NASA has launched a $1.5 billion weather satellite into orbit that aims to help improve weather forecasts and monitor long-term climate change.

The satellite, known as the National Polar-Orbiting Operational Environmental Satellite System, is being carried by a Delta II rocket 800 kilometers above the surface of the earth.

The U.S. space agency says the two-ton weather satellite, about the size of a small bus, is carrying five different types of instruments that will gather weather information to be used by national weather services across the globe.

It will also monitor other environmental data, such as ice cover and the ozone layer, that will provide scientists with better information on the effects of long-term climate change.

The satellite will enter a polar orbit, crossing both the north and south poles, which will allow it to view every part of the globe.

It will spend the next five years circling the earth about a dozen times per day.

The satellite was initially scheduled to be launched in 2006, but was delayed after scientists ran into problems with the development of several of the instruments.