I am Dr. Susan Bailey, researcher for NASA's twin experiment. AMA!

Have you considered using Danny DeVito and Arnold Schwarzenegger as participants in your study?

No.. but great idea!

What are you expecting to find by using twins? How many people do you plan to run though this study? I can imagine that it is going to be hard to find enough people that you can do this with to make definitive findings.

Also, how many tacos can you eat in one sitting?

Since the twins are as identical as it gets, we are expecting to find things specific to space flight. We will be able to compare the twins to each other - and to other related astronauts, hopefully at least 10 others to get significant results.

I can eat lots of tacos!

Thank you for answering my questions, I really appreciate it.

I have logged your taco response in my taco tracker. You are the first scientist that has answered my question and the first female that has not given me an actual number amount of tacos. So that is something you can add to your resume if needed.

Will do!

A quick follow up, what's your favorite place for tacos in Fort Collins?

No fav. I love them all :)

Hi! I requested this AMA over on /r/IAmARequests, so I'll copy my questions from there:

1. Will the "Earth Twin" (Mark) be subject to controlled environments to help eliminate some of the extraneous variables?

2. How far will that extend? Food? Air? Exercise?

3. What are some of the differences that you already expect to be able to observe once the "Space Twin" (Scott) returns to Earth?

4. What are some of the differences that would be the most surprising to see?

5. Can we make "Earth Twin" and "Space Twin" official nicknames?

I understand you probably can't answer all 5, so I am most concerned with how you plan to treat the variables associated with the experiment. Will the "Earth Twin" be living under controlled conditions for the span of the year? What will those conditions be like?

Thanks for doing this AMA with us!

Mark Kelly is willing to do just so much for the sake of science. For example he will not be eating the same food as Scott does in space. Mark will be giving blood samples taken at about the same times as Scott. For our study, we expect to see accelerated telomere shortening and elevated telomerase activity, both of which may contribute to aging and or disease.

I like those nicknames!

Being able to see differences in telomerase activity would be a huge breakthrough. I don't know much about biology or genetics, but even I can see the implications of that research.

Would decelerated telomere shortening make the idea of longer space trips possible? If we don't have to worry so much about astronauts aging, doesn't that make the possibility of longer missions greater?

You are correct. However, many different types of stress have been shown to shorten telomeres - including life stress, like inadequate nutrition, physical and psychological stress... Hard to imagine a more stressful thing to do than strap yourself on a rocket and then live in space for a year.. Other factors also pose grave risks to the astronauts for longer missions - high on the list is radiation exposure.

have you taken any precautions against twin shenanigans, such as switching bodies at launch?

Hmm.. no.. but we'll be on the lookout!

a more serious question, how have you benchmarked the current differences between the development of the twins' biological features? have you measured differences in changes between the twins for some time on earth?

what sort of practical ramifications could results from this experiment have?

thanks for taking time to answer these questions.

We will be able to establish some baselines in each of the twins prior to space twin's one year mission. For example, we will getblood samples several times pre-flight for both. The ramifications of the genomics based studies could include not only informing the twins of the effects of space flight, but also influence future astronaunts by helping them to mitigate some of the effects - perhaps as simple as taking antioxidants, or as serious as realizing they are at unusually high risk of developing disease.

How will the twin who gets to go to the International Space Station be picked? Does it matter?

Mark, the Earth twin, is retired from NASA so is participating to support his brother. Scott has been training for the mission for over a year.

Thanks everyone for your interest and your questions! I'll be checking back this afternoon if anyone has anything else.

First off, congratulations on this research opportunity!!! I heard about this study in my Science & Technologies class at UC Davis! My question to you is what is your advice for a student looking for research opportunities in the field of science and society? Any resources you would recommend? Also asada tacos or carnitas tacos?

