Baku, October 24, AZERTAC
Nasa believes it has fixed a malfunction with the Hubble telescope which threatened to limit the orbiting observatory's performance, according to BBC.
Earlier this month, one of Hubble's gyros - needed to point the spacecraft - failed, forcing controllers to place the telescope in "safe mode" - where it operates with essential functions only.
This was required because a backup gyro also malfunctioned when switched on.
But after a series of tests, the backup appears to be working normally.
The telescope, launched in 1990, has been described as one of the most important scientific instruments ever created.
The failure of a another gyro, and the discovery that a backup was faulty left Hubble with only two fully functional gyros.
But this mode would probably have placed limitations on which part of the sky Hubble could observe at any one time. It might also have taken the telescope longer to move from observing one target to another.
Nasa said the malfunctioning backup gyro - which had been turned off for 7.5 years - had been showing "extremely high rotation rates".
In an attempt to correct the problem, the Hubble operations team performed a running restart of the gyro on 16 October.
This procedure turned the gyro off for one second, and then restarted it before the spinning wheel inside the gyro slowed down.
However, controllers saw no improvement.
Two days later, the operations team commanded the spacecraft to make a series of manoeuvres. This was designed to dislodge any blockages within the gyro itself.
It added: "Hubble then executed additional maneuvers to make sure that the gyro remained stable within operational limits as the spacecraft moved. The team saw no problems and continued to observe the gyro through the weekend to ensure that it remained stable."
The James Webb Space Telescope (JWST) is Hubble's designated successor, but it has experienced a series of delays and will not launch until 2021, at the earliest, NASA said.
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