text: Chandra Celebrates Five Years of Scientific Breakthroughs Marshall Space Flight Center -- On August 12, 1999, NASA's Chandra X-ray Observatory opened its sunshade doors for the first time, allowing celestial X-ray light to reach the observatory's mirrors. This one small step for the observatory proved to be a giant leap for science as Chandra began its mission to shed new light on a violent, mysterious universe invisible to the human eye...