Mean weight was 77.2 kg at the preflight annual examination, 73.8 kg at FD 90, 77.3 kg at R+3, and 78.1 kg at the postflight annual examination. There was a downward shift in mean weight inflight, with return to preflight mean weight occurring by R+3. However, inflight mean weight was not statistically significantly different from the preflight and postflight mean weights.
Another way to look at this type of data is to calculate and examine the percent change between preflight and inflight values. Data are inflight data, comparing weight on FD 30, FD 60, and FD 90 to weight at preflight annual examination. Percent of change is calculated by the difference between the preflight annual examination weight and the inflight weight divided by the preflight weight multiplied by 100. The resulting negative value indicates that weight decreased early in the mission (-3.5% by FD 30) and then remained relatively constant at the next two inflight intervals (-4.0% by FD 60 and -4.25% by FD 90).
The method of measurement is different for inflight and on ground, which may contribute to the differences in weight reported here. These results suggest that during periods of prolonged weightlessness, astronauts may experience weight loss early in the mission. Inflight weight appears to stabilize at the new level, and return to preflight levels after return to Earth. Further research into nutritional status during long duration spaceflight may reveal the causes and consequences of this temporal weight loss.
|Mission||Launch/Start Date||Landing/End Date||Duration|
|Mir 18||03/14/1995||07/07/1995||116 days|
|NASA 2||03/22/1996||09/26/1996||189 days|
|NASA 3||09/16/1996||01/22/1997||130 days|
|NASA 4||01/12/1997||05/24/1997||133 days|
|NASA 5||05/15/1997||10/06/1997||134 days|
|NASA 6||09/25/1997||01/31/1998||129 days|
|NASA 7||01/22/1998||06/12/1998||142 days|