The US National Aeronautics and Space Administration (Nasa) successfully returned the renowned Hubble Space Telescope to operational status on Saturday. The telescope had been non-operational since June 13, when its payload computer had developed a problem.
“Hubble is an icon, giving us incredible insight into the cosmos over the past three decades,” highlighted Nasa administrator Bill Nelson. “I’m proud of the Hubble team, from current members to Hubble alumni who stepped in to lend their support and expertise. Thanks to their dedication and thoughtful work, Hubble will continue to build on its 31-year legacy, broadening our horizons with its view of the universe.”
When the payload computer malfunctioned, the telescope’s instruments entered a safe configuration and all science operations ceased. The Hubble team has been investigating the cause of the problem ever since.
On July 14 the Hubble team identified the possible cause of the computer failure. However, the problem continued and so it was decided to activate the space telescope’s backup hardware. This process was started on July 15.
Central to the functioning of the instrument is the Science Instrument and Command and Data Handling unit. This receives power from the Power Control Unit (PCU) and receives formatted data and commands from the Command Unit/Science Data Formatter (CU/SDF). The reactivation process involved bringing both the backup PCU and backup CU/SDF online. Further, other hardware units onboard the space telescope were switched to their alternate interfaces, to be able to connect to the backup PCU and CU/SDF. After these steps were completed, the backup payload computer was activated and then loaded with flight software, before being set to normal operations mode.
Hubble was launched in 1990 and has so far made 1.5-million observations of the universe. More than 18 000 scientific papers have been published using data from the instrument. Nasa expects the space telescope to now successfully operate for “many” years to come.