Mark I ELSS

American space suit, tested 1958-59. The USAF Mark I Extravehicular and Lunar Surface Suit was tested during 1958-59, and led to subsequent development of more refined and satisfactory RX-series "Moon Suits" for NASA.

The USAF Mark I Extravehicular and Lunar Surface Suit, designed and built by Litton Industries, predated both the launch of Sputnik I by the Soviet Union and the creation of the National Aeronautics and Space Administration (NASA) by the United States. Based on a Litton "constant-volume" concept for a so-called "hard suit" in early 1955, the Mark I was tested during 1958-59 for more than 600 hours at simulated altitudes exceeding 100 miles. The unique construction of this suit permitted almost a full range of body motions by the person wearing it. The great success of the Mark I led to the subsequent development of a more refined and satisfactory RX-series "Moon Suits" for NASA. On June 9, 1958 Captain Iven C. Kincheloe Jr., USAF test pilot, tested the Mark I in a simulated flight to 100 miles and found it completely satisfactory.