Relevance: GS III – Space Technology, Climate Change • Source: Indian Express, ESA–NASA briefings

The European Space Agency (ESA) and NASA are preparing to launch Sentinel-6B, the second satellite in the Copernicus Sentinel-6 mission, aimed at providing precise global sea-level measurements for the next decade.

What is Sentinel-6B? 

• A joint mission of ESA, NASA, NOAA, EUMETSAT, under the Copernicus Programme.
  
• Follows Sentinel-6A (Michael Freilich) launched in 2020.
  
• Uses radar altimetry to measure sea-surface height with millimetre-level accuracy.
  
• Also gathers data on ocean currents, temperature, atmospheric humidity.
  
• Supports monitoring of El Niño–La Niña, storm intensification and long-term climate trends.
  

Why Sea-Level Monitoring Matters

• Global sea levels have been rising at over 3 mm per year, accelerating due to ice melt and thermal expansion.
  
• Critical for planning in low-lying cities, coastal ecosystems, and disaster-preparedness.
  
• Supports SDG 13 (Climate Action) and global climate modelling.
  

Link to Biodiversity

• Although a climate mission, continuous sea-level data also helps assess threats to coral reefs, mangroves and coastal biodiversity—key areas in IUCN conservation analyses.

Prelims Practice Question

1. Sentinel-6B is part of the Copernicus Programme and is designed primarily to monitor ocean sea levels.
   
2. Sentinel-6 satellites use optical imaging sensors to map global sea-level rise.
   

Which one is correct?
A. Only 1 B. Only 2 C. Both D. None

Answer: A
(Sentinel-6 uses radar altimetry, not optical imaging.)