Eyes on Earth

In this episode of Eyes on Earth, we talk with several people involved with the next Landsat mission. In Part 1, we’ll hear about how different Landsat Next will be from previous Landsat missions and how its additional spectral bands, higher resolution and 6-day revisit will benefit science and society.

Landsat has documented changes all over the world for over 50 years. Changes in polar regions are happening especially rapidly. But it’s dark in polar regions much of the time. Therefore, a new acquisition scheme is adding more imagery of these dark, polar regions so these changes can be studied in more detail, even in polar twilight.

Women have been crucial to the EROS workforce from the very beginning in a variety of areas, from customer service and computers to film processing and administration.

Typically, we use Landsat data to study changes on the land—you know, Landsat. In this episode of Eyes on Earth, we learn how satellite images and pixels of water, along with actual water samples, are helpful in determining the productivity of lakes across the United States. We talk with Mendenhall Fellow and Research Geographer Dr.

Terry Sohl helped develop the National Land Cover Database, NLCD, when he first arrived, and now he’s overseeing significant improvements to the widely used product. But that’s just one part of his new role.

In this episode of Eyes on Earth, we aim to separate science fiction from science fact when it comes to how Landsat satellites and the EROS Center are portrayed in popular media. To do that, we consulted experts on a range of potential uses, including military, heat signatures, paleontology, and forests.

In this episode of Eyes on Earth, we spoke with Mikael Hiestand, a Mendenhall Postdoctoral Fellow. Using algorithms developed at EROS, Mikael is working on near-term drought forecasting. With synthetic Landsat data, he found that predicting evapotranspiration could be used as a means of drought prediction and monitoring.

First responders need reliable, accurate mapping capabilities as quickly as possible in the wake of a disaster—and they don’t have time to download and organize it.

In this episode of Eyes on Earth, we hear from several EROS staff members and university graduate students who took part in our Fall Poster Session. Lively conversations filled the EROS atrium during the hour-long event. Participants got to learn from one another as they shared their work. We talked to a few of them to get quick summaries of their research.

The Landsat Program is considered the gold standard for satellite Earth-observation imagery. To keep it that way, the USGS EROS Flight Operations Team continually monitors the flight paths of the Landsat satellites to make sure they stay at a consistent 705-kilometer altitude. That means frequently speeding it up to counter the effects of atmospheric drag.

The National Land Cover Database (NLCD) has a long history as the definitive U.S. land cover product. But the newer Land Change Monitoring, Assessment and Projection (LCMAP) effort takes a longer look back in time.

Several decades ago, USGS EROS employees were pioneers in land cover mapping—turning satellite imagery into a record of what covers the land, from farmland to forest to urban areas. National and global datasets with a variety of uses resulted from these efforts.

In this episode of Eyes on Earth, we focus on Alaska. Rich in wildlife and natural resources, not to mention its sheer size, Alaska has long been a source of fascination for remote sensing scientists. But it is also a source of frustration, with frequent cloud and snow cover and months of darkness each year.

At the USGS EROS 50^th anniversary events on August 17-19, 2023, a special effort was made to include alumni who had worked at the center, especially those from the earliest years of EROS’ existence. This episode of Eyes on Earth is the second to highlight their stories, with emphasis on science, technology, and EROS’ international outlook.

At the USGS EROS 50^th anniversary events on August 17-19, 2023, a special effort was made to include alumni who had worked at the center, especially those from the earliest years of EROS’ existence. This episode of Eyes on Earth highlights their stories, with emphasis on EROS’ history and its dedicated employees.

LANDFIRE, short for Landscape Fire and Resource Management Planning Tools, is a key national data source for the management of wildfires, management of the plant materials that fuel fires, and planning for prescribed fires across all 50 states and the U.S. territories.

EROS Center Director Pete Doucette has been at EROS for a fairly short stretch of the center’s 50-year history, but his passion for the mission of EROS and its opportunities in the future are clear in this episode of Eyes on Earth.

As USGS EROS turns 50 this month, our Eyes on Earth podcast also marks a big moment: Episode 100. To celebrate, we bring together some treasured moments from previous episodes in which people inside and outside of EROS share their thoughts on EROS and its role in the world of remote sensing, including as keeper of all Landsat satellite data.

EROS has a long history of reaching out to universities to welcome interns who can both contribute to the center and gain valuable skills and experience. A good number of them went on to spend their careers at EROS, some for more than three decades.

