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One-on-one with Scott Kelly
01:36 - Source: CNN

Story highlights

Astronaut Scott Kelly is retiring but will continue to participate in the NASA Twin Study

Kelly feels strongly about a mission to Mars

CNN  — 

Astronaut Scott Kelly has been back on Earth for about three weeks since completing his groundbreaking year in space and he’s still adjusting to the sensation of having solid ground beneath his feet.

“The most overwhelming part of it is gravity itself and I still haven’t gotten over it completely,” Kelly told CNN Chief Medical Correspondent Dr. Sanjay Gupta during a live Facebook chat Monday night.

Although Kelly announced that he will be retiring from NASA, he said he is still dedicated to the formal data collection process of the Twin Study, which is an ongoing look at the effects on Kelly after a year in space, versus that of his twin brother, Mark, who remained on Earth. And while he doesn’t miss living “in constant noise” with fans, pumps and motors constantly whirring in the background on the International Space Station, Kelly seems in awe of the incredible experience he was able to have in his “second home.”

And the surprising thing that made the return trip home? His glasses. “These are the glasses that launched with me and I never lost them in space,” Kelly said, referring to the lenses he wore during the chat. “This is more of a miracle because stuff just floats away up there.”

Kelly also believes that the space station is proof that we can do anything. “That space station is such a complicated facility and was so difficult to build and such an achievement. If we put our minds to it, we can achieve anything we want, whether that’s curing cancer or going to Mars, we can do it, we just have to put the resources behind it.”

Kelly answered questions for nearly an hour. Here are some of them. Some of them have been edited for clarity or brevity.

How are you feeling? I felt significantly different coming back. Initially, I felt better coming out of the Soyuz. Maybe it was adrenaline or that I had experienced that once before. After that, I felt much different. My legs have had kind of a negative reaction to gravity and it’s kind of shocking how for the first couple of weeks my legs were swollen, sore, the joints, my muscles, and when I stood up at night I could tell my whole cardiovascular system wasn’t used to keeping the blood out of my legs. Its like when you turn upside down on the monkey bars and feel the rush of blood to your head. It was the same way with my legs and I could feel them swell up and it was kind of alarming. But I’m slowly getting better, but I still get up very slowly. I’m not really able to run yet. I think I’m already improving and will over time.

What was happening to your legs to cause you pain? Being in space for so long, your cardiovascular system doesn’t have to keep the blood from pooling in your legs due to gravity when you’re standing up – that’s why your head gets swollen when you’re in space. Over the course of the first several months you’re there, you lose fluid. Now you have gravity pushing all of that fluid back into your legs. I think the muscles in your cardiovascular system aren’t able to physically adjust the pressure like they do when you live in gravity all of the time.

What are your thoughts on Mars? If you were asked to be that guy who goes to Mars, what would you say now? A couple of weeks ago, I would’ve said I’m not that interested in Mars, but now I am probably more interested. If we go to Mars and we land on Mars and we stay on Mars, we can experience Martian gravity and don’t have an ultra-long time in microgravity, which I think is helpful. I think where we run into issues is flying around Mars and coming back, because then you have guys in space for a year and a half. I wouldn’t say you can’t but I would say that’s pretty significant based on my experience.

My first flight was seven days, my second 13, my third 159, my fourth 340. If I had to graph how I felt, it’s a linear of things. You add another couple hundre