Many cars never make it much further than the drawing board. In the case of the following vehicles, there are solid reasons why that is.

The Ford Nucleon

In the 1950s, nuclear power was the wave of the future and a way to power super-cities and super efficient vehicles. A design crew at Ford were convinced of the merits of atomic energy and drew up conceptual plans for the Nucleon. Instead of a conventional combustion engine, this sleek black car would’ve contained a small nuclear reactor in the rear. Designers were convinced the Nucleon could be powered by uranium fission, much in the same manner as a nuclear submarine. They also hoped that the car would one day be able to drive 5,000 miles without refueling. The company designed a scale model but the project didn’t get much further than that for some pretty obvious reasons. Imagine what might happen if a car had a meltdown in the middle of rush hour traffic. However, the electronic converters in the original design scheme were eventually used to power hybrid cars.

1969 Chevrolet Astro

This spacey concept car went through three different design phases in the late ‘60s when all things interstellar had captured the hearts and minds of Americans. While NASA was plotting a course to the moon, a group of engineers from Chevrolet and GM tried to come up with a sports car that would look as cool as a spaceship. The Astro I had a sleek design but its low frame proved impractical. Passengers had to use elevator seats to get in and out of it. The Astro II was a more down to earth but the designers came up with a third idea: the Astro III. This version, which had a tricycle-wheel arrangement. The prototype didn’t have a rear window or rearview mirrors, which meant that drivers had to use a then-revolutionary closed circuit television to see what was happening behind the vehicle. The Astro III was certainly futuristic but its unique wheel placement, more than anything, killed its chances of reaching the market.