In the wake of World War II, the U.S. Naval Research Laboratory began experimenting with German-designed V-2 rockets as well as smaller, lighter launch vehicles called "sounding rockets." In order to monitor which way the rockets were pointing during their flights, scientists began putting aircraft gun cameras on them. During one of these flights, on March 7, 1947, the first space-based picture of Earth was taken at an altitude of 100 miles over New Mexico. In 1950, upon developing the film after another of these flights, scientist Otto Berg discovered a series of pictures of a huge tropical storm over Brownsville, Texas. He pieced the pictures together into a mosaic of the region enveloped by the storm, thus demonstrating the potential for space-based cameras to help us monitor our changing world.
Interest quickly grew among the international community of Earth scientists in using sounding rockets to study the Earth's upper atmosphere. In 1952, the International Council of Scientific Unions proposed declaring 1957 the "International Geophysical Year" (IGY) to satisfy a growing desire among the science community to expand the study of our home planet to include the whole Earth system and its surroundings. In 1954, the IGY committee challenged participating countries to launch a satellite as part of the IGY activities. On July 29, 1955, President Dwight Eisenhower announced that the United States would launch about six Earth satellites as a contribution to the IGY. On the following day, Premier Nikita Kruschev said the Soviet Union would also launch satellites during the IGY and the race was on between the superpowers.
In October 1957, the Soviet Union successfully launched Sputnik Ia 22-inch spherical satellite weighing 175 poundsinto a low Earth orbit. In January 1958, the United States successfully launched Explorer I, followed by the launch of Vanguard I two months after that. But the Russians' success and the United States' initial failures spread a sense of crisis in the latter country. The Americans declared space exploration a national priority, and in 1958 President Eisenhower asked his Science Advisory Committee to write a policy on space. Later that year Congress signed the act creating the National Aeronautics and Space Administration (NASA). Since then, NASA has played an international leadership role in developing and deploying satellite technologies for Earth observation.
Space-based Observations of the Earth