Tantalus V

Tantalus V was the inhabited ringed fifth planet of its star system. In 2266, this was the home of Tantalus Penal Colony, a Federation rehabilitation colony.

That same year, the USS Enterprise (NCC-1701) delivered supplies, including infra-sensory drugs, to this planet. 

Background information
According to the, Tantalus V was "named for who stole ambrosia from the tables of the gods, feeding it to mortals."

In the script of "Dagger of the Mind", Tantalus V was described as "a planet almost featureless except for the ravages caused by its extreme climateric." Also, the planet's landscape was described as "eerie".

In the original aired version of "Dagger of the Mind", the surface of Tantalus V was represented with a reused matte painting of Delta Vega, from.

For the remastered edition of "Dagger of the Mind", Tantalus V was depicted with newly created computer-generated shots which added the planet's ring system. The digital footage also completely replaced the matte painting representing the planet's surface. The footage of the planet was co-created by Max Gabl, who commented, "I only did the planet, the rings were added later. I remember putting them into the surface painting though."