It’s been a rough few weeks for the Hubble Space Telescope. On October 5th one of the three functioning gyroscopes on board failed. The telescope began floating off-center and vital instruments were producing high readings. Following weeks of trouble-shooting and “test observations,” the Hubble is back up and running.
The gyroscope measures the telescope’s turning speed and helps it lock on to new targets. The recent problem arose when the gyro sent back readings that were too high. One NASA scientist described it like your vehicle’s speedometer showing a speed 100 mph faster than your actual speed. To protect the telescope during trouble shooting, NASA switched the telescope to “safe mode.” For the past three weeks no science operations or observations were completed.
Like anyone experiencing tech problems, engineers first tried turning the failing gyro off then back on again. Turns out that approach doesn’t work in space. The back-up gyroscopes were still sending back high readings. The engineers then tried performing spacecraft maneuvers, or turns, in the opposite direction in hopes of clearing any blockages. Essentially jiggling it a bit. This did the trick. Readings returned to normal. The Hubble remained stable during test operations.
NASA brought the Hubble Telescope back online late Friday night with three fully functioning gyroscopes. Normal science operations and the first observations of a distant galaxy were made soon after.
The telescope was launched into orbit in 1990, and last serviced in 2009. To further extend the live of the Hubble into the 2020s, observations may need to be run on only one gyroscope.
NASA’s latest space telescope is expected to be launched in 2021. The James Webb Space Telescope, also called Webb or JWST, will have optimized infrared wavelengths, which will complement and extend the discoveries of the Hubble Space Telescope. It will cover longer wavelengths of light than Hubble and have improved sensitivity, enabling the Webb to look further back in time to see the galaxies that formed in the early universe.