Indian Space Programme: Launch Vehicles, Orbits and Missions
ISRO's launch vehicles, orbit types, satellite systems, Chandrayaan, Mangalyaan, Aditya-L1, Gaganyaan and space-sector reform for UPSC.
SyllabusGS III · Awareness in the fields of IT, space, computers, robotics, nano-technology, bio-technology and IPR
Prerequisites: Space Technology — overview · The Universe and the Earth
The Hook: A Lander Near the Lunar South Pole
On 23 August 2023, the Vikram lander of Chandrayaan-3 soft-landed near the Moon’s south polar region. India became the fourth country to soft-land on the Moon (after the USSR, the USA and China) and the first to land near the south pole. The mission had been launched on 14 July 2023 by LVM3 from Sriharikota, and the government later declared 23 August as National Space Day.
Four years earlier, Chandrayaan-2’s lander had crashed. The question this topic answers: what does it take — rockets, orbits, guidance, institutions — for a developing country to reach the Moon, Mars and the Sun, and why should it bother?
The Core Concept
A space programme has three parts: access to space (launch vehicles), use of space (satellites and missions) and the ground segment (tracking, control and data users). UPSC asks about all three.
How a rocket reaches orbit (in one paragraph)
A rocket works on Newton’s third law: hot gases thrown backwards push the vehicle forwards. To stay in low Earth orbit, a satellite must reach a horizontal speed of roughly 7.8 km/s, so that it keeps “falling” around the Earth instead of into it. No single engine can carry its own dead weight that far, so rockets are built in stages that are dropped once their propellant is spent. Propellants come in three families — solid (simple, powerful, cannot be throttled or restarted), liquid (can be throttled and restarted), and cryogenic (liquid hydrogen and liquid oxygen stored at extremely low temperatures, giving the highest efficiency per kilogram of propellant, which is why it is used in the upper stage that pushes heavy satellites to high orbits).
| Propellant | Example in ISRO vehicles | Strength | Limitation |
|---|---|---|---|
| Solid | PSLV first and third stages; LVM3 S200 boosters; all SSLV main stages | High thrust, simple storage | Cannot be shut down and restarted |
| Earth-storable liquid | Vikas engine (PSLV second stage, LVM3 L110 core stage) | Throttle and restart possible | Toxic propellants |
| Cryogenic (LH2 + LOX) | GSLV upper stage; LVM3 C25 stage | Highest efficiency | Hard to master — very low temperatures |
| Semi-cryogenic (refined kerosene + LOX) | Under development by ISRO | Cleaner, cheaper than storable liquids | Not yet flown by ISRO |
Types of orbits
| Orbit | Altitude / location | Typical users |
|---|---|---|
| Low Earth Orbit (LEO) | Up to about 2,000 km | Earth observation, space stations, broadband constellations |
| Sun-synchronous orbit (SSO) | Near-polar LEO, typically 600–800 km | Remote sensing — passes over a place at the same local solar time, so lighting is consistent |
| Medium Earth Orbit (MEO) | Between LEO and GEO | Global navigation systems such as GPS |
| Geosynchronous orbit (GSO) | About 35,786 km; period equal to one sidereal day | Communication; NavIC’s inclined satellites |
| Geostationary orbit (GEO) | A GSO directly above the equator with zero inclination | Communication, broadcasting, weather — appears fixed in the sky |
| Geosynchronous Transfer Orbit (GTO) | Elliptical orbit used to reach GEO | Launch vehicles drop GSO satellites here; the satellite raises itself |
| Lagrange point L1 | About 1.5 million km from Earth towards the Sun | Uninterrupted view of the Sun (Aditya-L1, NASA–ESA SOHO) |
Every geostationary orbit is geosynchronous, but not every geosynchronous orbit is geostationary.
