Science and Technology › Space
हिन्दी — Read in HindiHuman spaceflight and space stations
Gaganyaan and its test flights, the Bharatiya Antariksh Station, astronauts on foreign missions, and what it takes to keep a crew alive in orbit and bring it home. Prelims has asked about Gaganyaan and other microgravity missions.
Foundation note: Gaganyaan and the Bharatiya Antariksh Station
UPSC has asked
- Prelims 2025: Axiom-4, SpaDeX and Gaganyaan as microgravity missions
All 3 articles shown; the 1 that changed from 1 July to 30 September 2026 are marked.Show only these
Gaganyaan
Copy link to GaganyaanPrelims and Mains
Gaganyaan is the first human spaceflight programme of the Indian Space Research Organisation (ISRO), and it will carry a crew module to low Earth orbit and bring it back. The programme is being proved in stages, and each test clears one of the things that can kill a crew.
- The first uncrewed flight, carrying the half humanoid Vyommitra, is targeted for the last quarter of 2026, with two more uncrewed flights and the first crewed flight by 2027.
- The baseline design review of BAS-01, the first of five modules of the Bharatiya Antariksh Station, is complete.
- The government has approved indigenous development of the flight suit, the view port, the crew seat and the docking system, now bought abroad.
Gaganyaan targets
2022
The original target
February 2026
Crewed flight said to be by the end of 2027
June 2026
First uncrewed flight in the third quarter of 2027, crewed flight in 2028
What changed
27 Jun 2026
- The ISRO chairman indicated that the first uncrewed test flight could slip to the third quarter of 2027, pushing the crewed flight to 2028.
- He cited two successive Polar Satellite Launch Vehicle (PSLV) failures and NavIC down to three satellites.
- Three uncrewed missions are planned and a continuation programme has been approved.
The Indian Express, 27 Jun 2026: Gaganyaan mission: Isro chairman hints first uncrewed test flight may slip to 2027 (opens in a new tab) · The Indian Express, 27 Jun 2026: ISRO's Gaganyaan delay, Axiom-4 and the SpaceX rocket leak (opens in a new tab)
Re-entry heat shielding
Copy link to Re-entry heat shieldingPrelims and Mains
A heat shield is the thermal protection system that keeps a returning crew module from burning up, because the whole energy of orbit has to be shed as heat in a few minutes.
- The crew module meets the atmosphere at 7,500 to 8,000 metres a second, which takes its outside to about 1,800 °C while the structure beneath has to be held below 150 °C.
- Between the two is a thermal protection system 30 to 35 mm thick.
- The Gaganyaan module uses an ablative shield: its outer layers char, decompose and burn away, carrying the absorbed heat off with them, so it is used once.
Ablative
- The surface chars and burns away, taking the heat with it
- Single use
- Chosen for the Gaganyaan crew module
Radiative
- A hot outer skin radiates the heat back out
- Can be reused
- Needs materials that stay sound at high temperature
Heat sink
- A thick mass of metal soaks up the heat and holds it
- Heavy, so suited to small capsules
What changed
21 Aug 2026BriefThe Hindu set out the three kinds of thermal protection and why the Gaganyaan crew module uses a single use ablative shield. The Hindu, 21 Aug 2026: How Gaganyaan's heat shield will protect the crew (opens in a new tab)
Deorbiting the International Space Station
Copy link to Deorbiting the International Space StationPrelims and Mains
The International Space Station, occupied since 2000, is to retire around 2030.
- A SpaceX built US Deorbit Vehicle will guide a controlled re entry into Point Nemo in the South Pacific, the largest controlled re entry ever attempted.
- Treaties require compensation when space debris damages property or territory on land; no equivalent covers the open ocean.
What changed
24 Jun 2026BriefA US Government Accountability Office report noted that parts of the station and the deorbit vehicle will survive re entry, and the Ocean Foundation asked for a full environmental assessment. The Indian Express, 24 Jun 2026: Nasa's plan to sink the ISS sparks concerns over ocean health and legal accountability (opens in a new tab)
See also: India's re-entry rules