been used during an open-basket balloon stratospheric flight scheduled for early 1936. Wiley Post experimented with a number of pressure suits for record-breaking flights. Russell Colley created the space suits worn by the Project Mercury astronauts, including fitting Alan Shepard for his ride as America's first man in space on May 5, 1961. List of space suit models Soviet and Russian suit models SK series (CK)the spacesuit used for the Vostok program (1961–1963). Worn by Yuri Gagarin on the first crewed space flight. No pressure suits were worn aboard Voskhod 1. Berkut (Беркут meaning "golden eagle")the spacesuit was a modified SK-1 used by the crew of Voskhod 2 which included Alexei Leonov on the first spacewalk during (1965). From Soyuz 1 to Soyuz 11 (1967–1971) no pressure suits were worn during launch and reentry. Yastreb (Ястреб meaning "hawk")extravehicular activity spacesuit used during a crew exchange between Soyuz 4 and Soyuz 5 (1969). Krechet-94 (Кречет meaning "gyrfalcon")designed for the canceled Soviet crewed Moon landing. Strizh (Стриж meaning "swift (bird)")developed for pilots of Buran-class orbiters. Sokol (Сокол meaning "falcon")suits worn by Soyuz crew members during launch and reentry. They were first worn on Soyuz 12. They have been used from 1973 to present. Orlan (Орлан meaning "sea-eagle" or "bald eagle")suits for extravehicular activity, originally developed for the Soviet lunar program as a lunar orbit EVA suit. It is Russia's current EVA suit. Used from 1977 to present. United States suit models In the early 1950s, Siegfried Hansen and colleagues at Litton Industries designed and built a working hard-shell suit, which was used inside vacuum chambers and was the predecessor of space suits used in NASA missions. Navy Mark IV high-altitude/vacuum suitused for Project Mercury (1961–1963). Gemini space suits (1965–1966)there were three main variants developed: G3C designed for intra-vehicle use; G4C specially designed for EVA and intra-vehicle use; and a special G5C suit worn by the Gemini 7 crew for 14 days inside the spacecraft. Manned Orbiting Laboratory MH-7 space suits for the canceled MOL program. Apollo Block I A1C suit (1966–1967)a derivative of the Gemini suit, worn by primary and backup crews in training for two early Apollo missions. The nylon pressure garment melted and burned through in the Apollo 1 cabin fire. This suit became obsolete when crewed Block I Apollo flights were discontinued after the fire. Apollo/Skylab A7L EVA and Moon suitsThe Block II Apollo suit was the primary pressure