Orllensa

 was the Commander of the Cimmeria IV mining base. She and her fellow workers Haliard and Ferras were responsible for setting up and activating a series of mini-suns placed in orbit around Cimmeria IV, in preparation for planetary mining.

On activating the EPU array to power the suns, an unknown force threw the system out of alignment. Orllensa had just enough time to send a distress call before the base was plunged into blackness. That same unknown force then burned out the eyes of everyone on the base.

Soon after, the Eighth Doctor and Charley arrived in the company of ROSM -- a rescue ship. Sensing that there were aliens at work, ROSM  assaulted them, but the same particles that blacked out the base disabled ROSM as well. The Doctor worked with Orllensa and the others to realign and activate the EPUs to bring light back.

The Doctor got the array working just as the aliens revealed themselves to be Cimmerian healers who were removing the light to hide from their persecutors, the Solarians. They regretted the misunderstanding and healed Orllensa and the others, restoring their vision. (BFA: Embrace the Darkness)