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The biosensors that will be used during exploration missions must be
small, robust and use as little electrical power as possible. Additionally,
they must survive in and around an environment that is hostile to
most sensors: the human body.
BioWatch
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BioWATCH unit shown for
size next to an ECG lead and a ruler. |
Data from sensors measuring physiological performance
must be properly collected and managed. Because biosensors are frequently
worn on the body, lightweight and wireless systems are preferred,
but have not been readily available. Based on a desire to improve
biosensor data management onboard the International Space Station
(ISS), NASA funded a Small Business Innovation Research (SBIR) grant
for ZIN Technologies to develop a wearable data collection, storage
and transmission device. ZIN developed a device called Biomedical
Wireless and Ambulatory Telemetry for Crew Health (BioWATCH), which
can be easily reconfigured between numerous sensors and data transmission
protocols. Additionally, BioWATCH can simultaneously support up to
five sensors and their data streams.
Reconfiguration is easy because BioWATCH was designed
to use CompactFlash cards and the control unit runs a form of the
Unix operating system. As such, integrating a new sensor is rapid
and inexpensive. BioWATCH is able to communicate using standard wireless
protocols such as 802.11, Bluetooth, EDGE, EVDO, and wired protocols
such as USB, Ethernet and RS-232.
Based on the success of the initial prototype modules,
ZIN and the Cleveland Clinic teamed to deploy BioWATCH in an application
monitoring heart rhythm in patients following a procedure designed
to eliminate a heart rhythm irregularity known as atrial fibrillation.
BioWATCH has been demonstrated to be compatible with
the following classes of biosensors: ECG, EEG, EMG, EOG, heart rate,
blood glucose, blood pressure, temperature, and pulse oximeters.
PUMA
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PUMA headgear |
As a spin-off from other research efforts, Glenn
has developed sensors that are capable of taking metabolic measurements
inside space suits. One example is the Portable
Unit for Metabolic Analysis (PUMA).
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PUMA electronics box |
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PUMA data from actual
test subject |
The PUMA measures the amount of oxygen an astronaut
consumes and the amount of carbon dioxide produced. When combined
with PUMA’s heart rate measurement, PUMA software quantifies
how hard the astronaut is working. This information helps the astronaut
manage and conserve the limited supply of consumable resources available
within the space suit. Additionally, the data are used to present
the most accurate picture of the astronaut’s fitness level and
to prevent the astronaut from working past the point of exhaustion.
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PUMA being used in Aquarius,
NOAA's underwater ocean laboratory, during NASAís NEEMO-12 mission. |
PUMA is battery operated and self-contained, featuring
an electronics box that fits into a small, wearable pack. It was deployed
during NASA’s Extreme Environment Mission Operations (NEEMO)
mission in May 2007. Twice during the mission, the NEEMO crew wore
the PUMA for twenty minutes to determine their resting metabolic rate.
This activity was PUMA's first use in an environment different from
Earth's standard atmosphere. Pressure in Aquarius was 2.5 times higher
than is experienced at sea level, which may cause changes in human
metabolic performance.
MEMS Sensors
Glenn has a long history in developing Micro-Electro-Mechanical
Systems (MEMS) sensors for the harsh environments found in aircraft
engines. Rather than use the traditional silicon as the substrate
material, Glenn uses silicon carbide, which is much more durable. This
technology has already been used to produce compact oxygen and carbon
dioxide sensors operating within a mask system used to detect the onset
of an asthma attack. Other GRC MEMS systems can be used to quantify
the amount of dust present in a lunar or Martian habitat.
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