ISRO’s launch vehicles
| Vehicle | Configuration | Milestones |
|---|---|---|
| SLV-3 | Four solid stages | Placed Rohini RS-1 in orbit on 18 July 1980 — India’s first successful satellite launch with its own rocket; project led by A.P.J. Abdul Kalam |
| ASLV | Five solid stages | Experimental; successful flights in the early 1990s |
| PSLV | Four stages: solid–liquid–solid–liquid, with strap-on boosters | First successful flight in October 1994; Chandrayaan-1 (2008), Mars Orbiter Mission (2013), Aditya-L1 (2023); 104 satellites in one launch (PSLV-C37, February 2017) |
| GSLV (Mk II) | Three stages; cryogenic upper stage | First indigenous cryogenic stage flew successfully on GSLV-D5 in January 2014; earlier flights used Russian cryogenic stages |
| LVM3 (GSLV Mk III) | Two S200 solid boosters, L110 liquid core, C25 cryogenic upper stage | First orbital flight June 2017; Chandrayaan-2 (2019), Chandrayaan-3 (2023); human-rated version for Gaganyaan |
| SSLV | Three solid stages plus a liquid Velocity Trimming Module | Small satellites, launch on demand; first flight failed (August 2022), succeeded in February 2023 and August 2024 |
In September 2024 the Union Cabinet approved a Next Generation Launch Vehicle (NGLV), designed to be partially reusable.
Satellite systems — what ISRO puts up there
- INSAT/GSAT — communication, television, telemedicine, and meteorology (INSAT-3D series).
- IRS / EOS — Indian Remote Sensing satellites (IRS-1A, 1988 onwards) for agriculture, forestry, water, urban planning; Cartosat for high-resolution mapping; Oceansat for ocean and fisheries data.
- RISAT — radar imaging satellites that see through clouds and at night; vital for floods and border surveillance.
- NavIC (Navigation with Indian Constellation, originally IRNSS) — a regional navigation system of seven satellites (three geostationary, four in inclined geosynchronous orbit) covering India and about 1,500 km beyond. It offers a Standard Positioning Service for all users and a Restricted Service for authorised users. The newer NVS series adds the L1 band used by most consumer phones.
Milestone missions
| Mission | Launch | Highlight |
|---|---|---|
| Aryabhata | 19 April 1975 (Soviet rocket) | India’s first satellite |
| Chandrayaan-1 | 22 October 2008, PSLV-C11 | Moon Impact Probe; its instruments helped detect water molecules on the lunar surface |
| Mars Orbiter Mission (Mangalyaan) | 5 November 2013, PSLV-C25 | Entered Mars orbit on 24 September 2014 — first Asian nation to reach Mars orbit, and on its first attempt |
| AstroSat | September 2015, PSLV | India’s first dedicated multi-wavelength space observatory |
| Chandrayaan-2 | 22 July 2019, GSLV Mk III | Orbiter continues to work; Vikram lander crashed in September 2019 |
| Chandrayaan-3 | 14 July 2023, LVM3 | Soft landing on 23 August 2023; Pragyan rover confirmed sulphur near the south pole |
| Aditya-L1 | 2 September 2023, PSLV-C57 | India’s first solar observatory; placed in a halo orbit around L1 on 6 January 2024 |
| XPoSat | 1 January 2024, PSLV-C58 | India’s first dedicated X-ray polarimetry mission |
| SpaDeX | 30 December 2024, PSLV-C60 | Two satellites docked in January 2025 — India became the fourth country to demonstrate docking in space |
Human spaceflight
Gaganyaan aims to fly a crew to low Earth orbit on a human-rated LVM3. The crew-escape system was tested in the TV-D1 flight on 21 October 2023. Four Indian Air Force officers were named as astronaut-designates in February 2024. The longer-term targets announced by the government are an Indian space station (Bharatiya Antariksh Station) by 2035 and an Indian on the Moon by 2040.
Institutions and reform
graph TD
A[Department of Space - 1972] --> B[ISRO - 1969: research, development, missions]
A --> C[NSIL - 2019: commercial arm]
A --> D[IN-SPACe - 2020: authorises and promotes private activity]
E[Indian Space Policy 2023] --> B
E --> C
E --> D
D --> F[Private launchers and satellite makers]- ISRO was set up on 15 August 1969, growing out of INCOSPAR (1962), founded under Vikram Sarabhai.
- NewSpace India Limited (NSIL), a public sector company, commercialises ISRO-developed technologies and runs demand-driven satellite missions.
- IN-SPACe is the single-window body that authorises and supervises non-government space activities.
