1956 – Powered Space Suit – Constantin Lent (American)
Constantin Paul Lent 3034131 MOBILE SPACE SUIT – see pdf here.
Patent number: 3034131
Filing date: Aug 7, 1956
Issue date: May 15, 1962
Although the suits key features were related to the aviator's 'needs' for long-duration flights, the invention predicted that as the air became more rarified the higher one could travel, the internal pressure of the suit would be such that the legs and arms would become taunt and inflexible necessitating outside assistance to move. To quote the inventor, "Before it is too late, it is necessary to plan now ahead of time for improvements in aviation garments and suits which not only may be safe, but also provide greater comforts. Interstellar navigation (a thing of the very near future) too needs better pilot suits."
The inventor mentions two of his seven requirements to allow "easy manipulation in a vacuum" and "it must have motive means to help the flexing of the limbs and arms in the suit." To achieve this, "the invention is to provide hydraulic, mechanical, or electrical means to help moving and flexing the extremities of the suit, the limbs, and the arms."
To put the date into perspective, on April 12, 1961, the Russian Yuri Gagarin becomes the first man in space, some five years following the filing of this patent. There is no evidence to date that suggests this patent was realised. Robert Heinlein published his book "Starship Troopers" in 1959.