UPSC GS Paper III: Science Tech Space Technology ISRO Missions PSLV GSLV Chandrayaan Gaganyaan

Must‑Know

• Polar Satellite Launch Vehicle (PSLV) – first launched in 1993; successfully deployed IRS-1D; uses solid and liquid stages with strap-on boosters; workhorse for Indian remote sensing and small satellite missions.
• Geosynchronous Satellite Launch Vehicle (GSLV) Mk II – first successful flight in 2014 (GSLV-D5); uses indigenously developed cryogenic upper stage (CUS); enables launch of 2-tonne class satellites into GTO.
• Chandrayaan-1 – launched October 2008 by PSLV-C11; discovered water molecules on Moon’s surface via NASA’s Moon Mineralogy Mapper (M3) instrument; orbited at 100 km altitude.
• Moon Impact Probe (MIP) – released by Chandrayaan-1 in November 2008; carried Indian tricolour; confirmed presence of water vapour in lunar exosphere during descent.
• Chandrayaan-2 – launched July 2019 by GSLV Mk III; consisted of orbiter, lander (Vikram), and rover (Pragyan); orbiter remains operational, studying lunar surface and exosphere.
• Vikram lander – attempted soft landing on Moon on September 7, 2019; crash-landed near south pole due to software glitch in braking sequence; ISRO recovered data from descent phase.
• Chandrayaan-3 – launched July 14, 2023 by LVM3; successfully achieved soft landing on Moon on August 23, 2023 at ~70°S latitude; India became first nation to land near lunar south pole.
• Propulsion Module of Chandrayaan-3 – carried SHAPE payload; after lander separation, returned to Earth orbit; demonstrated fuel-efficient trajectory for future sample return missions.
• LVM3 (Launch Vehicle Mark-3) – formerly GSLV Mk III; can carry 4-tonne payloads to GTO or 8 tonnes to LEO; used for Chandrayaan-2, Chandrayaan-3, and planned Gaganyaan missions.
• Gaganyaan – human spaceflight mission; aims to send 3 crew members to 400 km orbit for 7 days; first uncrewed test flight (G1) scheduled for 2024 using LVM3.
• Crew Module – part of Gaganyaan; designed for re-entry and splashdown; tested in Crew Module Atmospheric Re-entry Experiment (CARE) in 2014 during LVM3 suborbital flight.
• Vyommitra – humanoid robot developed by ISRO; will fly in uncrewed Gaganyaan test missions; monitors cabin parameters and simulates human functions.
• Human Space Flight Centre (HSFC) – established in 2019 in Bengaluru; coordinates Gaganyaan program; collaborates with DRDO, IIST, and private sector.
• ISRO System for Safe and Sustainable Space Operations Management (IS4OM) – established 2022 at SHAR; monitors space debris, collision avoidance, and safeguards Indian assets.
• SpaDeX (Space Docking Experiment) – planned ISRO mission in 2024; will demonstrate rendezvous and docking of two small satellites in LEO; critical for future space stations and crewed missions.
• Aditya-L1 – India’s first solar observatory; launched September 2, 2023 by PSLV-C57; placed in halo orbit around Sun-Earth L1 point (~1.5 million km from Earth).
• Aditya-L1 carries seven payloads; includes Visible Emission Line Coronagraph (VELC) to study solar corona and coronal mass ejections.
• NISAR (NASA-ISRO Synthetic Aperture Radar) – joint Earth observation satellite; scheduled launch 2024; uses L-band and S-band radar to study ecosystems, ice dynamics, and crustal deformation.
• Small Satellite Launch Vehicle (SSLV) – developed for launching <500 kg satellites to LEO; first developmental flight SSLV-D1 in 2022 failed due to sensor malfunction; SSLV-D2 succeeded in 2023.
• INSAT-3DS – meteorological satellite; launched February 17, 2024 by GSLV Mk II; enhances weather forecasting and disaster warning capabilities.
• XPoSat (X-ray Polarimeter Satellite) – launched January 1, 2024 by PSLV-C58; carries POLIX and XSPECT payloads; studies X-ray polarization from cosmic sources like black holes and neutron stars.
• PSLV-XL variant – uses six extended strap-on boosters; used for Chandrayaan-1, Mars Orbiter Mission, and AstroSat; higher payload capacity than standard PSLV.
• Mars Orbiter Mission (Mangalyaan) – launched November 5, 2013 by PSLV-C25; entered Mars orbit September 24, 2014; made India first Asian nation to reach Mars orbit.
• MOM made ISRO fourth space agency globally (after NASA, ESA, CNSA) to reach Mars; mission cost ~₹450 crore, noted for cost efficiency.
• AstroSat – launched September 28, 2015 by PSLV-XL; India’s first multi-wavelength space observatory; studies celestial sources in UV, optical, and X-ray bands.

