Actiwatch Spectrum System (Actiwatch Spectrum) - 12.03.13
Science Objectives for Everyone
The Actiwatch Spectrum is a waterproof, nonintrusive, sleep-wake monitor worn on the wrist of a crewmember. The device contains an accelerometer for measuring motion and color sensitive photodiodes (a photodetector capable of converting light into voltage) for monitoring ambient lighting. Together, these capabilities enable the Actiwatch Spectrum to be used to analyze circadian rhythms, sleep-wake patterns, and activity.
Science Results for Everyone
Information PendingFacility Representative(s)
Johnson Space Center, Human Research Program, Houston, TX, United States
Respironics Inc., Murrysville, PA, United States
National Aeronautics and Space Administration (NASA)Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)ISS Expedition Duration
September 2010 - September 2012Expeditions Assigned
25/26,27/28,29/30,31/32Previous ISS Missions
- The Actiwatch Spectrum captures data on subject activity and motion and the amount of ambient light to which the subject is exposed.
- The Actiwatch Spectrum is a replacement for an older Actiwatch system and comes with the added capability to differentiate between multiple wavelengths or colors of ambient light across a broad spectrum (400-700 nm). The Actiwatch Spectrum also has the added capability to display time and function as a watch.
- The Actiwatch Spectrum can be used to investigate a number of activities such as sleep quality, sleep onset, hyperactivity and other daily routines.
The Actiware Software is used for data analysis, file management, configuring an Actiwatch Spectrum for data collection and retrieving data from an Actiwatch. Data downloaded from an Actiwatch is stored in a user-specified database file and organized by the subject ID used to configure the Actiwatch. The Actiware Software may be used to access subject information and view or analyze data for sleep parameters and rhythmicity. Raw data or statistics may also be exported for external analysis or archival. Battery life may be checked using the Actiware Software while communicating with an Actiwatch. While the Actiware Software supports older versions of the Actiwatch hardware, the Actiwatch Spectrum and Actiwatch Spectrum Dock cannot be used with older versions of Actiware, Actiwatch Readers or Actiwatches.
The Actiwatch Spectrum System was first launched on STS-133/Flight ULF-5 in February 2011. Replacement of internal batteries will not be performed on-orbit, therefore, periodic resupply of fresh Actiwatches is planned. The Actiwatch Spectrum is currently used in the ambulatory monitoring portion of the Integrated Cardiovascular experiment aboard the ISS. Activity data collected by the Actiwatch is analyzed in conjunction with cardiovascular data from other devices to estimate the amount of work the crewmember?s heart performs on a daily basis. Operations
- Use of the Actiwatch Spectrum involves a small number of basic operations: initialization, data collection, downloading data and downlinking data.
- Initialization of the Actiwatch Spectrum involves configuring the hardware to start recording data at a specific sampling rate at a specific time.
- The period over which the Actiwatch Spectrum may be used to collect data depends on the sampling rate and is limited by the internal storage capacity of the device.
- Data collection using the Actiwatch Spectrum is very similar to wearing a standard wristwatch. Once the device has been initialized and begins collecting data, the user need merely wear it at the location specified by the experiment for which data is being collected.
- Downloading the Actiwatch Spectrum involves connecting the device to a reader plugged into a computer and transmitting the data from the Actiwatch Spectrum to the computer.
- Downlinking the data from the Actiwatch Spectrum is a matter of transmitting the data stored on the ISS servers to the science teams on the ground.
Ground Based Results Publications
Mallis MM, DeRoshia CW. Circadian Rhythms, Sleep, and Performance in Space. Aviation, Space, and Environmental Medicine. 2005; 76(6 Suppl): B94-107.