Biomass Satellite: ESA’s P-band Forest Carbon Mission

Why in the news

The European Space Agency’s Biomass mission was launched on 29 April 2025 to weigh the world’s forests from orbit and clarify how much carbon they hold.

Key facts

• Rank: seventh Earth Explorer of ESA; five-year mission.
• Launch: 29 April 2025, Vega-C, Europe’s spaceport in French Guiana.
• Radar: first P-band SAR flown in space (435 MHz, 70 cm wavelength).
• Antenna: 12-metre deployable mesh reflector, among ESA’s largest.
• Orbit: Sun-synchronous, 666 km, dawn-dusk, for steady lighting.

Objectives

• Measure forest biomass and carbon content globally.
• Create 3D models of forest structure and follow biomass change over time.
• Track carbon absorbed and released by land ecosystems, aiding climate models and REDD+ accounting.

Why P-band

• Short wavelengths bounce off leaves, but 70 cm waves pass through the canopy and scatter from trunks and big branches, where most carbon is stored.
• Repeated passes build 3D slices of forests, a technique called tomography, similar to a CT scan.
• The radar can also reveal buried geology in deserts, ice-sheet structure and terrain under vegetation.
• P-band frequencies are reserved for some military radars, so it cannot operate over North America and Europe; it covers the tropics, Asia, Africa, South America and Siberian boreal forests.

Earth Explorer programme

India link

• Forest carbon stocks underpin India’s pledge of an extra 2.5-3 billion tonnes CO2 sink by 2030; Biomass data can help verify them.
• India’s NISAR (NASA-ISRO SAR, launched 2025) carries L-band and S-band radar to watch vegetation and land change, so the two missions complement each other.

Exam angle

• Frequency and wavelength: P-band, 435 MHz, 70 cm.
• Builder: Airbus Defence and Space (UK); rocket: Vega-C.
• Related terms: synthetic aperture radar, tomography, REDD+, NISAR.