Eye in the sky

摘要

The US Geological Survey (USGS) says that data from its latest environmental satellite, Landsat 8, are now publicly available (at go.nature.com/u81wkh; shown, an image over Northwest Arctic Borough in Alaska). The US$855-million spacecraft extends the worlds longest continuous Earth-observation project, which has documented global land-use trends through more than 3.7 million images dating back to 1972. Landsat 8 will collect at least 400 images per day at several visible and near-infrared frequencies, covering the planet every 16 days. The USGS has accommodated 11 million downloads since 2008.