being wornd being warned of extreme weather across the country. a strong storm pushing into the midwest today and tomorrow. chicago and other parts of the midwest could get as much as a foot of snow this weekend. we thank you so much for watching ne"newsroom" today. vit "vital signs" starts right now. what if you had to live somewhere and could never go outside, never experience weather, like a rainstorm or the warm sun. what if you had to live that way for nearly six months? could you do that? this is "vital signs." six months is the usually time astronauts spend living on board

the international space station. double that to nearly a year and you will have scott kelly ace historic mission. the first step in trying to get us into deep space, mars, maybe beyond. the biggest variable keeping us from getting there is likely ourselves. can humans physically and mentally handle it? >> a lack of gravity is going to be one of the biggest challenges. as much as two litres of fluid shifts from the legs to the head producing changes in eyesight, while muscles and bones weaken without any force pushing down on them. with so many unknowns, it is risky but scott kelly was up for it and we went along for the ride. more than 200 miles above the earth, whipping around at 17,000 miles an hour, scott kelly is on board the international space station. >> please stand by for a voice check from cnn. >> station, this is cnn. how do you hear me?

>> we're talking to him live. >> i hear you loud and clear. welcome aboard the space station. >> it is february 11th, 2016. scott has already been in space for more than ten months. >> as you travel at a rate of 5 miles per second, i understand 200 miles above us, getting close to finishing a year in space. first question, how are you doing? what has surprised you most about any changes in your health? >> i'm doing pretty good. i do feel like i've been up here for a really long time. i kind of knew what to expect going into this, because i had flown a long duration flight before. so, overall, nothing alarming. >> and liftoff. the year in space starts now. >> this is scott kelly's fourth trip to sfas. by far, the longest in duration. in fact, it is now the longest

for any american astronaut. >> miguel kornieko making his way into the new home he will occupy. >> reporter: he and russian cosmonaut, mig get kornieko signed up for a year in space and they realized there was a second benefit here. >> i'm adjusting to life back on earth pretty well. i'm only wearing these pants for a month. >> scott kelly is an identical twin. his brother, mark, shares the same dna. like scott, mark too was an astronaut. having flown in space four times. nasa could study one twin in space while the other was back on earth. i sat down with the kelly brothers in san diego this summer for their first television interview since scott's return. >> reporter: mark, what was it, do you think, that attracted you to this sort of work? was it the adventure, the

science? what was it initially do you think? >> certainly, the excitement. also, being able to serve my country in a different way than i had before. i was in the navy about ten years before. both of us applied to be astronauts. i think i've always -- our parents were police officers, public service was kind of in our family. >> reporter: scott and mark grew up in new jersey. as kids, they were always active and in their father's word, a bit ram buncious. >> we had a chance to talk to your father. he said if you went to play, he was unlikely to find you. you would have to look somewhere specific. >> like on the roof of the building? >> that's true. >> you guys were always playing on the roof? >> this isn't recently. this is when we were kids. >> both brothers were selected for nasa's elite astronaut program after serving their country as pilots in the navy.

there was always the chance they might fly in space at the same time but it never happened. that's okay with them. your family, how much do they worry for you, mark, when you are up in space? >> i athink our mother and fathr would get pretty freaked out, specially on launch day. more for me, because they liked me better. >> i heard that. the rumors are true? >> i don't know. i've never been told that. >> maybe they told him something and just kept that from me. >> for 340 days, scott would not be able to come home, no matter what happened back on earth. it was a risk he and his family were willing to take. it is not the only one. scott was charting new territory. no american had ever been in space that long and no one from any country has ever been studied this closely. we have no idea how scott's body would react to being in space for that amount of time or what could potentially develop later

in life. here is an example of what we do know. a lack of gravity has a big impact on our bones and muscles. according to nasa, astronauts experienced up to a one-third reduction in muscle fiber size in less than two weeks on the space shuttle. to put that in context, on earth, post-menopausal women untreated for bone loss can lose 1 poto 1.5% of their bone mass loss in one year. think about what that could mean for scott in space for a year? nasa has developed special he canner size equipment to help mitigate those factors. proven effective for six months missions. an unknown in scott's case, he would be up there for a year. >> my big lingering effect, my feet are still bothering me at times. i think it is more plantar

fasciitis rather than anything. >> not so much from the fluid shifts but more from not using your feet? >> not using your feet. not using the bottom of your feet. you use the top. >> you use the top to move around. >> with scott in space for a year and mark on earth, the idea for a twin study started to take shape. scott would be the test subject. mark, the control. it is a one of a kind study that could change the future of space travel. in the meantime, scott had to make it through the mission, not just physically but mentally. "vital signs" with dr. sanjay gupta is brought to you by --

