| definition |
- Landsat 1, 2 and 3 operated in a circular, Sun-synchronous, near-polar orbit at an altitude of approximately 913 km (567 miles), with a nominal 9:30 a.m. crossing of the Equator during the descending mode. They circled the Earth every 103 minutes, completing 14 orbits per day and viewing the entire Earth every 18 days. The Landsat orbits are selected and trimmed so that each satellite ground trace repeats its Earth coverage at the same local time every day. Repetitive image centers are maintained to within 37 km (23 miles). The orbits of Landsat 4 and 5 are repetitive, circular, Sun-synchronous, and near-polar at a nominal altitude of 705 km (438 miles) at the Equator. The satellites cross the Equator from north-to-south on a descending orbital node at approximately 9:45 a.m. on each pass. Each orbit takes nearly 99 minutes, and the spacecrafts complete just over 14 orbits each per day, covering the entire Earth (poles excepted) every 16 days. During processing, data obtained is framed into individual scenes of the Earth's surface. The ground instantaneous field of view (IFOV) of the Landsat 1-3 MSS is 79m x 79m pixel (resolution elements); the Landsat 4 and 5 MSS IFOV is 82m x 82m pixel. MSS line scanning devices continually scan the Earth in a nominal 185 km swath perpendicular to the Landsat orbital track. The coverage patterns result in 14-percent image sidelap at the Equator for Landsat 1-3 data; Landsat 4 and 5 image side lap at the Equator is 7.3-percent. Image sidelap percentages increase proportionally as the latitude increases. __________ Taken from the NSSDC System for Information Retrieval and Storage (SIRS). For more information contact the NSSDC Coordinated Request and User Support Office, 301-286-6695 (NASA Goddard Space Flight Center, Code 933.4, Greenbelt, Maryland 20771, USA) _________ See Also: U.S. Geological Survey, 1979, Landsat Data Users Handbook, (Revised): U.S. Geological Survey, p. 1-1 to AH-1. U.S. Geological Survey and National Oceanic and Atmospheric Administration, 1984, Landsat 4 Data Users Handbook: U.S. Geological Survey, p. 1-1 to 5-1. National Oceanic and Atmospheric Administration, 1986, Landsat Data Users Notes, Number 35, 20p. Group: Platform_Details Entry_ID: LANDSAT Group: Platform_Identification Platform_Category: Earth Observation Satellites Platform_Series_or_Entity: LANDSAT Short_Name: LANDSAT End_Group Group: Synonymous_Platform_Names Short_Name: LANDSAT End_Group Group: Orbit Orbit_Type: LEO > Low Earth Orbit > Polar Sun-Synchronous End_Group Creation_Date: 2007-10-10 Online_Resource: http://landsat.gsfc.nasa.gov/about/history.html Sample_Image: http://landsat.gsfc.nasa.gov/graphics/ERTS-A-at-GE.jpg Group: Platform_Logistics Primary_Sponsor: NASA End_Group End_Group
|
