Hubble Space Telescope: US space agency NASA last Thursday began the process to fix a technical glitch in the Hubble Space Telescope, which has not been able to be used for work related to science for over a month. According to a report in IE, the glitch has been called the most serious issue that the Hubble Space Telescope has faced in a decade, and due to this malfunction, the observatory was working in the “safe mode”. After a computer onboard the Hubble halted on June 13, the telescope’s safe mode was activated, meaning that all non-essential systems were shut down. This had rendered NASA unable to use the Hubble Space Telescope for any astronomy observations.
The report added that if NASA were able to carry out the repair work successfully, it would take a few days for the telescope to return to normal and function properly. The Hubble is significant to NASA, as the telescope which has been scouring space for over three decades now and has often been described to be the most important scientific tool to have been built. Since being launched in 1990, Hubble has sent out over 15 lakh observations.
Hubble entered safe mode when its payload computer controlling and coordinating the science instruments onboard suffered a problem. Following this, the ground team coordinating Hubble spent a month running tests and analyses to find out the issue, which was found to be likely present in the Power Control Unit (PCU). The PCU is supposed to ensure that the payload computer’s hardware gets a steady supply of voltage.
Last week, NASA explained in a statement that the payload computer and its memory received a constant five volts of energy from a power regulator in the PCU. The space agency added that this power regulator also had a secondary circuit which told the computer to cease operations in case of the voltage fluctuating to levels below the allowable levels or exceeding them. The analysis of the Hubble ground team has suggested that either the voltage being provided by the regulator has gone outside of the acceptable levels or gradual degradation of the secondary protection circuit has caused it to be stuck in this state.
NASA tried to restart the PCU, but its attempt failed, and therefore, the agency decided to switch the PCU aboard the Science Instrument Command and Data Handling (SI C&DH) unit of the telescope, transferring the operations to the backup PCU. The process began on July 15, and the agency expected the process to take a few days, but the telescope was able to switch to the backup the next day itself. This allowed NASA to return Hubble to science operations on July 17 itself.
While the stopping of the Hubble was a major concern, the switch to backup PCU has given hopes that the telescope would continue to function for a long time, since it has greatly contributed to a better understanding of outer space by providing clear pictures.