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by the end of the sent true, the united nations projects the earth's population will top 11 billion people. currently, there are 7.3 billion. already, a strain on resources for our planet. where else could we go? it is certainly part of the appeal of deep space travel. colonnizing other planets, like mars has long been the stuff of science fiction but it could become a necessity. it also means scott kelly's year in space is a critical first step in exploring the options of man mission to deep space. year in space, 11 months in, in a place the astronauts can never leave it can be tough mentally, to keep things interesting, scott kelly decided to monkey

around. there is no such thing as a true vacation up here. that can take a toll. eve on a day off, without any scheduled experiments or maintenance work, the astronauts are always on alert. >> you wake up, you are at work. you go to sleep, you are at work. you never leave. you are very busy. one of the underlying stressors of being up there for so long is that you are always thinking, if we have a fire, if we have a depressurization, i have to be able to respond to this. that's something that's always in the back of your mind where you never really have a minute off from those kind of things happening. >> in san diego, i moderated a panel with scott and mark kelly. dr. steven gilmore joined us, scott's flight surgeon for his past two missions. >> this lack of a mental break was one of his biggest concerns going into a year in space. zi asked you or the other astronauts if they could describe what time off would be

on stalgs. that's a difficult thing to do, because for the six-month missions, you are going up there with an attitude of all the things you want to get done it is a very achievable thing. it was often on mark's mind. if anyone could relate to what scott was going through, it is mark. sometimes he would need a little reminder. >> i was on the phone with him after he had been in space about three months. i was talking about how i had been traveling a lot. i was walking down the street in new york city saying, yeah, i'm on this trip and i'm not going to be home for like three weeks. that's a really long time, forgetting who i was talking to. he said two words. i didn't tell you what they were. >> reporter: if you want to eventually get to mars, that mission would last roughly 30 months, 2 1/2 years. for the duration of scott's year-long flight, he would have only just arrived on mars.

in addition to being able to mentally handle it, radiation would be a big concern. consider this. beyond low earth orbit, the protection of the earth's atmosphere is gone. nasa says astronauts are exposed to radiation, anywhere from 50 to 2000 mili receive verts. it is equivalent to three chest x-rays. that's an exposure equal to at many as 6,000 chest x-rays. >> with all that you have learned and all you have seen, do you think mars is feasible. >> i think mars is feasible. there are certain challenges. the radiation environment is something we are going to have to figure out. we get protection here on the space station. we get a lot more radiation than you do on erg. you get much, much more on the way to mars. that's a challenge. >> another aspect of being in

space for so long. nutrition? in 2014, i visited nasa's johnson space station and got to taste some of the food. i have to tell you, it's come a long way. i tried a crab cake and some fish curry, even so, though, i am not sure i could eat out of a bag every meal for 340 days, let alone the time it would take for a mars mission. for the study, they monitored everything scott and mark ate and drank and closely monitored scott's heart. in space, body fluids shift from the head to upper body. as much as two litres of fluid. nasa says a natural reaction is a decrease in the total amount of circulating blood in the body. that can result in low blood pressure. upon reentry back to gravity, some astronauts experience fainting until their blood

pressure normalizes. that reentry is the last piece of the complicated coordinated effort for space travel. it is the riskiest, most exciting element and happens to be the final part of the mission. >> scott kelly back on mother earth after 340 days in space. e trying your best. along with diet and exercise, once-daily toujeo® may help you control your blood sugar. get into a daily groove. ♪ let's groove tonight. ♪ share the spice of life. ♪ baby, from the makers of lantus®, ♪ slice it right. toujeo® provides blood sugar-lowering activity for 24 hours and beyond, ♪ we're gonna groove tonight. proven blood sugar control all day and all night, and significant a1c reduction. toujeo® is used to control high blood sugar in adults with diabetes. it contains 3 times as much insulin in 1 milliliter as standard insulin. don't use toujeo® to treat diabetic ketoacidosis, during episodes of low blood sugar or if you're allergic to insulin. allergic reaction may occur and may be life threatening.

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keeping the power lines clear,my job to protect public safety, while also protecting the environment. the natural world is a beautiful thing, the work that we do helps us protect it. public education is definitely a big part of our job, to teach our customers about the best type of trees

to plant around the power lines. we want to keep the power on for our customers. we want to keep our community safe. this is our community, this is where we live. we need to make sure that we have a beautiful place for our children to live. together, we're building a better california. back in 2014, when i visited johnson space center in houston, texas, i first met julie robinson. she is the chief scientist of the international space station with a critical hand in the science experiments happening during scott kelly's year in space. another element to consider is your personal space. >> these are the sleep quarters. this is your personal space.

