I started the game with high intelligence so I thought I'd have to do another playthough to unlock this achievement.
Fortunately that was not the case as I was able to lower all my stats using Adrena-Time withdrawal which gives -1 to all attributes. Once I reached the console on the bridge of hope I used about 10 of them a few seconds apart and eventually my intelligence was below average. Then I interacted with the console and I was able to choose the dumb option and skip the Hope myself right into the sun.
Not sure if it matters but this happened on supernova difficulty. You could probably lower your stats more through hunger, thirst and lack of sleep.
Great find from Throni360 - "You CAN do it with +3 intelligence! Just get the Permanent Concussion Flaw. You can get it by stepping on mines and shooting exploding barrels. Repeat it after every cooldown. Switch difficulty to hard if you already have three flaws (maximum on normal)."