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Contact:
Laura
Ost, (301) 975-4034
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Space
NIST Assists
NASA in Columbia Accident Investigation
The
National Institute of Standards and Technology (NIST) has provided
significant assistance to the National Aeronautics and Space
Administration (NASA) in its investigation of the space shuttle
Columbia disaster on Feb. 1, 2003. NASA has drawn upon NIST’s
expertise in cold temperature research for data on the properties
of liquid and solid nitrogen and for measurements of thermal
conductivity in foam insulation.
According to NASA, one theory for the disaster is that pieces
of foam insulation broke off from the shuttle’s external tank
shortly after liftoff and struck the leading edge of the Columbia’s
left wing. This may have caused a failure in the insulation on
the wing, which proved disastrous upon re-entry. According to the
theory, liquid and solid nitrogen between the foam and the tank
wall may have contributed to the breaking away of the foam from
the fuel tank.
NIST was able to supply immediately the properties of liquid
nitrogen from its cryogenic database, and it provided NASA
with properties
data on solid nitrogen from 20 Kelvin up to its melting temperature
of 63 Kelvin after a search of relevant cryogenics research papers.
NIST also helped NASA repair and calibrate an instrument for
measuring the thermal conductivity of the foam at extremely
cold temperatures,
a critical part of the accident investigation tests. The unique
instrument—a very low temperature guarded hot plate—was
developed at NIST and later transferred to NASA’s Marshall
Space Flight Center in Huntsville, Ala.
First Responders
A New
Wireless Network for Emergency Communications
First
responders would like to be able to send messages simultaneously
to all the emergency workers at the scene of a disaster if necessary,
but lack of interoperability among various types of radio equipment
prevents them from doing so today. In the future, first responders
converging on a disaster scene may be able to quickly and easily
exchange emergency messages and data using a wireless ad hoc
network recently developed and tested by scientists and engineers
at the National Institute of Standards and Technology (NIST).
NIST’s work in this area is part of the federal government’s
efforts to improve first responder communications in light of
the September 11 terrorist attacks.
The
network consists of personal digital assistants (PDAs) equipped
with wireless local area network (WLAN) cards.
Transmission routes
among the PDAs are established automatically and without need for
networking infrastructure at the emergency site as the first responders
arrive on the scene. The network may use any nearby PDA to relay
messages to others at the scene and allows transmission of voice,
text, video and sensor data. If a
worker leaves the disaster scene or a device is destroyed, the
network automatically reorganizes itself.
Small video screens can display the names of workers and their
roles. In buildings equipped with radios at reference locations,
the network
would determine the locations of first responders and track their
movements. The devices also could receive information from smoke,
heat or vibration sensors embedded in smart buildings that could
be transmitted by wireless sensor networks or distributed by
first responders during emergencies.
Security
Novel Spectroscopic
Method Can Detect Terrorist Threats
A novel
technique that uses far-infrared (terahertz ) radiation to rapidly
identify bulk or airborne materials inside sealed paper or plastic
containers
has been demonstrated by scientists at the National Institute
of Standards and Technology (NIST) and SPARTA Inc., of Rosslyn,
Va. Described at a recent technical conference,* the technology
has potential applications in homeland security such as detection
of explosives in the mail or other non-metallic portable containers.
The method involves directing a far-infrared light source at
a sample in a closed container, detecting the light transmitted
through the materials, and then analyzing
the light that was absorbed by the sample while making adjustments for the
light absorbed by the container. Far-infrared radiation,
which falls between visible
light and radio waves on the electromagnetic spectrum, is partially transmitted
through many materials. The pattern of light frequencies or spectra absorbed
by a material depends specifically on the vibrations of the material’s
atoms and its crystalline structure.
This method can readily identify compounds made of molecules containing
three to hundreds of atoms, the size of many threat materials. The
two instruments employed, one using a pulsed laser and the other
a glowing filament, are tabletop-sized and work at room temperature.
Two years of experiments have demonstrated that the technique detects
aerosols (such as those that might contain anthrax spores), pharmaceutical
powders, most gases, several explosives and other common materials.
The researchers have compiled a database of spectral characteristics
for more than 100 materials and developed an automated software tool
for rapidly identifying bulk materials based on their absorption
spectra. Further research aims to increase the sensitivity and throughput
speed of the technology.
*Campbell, M.B. and Heilweil, E.J., “Non-invasive detection
of weapons of mass destruction using THz radiation,” in Proceedings
of SPIE Vol. 5070 Terahertz for Military and Security Applications,
edited by R. Jennifer Hwu, Dwight Woolard, (SPIE, Bellingham, WA,
2003) in press.
