Relevance: UPSC GS-III (Science & Tech): space science, microgravity, applications for India’s human spaceflight

A recent video from Chinese taikonauts shows a match burning in microgravity—its flame turns small, round and bluish instead of the tall, teardrop orange we see on Earth. In orbit there is no buoyant convection to pull hot gases up and draw fresh oxygen from below, so the flame becomes a slow, diffusion-controlled sphere with lower soot and temperature. Similar behaviour was documented on the ISS in NASA’s combustion studies (FLEX/BASS), including “cool flames” that persist at low temperature and emit little light.

Why this matters

• Safety & design: Understanding microgravity flames helps design fire-safe habitats and extinguishers for crewed missions.
  
• Gaganyaan & beyond: India is scaling up microgravity research (e.g., Axiom-4 Indian experiments; Gaganyaan systems and tests), and policy is opening the sector to investment—knowledge of space combustion aids life-support and materials planning. 

Key takeaways

• No “updraft,” spherical flame: microgravity removes hot-air rise → round, dimmer flame.
  
• Diffusion-limited burning: oxygen mixes slowly → slower, cleaner combustion; potential cool-flame regimes.
  
• Direct utility: informs fire control, airflow design, and crew safety in space stations and capsules.
  
• Indian context: active microgravity experiments and human spaceflight testing make this immediately relevant.
  

UPSC Prelims question

With reference to combustion in microgravity, which of the following is/are correct?

1. Candle or match flames tend to become spherical and bluish.
   
2. The change occurs mainly due to the absence of buoyant convection.
   
3. Microgravity flames typically produce more soot than on Earth.
   Select the correct answer using the code below:
   (a) 1 and 2 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3
   Answer: (a).
   

One-line wrap: No gravity, no teardrop—space turns fire into a quiet blue sphere and teaches engineers how to keep astronauts safe.