During my time in orbit, I lost bone mass, my muscles atrophied, and my blood redistributed itself in my body, which strained my heart. Every day, I was exposed to ten times the radiation of a person on Earth, which will increase my risk of a fatal cancer for the rest of my life.
The calluses on your feet in space will eventually fall off. So, the bottoms of your feet become very soft like newborn baby feet. But the top of my feet develop rough alligator skin because I use the top of my feet to get around here on space station when using foot rails.
I don't mean to say it's not fresh on the space station, but there's nothing like new, cold air coming into the capsule.
Going to Mars is a bunch of baby steps, and it started off with the first human in space, Yuri Gagarin.
Sleeping here is harder here in space than on a bed because the sleep position here is the same position throughout the day. You don't ever get that sense of gratifying relaxation here that you do on Earth after a long day at work.
The thing I like most about flying in space is not the view. The thing I like about it is doing something I feel very, very strongly about.
We would go in there with our parents once in a while for – actually go into Manhattan for dinner, weekends occasionally to a museum, but most of my memories of traveling into Manhattan was with the school trips and then later on as we got, you know, into high school, kind of on our own and with friends.
I think anyone that's in the same building or the same place for a really long period of time, some parts of it become routine.
It is a little bit surreal to know that you are in your own little spaceship, and a few inches from you is instant death.
I personally think going to Mars, if it takes two years or two and a half years, that's doable. Certainly, the first people who go there, that's going to be a big motivator, being first getting to Mars.
When we do things that are really hard, we can achieve great things – and that has worked as a great model for me.
Flying in space is a privilege, whether it's the first time or the fourth time.
It's an international space station. We have crew members from both the U.S. and Russia and now the United Kingdom with Tim Peake from the U.K… It's great to see that, on this space station, that we can work across cultures in a very cooperative way.
I think what most people miss, and what I missed last time, are the people that are important in your life. You know, the relationships you have with people on the ground.
There are few aspects of everyday life that aren't touched by the technologies developed for space travel.
A lot of the data we collect is stuff that has to be analyzed on the ground. For instance, we can't see, you know, bone loss. Our cells, you know, that's something that we'll have to notice with imaging technology when I get back.
There's a lot of work to do – not only the science but maintaining the facilities up here. When you go down from a crew of six to a crew of three, obviously you've lost half of your crew time available, so it does have an impact. But it's an impact we plan for.
I think a good life-work balance is important, and that's even more important in some cases on the space station.
We've got to get rid of the stuff on the space station somehow. So we do have a pretty significant capability to bring back stuff on SpaceX that you might not imagine.
Space has its own unique smell. So whenever a vehicle docks, or if guys are out doing a spacewalk, the smell of space when you open up the hatch is very distinct. It's kind of like a burning-metal smell, if you can imagine what that would smell like.
The space station here is a magical place and an incredible science facility.
This year-in-space mission was a profound challenge for all involved, and it gave me a unique perspective and a lot of time to reflect on what my next step should be on our continued journey to help further our capabilities in space and on Earth.
We do a lot of science on the space station. Over the course of the year, there'll be 400 to 500 different investigations in all different kinds of disciplines. Some are related to improving life on earth in material science, physics, combustion science, earth sciences, medicine.
We used to have a crew of three on board the space station and even at one time a crew of two people, so it's something we can adjust to.
It seems like in the beginning of my flight, the space dreams were rare. And now, almost 150 days into it, the Earth dreams are more of the rare ones.
I don't think people have an appreciation for the work that it takes to pull these missions off, like humans living on the space station continuously for 15 years. It is a huge army of hard-working people to make it happen.
Now, space has its own unique smell. So whenever a vehicle docks, or if guys are out doing a spacewalk, the smell of space when you open up the hatch is very distinct. It's kind of like a burning-metal smell, if you can imagine what that would smell like.
I believe in exploration, and I will miss being on the front lines of that endeavor. On one hand, I look forward to going home, but it's something that's been a big part of my life, and I'm going to miss it.
There are parts of the Earth that are covered with pollution all the time. I saw weather that was unexpected. Storms bigger than we've seen in the past. This is a human effect. This is not a natural phenomenon.
I believe in the importance of flying in space and the research that we do.
Your arms don't hang by your side in space like they do on Earth because there is no gravity. It feels awkward to have them floating in front of me.
Something people don't recognize is that being on the space station is probably a lot like being in some kind of confinement – like isolation.
I'm actually thinking about maybe, on a spacewalk, not wearing my glasses. I normally wear those both for reading and a little bit of a distance correction, but the distance vision seems like it's gotten a little bit better. So I might go without.
This is a really big space station. We do a lot of various kinds of work here, different kinds of science experiments; we have over 400 different experiments going on at any one time in different areas, from basic science research to medical technology, that hopefully will benefit more people on Earth.
