CAPE CANAVERAL, Fla. — Ah, there’s nothing like a blast of fresh, frigid air to welcome you back to the planet after nearly a year cooped up in space. That’s the word from astronaut Scott Kelly, NASA’s space-endurance champ who returned to bitterly cold Kazakhstan on Wednesday, along with his roommate for the past year, Russian cosmonaut Mikhail Kornienko. In a NASA interview before heading home to Houston, Kelly said it was “amazing” to feel the cold air when the hatch of his Soyuz capsule popped open after touchdown. “I don’t mean to say it’s not fresh on the space station,” he said, “but there’s nothing like new cold air coming into the capsule.” Both Kelly, 52, and Kornienko, 55, yearned for nature throughout their 340-day mission at the International Space Station, a dry run by NASA for eventual trips to Mars. “Just like Scott, I wanted to see Earth and I wanted to smell that fresh air.