A surgery team at St Luke's Hospital performing a hip joint replacement in a new clean room which helps lessen the danger of infection to the patient, Denver, Colorado, February 8, 1970. It is being performed in a foldable clean room which can be stored when not in use. Air is forced in through the front and exits out the back and the operating team upwind of the patient wears astronaut type helmets and garments which are impermeable to bacteria. The clean room technique for surgery was developed by the Martin Marietta Corporation for NASA and is being tested at St Luke's. (Photo by Underwood Archives/Getty Images)