On Monday, October 8, NASA officials announced the Hubble Space Telescope had been put into protective “safe mode” over the weekend while engineers troubleshoot problems with one of the spacecraft’s three remaining gyroscopes.
Ken Sembach, director of the Space Telescope Science Institute at Johns Hopkins University in Baltimore said the gyroscopes are used to keep the space telescope locked on a target, and the Hubble team was optimistic the problem could be solved.
But NASA said Friday that Chandra automatically went into a so-called safe mode Wednesday, possibly because of a gyroscope problem. Chandra is one of NASA’s four Great Observatories, along with the Hubble Space Telescope, Compton Gamma Ray Observatory (1991–2000), and the Spitzer Space Telescope.
Each of the four missions was designed to examine a specific wavelength/energy region of the electromagnetic spectrum (gamma rays, X-rays, visible and ultraviolet light, infrared light) using very different technologies. Chandra was launched from the Space Shuttle Columbia during STS-93, on July 23, 1999. and has been returning data since the month after it launched.
And like the Hubble telescope, which is the ripe old age of 28, Chandra is 19 years old. Both Great Telescopes have far surpassed their prime – yet they have continued to operate flawlessly, sending back images that have amazed scientists and space-buffs, alike.
It is just a coincidence
NASA officials say it is a coincidence that the two space telescopes went “asleep” within a week of one another. Astronomer Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics, who works on Chandra Tweeted on Friday that “Chandra decided that if Hubble could have a little vacation, it wanted one, too.”
Chandra is equipped with six sophisticated, high-speed gyroscopes to help it move from target to target and to provide data needed to keep the telescope solidly locked on while its cameras and spectrometers collect data. However, it actually only needs three gyroscopes to operate.
Three of the gyros are older models that are known to have some problems after 50,000 hours of service. The other three are newer and there have been fewer problems with their operation. NASA engineers believe they could operate for several hundred thousand hours.
As for Hubble, it has been operating normally with two newer gyros and one older model. The third newer unit was being held in reserve.
“Three of them were on and one was off,” Sembach said. “One of the (older-design models) that was on has been acting kind of flaky for a year, and we’ve expected it to reach its end of life. And, in fact, that actually happened on Friday night. It finally gave up the ghost and failed. Everybody said OK, no big surprise, we’ve been expecting that for a year, let’s turn on the gyro that was off at the time to get back onto science operations.”
In any case, NASA is working on several options to get the Hubble back on track and resume its mission. Everyone agress there is still a lot of life left in the telescope.