|A. St. John D. Caldera|
|Main actor:||Derek Pollitt|
|Main voice actor:||Barnaby Edwards|
However, Caldera's mind lived on in the Sphere. After the Doctor defeated Skagra, he took the Sphere to Drornid, where he had the minds of Caldera and the other victims of the Sphere transplanted into new bodies. (PROSE: Shada)
- Caldera was addressed as 'Professor' by Skagra. (WC: Shada, AUDIO: Shada)
- In the novelisation, Caldera becomes a woman, Daphne Caldera. Her speciality is 6-dimensional wave equations, instead of neurology. (PROSE: Shada)
- A caldera is a sunken area left behind by a volcanic eruption. The names of Caldera and the other Think Tank scientists are all derived from locations or geographical features associated with the volcanic Greek island Santorini.