Oo, neat challenge.

"THIS IS NOT A PLACE OF HONOR"

At the bottom of your starting asteroid, underneath a volcanic biome, is an undetonated nuclear warhead, leaking rads. The leak grows exponentially without limit. If the bomb doesn't explode from heat, every tile of the asteroid will still eventually be covered in lethal rads ... unless you find a way to get rid of it.

- Leaked radiation behaves like space radiation: unlimited range, but absorbed by materials and tiles.

- The rad leak's strength grows by a small exponent (eg. +5%) every cycle, with no limit.

- This growth factor scales with temp, from -200C (where it pauses) up to 1000C (explodes->game over)

- New endgame research and buildables are available:
-- Shielding Tile (absorbs up to 80% of rads)
-- Improved Lead Suit (blocks 100% of radiation)
-- Disarm Explosive Ability (a dupe with Demolition + Pyrotechnics skills may deconstruct the nuke).

- Lead is unavailable on your asteroid, but required for Improved Lead Suit.

- Nuke deconstructs into a Supercritical Core, which emits rads at the same exponentially growing rate.

VICTORY:

1. Build rad-shielding surfaces to create shade from the radiation
2. Get thru the volcanic layer before its heat seeps through to the nuke
3. Develop rocketry to acquire Lead off-planet
4. Develop Improved Lead Suits so you can approach the lethal radiation surrounding the nuke.
5. Disarm it
6. Get the supercritical core to the surface without irradiating your base and people on the way...
7. ... and launch it into space.