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 IRNSS-1D Navigation Satellite Mission —its objectives, timelines, key technologies, and strategic implications.

ISRO IRNSS-1D Navigation Satellite Mission Overview

IRNSS-1D Navigation Satellite was designed and executed with the primary aim of supporting advancements in Navigation.The trajectory and configuration of IRNSS-1D Navigation Satellite were optimized for operations in Earth.

• PSLV-C27 served as the launch platform for IRNSS-1D Navigation Satellite.
• The spacecraft was sent into orbit from Satish Dhawan Space Centre.
• The primary objective of IRNSS-1D Navigation Satellite was to Regional navigation services.
• The extended mission scope of IRNSS-1D Navigation Satellite included Augment NavIC constellation.
• As per ISRO documentation, the mission is Extended Mission / Partially Operational (atomic clock failed earlier, still used for messaging/other services).

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Timeline & Milestones of ISRO IRNSS-1D Navigation Satellite Mission

• IRNSS-1D Navigation Satellite lifted off from the launch pad on March 28, 2015.
• Mission planning documents suggest an operational window lasting until Around March 2025 (10-year design life).

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ISRO IRNSS-1D Navigation Satellite Mission Technical Specifications

As a Navigation mission, IRNSS-1D Navigation Satellite was built around a configuration involving I-1K bus, Rubidium atomic clocks.The choice of Geosynchronous Orbit (GSO) aligned with the mission’s overall strategy for scientific observation and technical validation.

• Navigation payload, CDMA ranging payload were integrated into IRNSS-1D Navigation Satellite to operate effectively in Earth.
• ISRO integrated L5-band, S-band into the communication architecture of IRNSS-1D Navigation Satellite to handle mission-critical signals.
• The design and execution of IRNSS-1D Navigation Satellite incorporated features like Satellite navigation technology.

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IRNSS-1D Navigation Satellite Launch Information

• The mission timeline of IRNSS-1D Navigation Satellite began with its launch on March 28, 2015.
• To execute the launch of IRNSS-1D Navigation Satellite, the PSLV-C27 was deployed.
• All pre-launch procedures were conducted at Satish Dhawan Space Centre.

Who are the Stakeholders & Collaborators?

ISRO participated in the planning and execution of the mission.

Outputs, Applications & Impact of ISRO IRNSS-1D Navigation Satellite Mission

IRNSS-1D Navigation Satellite is recognized for achieving Fourth satellite in NavIC constellation.Scientific analysis and public services were enabled through outputs like Navigation and timing data.

• Outputs from IRNSS-1D Navigation Satellite are used in civilian domains, particularly in Navigation, tracking, disaster relief, mapping, timing services.
• Enhanced regional navigation system, reducing foreign dependence reflects the larger purpose behind IRNSS-1D.
• Further NavIC satellites for constellation completion and replacement represent the next logical step in the mission series initiated by IRNSS-1D Navigation Satellite, reflecting ISRO’s commitment to iterative advancements in this area.

ISRO IRNSS-1D Navigation Satellite Space Mission Risks, Failures & Mitigation

One of the main difficulties during IRNSS-1D was Atomic clock failure.

• Mission performance assessments showed that Atomic clock failure occurred.
• ISRO responded to the issue by adopting measures such as Used for messaging services.
• From the outcome of IRNSS-1D Navigation Satellite, a major lesson was Importance of robust clock systems.

UPSC Relevance of ISRO IRNSS-1D Navigation Satellite Space Mission

• ISRO missions are frequently asked in the UPSC Prelims examination, especially under the Science and Technology section, where candidates are expected to know key facts like launch dates, objectives, and agencies involved.
• Writing effective GS answers often involves citing ISRO’s missions as examples of indigenous technological advancement, innovation, and self-reliance under programs like ‘Make in India’ or ‘Atmanirbhar Bharat’.
• ISRO’s mission culture — defined by simplicity, frugality, and collaboration — embodies many values discussed in the Ethics paper, such as integrity, public service motivation, and accountability.
• In optional papers dealing with Indian economy or policy, ISROs commercial arm NSIL and its growing role in global markets serve as economic case points.

