When a satellite is in the space, then possibilities to detect and fix software problems working on its board is very limited. Narrow communication windows, low transfer’s bandwidth and limited numbers of software tools...
Software in space, Space radiation and fault tolerant systems for spacecrafts
NASA's Chandra X-ray Observatory suffers camera glitch, stalling science https://www.space.com/chandra-xray-space-telescope-camera-power-problem
New Sun Missions to Help NASA Better Understand Earth-Sun Environment https://www.spacedaily.com/reports/New_Sun_Missions_to_Help_NASA_Better_Understand_Earth_Sun_Environment_999.html