The Chandra X-ray Observatory is the X-ray mission of NASA’s four Great Observatories in space. It was launched on July 23,1999, aboard the space shuttle Columbia. It orbits Earth on a highly elliptical trajectory, coming as close as 6,200 miles (10,000 kilometers) and going as far as 87,000 miles (140,000 kilometers) from Earth’s surface. Although challenging to operate as a result, this extreme orbit allows scientists to make observations of many different kinds that would not be possible at only one orbital altitude. Chandra obtains X-ray images of astronomical objects with much greater resolution than any other X-ray telescope ever flown; thus, it has returned detailed images of complex, highly energetic astronomical systems, such as supernova remnants, supermassive black hole systems (including Sagittarius A*, the one at the center of our Milky Way galaxy), shock waves from exploding stars, the X-ray shadow of Saturn’s moon Titan, and multi-million-degree gas in dense clusters of galaxies.