Hubble is finally back online after a procedure involving the swap of the telescope's payload computer seems to have fixed the issue that has kept it on safety mode for weeks, a statement by NASA explains.
On Thursday, July 15, NASA announced it had begun a "risky" switchover procedure to backup spacecraft hardware on Hubble as part of its efforts to resolve an outage that had started on June 13.
Today, July 16, the US space agency announced that the backup payload computer was turned on, "loaded with flight software and brought up to normal operations mode."
Hubble's backup hardware does the trick
In its update prior to resuming normal operations mode, NASA announced that it had finally pinpointed what it believed to be the reason behind the outage — namely, that a secondary protection circuit was either faulty, or it was detecting an abnormally high voltage level from the telescope's Power Control Unit (PCU).
As NASA explained in its statement, the steps required to resume normal operations included "bringing online the backup Power Control Unit (PCU) and the backup Command Unit/Science Data Formatter (CU/SDF) on the other side of the Science Instrument and Command & Data Handling (SI C&DH) unit."
The Power Control Unit is tasked with relaying a steady voltage supply from Hubble's solar arrays to several of its onboard instruments, including the payload computer.
"The Hubble team is now monitoring the hardware to ensure that everything is working properly," NASA said in its statement. "The team has also started the process for recovering the science instruments out of their safe mode configuration."
31 years of historic observations... and counting
The Hubble outage began on June 13, when a problem with the orbital telescope's payload computer caused it to switch to safe mode in order to prevent any damage to its systems.
Since that time, astronomers and scientists worldwide have highlighted over 30 years of discoveries and observations made by the telescope, which was launched in 1990. Over those three decades, more than 1.5 million observations have led to the publishing of over 18,000 scientific papers on subjects ranging from dark energy to black holes and gamma-ray bursts.
Amid the celebration over the successful return to normal operations mode, it is worth noting that Hubble has faced several near-death moments in recent years, and it is inevitably coming to the end of its lifetime.
Still, unsurprisingly, the folks over at Hubble Mission Operations are thrilled to be back online. A report by ScienceMag, for example, highlights correspondence from Tom Brown, head of the Hubble mission office, and staff at the Space Telescope Science Institute:
"Hubble is back!" Brown wrote in an email at 5:56 am EDT. "I am excited to watch Hubble get back to exploring the universe."
In its statement, NASA said the Hubble team will check if the telescope's instruments are at stable temperatures before conducting an initial calibration and resuming normal science operations, likely sometime over the weekend.
This was a breaking story and was updated regularly as new information emerged.