- The Indian Space Policy, 2023 lets private entities carry out end-to-end space activities; ISRO is to focus on research and advanced technology.
- FDI (February 2024): up to 74% automatic route for satellite manufacturing and operation, up to 49% for launch vehicles and spaceports, and up to 100% for components and systems.
- Private milestones: Skyroot’s Vikram-S became the first privately built Indian rocket to fly (sub-orbital, November 2022); Agnikul’s Agnibaan SOrTeD flew in May 2024 with a 3D-printed semi-cryogenic engine.
Memory Anchors
PSLV stages: “Some Like Some Like” → Solid – Liquid – Solid – Liquid.
LVM3 recipe: “200 – 110 – 25” → S200 boosters, L110 core, C25 cryogenic stage. The number is the tonnes of propellant, and the letter is its type.
Moon–Mars–Sun launchers: Chandrayaan-1, Mangalyaan and Aditya-L1 all went on PSLV; Chandrayaan-2 and Chandrayaan-3 went on LVM3 (“the two lander missions took the heavy rocket”).
| Confusable pair | Difference |
|---|---|
| GEO vs GSO | GEO is a GSO over the equator with zero inclination; it looks stationary |
| SSO vs GEO | SSO is low and near-polar (imaging); GEO is high and equatorial (communication) |
| NavIC vs GPS | NavIC is regional (India + about 1,500 km); GPS is global (MEO constellation) |
| Cryogenic vs semi-cryogenic | LH2 + LOX vs refined kerosene + LOX |
One-line Mains hook: Vikram Sarabhai argued that India must be “second to none in the application of advanced technologies to the real problems of man and society.”
For Prelims
- India’s first satellite, Aryabhata (1975), was launched by a Soviet rocket; the first Indian rocket to orbit a satellite was SLV-3 (Rohini, 1980).
- PSLV’s stages alternate solid and liquid; the cryogenic stage belongs to GSLV and LVM3, not PSLV or SSLV.
- Aditya-L1 orbits the L1 point, about 1.5 million km away — not the Sun itself and not the Moon.
- NavIC has seven satellites and is regional; it is not a global system.
- Chandrayaan-3 carried a propulsion module, the Vikram lander and the Pragyan rover — no new orbiter; it relied on Chandrayaan-2’s orbiter for communication backup.
- SpaDeX (January 2025) made India the fourth country to dock two spacecraft in orbit.
For Mains
- Dimensions: development (communication, weather, disaster warning, land records, crop estimation); strategic (navigation independence, surveillance, deterrence); economic (commercial launches, start-ups, the space economy); scientific (planetary science, solar physics); diplomatic (South Asia Satellite, launches for other countries).
- Keywords: strategic autonomy, launch-on-demand, reusable launch vehicles, space situational awareness, space debris, end-to-end private participation, regulatory clarity.
- Value-addition: Indian Space Policy 2023; IN-SPACe as a single window; the February 2024 FDI changes; India signed the Artemis Accords in June 2023; India is party to the Outer Space Treaty (1967).
Common Traps
In the News
- January 2025 — GSLV-F15 launched the NVS-02 navigation satellite; it was the 100th launch from Sriharikota.
- January 2025 — SpaDeX satellites docked in orbit.
- June–July 2025 — Group Captain Shubhanshu Shukla flew on the Axiom-4 mission to the International Space Station, becoming the first Indian to visit the ISS and the second Indian in space after Rakesh Sharma (1984).
- July 2025 — NISAR, the NASA–ISRO Synthetic Aperture Radar satellite, was launched on GSLV-F16. Follow developments on the current affairs page.
Practice
Prelims
Consider the following statements about Indian launch vehicles:
- The first and third stages of PSLV use solid propellants.
- The upper stage of LVM3 uses cryogenic propellants.
- SSLV uses a cryogenic upper stage to place satellites in low Earth orbit.
Which of the statements given above is/are correct?
Solution
Statement 1 is correct — PSLV alternates solid (stages 1 and 3) and liquid (stages 2 and 4). Statement 2 is correct — LVM3’s C25 upper stage burns liquid hydrogen and liquid oxygen. Statement 3 is incorrect — SSLV has three solid stages and a small liquid Velocity Trimming Module; it has no cryogenic stage.
