Landsat 7 acquired on average 438 images per day (90 percent of available candidate images) in 2014 — up from the 300 scene daily limit in 2010. In the Northern Hemisphere Summer, an average of 470 images per day (86 percent of candidates) and in the Southern Hemisphere Summer, an average of 357 images per day (99 percent of candidates) were acquired.
The Landsat 7 and Landsat 8 satellite acquisitions are managed as a constellation. In November 2013 following the launch of Landsat 8, Landsat 7 shifted to a continental acquisition strategy in which Antarctica, oceanic islands, Greenland and row 9 and above are no longer acquired. Landsat 8 acquires Row 9 and above approximately every 4 days, always acquires the island areas, and acquires Antarctica and Greenland at rates higher than before (see LTAP-8 for more details).
The candidate scenes are day-lit continental land scenes, as shown in green in the map below. Day-lit images are defined as images with sun elevations greater than five degrees in the Southern Hemisphere and fifteen degrees in the Northern Hemisphere.
Figure 1. Candidate day-lit land areas shown in green; white areas are not included as candidate scenes for acquisitions.
You can download a list of Landsat 7 continental-acquisition path/rows: .csv (69.2 KB)
Landsat 7 has no maximum daily limit established. Acquisitions are limited by physical constraints of the instrument. Cloud avoidance is a major factor in the selection of the scenes rejected. The benefits of this acquisition strategy are an increase in the number of scenes that can be acquired, along with a reduction in instrument duty cycle and the number of power cycles required. The goal is to acquire more images with more frequent revisits over the continental land masses without increasing risk to the mission.