment of the Third Launch Pad TLP at ISROs Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh, with an investment of Rs 3984 crore, including associated facilities. The TLP will support ISROs Next Generation Launch Vehicles NGLV, which are heavy-lift vehicles and partially reusable. It will also support the Launch Vehicle Mark-3 LVM3. This launch pad will function as a standby for the Second Launch Pad SLP at Sriharikota, improving the nations capacity for future human spaceflight missions and enhancing launch capacity for space exploration. The TLP project will be realized with maximum industry participation and will leverage ISROs prior experience in building launch pads, while utilizing existing launch complex facilities. The TLP is expected to be operational within four years, boosting Indias space ecosystem by facilitating higher launch frequencies.

Q10. What is the distance of the Lagrange point 1 L1 of the Sun-Earth system?
1. 1.5 million km from the Earth
2. 1.5 million km from the Sun
3. 1.5 lakh km from the Earth
4. 1.5 lakh km from the Sun
Answer: 1.5 million km from the Earth
Solution: The Lagrange Point 1 L1 of the Sun-Earth system is located approximately 1.5 million kilometers from Earth towards the Sun. L1 is one of the five Lagrange points where the gravitational forces of the Sun and Earth balance, allowing objects to stay in a stable position relative to both celestial bodies. The L1 point is an ideal location for solar observation satellites because it provides an uninterrupted view of the Sun. There are five Lagrange points L1 to L5 in the Sun-Earth system where gravitational forces create equilibrium conditions. These points allow spacecraft to maintain a stable position with minimal fuel consumption.