The space agency revealed on Friday that an investigation into the incident is now underway, though it added data analysis indicated the safe mode transition to be "normal behaviour".
NASA announced on Monday it traced the cause to a gyroscope glitch that generated "a three-second period of bad data that in turn led the onboard computer to calculate an incorrect value for the spacecraft momentum".
Barely a week after NASA's Hubble Space Telescope entered safe mode, the Chandra mission has also suffered a glitch possibly due to the failure of the gyroscope, the USA space agency said. The observatory spies on objects that include black holes, galaxies, supernovas, high-temperature gases, and quasars throughout the x-ray portion of the electromagnetic spectrum to help us better understand the universe. It is normal behavior for the spacecraft to enter safe mode when it is experiencing a hardware or software failure or glitch.
Since the spacecraft was launched in 1999, it has been closely monitoring and X-raying our universe.
A set of high-tech mirrors make Chandra sensitive to X-ray sources 100 times fainter than previous instruments of its kind.
NASA refers to the spacecraft as "incredible" and describes it as "the worlds [sic] most powerful X-ray telescope".
Meanwhile, the USA space agency said that it continues to work towards resuming science operations of the Hubble Space Telescope. The spacecraft went into safe mode because another one of its six gyroscopes failed. Notably, Chandra and Hubble observatories both are a part of the space agency's Great Observatories Program, in which four space shuttles were launched in the 1990s. NASA said the issue could involve a failed gyroscope.
An anomaly review board was formed to find the cause of these issues and try to fix them.
Just before 10 a.m. EDT on October 10, the telescope automatically entered a safe configuration, swapping critical hardware to back-up units and changing direction for optimal solar panel charging. "All systems functioned as expected and the scientific instruments are safe", it added.
Grant Tremblay, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, tweeted that there is a "clear pathway to recovery" for Chandra.