Houston, Texas, US, is featured in this image captured by the Copernicus Sentinel-1 mission.
The two identical Copernicus Sentinel-1 satellites carry radar instruments to image Earth’s surface. Images acquired with radar are interpreted by studying the intensity of the signal scattered back to the satellite – which is related to the roughness of the ground.
The colours of this week’s image come from the combination of two polarisations from the Copernicus Sentinel-1 radar mission, which have been converted into a single RGB image. Interpreting polarisation can help scientists analyse Earth’s surface.
In this composite image, captured on 21 June 2019, the city of Houston appears in shades of white and grey which contrasts with the yellow tones of the surrounding land and the dark blue waters of the Gulf of Mexico.
With a population of over two million and covering an area of over 1600 sq km, Houston is the state’s most populous city and the fourth largest city in the US.
Houston is dissected by a series of bayous passing. Buffalo Bayou can be seen cutting through Houston, before joining Galveston Bay visible at the bottom of the image. Galveston Bay is around 55 km long and around 30 km wide, making it the largest estuary in Texas. The shallow bay has an average depth of around 2 m, which is unusually shallow for its size.
The Port of Houston, which spreads across the northwest section of the bay, is one of the world’s largest ports, and many ships can be seen as multi coloured dots in the bottom-right of the image.
Houston is home to the NASA Lyndon B. Johnson Space Center, which lies west of Galveston Bay. The centre acts as NASA’s lead centre for astronaut training as well as the International Space Station mission operations. It was identified as mission control or simply ‘Houston’ during the Apollo, Gemini and Space Shuttle flights.
The centre also collaborates with other international facilities in a variety of scientific and engineering programmes related to human space flight and planetary exploration. The Johnson Space Center is where many ESA astronauts are sent as part of their training and preparation for future space missions. This is where Luca Parmitano, who recently returned to Earth, trained for his Beyond mission to the International Space Station.
This image is also available in the Earth from Space video programme.