Context: Powered by an Atlas V 401 rocket, Landsat 9 lifted off from Vandenberg Space Force Base in California. 
Key Points

• This Joint satellite mission by USGS and NASA will inform scientific decision-making regarding climate change, wildfire management, and water usage.
• Landsat 9 replaces the 22-year-old Landsat 7 satellite. 
• Landsat images have been used to study the health of forests, coral reefs, monitor water quality and melting glaciers.
• In tandem with the currently operational Landsat 8 mission, Landsat 9 will provide major improvements to our Earth observation capabilities and will ensure the continuation of the 50-year Landsat data record of Earth observations.

Earth Observation Satellites of India
Recently, India has launched EOS-01 satellite.

• It is an earth observation satellite and is intended for applications in agriculture, forestry and disaster management support.
• Earth observation satellites are the satellites equipped with remote sensing technology. Earth observation is the gathering of information about Earth's physical, chemical and biological systems.
• Many earth observation satellites have been employed on sun-synchronous orbit.

Other earth observation satellites launched by ISRO include RESOURCESAT- 2, 2A, CARTOSAT-1, 2, 2A, 2B, RISAT-1 and 2, OCEANSAT-2, Megha-Tropiques, SARAL and SCATSAT-1, INSAT-3DR, 3D, etc.