With satellites in orbit since 1972, the Landsat program is the longest running Earth observation program. The Earth imaging program, which was initially created to investigate the landmasses of Earth, has since contributed to a variety of subjects, spanning from the natural to the social sciences.
What is Landsat?
Landsat is a series of Earth-observing satellite missions jointly managed by NASA and the US Geological Survey.
The purpose of Landsat satellites is to collect data about the Earth’s surface, including information about the vegetation, soil, and water. The data collected by Landsat satellites is used for a variety of purposes, including environmental monitoring, disaster response, and land-use planning.
When was the first Landsat satellite launched?
Since the first satellite images from Landsat 1 in 1972, multiple Landsat satellites have been launched with the ability to take increasingly detailed pictures of our world. Over the past 50 years of the Landsat satellite program being in operation, more than 10 million satellite images of the Earth have been acquired.
These two images show the improvement in image resolution and data sensor quality in Landsat imagery of the Silicon Valley which is located in Northern California. The image on the left is Landsat 1 imagery acquired in 1972 and the image on the left is Landsat 8 imagery acquired in 2016.
Timeline of Landsat Satellite Launches
The first Landsat satellite was launched on July 23, 1972 and was originally named Earth Resources Technology Satellite (ERTS-1). Originally designed to be in space for one year, Landsat 1 lasted six years before it was decommissioned on January 6, 1978.
Landsat 1 orbited the Earth at 917 km (570 mi) in a sun-synchronous, near-polar orbit. 14 times a day, Landsat 1 circled the Earth.
Landsat 1 captured this false-color satellite imager of Fort Worth Texas on July 25, 1972. The red areas are vegetation and grays and whites are urban areas.
Fun fact: An analysis of Landsat 1 images led to the discovery of a small island off the coast of Labrador, Canada. The discovery of the small rocky island was important as it demonstrated to Earth observation researchers how small of a land mass satellite technology at the time could capture.
The discovery of this unexplored Canadian island extended the country’s border offshore and increased its territorial waters by 68 square kilometers. The island was named Landsat Island after the origins of its discovery.
On January 22, 1975, Landsat 2 was launched into orbit as Earth Resource Technology Satellite B (ERTS-B) before being renamed. As with Landsat 1, Landsat 2 had a one-year life design but lasted seven years before being decommissioned on July 27, 1983.
Landsat 2 orbited the Earth at 900 km (559 mi) in a sun-synchronous, near-polar orbit (99.2 degrees inclination). As with Landsat 1, Landsat 2 orbited the Earth every 103 minutes for a total of 14 times a day.
The first light image from Landsat 2 was captured over Alberta, Canada on January 24, 1975.
Developed to extend the length of Earth observation time, Landsat 3 was launched on March 5, 1978 and was decommission five years later on September 7, 1983.
Landsat 3 improved on the spatial resolution of the first two Landsat with its Return Beam Vidicon (RBV) sensor carrying a resolution of 40 meters compared to 80 meters. Landsat 3 also carried a thermal infrared band on its Multispectral Scanner System (MSS) sensor but that failed shortly after launch.
Landsat 3 orbited the Earth at 917 km (570 mi) in a sun-synchronous, near-polar orbit (99.2 degrees inclination) 14 times a day.
On March 7, 1978, Landsat 3 captured its first image over the Silicon Valley in Northern California.
Landsat 4 was launched on July 16, 1982 and the satellite collected data until December 1993 but wasn’t decommissioned until 2001.
Landsat 4 orbited the Earth in a sun-synchronous, near-polar orbit (98.2 degrees inclination). Landsat 4 had a lower orbit than the first three satellites with an altitude of 705 km (438 mi).
Landsat 4’s improved spatial resolution was 30 meters and the satellite’s data collection included a thermal band. The new Thematic Mapper sensor onboard Landsat 4 allowed for the first time the depiction of data as natural color.
On July 25, 1982, the first light image from Landsat 4 captured eastern Lake Erie, Toledo, Detroit, and Windsor.
Landsat 5 has been the longest Earth Observation satellite, having orbited the Earth for almost 29 years from March 1, 1984 to June 5, 2013. Landsat 5 holds the Guiness World Record for ‘Longest Operating Earth Observation Satellite.’ The original lifespan of Landsat 5 was three years.
Landsat 5 orbited the Earth at 705 km (438 mi) in a sun-synchronous, near-polar orbit (98.2 degrees inclination). The satellite circled the the Earth every 99 minutes for a total of fourteen orbits a day.
As with Landsat 4, Landsat 5 carried both the the Multispectral Scanner (MSS) and the Thematic Mapper (TM) instruments and produced satellite imagery with a spatial resolution of 30 meters. When the TM sensor failed in 2011, the MSS sensor continued to collect satellite data until 2013.
Landsat 6 was launched on October 5, 1993 and failed to reach orbit. Landsat 6 is the only satellite in the Landsat program that failed.
Landsat 7 was launched on April 15, 1999. Improvements to Landsat 7 over the previous satellites in the program included feature a thermal infrared channel with a four-fold increase in spatial resolution over Thematic Mapper (TM), an onboard full aperture solar calibrator, a panchromatic band with a 15-meter spatial resolution, and five percent absolute radiometric calibration.
Landsat 7 orbits the Earth at 705 km (438 mi) in a sun-synchronous, near-polar orbit (98.2 degrees inclination) every 99 minutes.
Data from the Landsat 7 was made free to the public in October of 2008. About four months later, the government expanded the free data option to the entire Landsat program.
Landsat 8 was launched on February 11, 2013. Landsat 8 carries the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS) instruments.
Landsat 8 images have 15-meter panchromatic and 30-meter multi-spectral spatial resolutions along a 185 km (115 mi) swath.
Landsat 8 orbits the Earth in a sun-synchronous, near-polar orbit (98.2 degrees inclination) with an altitude of altitude of 705 km (438 mi). The satellite circles the Earth every 99 minutes.
Landsat 9 is the latest satellite in the Landsat mission to be launched. Landsat 9 was launched on September 27, 2021 and carries the Operational Land Imager 2 (OLI–2) and the Thermal Infrared Sensor 2 (TIRS–2).
Landsat 9 acquired several first light images:
Gray, E. (2013, March 21). A closer look at LDCM’s first scene. NASA. https://www.nasa.gov/mission_pages/landsat/news/first-images-feature.html
Landsat missions. (n.d.). USGS.gov. https://www.usgs.gov/landsat-missions