Space Acceleration Measurements System II
measures vibrations and transient acceleration disturbances resulting from
ISS vehicle activities, ISS systems operations, experiment operations, crew
movements, and ISS structure thermal expansion and contraction. SAMS Remote
Triaxial Sensor (RTS) systems are used to monitor on-board ISS accelerations
for individual experiments requiring direct acceleration measurement support.
Each RTS is capable of measuring acceleration disturbances between 0.01 Hz
and 400 Hz. This aggregate set of acceleration disturbances is commonly
referred to g-jitter. Each RTSs consist of two components: the RTS sensor
enclosure (SE) and the RTS electronics enclosure (EE). The RTS-SE, placed
as close to the experiment as possible, translates the g-jitter into a digital
signal. The RTS-EEs provides power and command signals for up to 2 RTS-SEs
and receives the g-jitter data from the RTS-SEs.
An additional sensor called the RTS Ethernet Standalone (RTS-ES) is available
for acceleration measurement support. The RTS-ES is just that, a sensor
capable of making acceleration measurements in a standalone fashion; the RTS-ES
does not require an RTS-EE to function.
All SAMS RTSs are linked together by the Interim Control Unit (ICU), which coordinates
the command and telemetry data for the various RTS systems being used throughout
the Station. All acceleration data obtained by each SAMS RTS are routed
to the ICU for downlink to the ground. All command and control for each
RTS is accomplished through the ICU. The main component of the ICU is a laptop
computer. Once the ICU receives the measurements from the RTS systems, it checks
the data for completeness, breaks the data into well-defined information packets,
and sends the packets to the SAMS Ground Operations Equipment located at the
Telescience Support Center (TSC) at Glenn Research Center.