Study Examines Effects of Spaceflight on Immune System

NASA astronaut Kate Rubins removes samples from the Minus Eighty-Degree Laboratory Freezer for ISS (MELFI). Blood, saliva and urine samples will be stored in MELFI until they can be transported back to Earth for analysis. (Credit: NASA)

HOUSTON (NASA PR) — Getting sick isn’t fun for anyone, but it could be especially taxing for crew members aboard the International Space Station. Protecting crew health is important as NASA prepares for long duration, deep-space missions. Functional Immune, a new investigation taking place in the orbiting laboratory, studies previously uninvestigated areas of the body’s immune response and if spaceflight alters a crew member’s susceptibility to disease.

The immune system is a complex weaving of biological structures and processes. Decreased activity in just one piece can cause changes in disease risk within the human body. Studies have shown in microgravity there are immune system modifications. This may create an environment where, in some crew members, rashes, unusual allergies and latent virus reactivation may present themselves.

“We’re seeing alterations in the numbers of immune cells in the blood, reduced function in some of these populations, and changes in the proteins cells make,” said Hawley Kunz, an immunologist at KBRwyle. “Your immune system is relatively stable, so when you start seeing changes, it is often indicative of the presence of environmental stressors with increased clinical risk.”

Expedition 30 crew members Dan Burbank and Andre Kuiper perform blood draws for the Integrated Immune investigation. Data collected during the Functional Immune study will build upon findings from this investigation. (Credit: NASA)

Researchers are also finding latent viruses are reactivating, but do not cause sickness in crew members. Evidence of viral ‘shedding’, virus DNA present in otherwise healthy individuals, has been found in crew member blood, urine and saliva samples. This can happen anytime the immune system is weakened in microgravity or even in stressful situations on Earth. Scientists are working to define, and perhaps develop mitigations for, immune issues before embarking on deep space missions, where the immune system will be subjected to microgravity conditions for longer periods of time.

“We evolved to exist in a sea of microbes, and we evolved an immune system to mitigate that,” said Brian Crucian, immunologist and principal investigator at NASA’s Johnson Space Center in Houston. “When the immune system is a little bit compromised, we may observe these alterations without progression to illness. This is basically where we are during orbital spaceflight. However, changes in physiology we are seeing on station have the potential to be greater on the way to Mars.”

The current Functional Immune investigation builds on other immunological studies, but examines previously uninvestigated aspects, in an effort to better characterize the effect of spaceflight on the immune system as a whole. The new study also includes investigators from the NASA Space Radiation Laboratory, as well as external investigators from the University of Houston and Stony Brook School of Medicine.

European Space Agency astronaut Andre Kuiper, shown here in the Human Research Facility, prepares samples for the Integrated Immune study. Samples received during the Functional Immune investigation will be used to determine the changes taking place in crew members’ immune system during spaceflight. (Credit: NASA)

Knowing how the immune system functions in flight will guide the way toward countermeasures that may need to be developed in the future. Some basic immune preventative measures such as standard use of protective vaccines, good nutrition, and exercise as well as pre-flight quarantine of astronauts, protection from microbes by screening and treatment of food and drink (pasteurization), and HEPA air filters are already in place to help prevent diseases, bacteria and viruses finding their way on to the station and causing a problem for the crew. For deep space missions, where crew members won’t have access to rapid-return options, remaining healthy is important both for the crew member’s safety and the success of the mission.

“On Earth, you usually don’t go to the doctor until you get sick,” said Crucian. “There aren’t a lot of areas of research looking at the immune changes that might precede disease or increase your susceptibility to disease. We are looking at just such [a] state during flight.”

Results from this investigation will benefit more than just crew members. In addition to the ability to detect and treat a disease before its onset, the methods developed to stabilize samples for transportation can be used to benefit immune studies on Earth, such as in areas without a laboratory readily available.

“The number one goal of this investigation is to complete the characterization of the immune system,” said Crucian. After the characterization is complete, plans to counteract potential clinical risks can be made to bring us one step closer to our Journey to Mars.

Jenny Howard
International Space Station Program Science Office
Johnson Space Center

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  • newpapyrus

    The solution to all problems related to long term microgravity exposure is to slowly spin twin pressurized habitats connected to a central pressurized habitat by 100 meter long cables and twin expandable booms.

    Marcel

  • Kenneth_Brown

    Unless you are conducting experiments that will be disturbed by vibrations or gravity. It might be a viable option for manned flights to Mars or the asteroids, but won’t work for something like ISS. There are structural requirements that are different from ISS to handle spinning such as keeping the solar array and antenna oriented correctly and if they have to stop the spin to receive supplies and for crew changes, it would put much more stress on a structure that was built to be light.

