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Above: Living things in space require sophisticated systems to monitor
their health, safety, and to collect scientific data.
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Above: NASA is developing a system for monitoring fetuses following
surgery to treat congenital birth defects.
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Above: A fetus in the womb is part of system much like that of an
astronaut in a spacecraft or spacesuit.
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Building a Space Age Stethoscope - Biological Monitoring Challenge
If you were playing word association, your first response to the word “astronaut”
wouldn’t likely be "fetus.” But in fact, it’s a better answer
than you might think. An astronaut, or for that matter any living thing, floating
in a spacecraft or on a space station has a good deal in common with a fetus developing
in
the womb.
A fetus depends entirely on its mother for survival. The
womb provides a mechanism for oxygen and nutrient delivery,
thermal control, and waste disposal, as well as protection
from the outside environment. For an astronaut, the situation
is remarkably similar. While the members of a Space Shuttle
crew can feed themselves, they rely on the spacecraft for
breathable air, a climate-controlled environment, waste processing,
and protection from the vacuum of space.
One critical difference between the astronaut and the fetus
is that the fetus is part of a naturally occurring system
that has evolved over many thousands of years to regulate
itself. During space flight, living organisms become part
of an artificial system that has evolved over only a few decades.
Within this man-made life support system, there must be a
mechanism for monitoring the plants, animals, cells, and,
of course, astronauts that are part of it. A critical element
of that mechanism consists of biosensor systems.
Biosensors are instruments that take biological and physiological measurements.
They can be implanted internally, worn externally, or mounted throughout a spacecraft.
They monitor a wide range of data encompassing the health and well-being of the
crew and research subjects, experimental parameters, and the status of the living
environment. The data signals generated by the sensors are gathered, processed
and stored. The use of wireless biotelemetry is desirable when monitoring living
organisms so that subjects can go about their business while data is being collected.
Listening to Life in Outer Space
Developing biosensor systems is a high priority for NASA. The virtual absence
of gravity during space flight affects living organisms in ways that are not fully
understood. Monitoring the health of astronauts is essential for safety reasons,
and monitoring experimental parameters in astronauts and other research subjects
offers insight into the short- and long-term effects of space flight.
Common measurements to assess overall health include heart rate, blood pressure,
and body temperature. These measurements are also important for research purposes
but provide only the most basic information. A variety of blood chemistry measurements
are necessary to better understand the various ways organisms adapt to space flight.
They include acidity, calcium, potassium, carbon dioxide, and oxygen.
Developing implantable biosensors to support these science goals is a significant
technological challenge. Sensors must be miniaturized so as to be safe in humans
and unobtrusive to animal health and behavior. The body’s immune system treats
implanted sensors like foreign invaders, sending white blood cells to surround
and kill them. The implants must be able to withstand these attacks for periods
of up to a month
or more. All associated hardware must also meet strict size, weight, reliability,
and power specifications.
NASA’s demanding size and performance requirements are pushing the technology
envelope and opening up new scientific possibilities. The agency is creating biosensors
and transmitters approaching the size of an ingestible pill, as well as systems
to monitor air quality in sealed plant growth chambers, nutrient delivery in cell
culture systems, and bacterial contamination of drinking water. In fact, one NASA-developed
system has even given the womb a leg up.
Listening to Life in Inner Space
NASA is working with the University of California at San Francisco (UCSF) to
develop a system to monitor human fetuses with life threatening congenital defects.
Doctors at UCSF have pioneered surgical procedures to treat certain defects prior
to birth.
The operation is generally performed when the fetus is 6 months old. This disruption
of the birth process increases the likelihood of premature labor, but serious
consequences can be avoided with early detection. NASA developed a compact telemetry
receiver and fetal implant to allow for home monitoring of these at-risk fetuses.
This procedure saves up to $1 million per child over conventional treatment,
boosts survival rates, and allows the mother to spend most of the remainder of
her pregnancy at home rather than in the hospital. NASA is currently developing
a pill-sized implant that will provide more sensitive early warning of fetal distress.
Fetal monitoring is just one example. These and the other monitoring technologies
that support NASA’s biological research help open a window on the inner workings
of life in space while reducing the costs and improving the effectiveness of health
care. Before long, the fetus floating in the womb and the astronaut floating in
space may have
something else in common–NASA–developed biosensor systems that monitor
their health and well-being.
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