In this episode of Eyes on Earth, we talk about the 50-year history of EROS efforts to preserve the environment and conserve energy. EROS was born in the ’70s, the same decade as Earth Day, the EPA, and the oil crisis.

Satellites capture an incredible variety of views of Earth. In this episode of Eyes on Earth, we talk with the three engineers at USGS EROS who started the USGS Earth As Art project. The Earth As Art origin story is an example of the initiative and creativity of EROS staff.

In this episode of Eyes on Earth, we talk with Peder Nelson about generational science and the responsibility we have to future generations to study our changing planet. It takes more than just data to make sense of land change.

The members of the five-year Landsat Science Teams, led jointly by the USGS and NASA with a strong tie to EROS, have brought a wide breadth of expertise, backgrounds and geographic locations to the table.

South Dakota State University opened its Remote Sensing Institute even before the launch of Landsat 1 and the selection of South Dakota as the location for EROS.

Working with film has always been part of EROS’ 50-year history. How did EROS end up with an extensive film archive, and how are we making that data available to users? In this episode of Eyes on Earth, we talk about the custom scanners built in-house from discarded parts to digitally capture historical aerial photos and declassified spy satellite images.

The Don Lee Kulow Library has been supporting scientific research at EROS since before the facility opened its doors in 1973.

AmericaView aims to advance Earth observation education through a network of programs based at universities in more than 40 states.

Originally called the Landsat Data Continuity Mission, Landsat 8 launched on February 11, 2013. In this episode of Eyes on Earth, we talk about the 10^th^ anniversary of Landsat 8 being in orbit and its value to the remote sensing community.

When the snow gets deep and the wind blows, it can be challenging for workers to travel to the USGS EROS Center, located several miles north of Sioux Falls, SD, on what used to be farmland.

Designed to last three years, Landsat 5 was launched in 1984 and transmitted data until the launch of Landsat 8 in 2013.

Designed to last three years, Landsat 5 launched in 1984 and transmitted data until the launch of Landsat 8 in 2013.

The USGS EROS Center is the home of the Landsat satellite archive. This data center and science center located on a former farm near Sioux Falls, SD, is one of the largest civilian archives of land imaging in the world.

Landsat 7’s nominal science mission ended in April 2022 after nearly 23 years of acquiring Earth imagery from 705 kilometers above the Earth. Landsat 7 is now in an extended science mission after having its orbit lowered by about 8 kilometers to make way for Landsat 9.

When disaster strikes, near-real-time images of its effects can be invaluable. In this episode of Eyes on Earth, we learn about how a newly developed system using the Harmonized Landsat Sentinel-2 dataset and artificial intelligence was put to the test when Hurricane Ian tore through Florida in late September 2022.

ECOSTRESS, or ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station, data provides variables related to plant water stress, including evapotranspiration, evaporative stress index and water use efficiency. The NASA Land Processes Distributed Active Archive Center (LP DAAC) at EROS provides storage and distribution of ECOSTRESS data.

The Global Ecosystem Dynamics Investigation, or GEDI, instrument on the International Space Station acquires lidar waveforms to observe the Earth’s surface in 3D. The GEDI lidar measures the height and density of objects, so it provides information such as surface elevation and tree canopy height and cover.

The Landsat satellites have been collecting Earth imagery for more than 50 years. A key piece of equipment that moves the data from the spacecraft to the archive so researchers can use it is the antenna at the EROS Center. The antenna and its radome have a fascinating history of their own that adds to the overall Landsat story.

ECOSTRESS, which stands for the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station, collects land surface temperatures in an effort to answer questions about plants’ use of water. The NASA Land Processes Distributed Active Archive Center (LP DAAC) at EROS has provided storage and distribution of ECOSTRESS data for four years now and counting.

The Landsat archive at EROS contains an unparalleled 50 years of Earth observation data. But with earlier technologies, some Landsat scenes were collected and stored only by international ground receiving stations rather than in the central archive at EROS.

Government officials and scientists had high hopes for Landsat when the first experimental satellite launched July 23, 1972. Those hopes were soon realized when imagery came back depicting features never before seen. Since then, an archive of imagery surpassing 10 million scenes has amassed at EROS, collected from eight different Landsat satellites.

We don't need a scientist to tell us that city streets catch and hold heat. Anyone who's walked barefoot from a parking lot to a beach can tell you that. What scientists can help us understand, particularly scientists who work with spaceborne, remotely sensed data, is just how big a difference there is between cities and the countryside.

