(5x24) Pantheon Synthesis: Part 2, Episode 3
As the 20th century wore on, mortal technology began developing to the point that it threatened to expose the Pantheon's extraterrestrial operations, even hidden on the far side of the moon. The Cold War between the United Nations and the international communists spurred a space race that threatened to soon have mortals walking on the moon, and well before that, to have trans-Lunar vehicles capable of photographing the Foundation's mothership on the surface of the moon.
As the first such trans-Lunar mortal space mission began preparations, the Pantheon desperately relocated their mothership further out into the solar system, hiding it for the time being in the asteroid belt between Mars and Jupiter. The underground facilities they had build into the Lunar surface remained as a temporary base of operations for ongoing Foundation activities, but the presence of the Foundation on Earth was necessarily scaled back over time due to the increased difficulty.
As mortal civilization truly entered its space age, debate again began among the Pantheon over whether or not to just reveal themselves to mortal humanity. Some considered space-faring a threshold beyond which maintaining anthropological distance was pointless. Others countered that even the Pantheon themselved had not reached equality with the Ehrban who had created them, and it wouldn't be at least until humanity developed interstellar travel that it could be said that they had graduated from objects of study to peers on the galactic scene. In the end, the Pantheon resolved to continue hiding themselves from mortal humanity, scaling back their operations on Earth as much as possible while continuing to prevent a nuclear holocaust, as the Pantheon slowly relocated their base of operations further out into the solar system, to the Jovian system.