Many thanks! It is an exciting project that is getting a lot PR and I'm really looking forward to it. It is a difficult time for research in general with funding so limited, but the opportunities are out there and more will develop with recovery - so most importantly don't give up! The right doors will open. NASA has a number of student training opportunities that you might look into.

Is telomere shortening and telomerase activity the only thing you will be monitoring in the twins? It seems that there is an excellent opportunity here to study muscle and tissue atrophy, brain activity, and a whole host of things associated with space flight.

Absolutely! Together, the ten studies will be analyzing a host of things, including DNA and RNA sequencing, the microbiome, and behavior..

Are you involved in those projects enough to expand upon them a bit? What specific things are you looking for in DNA and RNA sequencing, for example?

We will all be collaborating and sharing data between the projects. All will be looking for differences between earth and space twin.

Hey Susan, believe it or not we share the same first and last name and I happen to have twin boys, age 23. One is in the military and the other graduating in a few days in Geoscience. They have always wanted to be astronauts, they would volunteer to be phase 2 testing!

Terrific! We'll definitely be needing more twins in the astronaut core!

corps?

yep. sorry.. it was very early when I responded :)

Are you concerned at all that Mark's previous exposure to space flight will bias your results in some way?

Mark's time in space is much less that Scott's - particularly after the one year mission.. so no, not concerned..

I'm not a twin, but I used to use my brother's ID to buy beer. Can we still participate in the experiment?

Hmm.. sorry but don't think that counts..

Why work on twins as opposed to triplets?

Hard enough to find twin astronauts, much less triplets..

Were you required to get permission before submitting this AMA? Is there any information that is classified for any reason?

No. There is a lot of information that NASA is releasing to the press. The confidential part will come with the results of the studies and how the twins want to handle that information.

Only 46 comments?? Geesh what's wrong with you all.

Anyway, thanks for doing this AmA!

Is it possible that this would make the Space-twins life ALOT shorter than Earth-twin's? Taking into account all the radiation and the fuss with telomeres and such.

That is the possibility we are investigating.. Thank you :)

I'm an identical twin, you're more than welcome to send one of us to space! What do you believe the most difficult part in sourcing test subjects is? Is there a preference for males or females?

NASA has a previously funded study of 15 pairs of female and male identical twins [Dr. Alan Hargens, UC] focused on testing countermeasures against weightlessness and understanding the hereditary contributions to bone mineral density, kidney stones, and cardiovascular function. The current studies are unique in that both twins are astronauts, the duration of the flight (one year), and the focus on genomics.

Does a sample size this small yield any meaningful results?

True that there are only two individuals - earth twin and space twin. However, we are also doing the same tests on a group of unrelated astronauts (not spending as long in space), but hopefully that will help us draw meaningful conclusions.

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In many ways this is the dream experiment - which is what's so great about it! Who knows - there may be some surprises, which of course is why the information will be protected.

This isn't really an experiment. Mark isn't eating the same food or restricting alcohol use, heck he isn't even breathing the same pressurized oxygen. This is more of a gimmick for PR than science.

If you wanted to just study radiation in shielded environment, you should find terrestrial twins where one travels a lot on long distance air travel and measure telomeres, in this case you might find twins that have one with thousands of hours of air travel, and no differences in gravity or air.

If you just wanted to study telomeres why not take a sample of the same cells that split rapidly and send half the same to space and measure the other half. Or better yet, twin mice studies where they are given exact same food.

It all depends on what question you are asking. This is really a remarkable opportunity to study real life situations - much more relevant to our every day lives than that in a controlled laboratory setting, or in a mouse. The identical twins (actual human beings), Mark will be living an everyday existence, typical of many, on earth, while Scott will be living under conditions typical of long duration space travel. The question being what are the effects of space flight? For me, on telomeres and telomerase activity, and for the other studies, a variety of other endpoints.

on telomeres and telomerase activity

Again, if you are scientifically interested in this, put twin mice, or even something with faster cellular splitting, that is even starting from exact same cells.

