landsat 7 satellite

Celebrating 17 Years of NASA’s ‘Little Earth Satellite That Could’

The satellite was little— the size of a small refrigerator; it was only supposed to last one year and constructed and operated on a shoestring budget — yet it persisted.

After 17 years of operation, more than 1,500 research papers generated and 180,000 images captured, one of NASA’s pathfinder Earth satellites for testing new satellite technologies and concepts comes to an end on March 30, 2017. The Earth Observing-1 (EO-1) satellite will be powered off on that date but will not enter Earth’s atmosphere until 2056. 

“The Earth Observing-1 satellite is like The Little Engine That Could,” said Betsy Middleton, project scientist for the satellite at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. 

To celebrate the mission, we’re highlighting some of EO-1’s notable contributions to scientific research, spaceflight advancements and society. 

Scientists Learn More About Earth in Fine Detail

This animation shifts between an image showing flooding that occurred at the Arkansas and Mississippi rivers on January 12, 2016, captured by ALI and the rivers at normal levels on February 14, 2015 taken by the Operational Land Imager on Landsat 8. Credit: NASA’s Earth Observatory  

EO-1 carried the Advanced Land Imager that improved observations of forest cover, crops, coastal waters and small particles in the air known as aerosols. These improvements allowed researchers to identify smaller features on a local scale such as floods and landslides, which were especially useful for disaster support. 

On the night of Sept. 6, 2014, EO-1’s Hyperion observed the ongoing eruption at Holuhraun, Iceland as shown in the above image. Partially covered by clouds, this scene shows the extent of the lava flows that had been erupting.

EO-1’s other key instrument Hyperion provided an even greater level of detail in measuring the chemical constituents of Earth’s surface— akin to going from a black and white television of the 1940s to the high-definition color televisions of today. Hyperion’s level of sophistication doesn’t just show that plants are present, but can actually differentiate between corn, sorghum and many other species and ecosystems. Scientists and forest managers used these data, for instance, to explore remote terrain or to take stock of smoke and other chemical constituents during volcanic eruptions, and how they change through time.  

Crowdsourced Satellite Images of Disasters   

EO-1 was one of the first satellites to capture the scene after the World Trade Center attacks (pictured above) and the flooding in New Orleans after Hurricane Katrina. EO-1 also observed the toxic sludge in western Hungary in October 2010 and a large methane leak in southern California in October 2015. All of these scenes, which EO-1 provided quick, high-quality satellite imagery of the event, were covered in major news outlets. All of these scenes were also captured because of user requests. EO-1 had the capability of being user-driven, meaning the public could submit a request to the team for where they wanted the satellite to gather data along its fixed orbits. 

This image shows toxic sludge (red-orange streak) running west from an aluminum oxide plant in western Hungary after a wall broke allowing the sludge to spill from the factory on October 4, 2010. This image was taken by EO-1’s Advanced Land Imager on October 9, 2010. Credit: NASA’s Earth Observatory

 Artificial Intelligence Enables More Efficient Satellite Collaboration

This image of volcanic activity on Antarctica’s Mount Erebus on May 7, 2004 was taken by EO-1’s Advanced Land Imager after sensing thermal emissions from the volcano. The satellite gave itself new orders to take another image several hours later. Credit: Earth Observatory

EO-1 was among the first satellites to be programmed with a form of artificial intelligence software, allowing the satellite to make decisions based on the data it collects. For instance, if a scientist commanded EO-1 to take a picture of an erupting volcano, the software could decide to automatically take a follow-up image the next time it passed overhead. The Autonomous Sciencecraft Experiment software was developed by NASA’s Jet Propulsion Laboratory in Pasadena, California, and was uploaded to EO-1 three years after it launched. 

This image of Nassau Bahamas was taken by EO-1’s Advanced Land Imager on Oct 8, 2016, shortly after Hurricane Matthew hit. European, Japanese, Canadian, and Italian Space Agency members of the international coalition Committee on Earth Observation Satellites used their respective satellites to take images over the Caribbean islands and the U.S. Southeast coastline during Hurricane Matthew. Images were used to make flood maps in response to requests from disaster management agencies in Haiti, Dominican Republic, St. Martin, Bahamas, and the U.S. Federal Emergency Management Agency.