Difficulty Level

Intermediate – requires precise knowledge of mission timelines, launch vehicles, payloads, and outcomes; questions often mix technical and programmatic details.

Common UPSC Traps

Trap: GSLV uses only indigenous cryogenic engine in all variants – Fact: GSLV Mk I and Mk II used Russian-supplied cryogenic stages initially; indigenous CUS was first successfully flight-tested in GSLV-D5 (2014); LVM3 uses indigenized C25 stage.

Trap: Chandrayaan-2’s lander Vikram successfully landed on Moon – Fact: Vikram attempted landing on September 7, 2019 but deviated during final descent and crash-landed; communication lost at 2.1 km altitude (ISRO Failure Analysis Report, 2019).

Trap: PSLV can launch satellites into geostationary orbit – Fact: PSLV is optimized for polar and low Earth orbits; maximum payload to GTO is ~1.4 tonnes; GSLV/LVM3 required for full geostationary insertion.

Trap: Gaganyaan will launch from Sriharikota using PSLV – Fact: Gaganyaan missions will use LVM3 (GSLV Mk III), the only ISRO vehicle human-rated for crewed launch; launch site is Second Launch Pad, SHAR.

Practice MCQs

Question: Consider the following statements about Chandrayaan-3:
1. It was launched using the LVM3 launch vehicle.
2. The propulsion module remained in lunar orbit after lander separation.
3. It achieved the first soft landing in the Moon’s equatorial region.
Which of the statements given above is/are correct?
A) 1 only
B) 1 and 2 only
C) 2 and 3 only
D) 1, 2 and 3
Answer: A
Explanation: Statement 1 is correct – Chandrayaan-3 was launched by LVM3 on July 14, 2023. Statement 2 is incorrect – the propulsion module returned to Earth orbit after mission completion. Statement 3 is incorrect – landing was near the south pole (~70°S), not equatorial.
Why others fail: Option B is tempting due to partial correctness of 1 and 2, but propulsion module did not stay in lunar orbit.

Question: Which of the following ISRO missions was primarily designed to study solar coronal mass ejections?
A) Aditya-L1
B) AstroSat
C) XPoSat
D) Mangalyaan
Answer: A
Explanation: Aditya-L1 carries the Visible Emission Line Coronagraph (VELC) to study solar corona and coronal mass ejections from Sun-Earth L1 point.
Why others fail: AstroSat observes multi-wavelength astronomy but not solar-specific; XPoSat studies X-ray polarization; Mangalyaan is Mars-focused.

Question: The first Indian mission to use an indigenously developed cryogenic upper stage successfully was:
A) GSLV-D3
B) GSLV-D5
C) GSLV-F06
D) LVM3-M1
Answer: B
Explanation: GSLV-D5, launched on January 5, 2014, successfully used the indigenous cryogenic upper stage (CUS), placing GSAT-14 into GTO.
Why others fail: GSLV-D3 (2010) failed due to CUS ignition failure; GSLV-F06 (2010) used Russian stage; LVM3-M1 (2017) used improved C25 stage but not the first.

