(AP) A rocket carrying an Earth-observing satellite launched Monday from a seaside military base to continue a mission to document changes to the planet's natural resources.
The Landsat satellite, tucked inside a 200-foot-tall Atlas V rocket, lifted off from Vandenberg Air Force Base under mostly clear skies and headed in a southwesterly direction over the Pacific.
Mission controllers tracked the rocket's path and monitored the next critical step when the satellite was to separate from the rocket expected to occur about an hour after launch.
The $855 million mission continues a four-decade legacy of keeping a continuous eye on Earth's glaciers, forests and shorelines from space.
Since the first Landsat launch in 1972, the satellites have been key witnesses to history, documenting the 1980 Mount St. Helens eruption and the 1986 Chernobyl nuclear disaster.
Through the decades, the Landsat satellites have monitored drought conditions, global crop output, shrinking glaciers and the effects of urban sprawl.
On the eve of the launch, NASA Administrator Charles Bolden Jr. reflected on the program's longevity, noting that the satellites have given people unprecedented views of Earth.
Each time we fly, we learn something different we didn't know about Earth, Bolden said Sunday.
The newest Landsat is equipped with sensors that are more powerful than its predecessors. Once in orbit 440 miles high, the satellite will circle Earth 14 times a day, snapping hundreds of pictures that will be beamed back to ground stations in South Dakota, Alaska and Norway.
Day-to-day operations will be managed by the U.S. Geological Survey, which intends to make images and data free on the Internet as in previous Landsat missions. NASA developed the spacecraft and its two instruments.
The latest satellite will join Landsat 7, launched in 1999. While Landsat 7 continues to provide daily observations, a problem with one of its instruments has cut the amount of data it can gather.
The USGS recently decided to retire its Landsat 5 satellite after nearly 30 years in service.