Aqua, Latin for water, is a NASA Earth Science satellite mission named for the large amount of information that the mission is collecting about the Earth's water cycle, including evaporation from the oceans, water vapor in the atmosphere, clouds, precipitation, soil moisture, sea ice, land ice, and snow cover on the land and ice.
Aura (Latin for breeze) was launched July 15, 2004. Aura is part of the Earth Science Projects Division, a program dedicated to monitoring the complex interactions that affect the globe using NASA satellites and data systems. Aura's four instruments study the atmosphere's chemistry and dynamics. The satellite's measurements will enable scientists to investigate questions about ozone trends, air quality changes, and their linkage to climate change.
The restructured Joint Polar Satellite System (formerly -- National Polar-orbiting Environmental Satellite System (NPOESS)), will address NOAA’s requirements to provide global environmental data necessary for NOAA’s missions to monitor the earth, manage resources, support the Nation’s economy, and protect lives and property. source: NOAA
The National Polar-orbiting Operational Environmental Satellite System (NPOESS) was a joint program of the Air Force, NOAA, and NASA. Its polar-orbiting satellites were to provide long-term systematic measurements of key environmental variables for weather forecasting as well as climate studies. In February 2010, NPOESS was split into two programs. The Air Force-managed component will build satellites for the morning orbit, serving military needs.
The National Polar-orbiting Partnership (NPP) is a joint mission to extend key measurements in support of long-term monitoring of climate trends and of global biological productivity.