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Synchronization of Primate Circadian Rhythms in Space (COS 1514-4)
Principal Investigator
Research Area:
Species Studied
Scientific Name: Macaca mulatta Species: Monkey Strain: Rhesus


In natural conditions, mammalian circadian rhythms are normally externally and internally synchronized. Whereas many researchers feel that the circadian time- keeping system is endogenous, others argue that the timing system is exogenous, with an organism perceiving daily timing signals such as slight variations in gravity associated with the rotation of the earth. A test of this hypothesis would be to determine if circadian rhythms persist outside of the Earth's environment.

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Sulzman, F.M. et al.: Synchronization of Primate Circadian Rhythms in Space. Final Reports of U.S. Monkey and Rat Experiments Flown on the Soviet Satellite Cosmos 1514. R.C. Mains and E.W. Gomersall, eds., NASA TM-88223, 1986, pp. 71-102.

Sulzman, F.M. et al.: Thermoregulatory Responses of Rhesus Monkey During Spaceflight. Physiology & Behavior, vol. 51, 1992, pp. 585-591.

Circadian rhythm
Heart rate
Body temperature regulation
Oxygen consumption
Skin temperature

Data Information
Data Availability
Archive is complete. No data sets are available for this experiment. Please Contact LSDA if you know of available data for this investigation.

Activity, Heart rate, primate, EKG hard wire implants, recording
Activity, Heart rate, rat, Implanted transmitter, continuous EKG, rate algorithm
Activity, motor, Primate, Jacket piezoelectric sensors (rhythm)
Behavior, Sleep/wake period, primate, Activity sensor, digital data collection unit
Behavior, Sleep/wake period, primate, Time-lapse photography
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Cosmos 1514 12/14/1983 12/19/1983 5 days

Additional Information
Managing NASA Center
Ames Research Center (ARC)
Responsible NASA Representative
Ames Research Center LSDA Level 3
Project Manager: Sylvain Costes
Institutional Support
National Aeronautics and Space Administration (NASA)
Alternate Experiment Name
Protocol / Approach