>> this is it? >> julie showed me around the mock-up of the station, which has 935 cubic meters of liveable space. >> you have some real nice fans blowing on you at night so you don't suffocate. >> can i step in here? >> yes, don't tell anyone. >> scott slept in this small compartment every night. >> you have a sleeping bag that's velcroed to the wall. >> nasa says astronauts sleep on average less than six hours a day and before critical mission operations, it is even less. today, i met up with julie again. this time, in san diego for a look at what has changed since we last saw each other. >> last time we talked, it was before this year in space. from the chief scientist perspective, what has the year been like for you? >> it has been an amazing year. i have never had so much public interest in what we are doing in space from people. a lot of times people don't realize that the space station is up there all the time.

suddenly, everyone is aware, little kids, older ladies. i will meet someone at a party and they will say, how is scott kelly? it has really caught people's imagination. i think it helps people see how the space connection connects to mars and it helps people see how the space station connects to health. those themes are so important. they really capture everything we are doing on the space station. >> a lot of times you are talking about stuff that's already in textbooks and already published. this is happening real time. >> yes, yes. we are really solving problems real time. things that we really don't know. there is no analog on earth. there is nothing that looks like the vision syndrome on earth. so we have to solve a brand new medical problem. >> you just have this fast laboratory. >> these incredibly people that don't have other diseases and they have this problem and then it reverses. so the power of things like, the tw twin studies. if you can understand the genetics that was turning that problem on and off, you have

suddenly got a window into health on earth that you wouldn't get anywhere else. >> the twin study is really the crown jewel of this mission. ten studies with ten different groups of researchers are happening almost simultaneously, using the samples from scott in space and mark on earth. >> this is what we can see. >> dr. andrew fine berg is a researcher with johns hopkins and one of the principle investigators of the twin sud sdi. his focus is genetics. >> if you think about the area that the twin study was involved in, things like identifying what might be the epigenetic damage to the genome that might open the door with way toss mitigate that damage has practical applications for here on earth. >> by studying scott an mark, scientists will be able to identify any links between the environment and human health. there is another down side in

addition to the potential long-term health effects for scott. because genetic information is part of this study, privacy could be an issue for the kelly twins and their families. before anything is published, they will have the option of withholding certain information. >> your study is going to become a well-known study. people are going to know it is you two. you are the only twins that have been in a study at that time. pry sa privacy, security of that information. how much are you worried about? >> i am not worried about it for me but i am worried more for my kids. they could see i'm susceptible to having this disease and based upon the person, that could have a significant effect on them or not. maybe they would just like to know. >> do you have any reservations, mark, about being in a study like this? >> i realize the significance of putting that information out there. in flying in the space shuttle, there is a lot of risk involvt

risk versus reward, for our country and our nation. same thing with the science. there might be a bit of a down side for us. the benefit to the american people is enough to make it pretty obvious decision. >> getting ready to department the international space station again wrapping up 340 days on board the orbiting laboratory. scott's mission in space came to a close, there was one big part left. reentry. >> and undocking has occurred. perhaps the riskiest part of space flight happens at the very end. >> you described it as going over niagara falls in a barrel that also happens to be on fire. >> it is pretty scary. i watched the video and, first of all, you seem remarkably composed. >> you actually think about it. i have made it all the way through this whole year, the launch, space walks, the risk of being up there for a really long time. i'll tell you what, one of the

riskiest parts is at the very end when you come blasting back into the atmosphere and you're relying on this parachute to open in this russian soyuz. everything goes well when there is stuff flying by and hitting the windows, part of the insulation that comes off. it gets hot inside. >> then, as soon as the shoot opens and the motions stop and you realize it didn't kill you, it's the most fun you have ever had in your life. >> scott kelly, back on mother earth after 340 days in space. >> i said, even if i hated being up there for six months, maybe not a year. even if i hated being on the space station for six months, would i do it all over again for the last 20 minutes. it's a wild ride. >> when it was all said and done, scott kelly spent 340 consecutive days in space. from march 27th, 2015, to march 2nd, 2016, the most of any

american astronaut. he traveled more than 143 million miles and saw nearly 11,000 sun rises and sun sets. in that same time period, you and i saw just 684. he also returned home five milliseconds younger and two inches taller so gravity soon weighed in to shrink him back down to normal. he shared it all with us along the way through these stunning photos in social immediate yachlt he is goi media. he is going to continue to share next year. the result frs the twin studies will begin to come out next year. we will truly be able to see the results of this historic mission on all of us. for "vital signs" i'm dr. sanjay dpup ta. gupta.

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top of the hour. i'm poppy harlow in new york. president-elect donald trump is taking on u.s. intelligence agencies agencies, agencies that he will oversee very soon. in a stunning move, his transition team slamming the cia over reports that they believe russian hackers intervened in the election specifically in an effort to help donald trump win. trump's transition team reading a terse, unsigned statement which reads, quote, these are the same people that