Editing RTT Worldgen (section)

===== Hard Times =====
In a Long Night scenario, worlds are cut off from galactic trade and forced to rely upon their own technology. Colonies on unsafe worlds which have less than the required minimum Industrial Base have to be abandoned; reduce Population to 0, leaving ruins behind. 
:Atmosphere 4, 7, or 9 requires Industry 3+ to maintain filter production or air purification. 
:Atmosphere 2 or 3 requires Industry 5+ to maintain respirator production.
:Atmosphere 0, 1, or A requires Industry 8+ to maintain the pressure habitats.
:Atmosphere B or D requires Industry 9+ to maintain high-pressure or corrosion-resistant habitats.
:Atmosphere C or G, or Hydrosphere F, requires Industry A+ to maintain deep-pressure or aerostat habitats.
Outposts on unsafe worlds ''might'' be maintained. If there's a colony or homeworld nearby, make a roll at ''their'' Jump level, and if successful, the outpost remains. Otherwise, it too must be abandoned.

If you want to get really complicated, than for any terraformed planet during Hard Times, ''reverse'' the terraforming effects by points equal to half the difference between the local Industrial Base and the old galactic Tech Level (e.g. if you were at TL12, and are now at TL8, you lose 4 points of terraforming).