system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] In Episode 6 Return of the Jedi, the Empire was building another Death Star. Did they learn how the 1st one got blowed up so easy? Dis they fix the loophole Achilles’ Heel?
gpt
Actually, yes they did. Not only did they learn about what happened from Vader (the sole survivor) but in the Legends canon at least, Palpatine made sure that mistake would never be made again... by repeatedly torturing the lead engineer to death and resurrecting him via Sith Alchemy.

It's why the rebel resistance had to destroy it before it was finished, in case there was no new flaw.