DOI: 10.5066/p1wxq2jn
title: The Landsat 8/9 Long Term Acquisition Plan for Earth’s continental landmasses and near-shore coastal zones, Version 1.0

description: Landsat 8 and Landsat 9 Earth imaging acquisitions are guided by their respective Long Term Acquisition Plan (LTAP), that has been established for each satellite observatory. The LTAP is structured around the Worldwide Reference System-2 (WRS-2) grid, which partitions Landsat swath imaging of the Earth into ~185 × 180 km scenes using a path/row notation. These WRS-2 scenes represent the fundamental geographic unit of Landsat 8/9 acquisition for data product generation and archiving. The Landsat 8/9 imaging plan is scheduled based on the LTAP priorities of the WRS-2 path/row grid, adhering to strict cross-track tolerances. The acquisition priorities have been established and evolved over time with the development of each satellite’s LTAP, particularly following expanded global surveying capabilities introduced by Landsat 8. Under normal operations, nearly all day-lit imaging opportunities defined by the LTAP descending orbit are routinely scheduled for both satellites. Exceptions occur when there is an emergency imaging request or risk mitigation maneuver. A scene is considered day-lit when the solar elevation at scene center is at least 5 degrees above the horizon.

The USGS Landsat Multi-Satellite Operations Center (LMOC) oversees and ensures that Landsat 8/9 image acquisitions are scheduled and acquired. In addition to acquisition planning, the LMOC manages on-orbit calibration planning activities, and periodic orbit maintenance operations, such as inclination burns or drag makeup maneuvers. Each Julian calendar day, the LMOC assigns an acquisition priority to all Landsat 8 and Landsat 9 WRS-2 path/row scenes during scheduling, collectively referred to as the day’s candidate scenes. Nominal imaging priorities for Landsat 8/9 are assigned using a LTAP Collection Request (LCR) file, which is intended to maximize day-lit imaging opportunities. Scenes with a lower priority designation are typically acquired but their inclusion is subject to constraints such as daily ground station contact margins and efficient onboard solid-state recorder utilization. The LCR priority assignments support optimized mission planning and scheduling, particularly when accommodating any Special Collection Requests (SCR) that may be received from the scientific and application user community.

The Landsat 8/9 LTAP directs the following acquisitions:

Over 99 percent of descending day-lit continental land and near-shore coastal images between 57°N (Row 21) and 57°S (Row 104) latitudes, where the side lap area between adjacent paths is less than 50%. These path/row locations have a request priority value of 55 to 90 in the LTAP database.
Over 91 percent of the descending and ascending day-lit continental land and near-shore coastal images north of 57°N and south of 57°S degrees latitude with a decreasing priority that is inversely proportional to the amount of side lap area between adjacent paths. These path/row locations have request priority of 43 to 48.
Over 99 percent of open water scenes that complete continental land intervals (e.g., the Mediterranean, Baltic, and Caribbean seas). These path/row locations have a request priority of 49 or 50.
Ascending nighttime, open ocean, and Landsat Extended Acquisitions of the Poles (LEAP) scenes are only acquired by special request where the 5 degree sun elevation imaging constraint embedded within the LTAP can be disabled to enable low or no illumination imaging.


Landsat 8 and 9 are operated in a near-polar sun-synchronous orbit with a nominal ~10:12 a.m. mean local time equatorial crossing on the descending node of each orbit. At high latitudes and polar regions during hemispheric summer months, the sun remains continuously above the horizon, often referred to as ‘polar day’ or the ‘midnight sun’. This extended illumination offers the opportunity to image these latitudes on both descending and ascending orbits (often referred to as nighttime imaging).

The accompanying graphics show the geographic coverage of image acquisition priorities on a scale of 0-100 (i.e. from low to high) for the Landsat 8/9 LTAP for both descending and ascending orbits. Lower priority scenes (depicted in purple and red) have the highest likelihood of being rejected during scheduling while the highest priority scenes (shown in green, yellow, and orange) are only rejected if the satellite observatory resource is reserved for reasons described earlier.

The accompanied shapefile (L89_LTAP_DB_Ver1.shp) includes every WRS-2 path/row, their corresponding orbit pass designation (PASS field), and the assigned LCR priority values (PRIORITY field) on a scale from 0 to 100. The shapefile also includes a CATEGORY field that provides descriptive information for each path/row, identifying those over the U.S. (CONUS, Alaska, and Hawaii), low and high latitudes, arid regions, open water, reefs, and consistently dark scenes on the ascending orbit.