    The solution to long term microgravity exposure is to go faster. Nuclear propulsion built and launched from orbit, Earth or Luna, has the potential to shorten travel times and vastly extend the launch window for trips to Mars and the Belt. The US development program was shelved a number of years ago, but the facility is still in place. Cargo and supplies can go on slower craft a couple of years in advance of a crew to make sure it arrives safely before a manned craft begins its journey. It would be a disaster if a crew managed a botched landing on Mars but their supplies suffered damage.

  • Paul_Scutts

    You raise a valid point with (greatly) reduced transit times, Kenneth, but, that will not be sufficient for the extended period of stays either upon the Moon, Mars, Asteroids etc.. We just don’t know how our bodies will react over long periods of time in micro/reduced gravity. Marcel is right, we should have been experimenting with centrifugal force way before now, to see if, firstly, it will be a valid substitute for gravitational attraction and, secondly, at what minimum level(s) required, if it proves to be so. We don’t have to start with full scale human experiments, we could start at a greatly reduced scale using multi-generational experiments with mice/rats. Regards, Paul.

  • Kenneth_Brown

    My response was in regards to transit. I advocate a base on the moon first to study the effects of reduced gravity on human health before even considering a manned mission to Mars. I am not sure that a rotating habitat in Earth orbit would be less expensive and be able to also do useful science at the same time over a base on(in) Luna. There are lots of science and commercial opportunities for a moon base. Being able to work with dangerous viruses such as Ebola and Spanish Flu to develop vaccines is a great application. A physically separate lab could be sealed off and purged if there were any sort of accident. Semiconductor development, ISRU studies and anything that needs to be done in a vacuum are also good candidates for things that can be done on the moon. A long baseline study at 1/6g could go a long way to predicting how people will fare on Mars.

  • newpapyrus

    If you’re conducting microgravity experiments then you, obviously, conduct such experiments in microgravity habitat. But if your staying in orbit for several months or several years then you stay in an artificial gravity habitat.

    Marcel

  • newpapyrus

    There’s nothing that prevents us from deploying separate artificial gravity habitats and microgravity habitats. In fact, it has long been argued that humans shouldn’t live in the same habitats where microgravity experiments are being conducted.

    Marcel

  • newpapyrus

    You could argue that small animals on Earth already live in a low gravity environment since the smaller a creature is, the stronger it is relative to its mass.

    Humans require at least 0.1g in order to have enough weight traction to walk. And I suspect that humans could maintain their Earth-Man strength if they exercised regularly or even walked and ran around with a heavy weight vest on for a few hours a day on the Moon and Mars.

    But we’ll never know until we finally place people on the surface of the Moon for a year or two to see if there are any deleterious effects to a low gravity environment.

    If it turns out that humans can live and reproduce on low gravity worlds then it might be one of the most important discoveries in the history of the humanity!

    Marcel

  • Paul_Scutts

    Thanks for your reply, Kenneth, my main points with why we have to experiment with centrifugal force to simulate gravity are; Firstly, the need to locate human telerobotic operators within the micro-gravitational environments whilst extracting and processing off-Earth valuable materials at NEA’s and asteroids within the Asteroid Belt. Secondly, gauging the likely physical effects upon human colonists (well) before they have committed to the actual colonisation process (an ounce of prevention is worth a pound of cure). Regards, Paul.

  • Kenneth_Brown

    Yes, a separate microG habitat could solve the issue but I have already read stories about installed and proposed experiments on ISS that had to be cancelled due to vibration. Having people on board banging off of the walls is somewhat unavoidable, but mechanical systems, even if they are well balanced, are a problem. Spinning and non-spinning sections of a spacecraft holding pressure are difficult too. Maintaing a seal is possible but it’s also a huge single point of failure.

    I think on some surfaces 0.1g might be ok for walking and on others it might not be enough. I don’t think I’ve ever heard somebody ask an Apollo astronaut about traction on the moon. They fell over a bunch, but that was always attributed to them being top heavy. I know the lunar regolith is very jagged so it doesn’t seem like it would be all that slippery. It is pretty fine stuff. Somewhere I have a little bag of JSC-1A simulant. When I find it I’ll have to remember to see if it feels slippery.

  • Paul_Scutts

    Marcel, one of my favourite sci-fi novels was written by Arthur C. Clark called “Imperial Earth” where he postulated, amongst other things, the ship having a circular bicycle track where riders accelerating around the track experienced increase “weight” and the speedometers were rated in fractions of a G. They could build them eventually upon the Moon, Mars etc.. Great fun and keep muscle/bone toned at the same time. Regards, Paul.

  • Jacob Samorodin

    You can’t ignore precedent. A cosmonaut spent 14 months continuously in microgravity (and higher radiation) conditions a few decades ago. One or two other cosmonauts actually spent a total of between two-three years each in such conditions over a handful of missions. They are doing fine.

  • Paul_Scutts

    You are absolutely correct, Kenneth, it’s not going to be easy or cheap and they are, I suspect, the primary reasons why it hasn’t happened yet. It will be extremely expensive and difficult, but, maybe, it will prove to be unavoidable in the longer term. We have all the technological bits and pieces, fluid dynamic balancing mechanisms and maglev for non-contact bearings/control of rotational speed/recovery of deceleration energy etc., it’s just a matter of putting it all together. Regards, Paul.

