An astronaut aboard the International Space Station snapped this photo while in orbit over southeast Brazil. The image focuses on the Três Marias Reservoir, a human-made waterbody fed by the São Francisco River. The types of land cover vary across the image, with bold colors dominating the scene. Much of the unvegetated land, such as unplanted fields and unpaved roads, appears in bright shades of red and yellow. This coloration comes from the underlying clays and soils of Brazil’s state of Minas Gerais. These substrates are rich in iron and aluminum and can turn vibrant colors when weathered.
Access to freshwater for irrigation enables agriculture around the reservoir. Red- and green-toned areas can be distinguished as fields with center-pivot irrigation or straight-edged plots. An orange-tan contour line tracing the shoreline of the reservoir marks where water levels have been higher.
The Três Marias Reservoir is one of three major reservoirs along the São Francisco River. The lighter shades of blue on its surface are due to sunglint, an optical effect that occurs when sunlight reflects off smooth water at the same angle a sensor views it. Hydroelectric plants on the river, like at the Três Marias Dam (not pictured), generate power for the country.
Small towns in this region are concentrated near water, where fishing and farming are common ways of life. There are no major bridges visible crossing the reservoir. Red dirt roads lead to its gentle, tan-colored shores, where vehicles and boats can park.
Astronaut photograph ISS070-E-51989 was acquired on December 27, 2023, with a Nikon D5 digital camera using a focal length of 420 millimeters. It is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by a member of the Expedition 70 crew. The image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by Andrea Wenzel/Jacobs-JETS II Contract at NASA-JSC.
