ISS028-E-18218 Click the photo number to access all resolutions available and the database record.
At the time of the image, the ISS was positioned northwest of the Galapagos Islands, while Atlantis was roughly 2,200 kilometers (1,367 miles) to the northeast, off the east coast of the Yucatan Peninsula. The maximum angle of the shuttle’s descent was roughly 20 degrees, though it appears much steeper in the photo because of the oblique viewing angle from ISS. Parts of the space station are visible in the upper right corner of the image.
In the background of the image, airglow hovers over the limb of the Earth. Airglow occurs as atoms and molecules high in the atmosphere (above 80 kilometers, or 50 miles altitude) release energy at night after being excited by sunlight (particularly ultraviolet) during the day. Much of the green glow can be attributed to oxygen molecules.
Over the years, the space shuttle program has gathered many images and insights on earth’s space environment—including auroras—and on the planet below. We explore the role the shuttle has played in observing our home planet:
In the 1980s and early 1990s, NASA embraced a “systems” approach to studying Earth science. Where land- and ocean-based scientists could make observations in great depth from individual points, space-based sensors could examine entire regimes of Earth with a broader but shallower view—the global ocean surface, plant cover over all continents, the composition of the atmosphere both horizontally and vertically. Scientists could ultimately piece together the micro and macro scales for a deeper understanding of how the planet works.
Equipped with a 60-foot-long payload bay, a nimble robotic arm, and two to seven pairs of human hands and eyes (depending on the size of the crew), the Space Shuttle became an orbiting laboratory and observatory for Earth system science. The shuttle could not observe continuously for months to years, as satellites might. But the human touch and the frequent flights did allow some intensive and diverse studies.
Over three decades, the shuttle served as a critical testbed for remote sensing instruments that would eventually fly on satellites. In fact, many of the technologies in NASA’s Earth Observing System made their maiden flights in the back of NASA’s space pick-up truck.
