One potential retcon that deserves consideration: Vault 111's Cryogenics. In 2050~2076, the Sierra Army Depot was renovated & refitted with a state of the art research facility by the US Military. Part of that facility was Biostorage which had Cryogenic Suspension. Source. In Fallout 2 (the year 2241+) you could visit the Sierra Army Depot as the Chosen One. If you bothered investigating the Biostorage facility you would find many body parts that have been stored there have "long since turned to soup" and a living intact human named PFC Dobbs. If you release Dobbs he'll briefly speak with the Chosen One and then say he must get back to his army unit (he has no idea how much time has passed). When Dobbs is on his way out he suffers from Post-cryogenic syndrome and "disintegrates into a puddle of slime." Sierra Army Depot aside, Robert House himself experimented with Cryogenics. To quote the wiki: And then there's this: So Robert House too experimented with Cryogenics, but even his own chamber was flawed because his body was not fully preserved - he even aged. The discrepancy I see here is that Vault-Tec somehow managed to create a superior Cryogenics system than NOT ONLY the US Military, but also Big Mountain and the pre-war technological wonder-boy Robert House managed to pull off themselves.