NASA once envisioned life after Earth in these fantastical floating cities

This Sunday, July 29, 2018, marks the 60th anniversary of NASA's establishment as a US government agency, when President Dwight D. Eisenhower signed the 1958 National Aeronautics and Space Act, its founding legislation.

Nearly two decades later, NASA was already envisioning what post-Earth communities in space could look like.

In the 1970s, physicists from Princeton University, the NASA Ames Research Center, and Stanford University created fantastical illustrations of massive orbiting cities for life after Earth. The scientists imagined a worse-case scenario in which our planet would be destroyed, and humankind would move to space.

Take a look at these designs, unearthed by The Public Domain Review.

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In the '70s, the scientists expected that people could travel to the first space colony by 2060. They designed three types that would orbit the sun.

The first design is this donut-shaped spaceship that would house about 10,000 people.

The city would be full of homes, shrubbery, and sidewalks. A river would flow through the center of the half-mile-wide ship.