Why in news?
On 29 June 2025 Japan launched the GOSAT‑GW (Greenhouse Gases Observing Satellite – Water Cycle) aboard an H‑2A rocket. This mission marks the 50th and final flight of Japan’s H‑2A launcher.
Mission objectives
- Monitor greenhouse gases: The satellite carries the third Thermal And Near‑Infrared Sensor for Carbon Observation (TANSO‑3) to measure concentrations of carbon dioxide (CO2), methane (CH4) and other gases with high precision. Data will help verify national emission inventories and detect large emission sources.
- Observe water cycle: An Advanced Microwave Scanning Radiometer (AMSR3) monitors variables such as precipitation, soil moisture, snow depth, sea‑surface temperature and wind speed. Understanding the water cycle is crucial for climate models and disaster prediction.
- Support climate policy: Real‑time global data on greenhouse gases and hydrological parameters will inform international efforts to combat climate change. The mission is a collaboration between Japan’s Ministry of the Environment, National Institute for Environmental Studies and JAXA.
- Ensure continuity: GOSAT‑GW follows earlier missions GOSAT (2009) and GOSAT‑2 (2018) and will operate in a sun‑synchronous orbit at 666 km with a three‑day revisit time.
Significance
- Last H‑2A flight: The launch was the 50th and final mission of the workhorse H‑2A, marking a milestone for Japan’s aerospace industry as it transitions to the H3 rocket.
- Global cooperation: The satellite’s open data policy encourages international climate research and supports the Global Stocktake under the Paris Agreement.
- Comprehensive monitoring: Combining greenhouse‑gas and water‑cycle observations provides a more holistic understanding of Earth’s climate system.