At the ESRI International User Conference, U.S. Secretary of the Interior Dirk Kempthorne reiterated his direction to the U.S. Geological Survey (USGS) to make its 35-year Landsat satellite image archive freely-available over the Internet. Under the current plan, global Landsat 1-5 imagery dating back to 1972 will be available for free by February 2009. Newly-acquired Landsat 7 data is already available for download, with archived Landsat 7 imagery coming online in September 2008.
Anyone familiar with the long history of Landsat will recall the days when its management was privatized and turned over to EOSAT in the mid 1980’s. EOSAT operated Landsat 4 and 5 under contract for the federal government. During the era of privatization, many argued that cost was a barrier to the widespread use of Landsat Thematic Mapper (TM) and Multispectral Scanner (MSS) imagery. Pricing gradually fell to the “cost of fulfilling user requests” after management fully reverted back to the federal government in 2001.
Landsat imagery is commonly used for regional studies due to its relatively coarse resolution when compared to aircraft-based aerial photography. Instruments on the Landsat 7 satellite can produce 15-meter resolution panchromatic images, and 30-meter resolution color and near-infrared imagery. More details on Landsat MSS, TM, and ETM+ sensors can be found on the USGS Landsat product page.