The Chandra X-ray Observatory

The Chandra X-ray Observatory, one of NASA’s suite of Great Observatories, was launched in July 1999 on the shuttle Columbia. Its unique sub-arcsecond seeing, comparable for the first time with ground-based telescopes, low background, broad (0.3–10 keV) energy range, and high spectral and timing resolution have revolutionized X-ray astronomy and astronomy as a whole. Chandra provides detailed views of complex structures; deep, unconfused surveys; spectra of otherwise inaccessible lines; and light curves of transient and variable sources. Chandra science expands to include newly discovered kinds of sources, such as merging neutron stars, and collaborations with new facilities, e.g., the Event Horizon Telescope and James Webb Space Telescope. Chandra’s impact on science, the community, and the public continues to be high in its 23rd year of operation. In this chapter, we summarize Chandra’s development, hardware, instrumentation, capabilities, operation, science support, and impact on astronomy and worldwide.