The Landsat program is the longest running enterprise for acquisition of imagery of Earth from space. The first Landsat satellite was launched in 1972; the most recent, Landsat 7, was launched on April 15, 1999. Landsat 7 data has eight spectral bands with spatial resolutions ranging from 15 to 60 meters. Unlike its predecessors, Landsat 7 has a solid state memory of 378 gigabits (roughly 100 images). The main instrument onboard Landsat 7 is the Enhanced Thematic Mapper Plus (ETM+).

Potential oil and gas reservoirs in the earth are located utilizing a satellite equipped to receive reflected solar energy from the earth at a minimum of one selected frequency band, transmitting signals indicative of the received reflected energy to the earth, recording the received signals in a manner to provide a map of the earth’s surface, filtering the received signals to provide signals representative of bands characterized by hydrocarbon gas absorption of the solar energy, and displaying the filtered signals, the area of hydrocarbon absorption being indicated by low intensity levels. The satellite system can be equipped with a coherent infrared irradiation system which scans the area of observation, utilizing a selected infrared wave length beam to augment normal solar radiation at those wave lengths most effective for detecting the hydrocarbon gas cloud which appears above an oil or gas reservoir.