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. Which among the following is India's first Human spaceflight programme?
1. Chandrayaan - 1
2. Shukrayaan
3. Mangalyaan
4. Gaganyaan
Answer: Gaganyaan
Solution: The correct answer is Gaganyaan. Mission Gaganyaan has been dubbed as India's maiden human spaceflight program. India is planning to send the astronauts into space. Under the Gaganyaan schedule, three flights will be sent in orbit. Of the three, there will be two unmanned flights and one human spaceflight. The human space flight program, called the Orbital Module will have three Indian astronauts, including a woman.

Q2. Recently, the Indian Space Research Organisation (ISRO) has announced to launch DS-SAR satellite of which of the following countries through PSLV-C56?
1. Israel
2. USA
3. Singapore
4. UAE
Answer: Singapore
Solution: The correct answer is Singapore. The Indian Space Research Organisation (ISRO) successfully launched its PSLV-C56 rocket carrying seven Singaporean satellites from the Satish Dhawan Space Centre, Sriharikota. DS-SAR, a radar imaging earth observation satellite is a primary satellite for the mission. It was developed under a partnership between the Defence Science and Technology Agency representing the government of Singapore and ST Engineering. According to ISRO, DS-SAR carries a Synthetic Aperture Radar payload which allows it to provide all-weather day and night coverage.

Q3. What is the name of the abort mission that ISRO is scheduled to launch on recently?
1. Flight Test Vehicle Abort Mission-1 TV-D1
2. Crew Escape System Test Mission-1 CES-T1
3. Gaganyaan Abort Mission-1 GAM-1
4. Both 1 and 2
Answer: Flight Test Vehicle Abort Mission-1 TV-D1
Solution: ISRO is all set to launch the Flight Test Vehicle Abort Mission TV-D1, a key part of its ambitious human space mission Gaganyaan. The TV-D1 is a single-stage liquid rocket that will carry a crew module and crew escape systems to an altitude of 17 km. The abort sequence will then be executed, with the crew escape systems separating from the rocket and deploying parachutes to bring the crew module safely to the ground. The success of the TV-D1 test flight will be a significant milestone for the Gaganyaan programme, as it will demonstrate the ability of the crew escape system to safely transport astronauts away from a failing rocket. This test flight will be followed by three more tests of the same nature in the coming days. The Gaganyaan mission aims to launch a crew of three Indian astronauts to an orbit of 400 km for a three-day mission, and bring them back safely to Earth. If successful, India will become the fourth nation to launch a manned spaceflight mission, after the US, Russia, and China.

Q4. Which of the following Indian institution has recently demonstrated a hackproof quantum communication system?
1. IIT Madras
2. ISRO
3. DRDO
4. C-DAC
Answer: ISRO
Solution: The correct answer is ISRO. The Indian Space Research Organisation has a strong interest in developing technologies for secure satellite communication, which includes the potential for quantum communication to ensure security against eavesdropping and hacking attempts. ISRO's involvement in space and satellite technologies makes it a likely candidate for deploying and testing quantum communication systems. Quantum communication is considered potentially hackproof because it is based on the principles of quantum mechanics. Any attempt to eavesdrop on quantum communication would disturb the quantum states involved, alerting the communicating parties. One of the primary applications of quantum communication is Quantum Key Distribution, which allows two parties to generate a shared random secret key known only to them, which can then be used to encrypt and decrypt messages.

Q5. By which year is ISRO planning to have the Indian Space Station Bharatiya Antariksha Station ready?
1. 2025
2. 2026
3. 2027
4. 2028
Answer: 2028
Solution: The correct answer is 2028. India plans to build its own space station by 2035, with the first phase expected to be completed by 2028. ISRO is currently designing the space station, with detailed engineering completed for launch by 2028 using the LVM3 rocket. The space station's early phase will focus on robotic activities to build operational capability and confidence. While focusing on independent space activities, India remains open to collaboration with other countries on joint missions and space station efforts. ISRO acknowledges challenges in decommissioning the International Space Station and plans to stay focused on its own space initiatives. The Indian space station project aligns with India's human spaceflight mission, Gaganyaan, slated for operations.