Spaceborne sensors orbit hundreds of miles over our heads. Even the most advanced among them struggle to capture high-resolution imagery of individual human beings. Mosquitos, of course, are far smaller than we are. Clearly, sensors on a satellite or space station can’t see them.

Clouds of dust kicked up in places like the Sahara can travel thousands of miles across the planet. We can see those clouds in satellite imagery, but we don’t typically know much about the composition of that dust. That’s a huge blind spot, because those unknown characteristics—such as the particles’ lightness or darkness—have an impact on what they do.

When the first Landsat satellite launched 50 years ago, it was the only game in town in terms of civilian land remote sensing. In the years that followed, a host of satellites have launched to serve similar purposes. But that data doesn't always play well together.

Some plants are simply better at making use of their water supply than others. More efficient plants can capture more carbon with less water, which has implications for carbon sequestration and ultimately for climate change modeling. In other words, the more we understand about water use efficiency, the more reliable our climate change models can be.

The boreal forest, or taiga, stretches across nearly 5.7 million square miles in the northern latitudes. That’s nearly a quarter of all forested lands in the world. This sprawling biome also happens to be one of the most rapidly shifting in the face of climate change.

In this episode of Eyes on Earth, we zero in on the use of USGS Land Change Monitoring, Assessment, and Projection (LCMAP) products to examine the effects of drought on California’s Blue Oaks. LCMAP datasets are built from Landsat data and reveal the land cover and change of every pixel in the conterminous United States, dating back to 1985.

Summary: The Earth observation data archived here have plenty of value to the study of aquatic ecosystems. Landsat satellites can capture harmful algal blooms, for example. Spaceborne sensors can also record land surface temperatures, and that includes water surfaces.

Land change is a constant. Even land areas that see little major change can see disruptions from storms, heat waves, wildfires, or invasive species. But major changes aren't uncommon, either. Each year in the U.S., farm fields become tracts of suburban homes, wetlands become more permanent bodies of water, and shrublands burn to be replaced with grasslands.

The sturdy root systems of mangrove forests act as buffer zones along the coastlines of some of the planet’s most vulnerable communities, protecting lives, ecosystems and property from the rigors of hurricanes and tsunamis.

If you want to know how much rain fell yesterday, you can catch it and measure it. Water vapor? That's not so easy. Which is a problem if you want to know how quickly that rate is returning to the atmosphere. Water vapor is the single largest part of the water budget, but without space-based observations, it would be all but impossible to measure at wide scale.

The rangelands of the western United States are changing more quickly than many other parts of the lower 48. Miles upon miles of the area or semi-arid landscapes in states like Idaho, Montana and Nevada are now carpeted by fire fueling invasive grasses. Cheatgrass is the most prevalent, which is troublesome for several reasons.

Satellites like Landsat are valuable for mapping fire perimeters and for monitoring trends in burn severity or in post-fire recovery. Satellites can cover wide areas with a single pass, whereas helicopter, drone, or airplane fire line mapping can take hours.

Outbreaks of native bark beetles can lead to conspicuous changes in a forest landscape. They’ve been present for thousands of years with occasional outbreaks, but there’s a lot we don’t yet understand about them. Exactly when and where have outbreaks occurred? How severe were they? What happened to the forest afterward?

Fires can be destructive or healthy for a landscape—often both. Fires have grown larger and more destructive in recent years, though, thanks to human activity, climate change, and a host of other factors. Satellite data helps us to map and monitor fire activity, but the study of post-fire plant life using remote sensing data goes further than fire mapping.

For our third and final episode of Eyes on Earth from the September launch of Landsat 9, we hear from Virginia Norwood. She blazed a trail for women in remote sensing in the 1960s and 70s while working for Hughes Aircraft, a contractor for NASA.

Hundreds of scientists, officials, international representatives, and others witnessed the launch of Landsat 9 on September 27, 2021, from a handful of viewing sites around Santa Barbara County, California.

Landsat 9 launched into orbit from Vandenberg Space Force Base on Monday, September 27, 2021, to carry on the legacy of a nearly 50-year record of continuous Earth observation that began in 1972. The days leading up to the event saw guests from around the world descend upon Santa Barbara County in California to watch the historic event take place.

The launch of Landsat 9 in September of 2021 represents a milestone for a joint USGS/NASA program that stretches back nearly 50 years. Landsat 9 will continue the legacy of unbroken, repeat Earth observations and contribute to our understanding of a changing planet.

