Praiseworthy's mother
From Tardis Wiki, the free Doctor Who reference
Praiseworthy's mother was part of the set-up team who were awoken from stasis before the rest of the colonists to ensure the city was working properly. However, she was killed with the rest of her team when she showed grief over the deaths of her friends and colleagues. Her bones were turned into fertiliser.
The Twelfth Doctor later discovered a pendant she kept with a hologram of Praiseworthy in it and deduced he was her son. (TV: Smile)
Behind the scenes
In a deleted scene, Praiseworthy's mother is shown to be Goodthing.