title: Simulated shuttle egress: comparison of two Space Shuttle protective garments.
abstract: BACKGROUND
  In a previous study from our laboratory, we observed carbon dioxide (CO2) accumulation in the helmet of the NASA Launch and Entry Suit (LES) during a simulated emergency egress from the Space Shuttle. Of 12 subjects, 8 were unable to complete the egress simulation with a G-suit inflation pressure of 1.5 psi. The purpose of this report was to compare CO2 accumulation and egress walking time in the new Advanced Crew Escape Suit (ACES) with that in the LES.
  
  
  METHODS
  Four male subjects who previously were unable to complete the egress in the LES performed a simulated egress while wearing the ACES with the G-suit inflated to 1.5 psi. The egress simulation consisted of 6 min of seated rest, 2 min of standing, and 5 min of walking on a treadmill at 1.56 m x s(-1) (3.5 mph) and 0% grade. The helmet visor was closed with the subjects receiving 100% oxygen throughout the simulation. Inspired CO2 and walking time were measured.
  
  
  RESULTS
  The rate of CO2 accumulation was significantly less (ACES: 0.53 +/- 0.03, LES: 1.07 +/- 0.15 %CO2 x min(-1); p = 0.05) and walk time was greater in the ACES (ACES: 5.0 +/- 0.0, LES: 2.7 +/- 0.2 min; p = 0.002).
  
  
  CONCLUSIONS
  Changes in the design of the ACES from the LES resulted in a decreased rate of CO2 accumulation and an improved egress walking time compared with the LES.
authors.affiliation: Wyle Laboratories, Life Sciences Systems and Services Division, Houston, TX, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Lee
authors.forename: P A
authors.initials: PA
authors.lastname: Bishop
authors.forename: S M
authors.initials: SM
authors.lastname: Schneider
authors.forename: M C
authors.initials: MC
authors.lastname: Greenisen
mesh_terms: D000328:Adult; D002248:Carbon Monoxide / Q000032:analysis*; D004867:Equipment Design; D004868:Equipment Failure; D005676:Gravity Suits; D006801:Humans; D018471:Hypergravity; D008297:Male; D013026:Space Flight; D013647:Task Performance and Analysis
chemical_list: D002248:Carbon Monoxide