in-flight adjustment, along with provisions for complete removal of the suit. This configuration was designated the G5C suit. During the mission, Lovell was the first person to take his pressure suit off, which was achieved with great difficulty due to his size. Borman later was able to get his suit off, and biomedical data collected during the flight confirmed that astronauts would be more comfortable during Apollo lunar flights in a shirt-sleeve environment, wearing flight suits during "non-critical" phases of the mission. This led to the wearing of such flight suits from Apollo 7 to the present day. The G5C suit somewhat resembles the current Soyuz Sokol pressure suits worn by Russian-launched ISS crews. Apollo program The Gemini spacesuit was chosen by NASA for the initial Apollo Block I Earth orbital concept demonstrator phase of Apollo. Since EVA was impractical due to the hatch design of the Block I spacecraft, and with a design competition underway between ILC Dover, Hamilton Standard (later Hamilton Sunstrand), and David Clark for a new Block II lunar EVA suit, NASA decided to use the G3C as the base for the Apollo Block I suit, designated A1C. This version added new electrical and environmental disconnects, and a protective shell over the helmet visor, which reverted to the more economical Plexiglas. Since Apollo would use a launch escape system in place of Gemini's ejection seats, a yellow-colored U-shaped inflatable "Mae West" personal flotation device replaced the pilot parachute and its harness. Only two Block I flights were initially planned until December 1966, when the second one, to be flown by Wally Schirra, Donn F. Eisele, and Walter Cunningham, was canceled as unnecessary duplication. Astronauts Grissom, White, and Roger B. Chaffee were wearing A1C suits on January 27, 1967 in a preliminary countdown demonstration test for the planned February 21 Apollo 1 launch, when they were killed in a cabin fire, leading to NASA cancelling manned Block I flights and use of the A1C suit. Since the fire had burned through the suits, NASA added a fireproofing requirement to the new suit, which replaced the outer layer with beta cloth. The Block II suit was designated A7L and manufactured by ILC Dover. The new suit was first used on Apollo 1's replacement flight, Apollo 7 flown by Schirra, Eisele and Cunningham in October 1968. Post-Apollo applications The Gemini suit was looked at for the Manned Orbiting Laboratory