This last week has been a rough one for space news, to say the least. The iconic Hubble Space Telescope has been placed in safe mode following a hardware failure, and a Soyuz booster failure resulted caused NASA Nick Hague and cosmonaut Aleksey Ovchinin to abort their trip to the International Space Station. Now, a second NASA satellite is offline following a hardware failure. The Chandra X-ray Observatory shut down on Oct. 10, and NASA is still assessing the situation to determine how it can get the satellite operational again.
Both Hubble and Chandra are part of NASA’s Great Observatories program, which originally included four orbital instruments. Hubble is the most famous because it focused mainly on visible light, and those images are best for public consumption. The Compton Gamma Ray Observatory launched in 1991 just a year after Hubble to study gamma rays, but it failed in 2000. The Spitzer Space Telescope launched in 2003 to scan space in the infrared, and it’s still operational. The Chandra X-ray Observatory went up aboard the Space Shuttle Columbia in 1999 and has been investigating distant X-ray sources ever since.
Chandra doesn’t get as much attention as Hubble, but it’s a vitally important scientific instrument. Earth’s atmosphere absorbs X-rays very efficiently, so ground-based observatories aren’t an effective way to study them. From space, Chandra uses a series of angled mirrors to concentrate X-rays on its detection instruments to detect signals 100 times more faint than past X-ray telescopes.
According to NASA, Chandra entered safe mode in the early morning on Oct. 10. NASA is still looking into the cause, but the team currently believes one of the spacecraft’s gyroscopes has failed. If that sounds familiar, that’s also what happened to Hubble last week. You may also be interested to know that gyroscope failure is also what eventually took down the Compton Gamma Ray Observatory back in 2000. These devices used angular momentum to track movement, so they’re constantly spinning. Eventually, every gyro will fail. Hubble has only lasted this long because it has been serviced several times to get new gyroscopes installed.
Chandra has four pairs of gyroscopes inside, so it’s possible NASA will have enough functional hardware to get it fully functional again. It’s unclear if Hubble will have enough working gyros to operate at full capacity going forward. Even if Chandra doesn’t come back at full strength, it’s had a good run. It’s 19 years old and had an original operational life of 5 years. NASA says it expects Chandra to continue working for “many years to come.”