Question: Which of the following pairs is correctly matched?
1. NISAR – ISRO-NASA joint mission
2. SpaDeX – Reusable Launch Vehicle experiment
3. Vyommitra – Crew escape system
A) 1 only
B) 1 and 2 only
C) 2 and 3 only
D) 1, 2 and 3
Answer: A
Explanation: NISAR is a joint mission between ISRO and NASA; SpaDeX is for space docking, not RLV; Vyommitra is a humanoid, not part of escape system.
Why others fail: Option D is tempting due to high-profile nature of all terms, but only 1 is correct.

Question: The primary objective of the XPoSat mission is to:
A) Map lunar surface composition
B) Study X-ray polarization from celestial sources
C) Monitor Earth’s ionosphere
D) Detect gravitational waves
Answer: B
Explanation: XPoSat, launched in 2024, carries POLIX and XSPECT to measure polarization of X-rays from black holes, neutron stars, and pulsars.
Why others fail: Chandrayaan missions map Moon; Ionosphere monitored by other satellites like INSAT-3DS; gravitational waves not detectable by XPoSat.

Question: Which launch vehicle was used for India’s first successful interplanetary mission?
A) PSLV-C25
B) GSLV Mk II
C) LVM3-M1
D) PSLV-XL
Answer: A
Explanation: Mars Orbiter Mission (Mangalyaan) was launched on November 5, 2013, using PSLV-C25 from Sriharikota.
Why others fail: GSLV Mk II and LVM3 used for heavier payloads; PSLV-XL is a variant but C25 was the specific vehicle.

Question: Consider the following:
1. CARE module
2. Vyommitra
3. SHAPE payload
Which of the above were part of the Chandrayaan-3 mission?
A) 1 and 2 only
B) 2 and 3 only
C) 3 only
D) 1, 2 and 3
Answer: C
Explanation: SHAPE payload was on the propulsion module of Chandrayaan-3; CARE was part of 2014 LVM3 test; Vyommitra is for Gaganyaan.
Why others fail: Option B is tempting due to association with ISRO humanoids and experiments, but Vyommitra not on Chandrayaan-3.

Last‑Minute Revision

• ⚠️ PSLV first successful flight: 1994 (PSLV-D2), not 1993 (D1 failed).
• GSLV Mk II uses indigenized CUS; first success: GSLV-D5 (2014).
• Chandrayaan-1 launch: October 22, 2008.
• Vikram lander crash: September 7, 2019.
• ⚠️ Chandrayaan-3 landing date: August 23, 2023.
• LVM3 = GSLV Mk III; human-rated for Gaganyaan.
• First Indian satellite: Aryabhata (1975), not INSAT.
• First PSLV launch: September 20, 1993 (failed).
• Aditya-L1 launched: September 2, 2023.
• NISAR launch expected: 2024 (from Sriharikota).
• XPoSat launch: January 1, 2024.
• SpaDeX mission: 2024, for docking tech.
• ⚠️ MOM cost: ~₹450 crore; launched 2013, reached Mars 2014.
• AstroSat launch: September 28, 2015.
• INSAT-3DS launch: February 17, 2024.
• SSLV-D2 success: February 10, 2023.
• CARE experiment: December 18, 2014.
• Human Space Flight Centre: 2019, Bengaluru.
• IS4OM established: 2022.
• ⚠️ Gaganyaan first uncrewed flight: G1, 2024 (verify from standard source).
• Vyommitra: not a crew member, but a simulator.
• ⚠️ Chandrayaan-3 landed at ~70°S latitude.
• Aditya-L1 placed at L1 point, not Earth orbit.
• ⚠️ PSLV-XL used for Mars Orbiter Mission.
• LVM3 used for Chandrayaan-2, Chandrayaan-3, Gaganyaan.
• ⚠️ India is first nation to land near lunar south pole.