On July 23, 1999, NASA's Chandra X-ray Observatory was launched aboard the space shuttle Columbia and deployed into orbit. With Chandra, the most powerful x-ray telescope ever built, scientists can explore the exotic realm of super-hot, high-energy x-ray sources, including exploding stars and black holes. In 20 years of operation, the Chandra X-ray Observatory has had a widespread, transformative impact on 21st century astrophysics. Headquartered in Cambridge, Massachusetts, the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists study the origin, evolution and ultimate fate of the universe. Space features extraordinary images from Chandra, along with informative text. This twelve month wall calendar has spacious grids, international holidays and moon phases. There are sections at the back of the calendar for emergency contact information and birthdays/anniversaries and a full-page 3-year at-a-glance. Earth friendly, printed with soya-based inks on FSC certified paper.