General Science and Technology

Space systems and Indian missions

First systematic UPSC revision with school-level arithmetic and basic science vocabulary; no specialist science degree assumed.

Includes

• Assigned sections and concise recall notes
• Available mapped practice and analysis of mistakes
• One initial closed-book review

Separate time needed

• Specialist derivations and laboratory training
• Subsequent revision and full mock tests
• Continuing technology and mission updates
• Duplicated ecology, agriculture, health-administration or energy-policy study

Editorial planning estimate; not learner timing data

• Types of orbits ↗

  Types of orbit: GEO, LEO, polar, Sun-synchronous, MEO, transfer orbits and Lagrange points; exclude the dated Gaia example

• Launchers ↗

  PSLV, GSLV, LVM3, SSLV and reusable-launch-vehicle descriptions; architecture and purpose, not status statements

• Satellite Navigation Services ↗

  NavIC and GAGAN descriptions; intended services and system roles

• Space Applications ↗

  Satellite Communication Applications and Disaster Management Support sections

• Chandrayaan-3 mission details ↗

  Mission objectives, Lander and Rover payloads, and More Details: propulsion-module transfer/separation role, lander hazard detection/guidance and communication table. Read design functions; the August 2023 report separately verifies landing. Do not treat prelaunch future tense or contingency links as current operational status.

• Aditya-L1 mission and science objectives ↗

  Major science objectives and payload overview

• Gaganyaan frequently asked questions ↗

  Questions 1–2 for capability objectives and questions 4–6 for uncrewed validation, human rating, escape, life support, training and recovery requirements. Exclude original approved flight counts, budgets, schedules and station-status statements; use the dated systems page for architecture.

• What is remote sensing? ↗

  Passive and active sensors paragraphs under What is remote sensing? Use reflected or emitted energy for passive sensing and instrument-supplied illumination for active sensing. The introductory reflected-energy shorthand is not an exhaustive definition; do not infer earthquake prediction from application examples.

• Remote-sensing resolution ↗

  Radiometric, spatial, spectral and temporal resolution sections, followed by resolution trade-offs. Temporal resolution means the observation revisit interval, not simply orbital period. Bit depth and pixel size alone do not guarantee measurement accuracy. Exclude dated platform notices and rigid universal band-count definitions.

• Gaganyaan: systems and critical technologies ↗

  Page dated 23 November 2022: pre-requisites and precursor tests; Human rated LVM3; Crew Escape System; Orbital Module, Crew Module and Service Module; Crew training. Read design functions and safety requirements, not current launch dates, crew numbers, programme counts or achievement status.

• Hubble vs Webb ↗

  State of the Art Observatories, Mirrors and Orbits: wavelength complementarity, aperture/light collection, segmented-mirror alignment, redshifted galaxies, dusty star formation, exoplanet atmospheres and Sun-Earth L2 geometry. Avoid the simplistic identity of all infrared radiation with heat, universal superiority, life-detection promises and current servicing claims.

• Webb’s Sunshield ↗

  Sunshield purpose, five-layer separation/radiation and cold stable optics; instrument-cooling discussion distinguishing passive cooling from the MIRI cryocooler. Assign mechanisms, not numerical temperature memorisation or marketing superlatives.

• Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space ↗

  Articles I–II, IV and VI–IX. Distinguish national non-appropriation from registration-state jurisdiction over an object; state responsibility, authorisation/supervision, launching-state liability and due regard. Article IV has specific weapons/celestial-body prohibitions, not a ban on every military activity in all space. Do not infer the later Liability Convention fault standards from this text alone.

• Higher Airspace Operations: frequently asked questions ↗

  Where does airspace end and where does outer space begin? The 100 km Karman line and 80 km references are operational conventions, not an internationally agreed legal vertical boundary. Exclude current European regulatory programme/status claims.

• ICAO Statement on State Sovereignty over Airspace and Safety Assessments ↗

  Opening paragraph of the statement dated 1 December 2025, identifying Chicago Convention Article 1 and sovereignty over territorial airspace; read alongside the separate Outer Space Treaty and EASA delimitation explanation. This is an official explanation of the provision, not a substitute reading of every Convention article.

• GPS performance standards and specifications ↗

  Opening descriptions under GPS Standard Positioning Service (SPS) Performance Standard and GPS PPS Performance Standard. The PPS body uses Precise Positioning Service despite the heading wording. Assign civilian versus authorised military service, not dated accuracy or current constellation claims.

• International Space Station: facts and figures ↗

  International Space Station Facts: living/working facilities, muscle/bone effects in microgravity, maintenance, cargo support and research payloads. Use the station as a sustained orbital research platform; exclude changing crew, flight, experiment and module counts or record rankings.

• Department of Space monthly summary: September 2024 ↗

  PDF page 1 opening Cabinet-approval paragraph: Gaganyaan follow-on missions through BAS-01. This establishes a September 2024 approval only, not an operational station, a guaranteed launch date or the precise plan announced in 2019.

• Department of Space monthly summary: August 2023 ↗

  PDF page 1, A. Space Science: Vikram soft landing on 23 August 2023, Pragyan deployment and subsequent payload experiments. Exclude the dated sleep-mode sentence and other sections; do not retroactively count this as a 2016 achievement.

• Stars: birth, life and death ↗

  Birth, Life and Death sections: collapse, fusion, mass-dependent lifetime and end states; conceptual pathways, not a universal initial-mass cutoff.