Astraea

Astraea, located in the Sol Asteroid Belt, is home of the Astraea Maximum Security Prison, a prison asteroid of the Sol System Police Force famous for having had no successful escapes to date.
First discovered in 1845 AD, Astraea was designated as a S-type asteroid. Upon the establishment of the Sol System Police Force, a high-security prison was needed to house dangerous criminals. Astraea, having no appreciable resources worth mining was determined to be exactly what was required.