Satellite imagery is everywhere. We see it on TV news and weather coverage, in our Twitter and Facebook feeds, and on our phones’ mapping apps. The data behind that imagery is nothing like a screenshot, though.

The Great Lakes represent roughly 20% of the surface freshwater in the world and 90% in the United States. The Great Lakes Basin supports more than 30 million people in the U.S. and Canada and 3,500 plant and animal species. The region faces threats that range from climate change and invasive species to pollution and development.

Mapping land cover in the United States in the present isn’t a simple job, but satellites like Landsat make it possible. Mapping conditions in the pre-satellite era, which the LANDFIRE program does through its Biophysical Settings (BpS) GIS data products, is a far trickier proposition.

Urban heat islands occur in areas containing more impervious surfaces and fewer natural environments. The day and night surface temperature is higher in urban heat islands than in surrounding areas. During heat waves, this can lead to greater numbers of heat-related illnesses and deaths.

The National Land Cover Database, or NLCD, was the first and remains the most well-known set of satellite-based land cover mapping products released by EROS. It sorts the each 30-by-30-meter plot of land in the United States into a land cover class, such as cropland, pasture, high-intensity developed, deciduous forest, and the like.

Mapping fire perimeters is important work. It guides post-fire restoration efforts, fire mitigation strategies, and helps track of trends in burn severity over time. In the past, many of Canada’s fire agencies relied heavily on techniques like sketch mapping, which estimate burned area without exact measurements.

The invasive species hemlock woolly adelgid is a threat to eastern hemlocks, filling some southeastern U.S. forests with what are called “gray ghosts” of the trees. Until recently, the insect had stayed in the southern part New York, but late last summer, an infestation was discovered in the Adirondacks.

The fire science community is always on the lookout for the freshest satellite-derived fire disturbance maps. Aiming to meet those needs, the multi-agency partnership known as LANDFIRE has just released an update that adds three new years of disturbances across the U.S. to its 20-plus layers of GIS data.

About 15 million people rely on the Delaware River Basin for drinking water, including residents of Philadelphia, PA, Camden, NJ, and Wilmington, DE. What might happen to the water supply if climate change and population growth continue unabated? How might that impact land cover and land use patterns?

Teams at the USGS EROS Center have completed fire atlases for nine National Parks across the U.S. Each atlas defines the size and severity of each fire in each park since 1984, including fires too small to be mapped by other programs. Yellowstone National Park has had nearly 100 fires, for example, ranging from a few acres to thousands of acres.

It’s possible to map vegetation type with Landsat, but getting the maps right requires more than satellites alone. The teams behind LANDFIRE use an extensive network of ground control points to check their work, thereby bolstering the reliability and utility of their multi-layer GIS product suite.

Ladies of Landsat aims to help women and other underrepresented groups feel welcomed and supported in the field of remote sensing. The Twitter group has grown to 5,700 members and counting since Dr. Kate Fickas started it in 2018 during a Landsat Science Team meeting at EROS.

Deforestation is a significant concern for many parts of the globe, particularly in places like the rainforests of the Amazon or the Congo. Scientists, governments, and non-governmental organizations turn to satellite data to track deforestation, as well as to set targets for improvement.

Landsat satellites have monitoring the Earth’s surface for nearly 50 years, providing critical information for countless areas of study and real-world applications. But with observations only collected every 8-16 days, there are limits to what can be tracked.

Dr. Alan Belward has spent a lot of time thinking about the planet’s surface water. The former Landsat Science Team member uses satellite data to track changes to lakes, rivers, and streams, and recently published a book that uses Landsat data to tell some of those stories.

The St. Mary and Milk Rivers cross the U.S. and Canadian border and supply water to both countries. Managing that resource in the interest of both nations is a matter of international collaboration and cooperation, and Landsat data is helping offer objective information on water use.

The extensive rangelands across the Western United States are threatened by invasive grasses, climate change, and altered fire regimes that can disturb the landscape. The largely semi-arid lands are also important for the survival of species that need undisturbed sagebrush ecosystems to thrive.

Albedo—the amount of incoming solar radiation reflected into space from the Earth’s surface—is a key measurement for surface temperatures and plant productivity. It also factors into weather forecasting and climate modeling. Landsat Science Team member Dr.

Landsat data is more useful today than at any other point in its nearly 50-year history. The USGS Collections strategy is a major reason why. Landsat Collections align and correct satellite acquisitions from 1972 through the present to make the data easier to work with through time.

