Chapter 12: Earth, Moon, and the Sun

ISRO's Lunar and Solar Missions

Chandrayaan Programme:

• Chandrayaan-1 (2008): India's first lunar mission; MIP (Moon Impact Probe) crashed near the south pole; confirmed presence of water molecules on the Moon (using M³ instrument, NASA)
• Chandrayaan-2 (2019): Orbiter (still operational), Vikram lander (hard-landed), Pragyan rover; orbiter's Dual Frequency Synthetic Aperture Radar (DFSAR) continues mapping Moon
• Chandrayaan-3 (2023): Successfully soft-landed Vikram lander and Pragyan rover near the lunar south pole on August 23, 2023; first mission to land near south pole; Pragyan confirmed presence of sulphur, aluminium, calcium, iron, chromium, and titanium on the lunar surface

Aditya-L1 (2023): India's first solar observatory mission. Placed in a halo orbit at the Sun-Earth Lagrange Point 1 (L1), approximately 1.5 million km from Earth. Studies solar wind, corona, solar flares — relevant to space weather forecasting.

Gaganyaan Mission: India's first human spaceflight programme. Target: 3-astronaut mission to Low Earth Orbit for 3 days. ISRO is training "Vyomanauts" (Gaganyatris). TV-D1 abort test successful (Oct 2023); uncrewed mission with Vyomitra robot planned H2 2026; crewed mission now targeted for early 2027 (revised timeline).

[Additional] Recent ISRO Missions (2024–2025):

• XPoSat (January 1, 2024): India's first dedicated X-ray polarimetry satellite — studies high-energy radiation from black holes, neutron stars, and pulsars. Makes India only the 2nd country after NASA (IXPE, 2021) to operate such a mission. Carries POLIX (Polarimeter Instrument in X-rays) and XSPECT instruments.
• INSAT-3DS (February 17, 2024): India's third-generation meteorological satellite, fully funded by the Ministry of Earth Sciences. Launched on GSLV-F14; successor to INSAT-3D and INSAT-3DR; provides improved weather data for cyclone tracking, precipitation estimation, and sea surface temperature monitoring.
• SpaDeX — Space Docking Experiment (December 30, 2024): India became only the 4th country in the world (after USA, Russia, and China) to successfully demonstrate orbital docking technology. Two small spacecraft (SDX01 "Chaser" and SDX02 "Target") were launched and successfully docked in orbit on January 16, 2025. Orbital docking is an essential technology for future crewed missions, space stations, and sample return missions. This is a high-probability UPSC Prelims fact.
• NISAR (NASA-ISRO Synthetic Aperture Radar — launched July 30, 2025): India's first joint satellite mission with NASA. A dual-frequency (L-band + S-band) SAR satellite co-developed by ISRO and NASA/JPL over 12 years; became operational January 2026. Monitors Earth's surface changes — glacier movement, earthquakes, landslides, forest biomass, wetlands — with centimetre-level precision every 12 days. Costliest Earth observation satellite (~$1.5 billion total).

Indian Standard Time and Longitude:

• IST = UTC + 5:30 hours
• Based on 82.5°E meridian (passing through Mirzapur, Uttar Pradesh)
• India does not observe Daylight Saving Time
• Single time zone for the entire country (though critics argue Northeast India and the Andaman Islands deserve a separate time zone)

International Space Station (ISS) and India:

• India is not an ISS partner but has astronaut training programmes with NASA (Axiom mission) and Russia
• Gaganyaan astronaut Shubhanshu Shukla flew on Axiom Mission 4 to ISS (June 25 – July 15, 2025) — India's second human in space after Rakesh Sharma

[Additional] Chandrayaan-4 — Cabinet Approval, Technical Challenges, and India's 2040 Moon Vision (GS3 — Science & Technology / Space Policy):

Key facts:

• Cabinet approval: 18 September 2024 (Union Cabinet, PIB PRID: 2055983)
• Budget: Rs. 2,104.06 crore (~US$220 million)
• Target launch: ~2028 (36 months from approval date)
• Sample return target: 3 kg of lunar soil (regolith) and rock — vacuum-sealed in the Ascender Module
• Landing site: MM-4 in Mons Mouton area (latitude −84.289°, longitude 32.808°) — near the lunar south pole, in the same region as Chandrayaan-3; selected for lowest hazard rating (9.89% hazard) and gentle terrain slope (average 5°)
• Sample collection tools: Scoop + drill capable of penetrating up to 2 metres depth for subsurface samples

Key technical challenges (why this is harder than Chandrayaan-3):

