HOUSTON – NASA’s Chandra X-ray Observatory, launched 15 years ago this week, appears fit for another decade or more of observations, characterizing black holes and other high-energy cosmic phenomena from its elliptical orbit around the Earth.

Tucked in the payload bay of the shuttle Columbia, Chandra arrived in space on July 23, 1999. Columbia’s five astronauts deployed the 45-ft.-long observatory and its twin solid-rocket boosters within 9 hr. Subsequent burns of the SRBs guided the big telescope into its desired orbit with an apogee of 87,000 mi. and a perigee of 6,200 mi., for a science mission that was estimated to last at least five years.

"Now that Chandra has reached its 15th birthday, the Northrop Grumman engineering team has analyzed the performance of all of the critical subsystems and sees no ‘showstoppers’ to at least another 10 years of high-quality performance for Chandra," notes Harvey Tananbaum, who stepped down as director of the Chandra X-Ray Center (CXC) in Cambridge, Massachusetts, earlier this year. "This is rather amazing given that Chandra’s high Earth orbit does not allow access for servicing/repairs/upgrades," he wrote in a July 21 blog post.

The concept for the X-ray telescope project, managed by NASA’s Marshall Space Flight Center, dates back to 1976. The unusual orbit, with its 64-hr. period, permits continuous observing periods exceeding 50 hr.

Astronomers have used Chandra to study distant quasars and supernova remnants, and to chart the discovery of black holes across the universe, including Sagittarius A – the supermassive black hole at the center of the Milky Way – and the jet of high energy particles streaming from it.

"We are thrilled at how well Chandra continues to perform," Belinda Wilkes, the current CXC director, noted July 22. "We are looking forward to more groundbreaking science over the next decade and beyond."

The X-ray telescope, named for the Nobel prize-winning astrophysicist Subrahmanyan Chandrasekhar, is one of four NASA "Great Observatories." The others are the Hubble Space Telescope, which was launched in 1990 and continues to operate; the Compton Gamma Ray Observatory, which was launched in 1991 and de-orbited in 2000; and the Spitzer Space Telescope, which was launched in 2003 and continues to operate. NASA’s $8.8 billion James Webb Space Telescope, undergoing preparations for an October 2018 launch, will replace Hubble and Spitzer.