IN THE MUSEUM...NASA Technology
Watches Over Historic Documents

The original United States Constitution, Declaration of Independence, and Bill of Rights are stored at the National Archives in Washington, DC. Even though they are kept in helium-filled glass cases, the documents can still be damaged by light, vibration or humidity. The parchment may stretch or split, and ink may fade, flake or wear off.

In 1982, the National Archives asked NASA's Jet Propulsion Laboratory (JPL) to develop a method for determining the condition of these precious documents. JPL studied ideas based on imaging technology used in spacecraft such as the Galileo probe and the Hubble Space Telescope.

JPL asked the Perkin-Elmer Corporation, the prime contractor on the Hubble Space Telescope, to develop the imaging device. The resulting Charters of Freedom Monitoring System scans the documents at certain times, then compares the differences between the images. The system detects changes in contrast, shape and other features. This allows workers at the National Archives to plan a way to stop the damage.

The letter R shown above is from the US Constitution (the colors are computer-generated). The blue specks in the R show signs of flaking ink.

Our Founding Fathers would be glad to know that their history-making documents are still receiving such good care!