Aerodyne Research, Inc.
Charters of Freedom

 

Aerodyne Research Selected To Help Preserve

Nation's Historical Documents

December 10, 1999

Aerodyne Research, Inc., located in Billerica, Massachusetts, has been selected by the U.S. National Archives and Records Administration (NARA) to provide environmental monitoring equipment for the newly designed enclosures which house our Nation's "Charters of Freedom". These documents, comprising the original Declaration of Independence, Constitution and Bill of Rights, are on display in Washington, D.C.. Aerodyne Research will provide a single, non-invasive optical sensor that can monitor both the humidity and the presence of trace amounts of oxygen within the sealed enclosures. NARA, in collaboration with the National Institute of Standards and Technology, is in the midst of a major project to replace the deteriorating 50-year-old display enclosures now in use. As part of this project, the Rotunda of the National Archives building will be renovated so that all four pages of the Constitution can be displayed simultaneously, something that is not now possible.

The existing encasements are being replaced with state-of-the art enclosures that ensure that the documents continue to be displayed at a controlled humidity and in an oxygen-free environment. The Aerodyne Research sensor will measure both humidity (water vapor) and any significant infiltration of atmospheric oxygen using an optical absorption technique that does not require physical intrusion into the document enclosure. The enclosures are being built with specially designed internal optical components to accommodate the measurement technique. NARA considers the Aerodyne monitoring equipment to be a significant contribution to the enclosure project because it allows NARA conservators, for the first time, to monitor both the integrity of the encasement seals and the enclosure humidity on a regular basis.

In the Aerodyne instrument, water vapor (H₂O) and molecular oxygen (O₂) are monitored using a differential absorption technique that relies on the fact that both species absorb light at certain wavelengths in the near infrared region of the electromagnetic spectrum. Emission lines from a compact discharge lamp are magnetically (Zeeman) tuned so that they coincide with absorption features of the water vapor and oxygen molecules. The sensor first measures the amount of light transmitted through the oxygen and water vapor in the enclosures with these particular lines. Using a polarization filter, the sensor then switches to a second set of lamp emission lines that are close to the first set of lines in wavelength, but which are not absorbed by the oxygen and water vapor. The difference in transmitted light intensity is proportional to the concentration of ambient water vapor and oxygen.

The technology used in this sensor was developed in part with funding from the U.S. Department of Energy and the Office of Naval Research under their Small Business Innovation Research (SBIR) programs. It is covered under two U.S. Patents awarded to Dr. Paul Kebabian and assigned to Aerodyne Research. The company has also received a SBIR award from the National Aeronautics and Space Administration to develop a version of this instrument for use as an air quality monitor on Space Station Freedom.

Aerodyne Research, Inc. is a research and development organization engaged in developing and producing new instrumentation for a wide range of environmental monitoring and remote sensing applications. It currently produces state-of-the-art trace gas sensors that are used to monitor effluents from gas turbines and aircraft engines, remotely sense pollutant emissions from individual motor vehicles moving at highway speeds, and control industrial processes. Its instruments have also been used to detect airborne gases emanating from oil and gas deposits and to measure greenhouse gas emissions from natural and perturbed environments such as marshes, peat bogs and landfills.

For Further Details, Contact:

Dr. Charles E. Kolb, President
Aerodyne Research, Inc.
45 Manning Road, Billerica, MA 01821
(978) 663-9500 ext. 290 ; Fax: (978) 663-4918

email: kolb@aerodyne.com
 
For Further Information on the Charters of Freedom Restoration Project,

please see:

National Archives Public Affairs press release

or contact:

The National Archives Public Affairs staff at (301) 713-6000  

Aerodyne Research, Inc.  45 Manning Road Billerica, MA  01821-3976  978 663-9500