Source: Jan Nelson, USGS

In the past, the USGS and NASA collaborated on the creation of four global land datasets using Landsat images: one from the 1970s and one each from circa 1990, 2000, and 2005. To extend this multi-decadal Landsat data collection, the USGS and NASA have again partnered to develop the Global Land Survey 2010 (GLS2010), a new global land dataset with core acquisition dates of 2009–2010. The data will consist of both Landsat TM and ETM+ images. Around 2,000 scenes are now available onEarthExplorer for download. Processing will continue through next fall for the remaining areas.

Further Information:
Global Land Survey science