“It took awhile to come up with the exhibition design,” she says. “We were trying to balance the preservation needs of the artifact [with our desire] to create the opportunity for people to feel like they had a very personal experience with the flag.”

That flag, which was created by Mary Pickersgill during the War of 1812 at the behest of Major George Armistead, is the centerpiece of the Smithsonian’s dramatically redesigned National Museum of American History, which reopened in November 2008 after two years’ and $85 million worth of renovation. The National Museum of American History has long been known as America’s Attic for its collection of more than three million historically significant pieces, including the desk Thomas Jefferson wrote the Declaration of Independence on and the ruby slippers Judy Garland wore in The Wizard of Oz.

The museum acquired the famous Star- Spangled Banner in 1907 from New York stockbroker Eben Appleton, the grandson of Major Armistead. For years, it was mounted on a frame on the wall of the museum’s central Flag Hall, where it was protected by a screen (called an oleo) that was lowered every hour, revealing the flag as the national anthem played. Once the song concluded, the oleo would be raised again, covering the flag. But when a mechanical failure rendered the oleo temporarily inoperable in 1994, museum conservators decided that rather than simply repair the system, they would explore other preservation possibilities. The museum hosted a conference with 50 conservators, flag historians, scientists, and curators, and they developed a conservation plan for the artifact that would use the most advanced technologies available.

In December 1998, the plan was put under way. First, Thomassen-Krauss oversaw the removal of the flag from its longtime home and its transfer to the temporary 40-by-50-foot laboratory in the museum where it would be studied. The lab was equipped with an environmental-control system that kept the temperature between 68 and 70 degrees Fahrenheit and the humidity level at 50 percent, since mold can form at humidity levels higher than 60 percent and fibers get brittle at levels lower than 50 percent. After careful examination, Thomassen-Krauss and her team determined that the flag would never be able to fly again; it was simply too fragile. The lab featured a glass wall, which gave visitors the opportunity to watch the conservation work in progress and weigh in on the matter. “People told us they didn’t mind that the flag looked old and damaged. They expected it to,” Thomassen-Krauss says. “That helped us with the idea of not restoring it but preserving and conserving it.”

The next step was to stabilize the cloth. For six hours a day over the span of 10 months, conservators snipped away approximately 1.7 million stitches that held the worn, fragmented flag to a linen backing, which had been sewn on by Amelia Fowler in 1914 during the Smithsonian’s first major flag-preservation effort. It took another eight months to then turn the flag over and painstakingly pull the clipped stitches and soiled linen from it. As the team worked, they discovered 37 patches that had been used to repair pieces of the flag that had likely been torn away in high winds. “Flags have a hard life. Damage happens relatively quickly,” says Thomassen-Krauss, who notes that when the Smithsonian acquired the flag in 1907, it had already been worn down from its original size of 30-by-42 feet to 30-by-34 feet. Conservators left all of the patches in place, but more than 60 repairs and mendings were removed to relieve stress on the brittle fabric and restore the flag’s shape.