This study had the following specific aims:
To determine whether there were continuing changes in RST outcomes for ISS missions greater than a six-month duration, a study was conducted on the RST outcomes of two participants in the initial 1-year mission (i.e., one US astronaut and one Russian cosmonaut). The US astronaut and Russian cosmonaut were evaluated within the 1-year mission, and relative to data from the N=21 astronauts in 6-month missions.
The second part of this study had the following specific aims:
The five groups that were compared were: N=21 astronauts with valid data from the PVT on the ISS 6-month mission, first six months of data from astronaut Y and Z and second six months of data from astronauts Y and Z. Astronaut Y had no significant changes from the first six months to the second six months in the following inflight Visual Analog Scales (VAS): Time in Bed (TIB), Total Sleep Time (TST), Poor Sleep Quality, Sleepiness, Tiredness, Fatigue, Physical Exhaustion, and Workload. Astronaut Y did, however, have a significant increase in subjective Stress ratings from the first six months to the second six months in-flight.
Relative to PVT-B performance, Astronaut Y had no significant changes from the first to the second six months of the 1-year mission in PVT Response Speed or PVT Premature Responses. However, Astronaut Y did have significantly more PVT Lapses in the second six months of the mission. Moreover, Astronaut Y had significantly more PVT Lapses in both six month periods of the 1-year mission relative to the N=21 astronauts who undertook 6-month ISS missions. Therefore, Astronaut Y had a lower overall PVT-B Performance Score than the N=21 astronauts from the 6-month mission.
Astronaut Z had no significant changes from the first six months to the second six months in the following inflight VAS scales: TST, Poor Sleep Quality, Tiredness, and Fatigue. Astronaut Z did, however, have a significant decrease in TIB, increase in Sleepiness, increase in Physical Exhaustion, decrease in Stress, increase in Workload, and decrease in Caffeine Consumption in the second six months relative to the first six months.
Relative to PVT-B Performance, Astronaut Z had no significant changes from the first six months to the second six months of the 1-year mission in PVT Response Speed or PVT Premature Responses. However, Astronaut Z did have significantly less PVT Premature Responses in the second six months of the mission. Therefore, Astronaut Z had a significant increase in PVT Performance Score in the second six months relative to the first six months of the mission. The PVT-B Performance Score of Astronaut Y was more adversely affected by Slam shifts during the first six months of the mission than was PVT-B Performance of Astronaut Z.
|Mission||Launch/Start Date||Landing/End Date||Duration|
|Expedition 21||10/11/2009||12/01/2009||51 days|
|Expedition 22||11/30/2009||03/18/2010||109 days|
|Expedition 23||03/18/2010||06/01/2010||75 days|
|Expedition 24||06/01/2010||09/25/2010||117 days|
|Expedition 25||09/24/2010||11/25/2010||31 days|
|Expedition 26||11/26/2010||03/16/2011||111 days|
|Expedition 27||03/14/2011||05/23/2011||70 days|
|Expedition 28||05/23/2011||09/15/2011||115 days|
|Expedition 29||09/16/2011||11/21/2011||40 days|
|Expedition 30||11/14/2011||04/27/2012||166 days|
|Expedition 31||04/27/2012||07/01/2012||65 days|
|Expedition 32||07/01/2012||09/16/2012||78 days|
|Expedition 33||09/16/2012||11/18/2012||63 days|
|Expedition 34||11/18/2012||03/15/2013||117 days|
|Expedition 35||03/15/2013||05/13/2013||58 days|
|Expedition 36||05/13/2013||09/10/2013||166 days|
|Expedition 37||09/10/2013||11/10/2013||61 days|
|Expedition 38||11/10/2013||03/10/2014||120 days|
|Expedition 43||03/11/2015||06/10/2015||91 days|
|Expedition 44||06/10/2015||09/11/2015||93 days|
|Expedition 45||09/11/2015||12/11/2015||91 days|
|Expedition 46||12/11/2015||03/02/2016||82 days|