I've flown in space four times now, so it's going to be hard in that respect, but I certainly look forward to going back to Earth. I've been up here for a really long time and sometimes, when I think about it, I feel like I've lived my whole life up here.
We don't do laundry because that requires a lot of water, and water's at a premium up here. Plus, it'd be pretty complicated, I think, to make a space washer, although I guess you could do it. So we generally throw our clothes out. I think I've been wearing this pair of pants for about two months.
What we look for are people that are technically competent. You need a background in a scientific field, whether it's as a scientist, an engineer, medical doctor, or, you know, a person that's in the military with some kind of technical background.
The workouts have positively impacted the astronauts' bones and muscles, and they are coming back in really good shape. But some are losing bone and muscle but not as much as we saw in the early days.
We have a lot of systems here on board the space station, and we can't call a repair man when one of them breaks.
A year is a long time to live without the human contact of loved ones, fresh air, and gravity, to name a few.
When you look at the… atmosphere on the limb of the Earth, I wouldn't say it looks unhealthy, but it definitely looks very, very fragile and just kind of like this thin film, so it looks like something that we definitely need to take care of.
The majority of astronauts have to change their eyeglasses while in space. They bring eyeglasses with them and typically change a few months into the mission.
The planet will get better; it's us that won't be here because we'll destroy the environment.
There are definitely parts of Asia, Central America that when you look at them from space, you're always looking through a haze of pollution. As far as the atmosphere is concerned, and being able to see the surface, you know, I would say definitely those areas that I mentioned look kind of sick.
If you go on a journey to Mars and get into deep space, there is several hundred times, maybe 300 times the radiation.
Just like the bones and muscles, the heart is designed to work in one gravity here on Earth, so when you put the heart in space, it operates differently and changes shape.
We don't do laundry because that requires a lot of water, and water's at a premium up here. Plus, it'd be pretty complicated, I think, to make a space washer, although I guess you could do it.
I am humbled and excited by new opportunities for me to support and share the amazing work NASA is doing to help us travel farther into the solar system and work with the next generation of science and technology leaders.
If we're going to go farther from Earth, to Mars or somewhere else someday, we have to have a good understanding of the psychological impact on people. And not only psychologically, but how it affects their cognition. We're doing a lot of research on my cognitive abilities.
It's for us to take care of the air we breathe and the water we drink. And I do believe we have an impact on that, and we do have the ability to change it if we make the decision to.
Leaving the space station was bittersweet – I had been there for a long time and looked forward to leaving, but it is a remarkable place.
The ride to orbit was impressive, as it always is. But once I got on board the space station, it really felt like I was visiting an old home; it felt very comfortable.
My career with the Navy and NASA gave me an incredible chance to showcase public service to which I am dedicated, and what we can accomplish on the big challenges of our day.
The Earth is a beautiful planet. The space station is a great vantage point to observe it and share our planet in pictures. It makes you more of an environmentalist.
My dad worked nights mostly and while we were growing up, and my mother also worked, so there were times where, when it was just the two of us at home, and, you know, they gave us a pretty long leash, actually.
I went to the University of Maryland for a year and was considering maybe, you know, being a medical doctor but decided my other interest was maybe flying airplanes in the Navy and just kind of changed my mind and changed schools and changed majors and decided to focus a hundred percent on that.
As far as the sounds on the space station, it's pumps, fans, motors, certain modules are louder than others, but it's generally a pretty nice working environment. It's not too loud or too smelly.
There's certainly a loss of connection with folks on the ground who I care for and love and I want to spend time with.
What we get from building a space station, the economic return, the science return, is very, very important to our nation, to our economy.
On this flight, my fourth spaceflight, I also became the record holder for total days in space and single longest mission.
People do really well on space missions, but it's the physiological, the medical stuff, the stuff like radiation, loss of bone mass and muscle mass and density. It's those things that we need to figure out.
I feel more like an environmentalist since I've been up here. There are parts of the Earth that are covered with pollution all the time. I saw weather that was unexpected. Storms bigger than we've seen in the past. This is a human effect. This is not a natural phenomenon.
I am not a great sleeper. I don't think I have ever slept 8 hours straight in the last 20 years.
We had this incredible pass over the Himalayas, and to just see all of that pollution that's riding up against those mountains from the south is just really heartbreaking.
As far as whether there is life there on Mars or whether there was actually ever life there, I don't know. It would be great to find out, though.
It's a combination of science, maintenance, and general housekeeping. And then, occasionally, robotics activities or a spacewalk you might get to do.
When I look at the clouds over the Earth, and I know how high clouds are, I get a sense we are really, really far above those clouds. I wouldn't call it scary, but I am aware I am in space.