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 GSAT-8 Mission —its objectives, timelines, key technologies, and strategic implications.
Among ISRO’s various projects, GSAT-8 mission represents a targeted effort within the domain of Communication, Navigation.The trajectory and configuration of GSAT-8 were optimized for operations in Geostationary Orbit.
GSAT-8 Space Mission Overview for UPSC |
|
Mission Name |
GSAT-8 |
Mission Abbreviation |
INSAT-4G |
Mission Type |
Communication, Navigation |
Target Celestial Body or Orbit |
Geostationary Orbit |
Primary Objective |
Augment DTH, VSAT services |
Secondary Objectives |
Provide GAGAN navigation payload services |
Mission Status |
Operational |
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Timeline & Milestones |
|
Proposal Date |
N/A |
Critical Design Review (CDR) Date |
N/A |
Assembly Complete Date |
N/A |
Launch Date |
May 21, 2011 |
Landing / Flyby Date |
N/A |
End of Primary Mission Date |
12 years (planned) |
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ISRO engineered the spacecraft using 3093 kg lift-off mass, I-3K bus, in line with the objectives defined for Communication, Navigation.The mission trajectory for INSAT-4G was designed around Geosynchronous Orbit, 55° East longitude, aligned with its objectives.
Technical Specifications |
|
Spacecraft Technical Specifications |
3093 kg lift-off mass, I-3K bus |
Scientific Payloads |
N/A |
Orbit Details |
Geosynchronous Orbit, 55° East longitude |
Communication Frequencies / Band |
Ku-band, L1 & L5 (GAGAN) |
Key Technologies Used |
High power Ku-band transponders, GAGAN payload |
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Launch Information |
|
Launch Vehicle |
Ariane-5 VA202 |
Launch Site |
Kourou, French Guiana |
According to official information, ISRO were associated with the mission.The mission involved commercial support from Arianespace (Launch).
Stakeholders & Collaboration |
|
Agencies Involved |
ISRO |
Commercial Partners |
Arianespace (Launch) |
International Partners |
Launch by European company |
Payload Contributions by Partners |
N/A |
Data Sharing Policy |
N/A |
Enhanced communication and navigation capabilities is recorded as a notable outcome of GSAT-8.GSAT-8 contributed to the national space data repository by providing DTH services, GPS augmentation data.
Outputs, Applications & Impact of GSAT-8 Mission |
|
Data Outputs and Applications |
DTH services, GPS augmentation data |
Major Achievements |
Enhanced communication and navigation capabilities |
Applications in Civilian Life |
DTH, VSAT, GAGAN navigation |
Impact on Policy & Global Collaboration |
N/A |
Environmental Impact & Sustainability |
N/A |
Strategic Significance & Policy Alignment |
Communication, navigation augmentation |
Follow-up Missions or Extensions |
GSAT series |
Cost Estimate |
N/A |
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 |
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)
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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Q1. Consider the following:
A. Gaganyaan: ISRO plans seven-day space tour with three gaganauts in 2023 for science and technology advancement.
B. Vyommitra: A humanoid robot sent along with gaganauts to manage environmental information.
Which of the above is/are correct?
1. B only
2. Neither A nor B
3. A only
4. Both A and B
Answer: B only
Solution: Vyommitra is a humanoid robot developed by ISRO intended to be sent to space, designed to manage environmental information. The statement about Gaganyaan planning a three-day space tour with three astronauts in 2023 is correct. Gaganyaan is indeed ISRO's manned space mission, which aims to send Indian astronauts to space. The inclusion of a humanoid robot like Vyommitra in space missions represents a significant technological advancement, demonstrating capabilities in robotics and space exploration. Humanoid robots in space missions can perform tasks that are risky or impossible for humans, and they can also be used to simulate human presence in space for research purposes.
Q2. MOM stands for and the date in which it was launched
1. Mars Orbital Mission, 5th November 2014
2. Mars Orbiter Mission, 5th November 2014
3. Mars Orbiter Mission, 5th November 2013
4. Mars Orbital Mission, 5th November 2013
Answer: Mars Orbiter Mission, 5th November 2013
Solution: Mars Orbiter Mission (MOM) is primarily a technological mission to study various aspects of Mars. This mission was launched by ISRO on 5 November 2013 from Satish Dhawan Space Centre, Sriharikota, located in Andhra Pradesh. It was launched with the help of Polar Satellite Launch Vehicle PSLV C-25. It is an indigenously-built space probe, India's first interplanetary mission, in the Martian orbit since September 24, 2014. India is the first country in the world to achieve Mars Orbit intersection in its first attempt. It is the cheapest interplanetary space mission in the world.
Q3. Mars Orbiter Mission (MOM) is informally called as:
1. Mangalyaan
2. Mission water
3. Mystery Mars
4. Magnetic Mangal
Answer: Mangalyaan
Solution: The Mars Orbiter Mission (MOM) is informally known as Mangalyaan, which means Mars Craft in Sanskrit. It was launched by the Indian Space Research Organisation (ISRO) on November 5, 2013. Mangalyaan is India's first interplanetary mission, and it made India the first Asian country to reach Martian orbit and the fourth space agency in the world to do so. The mission's primary objective was to develop the technologies required for interplanetary missions.
Q4. Which of the following statements about Gaganyaan are true?
A. LVM-3 rocket is the launch vehicle for Gaganyaan mission.
B. It consists of solid stage, liquid stage and cryogenic stage.
C. It has an Orbital Module which comprises of Crew Module and Service Module.
D. It envisages demonstration of human space flight capabilities by launching crew of 5 to the Earth’s orbit at 500 kilometers.
