In an interview with Wired published Monday, Kelly went into detail about what its really like up there. He talked about the things he missed, and what got under his skin.
“[M]ostly what you miss is people,” he said. “Friends and family. And weather. Even just the wind, rain, sun, going outside.” A surprising comparison came when Kelly recounted a tour of Harris County Jail.
The sense of smell has long been connected to memory, and Kelly says he encountered a room at the jail that “smelled like space station,” citing the combination of “antiseptic, garbage, and body odor” that triggered his sense-memory. In space, even smell tends to float, so it can linger long after it would have dispersed on Earth
Source: Scott Kelly Details His Year in Space and What Got Under His Skin | Rare