The Actiwatch is a waterproof, nonintrusive, sleep-wake activity monitor worn on the wrist of a crewmember. The device contains a miniature uniaxial accelerometer that produces a signal as the subject moves. The data are stored in nonvolatile memory within the Actiwatch until they are downloaded for analysis.Facility Manager(s)
Information PendingCo-Facility Manager(s)
Cambridge Neurotechnology Ltd., Cambridge, MA, United Kingdom
National Aeronautics and Space Administration (NASA)Expeditions Assigned
14,15,16,17,18,19/20,21/22,23/24,25/26Previous ISS Missions
The Actiwatch has supported investigations on several space shuttle missions.
The Actiwatch is a small, lightweight, wrist-worn device that simultaneously detects body movement and light intensity. It is used to evaluate sleep-wake adaptation and circadian cycle. The device is battery powered and can be used to collect data continuously in intervals ranging from 90 hours to 227 days depending on the sampling rate. The Actiwatch's internal, nonvolatile memory and programming allows it to store data indefinitely until it can be downloaded.
Crewmembers will put on the Actiwatch as required by the investigation, download data from the Actiwatch as needed, and change the battery at the end of the increment. The Actiwatch provides computer software for setup and data retrieval via a RS-232 serial port connection to a personal computer (PC). The PC must be IBM compatible and have a 486 processor (minimum); 8-MB RAM (minimum); Windows 95, Windows 98, or Windows NT 4.0 or higher; a 100-MB hard drive; a 9-pin RS-232 serial port; and Super Video Graphics Array 9 SVGA (800 x 600 pixels required to display all data displays).
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Mallis MM, DeRoshia CW. Circadian Rhythms, Sleep, and Performance in Space. Aviation, Space, and Environmental Medicine. 2005; 76(6 Suppl): B94-107.