Norad ID: 25867
| Spacetrack Directory Name | CXO |
| Follow CXO | CXO Tracker |
| Pass predictions CXO | Pass predictions CXO |
| Orbit launches |
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| Days in orbit | 9788 |
| Country/organisation of origin | USA (US) |
| Starting point | AFETR (Kennedy Space Center/Cape Canaveral, USA) |
| Categories | |
| Perigee | 4601 km |
| Apogee | 144216 km |
| Orbit slope (inclination) | 55.59° |
| Laps per day | 0 |
| Orbit | Elliptical (Deep Highly Eccentric) |
| Height CXO | 101556.92 km |
The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched aboard the space shuttle Columbia during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources 100 times fainter than any previous X-ray telescope, enabled by the high angular resolution of its mirrors. Since the Earth's atmosphere absorbs the vast majority of X-rays, they are not detectable from Earth-based telescopes; therefore space-based telescopes are required to make these observations. Chandra is an Earth satellite in a 64-hour orbit, and its mission is ongoing as of 2019.
Chandra is one of the Great Observatories, along with the Hubble Space Telescope, Compton Gamma Ray Observatory (1991-2000), and the Spitzer Space Telescope. The telescope is named after the Nobel Prize-winning Indian-American astrophysicist Subrahmanyan Chandrasekhar. Its mission is similar to that of ESA's XMM-Newton spacecraft, also launched in 1999 but the two telescopes have different design foci; Chandra has much higher angular resolution.