1. Lunar Orbit Rendezvous and Docking: AM must ascend from Moon surface and dock with TM in lunar orbit — only USA (Apollo), Soviet Union (sample return probes), and China (Chang'e-5, December 2020) have done this before
2. Ascent Vehicle from Moon: Lifting off from the Moon with no launch pad, no infrastructure, limited power — a complex engineering challenge
3. Heat-shielded Re-entry Capsule: RM must safely re-enter Earth's atmosphere at ~11 km/s with the precious sample sealed inside — similar to China's Chang'e-5 return in December 2020
4. Sample Preservation: Lunar samples must be kept vacuum-sealed to preserve their scientific value; contamination by terrestrial atmosphere would destroy irreplaceable information

Chandrayaan-4 vs LUPEX (separate missions):

India's space roadmap — the 2040 Moon vision:

• 2028: Chandrayaan-4 sample return — first robotic sample return from Moon's south pole
• 2028 (approx): LUPEX rover explores water ice deposits at south pole
• 2035: Bharatiya Antariksh Station (Indian Space Station) operational
• 2040: Indian astronaut on the Moon

UPSC synthesis: Chandrayaan-4 is a 3-mission leap beyond Chandrayaan-3. C-3 proved India could land on the Moon; C-4 proves India can collect Moon material and bring it back — a capability currently possessed only by USA (Apollo missions, 1969-72), Soviet Union (Luna missions), and China (Chang'e-5, 2020). The SpaDeX orbital docking experiment (Chapter context: 4th country to dock, January 2025) was explicitly described by ISRO as a prerequisite technology for Chandrayaan-4. Key exam facts: Cabinet approval September 18, 2024; Rs. 2,104.06 crore; 5 modules, 2 LVM3 launches; 3 kg sample return; landing near south pole (MM-4 site); 2028 target; LUPEX is ISRO-JAXA separate mission for water ice.

[Additional] Artemis Accords, India's Signing, and Global Lunar Geopolitics (GS2 — International Relations / GS3 — Space Policy):

Artemis Programme status:

India signs the Artemis Accords:

• Date: 21 June 2023 — during PM Modi's official state visit to Washington D.C.
• India was the 27th signatory nation (as of May 2026: 67 countries have signed)
• PM Modi: "By taking the decision to join the Artemis Accords, we have taken a big leap forward in our space cooperation. Even the sky is not the limit."
• The Artemis Accords are a non-binding bilateral agreement between the US and each signatory — not a treaty requiring parliamentary ratification; grounded in the Outer Space Treaty 1967 (which India has ratified)

What the Artemis Accords commit to:

• Peaceful exploration; transparency; interoperability of space systems
• Registration of space objects (under Registration Convention)
• Emergency mutual assistance
• Release of scientific data
• Protection of heritage sites (e.g., Apollo landing sites)
• Responsible use of space resources (mining)
• Orbital debris mitigation

Geopolitical significance — the Moon race:

• Russia and China have NOT signed the Artemis Accords
• China and Russia are developing their own competing International Lunar Research Station (ILRS) framework — targeting south pole by 2030s
• India's signing of Artemis Accords is explicitly a strategic choice — aligning with the US-led multilateral framework vs the China-Russia ILRS
• This geopolitical dimension (which team India is on in the Moon race) is a major India-US strategic partnership signal

Chandrayaan-3 → Artemis south pole connection:

• Both Chandrayaan-3 and Artemis target the lunar south pole for the same reason: permanently shadowed craters may contain ancient water ice deposits
• Water ice enables: (1) drinking water for astronauts, (2) electrolysis → hydrogen + oxygen rocket propellant (in-situ resource utilisation, ISRU)
• Chandrayaan-3's Pragyan rover data (soil composition, terrain hazard maps, sub-surface temperature at −10°C just 8 cm below surface) directly feeds into global planning for Artemis-era south pole missions
• India's south polar data positions ISRO as a key knowledge partner for Artemis, even though ISRO is not a hardware partner for Artemis missions themselves

Lunar Gateway — March 2026 pause:

• The Lunar Gateway (space station in lunar orbit) was redesigned significantly in March 2026
• NASA announced it would pause the Gateway as originally designed, pivoting toward prioritising a lunar surface base (2029-2036) instead
• India was not a direct Gateway hardware partner; this change does not directly affect India's missions
• This is a significant policy change that may appear in current affairs-based UPSC questions

UPSC synthesis: Artemis Accords signing (June 21, 2023) is one of the three most significant outcomes of PM Modi's 2023 state visit to the US (along with GE-414 engine agreement for Tejas and MQ-9B Predator drone deal). It places India firmly in the US-led space governance framework vs China-Russia ILRS. Artemis II's April 2026 completion (first crewed lunar flyby in 50 years) is a landmark for human space exploration. For UPSC: the Accords are non-binding principles (not a treaty); 67 nations signed as of May 2026; Russia/China not signed; India was 27th signatory; Artemis III revised to Earth-orbit lander test; first crewed Moon landing pushed to Artemis IV (~2028). The Chandrayaan-3 south pole data → Artemis south pole target → LUPEX water ice search → Chandrayaan-4 sample return chain is a complete GS3 "India's space policy trajectory" narrative.