Rock Hermits are members of a space faring race which have decided to live a life of isolation inside a hollowed out asteroid. They may be retired traders or military personal or simply average citizens who wish to live a reclusive life.
The Rock Hermit's life is not entirely without danger. In Elite, they are at risk of being mistakenly targeted by asteroid miners, although a hollowed-out asteroid only provides few minerals and any sensible Rock Hermit will attach a beacon to notify of their presence.
Rock Hermits will have a ship, often a Krait as a means of escape and resupply.
Note On Other Versions of Elite
Rock Hermits appear in many other versions of Elite, and in some they release ships if fired upon (such as Spectrum Elite), while in Archimedes Elite they can be 'mined' (without releasing mineral fragments) for a value of 2₢ - however, this does earn you a black mark on your legal status, and as such is frowned upon by the police.