  • Paul_Scutts

    Unfortunately, Jacob, it appears not to be that simple. There are two clearly defined problems with human beings being off-Earth for extended periods. Firstly, the physical effects and secondly, the psychological effects. Roscosmos and NASA, at this point in time, appear to be far more concerned about the latter affecting the viability of humans to Mars. Four months appears to be the optimal period of confinement, after six months, humans tend to “go off their game” psychologically. Mars 500 experiment in Moscow showed “major” emotional problems with four out of the six “crew” at the conclusion of the experiment. I remember reading that they have both alluded to other performance implications with “longer term” occupants of both Mir and the ISS. Regards, Paul.

  • Chuck Lauer

    Gary Hudson of the Space Studies Institute has been proposing exactly this type of experimental facility for several years. It is a LEO station co-orbiting with ISS that would have Earth normal, Moon and Mars gravity in different places on the arm moving out from the center. The cost is some X hundreds of millions, but not billions. Doing this research in the ISS “neighborhood” allows lower cost logistics support through CRS / Commercial Crew class vehicles.

  • newpapyrus

    That’s why you have separate orbital habitats to live in and separate orbital habitats for microgravity experiments. Connecting all habitats together is simply a bad idea.

    If you want to visit a microgravity habitat, all you have to do is enter a Flexcraft docked to your habitat and travel a few hundred meters to the other habitat orbiting near by.

    Marcel

  • newpapyrus

    Nothing difficult about orbiting two or more habitats in the same location. Its just like deploying two or more ships on the water. But that doesn’t mean you can’t visit the other ships when you want to.

    Marcel

  • Kapitalist

    Nonsense that humans couldn’t go to Mars “for psychological reasons”. That’s the kind of stuff that space hypochondriacs make up. They always make up a story that is hard to measure. That Martian space bugs would eat up all life on Earth is another favorite of theirs. Totally anti-scientific superstition! But they never talk about the real risk, that the spacecrafts burns up in one of the atmospheres.

  • Kapitalist

    A Mars mission with Hohmann transfers takes 26 months. During a good conjunction, like 2033/3035, the single way trip time is 6 months with 14 months spent on Mars. Even if a huge investment in fuel manages to save 2 months, the total mission time would still be 22 months. The question is if that 16% saving in mission time is worth the many more launches required.

    Since 2000 hundreds of astronauts have spent 6 months on the ISS without anyone getting injured. We know that it is safe to travel to Mars in microgravity, that has become an extremely well established fact for human space flight. That’s why no single space agency have any plans for simulated gravity by rotation. There exists no need for it, no application relevant for human space flight. Some medical research team maybe wants to buy such a space station for its own experiments, but that hasn’t got anything to do with NASA’s human space flight.

  • Kenneth_Brown

    That’s not entirely true. While astronauts that have spent extended periods of time on ISS without injury, that doesn’t mean that their health hasn’t degraded. Bone loss is common. Some show symptoms the same as Type II diabetes and there is considerable loss of strength.

    Any team sent to Mars will need to be in top condition when they get there. There will not be any medical or physical support such as there is when they return to Earth. You should notice that the astronauts are placed in lounge chairs as they are removed from the capsule and not up walking around. There will also not be any chance to work back up their strength gradually. They will have to work very hard from the very first day to set up their habitat and collect pre-landed equipment and supplies.

    Rotating or tumbling the craft on the way out and back could help but that adds other complexities to the space craft so they can keep an antenna pointed at Earth, solar panels facing the sun and the ability to make course corrections. Course corrections aren’t a big problem, but the tumbling/rotating will need to be stopped and then restarted using fuel in the process. That fuel is added mass that needs to be lifted from Earth.

  • Kapitalist

    No one has been injured! Don’t be querulous. The small discomforts some of them have experienced is less than what anyone is required to stand in any type of job on Earth.

    The .38 gravity on Mars lowers the strain of bones and muscles. Even directly after a 6 months bone and muscle loss they might be supermen on Mars. The reason for the chairs after Earth landing is to examine them for scientific purposes in as a pristine microgravity shape as possible. When a Russian landing capsule landed way off target, the crew exited and walked around until the rescue team arrived.

    And in any case, spaceships spinning to simulate gravity won’t happen before the first crewed landing on Mars. It’s not on the visible agenda of any agency or bigger space company. It’s a luxury that’ll have to wait.

  • Jacob Samorodin

    Human beings are tougher than you imagine. There are voluntary adventurers from years gone by, Magellan’s crew to Admiral Byrd. They did fine enduring tough physical and psychological circumstances. If human beings have become ‘soft’ and spoiled since then, there are still those among us who would make SEALs & leathernecks look like wimps.