Translation:That scientist returned as a hero.
"Like" and "as" are often interchangeable in English, but not in this case. "As" in this case indicates that the scientist is actually a hero, while "like" implies he is trying to put on the airs of a hero. Not to mention that using "like" just sounds weird to my native English ears.
Yep, agreed! The reason I commented is because I understand "như" as "like" in this context since using "as" has a completely different meaning as you mentioned. But that wasn't accepted as a valid answer so I was checking if I misunderstood the usage of "như" in this context or if it was a mistake.