25 June

1998: On 25 June 1998, during routine maintenance operations, ground controllers lost contact with the ESA/NASA SOHO spacecraft. The satellite went into Emergency Sun Re-acquisition (ESR) mode. The ESR mode is activated when an anomaly occurs and the spacecraft loses its orientation towards the Sun. When this happens, the spacecraft automatically tries to point itself towards the Sun again by firing its attitude control thrusters under the guidance of an on-board Sun sensor.

Scientists could not re-establish contact for six weeks during which time many thought the mission had been lost. After six weeks, a signal was received from SOHO and it is currently still operating.