Due to environmental and light damage, a four-phase restoration project began in May 1999. In the first phase, the team removed the linen support backing that was attached to the flag during the 1914 restoration. The second phase consisted of the most comprehensive, detailed examination of the condition and construction of the Star-Spangled Banner to date, which provided critical information for later work. This included scientific studies with infrared spectrometry, electron microscopy, mechanical testing, and determination of amino acid content by a New Zealand scientist, and infrared imaging by a NASA scientist. Planning and executing a cleaning treatment for the flag following scientific analysis was the third phase. In the fourth and final phase of the project, curators, scientists, and conservators developed a long-term preservation plan. The restoration was completed in 2008 at a total cost in excess of $21 million.