Q6. What name has ISRO given to the Rover sent along with Chandrayaan-3 Mission?
1. Pragyan
2. Shiv-Shakti
3. Vikram
4. Mission Mangal
Answer: Pragyan
Solution: The correct answer is Pragyan. Pragyan is the name given to the rover that was part of the Chandrayaan-3 mission. The word Pragyan means wisdom in Sanskrit, symbolizing the rover's mission to gather knowledge about the lunar surface. The rover Pragyan is equipped with scientific instruments designed to study the composition of the lunar surface and analyze soil and rock samples. Pragyan operates on solar power and is expected to function for a lunar day, which is equivalent to about 14 Earth days. Chandrayaan-3 is the third lunar exploration mission by the Indian Space Research Organisation. It aims to demonstrate the end-to-end capability in safe landing and roving on the lunar surface.

Q7. NISAR satellite is designed to observe and take measurements of some of the Earth's most complex processes. It is a:
1. project of Canadian space agency
2. project of ISRO alone
3. joint project between ISRO and NASA
4. project of NASA alone
Answer: joint project between ISRO and NASA
Solution: The correct answer is joint project between ISRO and NASA. The NISAR satellite is a collaborative project between the Indian Space Research Organisation and the National Aeronautics and Space Administration. The primary objective of the NISAR mission is to observe and take detailed measurements of some of the Earth's most complex processes, including ecosystem disturbances, ice-sheet collapse, and natural hazards such as earthquakes, tsunamis, volcanoes, and landslides. NISAR stands for NASA-ISRO Synthetic Aperture Radar, emphasizing the synergy between the two space agencies. The satellite will utilize advanced radar imaging to provide high-resolution data that will be beneficial for scientific research and practical applications in disaster management and climate change monitoring.

Q8. The number of scientific payloads on Aditya L - 1 mission for systematic study of Sun is
1. 9
2. 6
3. 7
4. 5
Answer: option 3
Solution: The correct answer is option 3. Aditya-L1 is India's first space-based solar observatory, launched by ISRO on September 2, 2023. It is designed for a systematic study of the Sun from the Lagrange Point 1, about 1.5 million km from Earth. The mission carries 7 scientific payloads to observe the photosphere, chromosphere, and corona of the Sun in multiple wavelengths. Hence, option 3 is correct.

Q9. Aditya-L1 is a landmark Indian mission aimed at understanding solar phenomena. What specific celestial target is Aditya-L1 focused on studying from the Lagrangian point L1?
1. Moon
2. Mars
3. Venus
4. Sun
Answer: Sun
Solution: The correct answer is Sun. Aditya-L1 is India's first dedicated mission to study the Sun. It is designed to provide insights into the solar atmosphere and its impact on the interplanetary space environment. The mission is named after the Sun god Aditya in Hindu mythology and L1 denotes its placement at the Lagrange point 1, which is about 1.5 million kilometers from Earth towards the Sun. The L1 point is a strategic location for continuous solar observations because objects at this point maintain a stable position relative to the Earth and the Sun. Aditya-L1 will observe the solar corona, which is the outermost layer of the Sun's atmosphere, and study its dynamics and impact on space weather. The mission aims to understand the origin and development of coronal mass ejections and solar flares, which can affect satellite operations, communications, and power grids on Earth.

Q10. What is the name of India's first Solar mission which was launched by ISRO in September, 2023?
1. Aditya-L1
2. Aditya-S1
3. Aditya-P1
4. Aditya-M1
Answer: Aditya-L1
Solution: The correct answer is Aditya-L1. Aditya-L1 is India's first solar mission launched by ISRO on September 2, 2023. The spacecraft is designed to study the Sun's corona, chromosphere, and solar wind dynamics. Aditya-L1 will be placed in a halo orbit around the Lagrange point L1, approximately 1.5 million km from Earth. The mission aims to collect data to understand solar activities and their effect on space weather. Aditya-L1 carries seven payloads, including instruments for imaging the Sun and analyzing magnetic fields and plasma.