This twin thing is just a NASA gimmick. You might as well have him hold an atomic clock and take photos of his Earth twin holding a sync'd clock. It won't tell you anything, but will be neato PR.

Twins aren't identical. Sure if your understanding of biology is from the 1920s. Epigenetics plays a large part in any differences you plan to "measure".

Monozygotic (identical) twins do start from the same fertilized ovum, same sperm. Even so, and as you point out, they are not identical in every way - epigenetics will change patterns of gene expression between the twins, which is why one of the studies will be doing methylomics to analyze differences in methylation patterns between the twins - again, that will be due to space flight. I'm sure you can also imagine the difficulties of doing some of these experiments in space - not only are the human studies more relevant, in many respects they are more doable.

I have identical twin daughters, although lifestyle has now completely changed their appearance, interests, activities and values.

Some years ago they were a small cause célèbre as one had a plasia that lodged in her brain leading to epilepsy like symptoms and other, mostly drug induced, behaviours. Brain surgery was the cause for attention, for identical reasons as these ongoing space twin tests. However, research was suspended for two reasons: several medical researchers felt no useful data was being collected and we also felt it was not conducive to healthy recovery. The girls were pre-teens at the time. The information imparted was that most twin-based tests exhibit this phenomena: that which you are looking for is not meaningfully expressed in identical twin based managed studies.

Therefore, I agree with other commenter's, this test sounds fascinating, plausible, exciting even given extraordinary opportunity of identical twin astronauts, yet seems to be a specious academic exercise repeating previous data generation attempts.

However, for sure the opportunity to further space based physical biology knowledge is of inestimable value given the utter alien environment. From my girls' past experience, skepticism is strong, and can't but otherwise say to not be blind to no meaningful results.

Thank you - and most certainly. These are pilot projects. There may not be anything to follow up on - and then again there may be. These types of genomics based studies have not been done before on the astronauts, and certainly not on twin astronauts.

Do you think that we would be able to do more experiments like this if NASA were still a fully-funded governmental organization, capable of launching its own missions?

Most definitely. These studies are a good example of the potential of the space program to benefit of all mankind. The fact that we have to depend on the Russians to get our astronauts to and from the ISS is somewhat disconcerting.

Does privatization offer any hope for the future of US space exploration? SpaceX seems to be doing some great things, especially after yesterday's success.

Yes it does. SpaceX is a good example, but they've had problems too.. and it only takes supplies - no people.

The same could have been said of NASA 60 years ago, though.

Indeed.

Interesting, this was used as a plot device by influential science fiction author Robert A. Heinlein. The book is called Time for the Stars (wrote in 1956) and has the plot of sending one twin into space and keeping the other here on Earth to be used as a sort of ansible. In the book, the twins have a sense of telepathy between them without the inherent delay that radio waves and other forms of communication had.

I haven't read it in at least 10 years but it was still the first thing I thought of when I saw NASA was doing a twin experiment.

Interesting indeed. They definitely are both very invested in this.

Will this experiment be conducted in other areas of space in the future? Such as the Moon, or maybe even Titan?

NASA is interested in moving into more genomics based studies, so yes. Whether or not they will have opportunity to do so in twins will is yet to be determined.

Thanks for the reply. I find this topic to be extremely interesting :-)

Thank you.. Be sure to stay tuned!

Do these twins in particular share a commonality that other twins seem to have? Such as completing each others sentences and having that distant empathy correlation? Are you exploring any affects in relation to that stuff?

Not directly. But some of the studies are evaluating behavior.

Have you considered calling your study Project Gemini?

There is ongoing discussion about a name for the twin studies - Gemini was brought up, but it has already been used by NASA. Another suggestion was Sirius, which is a binary star system (Sirius A and B) perceived as a single star - the brightest in the night sky. To my knowledge, no name has been decided upon.

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Sorry.. afraid not..

It seems like this research could be used to characterize the risks inherent in transporting humans to Mars. Do you foresee any other direct applications of your research findings?

