

In 1961, NASA engineers began designing several types of lunar landers for the Apollo missions before settling on the Lunar Excursion Module. This super cute 1963 model was called a bug, for obvious reasons.

The engineers were particularly concerned with the unknown nature of the moon's surface, and worried about such things as how engine exhaust would affect the dust layer. Complicating matters, scientists disagreed about probable surface characteristics, including the depth of the dust layer.

The 1961 sketch below shows an artist's concept of a smaller lander that would carry just one man on top of the vehicle. This "shoestring" vehicle could spend two to four hours on the moon. NASA also designed an "economy" model that could carry two men and stay on the surface for 24 hours and a "plush" module that would allow a week-long visit.

Images: NASA