Thermal physiological consideration of precooling procedures in manned space craft.
OBJECTIVE
To explore a space craft precooling temperature at which excessive thermal stress on the crew member could be prevented or reduced in an overheated launch or reentry module.


METHODS
Five young male volunteers wearing a space suit participated in 25 tests at sea level. The space suit was either ventilated in a volume air flow rate of 100 L/min (STPD) with ambient air at temperatures (Ta) of 15 degrees C, 10 degrees C, and 5 degrees C, respectively, or not ventilated. Rectal (Tr), mean skin (Tsk) and mean body (Tb) temperatures were measured.


RESULTS
At Ta 15 degrees C, Tr decreased without significance (from 37.0 +/- 0.2C to 36.7 +/- 0.3 degrees C) in 120-min tests, whereas mean Tsk and mean Tb decreased significantly, and subjects had local cold strain whether the space suit was ventilated or not; while at Ta 10 degrees C, Tr decreased from 37.0 +/- 0.3 degrees C to 36.3 +/- 0.3 degrees C (P < 0.05), subjects had a whole body cold strain, and both mean Tsk and Tb dropped continuously and significantly.


CONCLUSIONS
Ambient temperature 15 degrees C, at which the thermal comfort states of crew was not significantly degraded, was acceptable after precooling in a space craft.
Yu
X J
XJ
Institute of Space Medico-Engineering, Beijing, China.
Chang
S Y
SY
Wu
J M
JM
Qiu
M
M
Song
D
D
Yang
T D
TD
D000293:Adolescent; D000328:Adult; D000337:Aerospace Medicine; D000389:Air Conditioning; D001831:Body Temperature; D001833:Body Temperature Regulation; D003080:Cold Temperature; D006801:Humans; D008297:Male; D013026:Space Flight; D018561:Space Simulation; D019442:Space Suits; D018531:Spacecraft; D013696:Temperature; D014691:Ventilation