Yes. That is the idea behind the one year mission - the longest anyone has been in space, and although in low earth orbit, it will still be very informative regarding how humans handle it. The genomics studies should also help to identify risks and possible mitigation strategies for extended space flight.

What is the best thing about your job?

I really enjoy interacting with students and the opportunities I have to interact with colleagues.. This has been a lot of fun too!

My question brings up some issues with ethics, but I'm curious anyway, so here's my question :

Assuming ethics and whatnot weren't a factor, and assuming this would take place once space stations are more common and people could live and grow up on them (however far in the future that may be), how much do you think we could learn by repeating this experiment in the future with younger twins, who would both grow up individually, as opposed to growing up together and then one going to space? Do you think that it's something that might actually be done in the future?

So you're getting at the role one's environment as opposed to one's genetics. The classic nature vs. nurture debate. The beauty of the current twins study is that as many of the variables as possible - including environment and genetics - are as similar as possible. Therefore, any differences observed can be attributed to effects of space-flight. We will also have opportunity to compare the results with the twins to unrelated astronauts to address the role of genetics.

Does NASA use any of the the data collected by Dr. Mengele during his twin experiments?

I'm not really sure. I do know that the current twin study is unique in a number of ways. The focus on genomics, the shared data plan, a year in space, and the fact that both are astronauts are first time evers.

Weekday specific vectors are you studying between the twins, and what do you hypothesize you'll find?

We are going to be analyzing changes in telomere length and telomerase activity before, during and after the one year mission. We expect to find shorter telomeres and higher telomerase activity in the space twin compared to the earth twin.

Is this because time moves slower away from the source of gravity or because of some other property of living in zero gravity?

I think it has more to do with stresses associated with space flight.

Seems without the stress of gravity, the telomeres wouldn't tick as quick. I guess you will find out.

Since telomeres shorten due to things like replication (cell division), and stress, they may be somewhat independent of gravity - but we shall see :)

I guess I don't understand the "stress of spaceflight" Seems that there is a 5 minute exposure to ~4gs during the burn then 6 months exposed to ~0gs. You don't need to build bone or mussel mass.

Astronauts do suffer from muscle wasting and bone loss in microgravity. They have very strict exercise programs while in space to combat such issues. The kinds of stress that I'm referring to are related to things like inadequate nutrition, the physical and psychological stresses associated with long term periods of space flight in relative isolation - very stressful!

Now I'm curious... Would sending a couple of introverts into space help with the stress of isolation? :P

Perhaps. That is actually a very real concern/danger of long duration mission - loosing it due to isolation.

Yeah, that's why I'm thinking that it might be good to send people who are used, or even prefer, to be isolated for long periods of time. :)

The problem may be in the training for such missions. Takes lots of folks and interaction for that.. Then in space, even if just a few people, they really do need and depend on each other..

But what do you expect to learn from this? We already know that perceived time slows down the faster you travel. What theory are you testing here?

that the stresses of space flight influence important age related pathologies, including reduced immune function, cardiovascular disease and cancer. The ISS is in low earth orbit and does not travel at the speed of light, so the theory of relativity is not so relevant.

Hello Dr. Bailey! I hadn't heard of this experiment before, and it sounds fascinating. In your answers thus far, you've stated your hypothesis that the telomere lengths of the two twins could change due to different stress levels. Alongside the genetics-based research, are there any plans for some psychological analysis before, during, or after the Space Twin takes off? While psychology can sometimes be biased, the comparison between reported stress levels and telomere length might be interesting.

Yes indeed. Results from all of the studies, including some on behavior, will be shared so that we can make relevant comparisons.

Does your experiment require identical or fraternal twins (fraternal twin asking)

Identical twins are ideal in this situation, as the more similar genetically the twins, the more we can conclude that any differences we observe are due to space flight - not genetics or individual susceptibility.