Answer: B
Consider the following pairs of missions and the launch vehicles that carried them:
- Chandrayaan-1 — PSLV
- Mars Orbiter Mission — PSLV
- Chandrayaan-3 — LVM3
- Aditya-L1 — GSLV Mk II
How many of the pairs given above are correctly matched?
Solution
Chandrayaan-1 (PSLV-C11), the Mars Orbiter Mission (PSLV-C25) and Chandrayaan-3 (LVM3) are correctly matched. Aditya-L1 was launched by PSLV-C57, not GSLV. Three pairs are correct.
Answer: C
With reference to satellite orbits, consider the following statements:
- A satellite in a sun-synchronous orbit always remains above the same point on the Earth.
- A geostationary satellite orbits directly above the equator.
- NavIC uses satellites in both geostationary and inclined geosynchronous orbits.
Which of the statements given above is/are correct?
Solution
Statement 1 is incorrect — that describes a geostationary satellite. A sun-synchronous satellite is in a low, near-polar orbit and passes over a given place at the same local solar time. Statement 2 is correct — zero inclination over the equator is what makes a geostationary satellite appear fixed. Statement 3 is correct — NavIC has three geostationary and four inclined geosynchronous satellites.
Answer: D
Mains
The opening of India’s space sector to private participation marks a shift from a state-led to an ecosystem-led model. Discuss the opportunities and the regulatory challenges involved.
Solution
Introduction: For five decades ISRO designed, built and launched almost everything in India’s space programme. Since 2020, reforms — IN-SPACe, NSIL, the Indian Space Policy 2023 and liberalised FDI (2024) — have opened every segment to private firms.
Body:
- Opportunities: launch-on-demand for small satellites (Skyroot’s Vikram-S, Agnikul’s Agnibaan); a larger share of the global space economy; satellite broadband and Earth-observation services; jobs and start-ups; ISRO freed to focus on deep-space science and human spaceflight.
- Institutional design: IN-SPACe authorises and supervises; NSIL commercialises ISRO technology; FDI up to 74% (satellites), 49% (launch vehicles) and 100% (components) under the automatic route.
- Challenges: no comprehensive space activities law yet; liability for damage under the Outer Space Treaty and the Liability Convention rests with the State; spectrum and orbital-slot allocation; space debris; data-security concerns in Earth observation; dependence on ISRO’s test and launch facilities.
- Way forward: a statutory framework for licensing and liability, insurance norms, a second spaceport for small launchers, and procurement by government as an anchor customer.
Conclusion: The reform is a move from “ISRO does everything” to “ISRO leads, India builds”. Its success depends on predictable regulation that balances commercial freedom with national security and international obligations.
Quick Revision
| Point | One-liner |
|---|---|
| First satellite | Aryabhata, 19 April 1975, Soviet launch |
| First Indian launcher success | SLV-3, Rohini, 18 July 1980 |
| PSLV | Solid–liquid–solid–liquid; 104 satellites in February 2017 |
| Indigenous cryogenic stage | GSLV-D5, January 2014 |
| LVM3 | S200 + L110 + C25; Chandrayaan-2 and Chandrayaan-3 |
| Chandrayaan-3 | Launched 14 July 2023; landed 23 August 2023 |
| Mars Orbiter Mission | PSLV-C25, November 2013; Mars orbit September 2014 |
| Aditya-L1 | PSLV-C57, September 2023; halo orbit at L1, January 2024 |
| NavIC | Seven satellites, regional, India + about 1,500 km |
| Reform | IN-SPACe (2020), NSIL (2019), Space Policy 2023, FDI 2024 |
Key Takeaways
- Launch-vehicle questions turn on propellants and stages — remember which vehicles carry a cryogenic stage (GSLV, LVM3).
- Orbit questions turn on altitude, inclination and purpose — sun-synchronous for imaging, geostationary for communication, L1 for the Sun.
- Mains questions turn on purpose and policy — development, security, the private sector and the regulatory gap.
Related Topics
- Space Technology — quick revision
- Space Technology — practice questions
- Defence Technology — anti-satellite test and missile technology
- The Universe and the Earth
- Disaster Management — satellites in early warning
- Science & Technology