NASA is taking additional steps to investigate the Hubble Space Telescope’s payload computer issue that began on June 13, suspending science observations. In parallel with the investigation, NASA is preparing and testing procedures to turn on backup hardware onboard the spacecraft. The telescope itself and science instruments remain healthy and in a safe configuration.
The source of the computer problem lies in the Science Instrument Command and Data Handling (SI C&DH) unit, where the payload computer resides. A few hardware pieces on the SI C&DH could be the culprit(s).
The team is currently scrutinizing the Command Unit/Science Data Formatter (CU/SDF), which sends and formats commands and data. They are also looking at a power regulator within the Power Control Unit, which is designed to ensure a steady voltage supply to the payload computer’s hardware. If one of these systems is determined to be the likely cause, the team must complete a more complicated operations procedure to switch to the backup units. This procedure would be more complex and riskier than those the team executed last week, which involved switching to the backup payload computer hardware and memory modules. To switch to the backup CU/SDF or power regulator, several other hardware boxes on the spacecraft must also be switched due to the way they are connected to the SI C&DH unit.
Over the next week or so, the team will review and update all of the operations procedures, commands, and other related items necessary to perform the switch to backup hardware. They will then test their execution against a high-fidelity simulator.
The team performed a similar switch in 2008, which allowed Hubble to continue normal science operations after a CU/SDF module failed. A servicing mission in 2009 then replaced the entire SI C&DH unit, including the faulty CU/SDF module, with the SI C&DH unit currently in use.
Since that servicing mission, Hubble has taken over 600,000 additional observations to exceed 1.5 million during its lifetime. Those observations continue to change our understanding of the universe.
Launched in 1990, Hubble has been observing the universe for over 31 years. It has contributed to some of the most significant discoveries of our cosmos, including the accelerating expansion of the universe, the evolution of galaxies over time, and the first atmospheric studies of planets beyond our solar system.