We return to talk about the Hubble Space Telescope which from 13 June can no longer operate normally due to a serious problem. Fortunately all scientific instruments have not been damaged and have been placed in a safe configuration, but this is not enough.
The engineers of the NASA have been trying for over a month to find the cause of the HST (Hubble Space Telescope) problem and fix it. More solutions “simple” how to restart the on-board computers had no effect and therefore the investigations had to investigate the causes of the problem. Now, perhaps, there is a possible answer.
The Hubble Space Telescope Problem
As previously written, after excluding some of the subsystems, the engineers of the US space agency focused on the Science Instrument Command and Data Handling unit, also called SI C&DH.
Over the weeks a series of tests were performed which, while not leading to a direct solution, have localized the problem in thepower control unit (which has the acronym of PCU). Over the past few days there had already been more than one clue pointing to this section, but now there are further confirmations.
The PCU is always inside theSI C&DH and allows to supply a constant power supply to the hardware of a part of the space telescope. It is therefore an essential component for the stable operation of the HST. According to reports, the PCU has a voltage regulator that delivers 5V to the computer and its memory.
Then there are control systems that allow you to avoid overvoltages or undervoltages that could damage the circuits. It seems that the PCU is supplying an inadequate voltage to the systems thus tripping the lockout which then caused the problem to the Hubble Space Telescope. A second hypothesis points his finger right in the direction of the control system which may have failed and is no longer able to return to the default configuration.
The engineers of the NASA they cannot restore the PCU with remote controls. Nor are recovery operations currently possible directly in orbit since the Space Shuttle program is no longer available (and there is currently no replacement).
For this reason it was decided to switch to the backup of theSI C&DH unit (which has a PCU inside). These days the engineers have tested the procedures which have been validated in two phases on 12 and 13 July. Today, however, the backup although it will take a few days for the HST to work again. All that remains is to wait to know the outcome of the restore operations.