The artificial intelligence software also allows a group of satellites and ground sensors to communicate and coordinate with one another with no manual prompting. Called a “sensor web”, if a satellite viewed an interesting scene, it could alert other satellites on the network to collect data during their passes over the same area. Together, they more quickly observe and downlink data from the scene than waiting for human orders. NASA’s SensorWeb software reduces the wait time for data from weeks to days or hours, which is especially helpful for emergency responders. 

Laying the Foundation for ‘Formation Flying’

This animation shows the Rodeo-Chediski fire on July 7, 2002, that were taken one minute apart by Landsat 7 (burned areas in red) and EO-1 (burned areas in purple). This precision formation flying allowed EO-1 to directly compare the data and performance from its land imager and the Landsat 7 ETM+. EO-1’s most important technology goal was to test ALI for future Landsat satellites, which was accomplished on Landsat 8. Credit: NASA’s Goddard Space Flight Center

EO-1 was a pioneer in precision “formation flying” that kept it orbiting Earth exactly one minute behind the Landsat 7 satellite, already in orbit. Before EO-1, no satellite had flown that close to another satellite in the same orbit. EO-1 used formation flying to do a side-by-side comparison of its onboard ALI with Landsat 7’s operational imager to compare the products from the two imagers. Today, many satellites that measure different characteristics of Earth, including the five satellites in NASA’s A Train, are positioned within seconds to minutes of one another to make observations on the surface near-simultaneously.

For more information on EO-1’s major accomplishments, visit: https://www.nasa.gov/feature/goddard/2017/celebrating-17-years-of-nasa-s-little-earth-satellite-that-could

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Exploring Our National Parks…from Space!

The United States has nearly 84 million acres of historic and scenic land in its national parks system. In celebration of National Park Week, here are some satellite views of a few of those national treasures.

Throughout National Park Week, you can #FindYourPark and visit for free.

Yosemite National Park – California

Naked summits alternate with forested lowlands in Yosemite Valley, part of California’s Yosemite National Park. Our Landsat 7 satellite captured this true-color image of part of the Yosemite Valley on Aug. 8, 2001.

Yellowstone National Park – Wyoming, Idaho and Montana

Established in 1872, it was the first national park in the United States, and the world! Its geological and biological wonders have led international groups to declare it a world heritage site and a biosphere reserve. Yellowstone National Park captures the spirit and purpose of the National Park Service, blending modern and ancient human history with nature in its raw complexity.

Hot Springs National Park – Arkansas

National Parks usually make us think of pristine landscapes untouched by human civilization. Most of the 59 national parks in the United States fit that mold, but there are a few exceptions. Arkansas’s Hot Springs National Park, the country’s smallest and most urban, is one of them. Hot Springs, a city of 96,000 people, lies at the southern edge of the park and partly within its boarders.

Shenandoah National Park – Virginia

This long, narrow park in the Blue Ridge Mountains spans more than 179,000 acres, with 40% of the land protected as wilderness. More than 95% of the park is forested, sheltering 1,300 plant species and 267 types of trees and shrubs. The park contains 577 archeological sites, more than 100 cemeteries, and some rocks that date back a billion years.

Olympic National Park – Washington

Possibly one of America’s most diverse national landscapes, Olympic National Park is situated on the Olympic Peninsula in northwestern Washington. If you walked from west to east across the park, you would start at the rocky Pacific shoreline, move into rare temperate rainforests and lush river valleys, ascend glaciers and rugged mountain peaks, and then descend into a comparatively dry rain shadow and alpine forest. From beach to the top of Mount Olympus, you would rise 7,980 feet above sea level.

Colorado National Monument – Colorado

Along the Interstate 70 corridor in western Colorado, well-watered croplands, residential properties and urbanized areas create a broad stripe of green and gray. Away from the interstate, dry climate conditions color the landscape shades of beige, brick and tan. Yet these arid regions offer treasures of their own, including stunning vistas and wildlife both living and extinct. The varied landscapes of this park show the effects of tens of millions of years of erosion.

The images above were produced by our Earth Observatory as part of its 2016 series featuring the National Park Service properties. Check out more HERE

Want to see more of our nation’s parks from space? Visit our Flickr gallery HERE.

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