Brazil is a fascinating study in water use. Brazil uses roughly 72 percent of its water for irrigated agriculture, and its herds of cattle, pigs and poultry are among the largest in the world.

In the past, remote sensing scientists looked for change on the Earth’s surface primarily by comparing one Landsat image to another.

The Green Revolution leaned on fertilizers, drought-resistant seeds and other modern innovations to boost agricultural production across much of the planet in the second half of the 20th Century. But many of those innovations never reached West Africa, partially because the lack of social safety nets and crop insurance made such investments too risky.

When a disaster like a hurricane, flood or major wildfire hits a remote part of the world, the International Charter Space and Natural Disasters springs into action.

Evapotranspiration is the process by which water transpires from the leaves and stems of plants and evaporates from the Earth’s surface. ET is an important metric for managing water use, but data availability has long been an issue.

Today, the world is awash in remotely sensed data. Satellites launched by countries and commercial companies circle the planet collecting data every day. Accessing data from multiple agencies and plaforms and turning it into useful analytics can be a daunting and complex endeavor, however.

Mapping land cover across the United States using Landsat satellite data is a difficult, time-intensive job, but there are jobs far larger. Matt Hansen, a Maryland-based professor and member of the Landsat Science Team focuses his efforts on mapping land cover and change on a global scale.

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.

In the days before LANDFIRE, fire scientists often struggled to find the vegetation and fuels data they needed to map the path of fires, keep firefighters safe, and to model fire recovery.

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.

Sea levels are rising globally. In some places, it is rising more than others, threatening communities and people as storm surges reach further inland and inundate more land.

The U.S. has plenty of data on wildfire risk. There are local and regional risk assessments, complex datasets like LANDFIRE and tracking tools like the EROS Fire Danger Monitor, as well as a host of resources and research projects devoted to the subject.

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.

The Mendenhall Program offers a range of two-year post-doctoral research fellowships within the U.S. Geological Survey. Heather Tollerud took advantage of the program in 2015 to study drought and land cover at the USGS EROS Center, and has since become a key player in the Center’s innovative Land Change Monitoring, Assessment and Projection (LCMAP) initiative.

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.

The Arctic is changing at a more rapid rate than the rest of the planet. Some of the most significant changes are tied to the thawing of near-surface permafrost, the layers of frozen soil containing vast stocks of stored carbon.

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.

Land cover and land use across the United States are the culmination of a complex web of interwoven factors: Climate, landscape types, and economic factors among them. Remotely-sensed data from satellites like Landsat and a variety of other sources are useful for documenting and monitoring land cover and land use.

Scientists at EROS have spent years refining their approach to mapping burn severity using remotely-sensed data from satellites like Landsat, but Landsat comes with limitations. Landsat data cannot see the vegetation below a thick tree canopy, for example.

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.

A farmer at the foot of a corn stalk can tell how well the plant is faring. That same farmer might survey his entire field for crop health. But assessing the health of crops or forests at regional, national, and international scales requires remote sensing, most often via satellite.

Each fall, EROS invites its staff scientists and area graduate students to visit for a noontime poster session. The poster sessions offer a change for those researchers to present their results to their peers and get feedback from their fellow scientists.

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.

Nearly 85 million people around the world are currently considered “food insecure,” and that figure continues to grow. Remote sensing technology enables scientists to feed data into the Famine Early Warning Systems Network (FEWS NET), which in turn can issue alerts that guide the distribution of humanitarian aid.

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.

EROS scientists track water availability and crop health around the world to help governments and non-profits manage resources and stave off food shortages. But EROS also teaches international scientists to track those resources themselves. In this episode, we hear about a recent training session at EROS for Iraq’s Ministry of Water Resources.

 

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.

 

There’s a lot more than Landsat in the EROS Archive. In this episode of Eyes on Earth, we hear from a professor who’s mined satellite data collected during once-classified military missions to peer into the history of land use in Eastern Europe during the height of the Cold War.

 

Earth observation used to be the province of a handful of countries with satellite technology. Today, hundreds of satellites built all over the world are launched every year. This episode of Eyes on Earth talks about the explosive growth in the civilian and commercial remote sensing and EROS’ role in it.

Sorting Landsat data into an accurate and reliable record of land cover in the United States is one of the most important jobs at EROS. This episode of Eyes on Earth explores the what, how, and why of the National Land Cover Database (NLCD).

 

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.

 

A rundown of the history of the USGS Earth Resources Observation and Science (EROS) Center, the Landsat program, and the Center's role in the observation and study of landscape change worldwide.