SOHO in safe mode
28 November 1999Over the Thanksgiving weekend the joint ESA/NASA SOHO recovery team stepped into action once again when the SOHO spacecraft switched to Emergency Sun Reacquisition mode(ESR) on Sunday 28 November. ESR is the safe mode that is automatically triggered to protect the spacecraft in the event of any unforeseen circumstance.
On Sunday 28 November the computer that controls the spacecraft's Attitude Control Unit A (ACU) reset for an undetermined reason. Normal recovery procedures were initiated and control of the spacecraft was quickly reestablished. The spacecraft is expected to return to normal science observations in time for the fourth anniversary of SOHO's launch on 2 December.