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Calibration teams at the USGS EROS Center use a variety of methods to make sure the data collected by Landsat satellites are an accurate representation of the Earth’s surface.

Just recently, in mid-July, the flight operations team charged with keeping the Landsat 7 satellite running smoothly achieved a major milestone. They have gone 8 straight years now without an operator error.

The U.S. Geological Survey took a bold step toward documenting change across the landscape with the launch of the first Landsat satellite in 1972. Since then, it’s collected nearly five decades of imagery. But it takes more than just imagery to understand change. It takes time, effort—and serious computing horsepower.

Remote sensing is not an especially venerable scientific discipline, at least in comparison to fields like biology, chemistry or medicine.

The continent of Australia experienced some of the most devastating wildfires in its history in late 2019 and early 2020. Remote sensing scientists in Australia, who collaborate closely with EROS, relied on satellites like Landsat to help assess and monitor the damage.

Between them, Landsats 7 and 8 image the entire land surface of Earth every eight days. The USGS orbiters are just two of many Earth observing satellites flying at the same altitude and collecting data at the same time of day.

Landsat satellites offer a wealth of information to scientists studying ecosystem health and recovery. Data products derived from Landsat open even more areas of inquiry. Landsat Burned Area products, for example, can help researchers identify previously unknown fires that took place from 1984 through the present.

In the West African nation of Ghana, tropical forests are more than landscape. They are woven into language, custom, and culture. They are also the source of timber for home heating and industry, as well as barriers to agricultural production. Those are just a few of the reasons why deforestation has come alongside the nation’s rapid population growth.

For decades, each Landsat image had a price tag – a hefty one at times, ranging from \$400 to as much as \$4,000. That all changed in 2008 with the enactment of an open data policy that made the entire Landsat archive available for download at no cost to the user.

Across the planet, in rural settings on uncluttered landscapes, there are satellite antennas receiving data directly from Landsat satellites as they pass 438 miles overhead at more than 17,000 miles per hour. It happens multiple times a day, in Australia, Brazil, Canada, Germany, South Korea, and elsewhere.

It’s easy enough to measure rainfall, and nearly as easy to measure streamflow. Calculating the efficiency of water use through the metric of evapotranspiration (ET) – evaporation off the Earth’s surface and transpiration from the leaves of plants – is a far trickier proposal.

Sixty years of manned and unmanned space flight have left a cosmic junkyard circling the planet. In 2017, the U.S. government reported that it logged 308,984 close calls with space junk and issued 655 emergency-reportable alerts to satellite operators.

Summary: Scientists at EROS use tools like Landsat to produce land cover maps, which tell us if landscapes are rural or urban, cropped or forested, wetland or shrubland. Those maps help scientists at EROS and around the U.S. study the impact of changes in land use on not just landscapes, but on ecosystems, patterns of resource use, wildlife habitat, and much more.

We tend to associate Landsat satellites with what we see on solid Earth, but they can also tell us much about the health of our inland and coastal ecosystems. Landsat can be used to monitor harmful algal blooms, for example. Eyes on Earth guest Dr.

Every year, the USDA’s National Agricultural Statistics Service (NASS) uses data from satellites like Landsat to estimate crop types and crop yields in the United States. The result is the Cropland Data Layer (CDL), which offers an annual look at more than 100 crop categories across the country.

How much does an Earth observation satellite weigh? How are they launched? How fast does it travel? Does Landsat have a gas tank? In this episode of Eyes on Earth, we answer some of the basic questions surrounding the satellites that define the EROS mission.

 

When an accident occurred at the Chernobyl Nuclear Power Plant's No. 4 reactor in Ukraine on April 26, 1986, Landsat satellites were among the first to capture visual evidence of its widespread impact. This episode of Eyes on Earth outlines how the disaster focused the world's attention on the value of remote sensing.