The European Space Agency (ESA) and NASA spacecraft, the Solar and Heliospheric Observatory (SOHO), has been lost in its deep space orbit after operating since December 1995.
The spacecraft went into an emergency sun reacquisition mode on 25 June. This is activated when orientation to the sun is lost after an anomaly. Efforts to re-establish contact failed.
SOHO successfully completed its nominal two-year mission observing the sun's atmosphere, surface and interior.
Source: Flight International