Choose the correct answer:
1. A, B and C only
2. B and C only
3. A and B only
4. B and D only
Answer: A, B and C only
Solution: LVM-3 rocket is the launch vehicle for Gaganyaan mission. This is true and confirms statement A. It consists of solid stage, liquid stage, and cryogenic stage. This validates statement B as accurate. It has an Orbital Module which comprises of Crew Module and Service Module. This supports statement C as correct. Statement D is incorrect because Gaganyaan envisages a crew of 3, not 5, and the planned orbit is around 400 kilometers, not 500 kilometers.
Q5. Which of the following is not a satellite of Indian origin?
1. XPoSat
2. IXPE
3. SROSS-C
4. HySIS
Answer: IXPE
Solution: IXPE (Imaging X-ray Polarimetry Explorer) is not an Indian satellite. It is a NASA mission in collaboration with the Italian Space Agency ASI. IXPE was launched on December 9, 2021, using a SpaceX Falcon 9 rocket. It is designed to study the polarization of X-rays from cosmic sources like black holes and neutron stars. Important Information: XPoSat (X-ray Polarimeter Satellite) is India’s first dedicated X-ray polarimetry mission. Launched by ISRO on January 1, 2024, using a PSLV rocket. SROSS-C (Stretched Rohini Satellite Series-C) is part of India’s early satellite program ISRO. Launched on May 20, 1992, to conduct scientific experiments and technology validation. HySIS (Hyperspectral Imaging Satellite) is an Earth observation satellite developed by ISRO. Designed to capture hyperspectral images for agriculture, forestry, and environmental monitoring. Launched on November 29, 2018, using a PSLV-C43 rocket.
Q6. The Indian Space Research Organisation's satellite GSAT-30 was successfully launched on 17 January 2020 from Kourou launch base. What is the main function of this satellite?
1. Search and rescue
2. Navigation
3. Space exploration
4. Telecommunication
Answer: Telecommunication
Solution: GSAT-30 is a communication satellite launched by the Indian Space Research Organisation (ISRO) on 17 January 2020. The satellite was launched from the Kourou launch base in French Guiana, using the Ariane-5 VA-251 launch vehicle. The primary function of GSAT-30 is to provide high-quality telecommunications, broadcasting, and broadband services across India. This satellite replaces the INSAT-4A, enhancing the capacity and extending the lifespan of India's communication satellite fleet.
Q7. Which space agency helps India in tracking the Solar Mission Aditya - L1?
1. NASA
2. ESA
3. JAXA
4. ROCOSMOS
Answer: ESA
Solution: ESA (European Space Agency) supports India in tracking the Solar Mission Aditya - L1. The Solar Mission Aditya - L1 is India's first dedicated mission to study the Sun. ESA provides tracking services through its deep space tracking network to assist ISRO in monitoring the spacecraft. This collaboration highlights international cooperation in space exploration and research. Aditya - L1 will study the Sun's corona, solar emissions, solar winds, and other phenomena to better understand solar activity and its impact on Earth's climate. It is placed in the halo orbit around the Lagrange Point 1 (L1) of the Sun-Earth system for continuous observation of the Sun. International collaboration plays a vital role in the success of such high-precision space missions.
Q8. Which of the following missions aims to send a crew of three astronauts to an orbit of 400 kilometres above the Earth for three days?
1. Gaganyaan
2. Chandryaan-2
3. Mission Mangal
4. Bhashkar-1
Answer: Gaganyaan
Solution: Gaganyaan is a human spaceflight mission by the Indian Space Research Organisation ISRO. The mission aims to send a crew of three astronauts to an orbit of 400 kilometres above the Earth for a duration of three days. It is part of India’s efforts to establish its capabilities in human space exploration. The Gaganyaan spacecraft will include an Orbital Module consisting of a crew module and service module. ISRO plans to conduct two unmanned missions before launching the crewed mission to ensure safety and reliability. The mission will focus on testing critical technologies such as crew escape systems, life-support systems, and re-entry capabilities. This program is a significant milestone for India, aiming to make it the fourth country to achieve human spaceflight, after Russia, the United States, and China. The mission will boost India's space exploration capabilities and contribute to scientific advancements and technological innovation.
Q9. ISRO successfully completed which type of mission in February 2025 with the second docking of satellites?
1. Mars Orbiter Mission
2. SpaDeX Mission
3. Chandrayaan Mission
4. Astrosat Mission
Answer: SpaDeX Mission
Solution: The second docking of satellites under ISRO’s Space Docking Experiment – SpaDeX Mission was accomplished successfully in February 2025. ISRO completed the second docking of satellites under the SpaDeX Mission, marking a significant achievement in satellite docking technology. The first docking was completed successfully on 16 January 2025, following the PSLV-C60 launch on 30 December 2024. Further experiments are planned in the next two weeks to advance ISRO’s space docking capabilities.
Q10. In which district of Andhra Pradesh is ISRO Satish Dhawan Space Centre located?
1. Guntur
2. Chittoor
3. Nellore
4. Anantpur
Answer: Nellore
Solution: ISRO's Satish Dhawan Space Centre (SDSC) is located in Sriharikota, a barrier island in the Nellore district of Andhra Pradesh, India. Sriharikota serves as the primary launch site for India's satellite launch vehicles, including the PSLV, GSLV, and Gaganyaan missions. SDSC is named after Dr. Satish Dhawan, one of the pioneers of India's space program and former chairman of ISRO. The center is strategically located near the Bay of Bengal, which provides a safe trajectory for rocket launches over the ocean. Established in 1971, the center has been instrumental in launching numerous satellites that contribute to communication, navigation, and scientific research.
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