Ptolemy's moon, Patience is a lifeless ball of silicates. A thin atmosphere clings desperately to the moon, and it is theorised that before the coming of man, the moon may have been capable of supporting life. The sole structure on Patience's surface is the Adeptus Mechanicus research facility designated Sigma Beta CLIV. The facility is located at the base of the long extinct volcano Adra Primaris and tunnels deep into the mountainside. What the Magi are digging for, none on the outside know, but the presence of three frigate-sized vessels in orbit around Patience show that they care deeply about their discovery and wish its secrets kept.