system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do spacecraft and satellite components need to be assembled in a sterile environment?
gpt
Most satellite components are not. Spacecraft that are likely to land on other planets are clean ed thoroughly to minimize the transfer of life to other bodies. 

In space with no atmospheric even oils from your skin can boil and condense to ruin lenses and other electronics equipment. Foreign object debris are one of the largest killers of satellites and to minimize this satellites are often assembled in clean rooms.