NASA 1965 vacuum suit test

NASA spacesuit technician Jim LeBlanc was not part of a 1965 mishap, according to records describing the incident that has resurfaced online. The vacuum-chamber accident took place on December 14, 1966, during a moon-suit test in Houston, when LeBlanc’s suit lost pressure inside a NASA chamber. His suit pressure fell from about 3.8 pounds per square inch to 0.1 psi, and he lost consciousness before the chamber was repressurized. Guinness World Records and later accounts say he regained consciousness after 87 seconds and suffered no lasting injury. (guinnessworldrecords.com) (nasa.gov) ### Was this really a 1965 NASA test? December 14, 1966, is the date given in multiple published accounts of the accident, including Guinness World Records and a detailed retelling by Space Safety Magazine. The social-media version circulating this weekend appears to shift the date back by a year, but the named test subject in the incident was Jim LeBlanc and the event is described as a 1966 chamber test tied to Apollo-era suit development. NASA’s own historical material places major Apollo thermal-vacuum testing in the mid-1960s at the Manned Spacecraft Center, now Johnson Space Center, including Chamber A in 1965. (guinnessworldrecords.com) Those records support the broader setting of moon-program environmental testing, though the accident itself is documented in secondary historical accounts rather than in the NASA pages surfaced here. ### Who was Jim LeBlanc, and what failed? Jim LeBlanc was a NASA spacesuit technician and volunteer test subject, according to Guinness and Space Safety Magazine. He was inside a vacuum chamber wearing an early moon-suit prototype when the hose supplying suit pressurization became disconnected, causing a rapid drop in suit pressure. (guinnessworldrecords.com) The Smithsonian’s air-and-space magazine archive, in an article on spacesuit failure scenarios, also describes the same basic sequence: an oxygen or pressurization hose outside the chamber was accidentally disconnected, and the suit pressure fell almost immediately to about 0.1 psi. (nasa.gov) ### How fast did he black out? About 10 to 15 seconds is the interval most often cited for LeBlanc’s loss of consciousness. Space Safety Magazine said the pressure drop from 3.8 psi to 0.1 psi occurred in 10 seconds, while LeBlanc remained conscious only briefly afterward. (guinnessworldrecords.com) Other summaries put the blackout at roughly 14 to 15 seconds. LeBlanc later recalled one physical sensation before passing out. “As I stumbled backwards, I could feel the saliva on my tongue starting to bubble,” he said, according to Space Safety Magazine. (repository.si.edu) That description has been repeated in later summaries of the event. ### Did he survive because space exposure is less lethal than movies suggest? Guinness World Records says LeBlanc regained consciousness when the chamber had been repressurized to the equivalent of 14,000 feet after 87 seconds. Space Safety Magazine and other retellings say he had no long-term effects, beyond short-term discomfort. (spacesafetymagazine.com) NASA’s current human-rated thermal-vacuum material shows why the incident still circulates in discussions of suit safety. The agency says Johnson Space Center remains a leader in human-rated vacuum and thermal-vacuum testing, and current NASA suit standards still center on low-pressure operating ranges around the 3.7 to 4.3 psi used in U.S. extravehicular suits. (spacesafetymagazine.com) ### Where did this happen, and what was being tested? Houston was the site of the test, according to Guinness, and the chamber was part of NASA’s Apollo-era environmental test infrastructure. NASA says Chamber A at Johnson Space Center is the large thermal-vacuum facility famous for testing Apollo spacecraft, with and without mission crew. (guinnessworldrecords.com) The Apollo program’s lunar suits operated at roughly 3.75 psi, according to NASA materials on extravehicular activity history. That figure closely matches the pressure cited in LeBlanc’s accident and places the test within the broader push to qualify moon-suit systems for lunar surface work. (nasa.gov) May 16, 2026, is the date this older incident resurfaced in a new online thread, but the underlying event remains a December 1966 chamber accident involving Jim LeBlanc. NASA’s current Johnson Space Center pages on Chamber A and human-rated thermal-vacuum testing remain public reference points for readers tracing the history of Apollo-era suit testing. (guinnessworldrecords.com) (nasa.gov 1) (nasa.gov 2)