Space

"Space brain" could make manned trips to Mars rather forgettable

"Space brain" could make manne...
The UCI study indicates that cosmic rays could cause dementia-like symptoms in astronauts on deep-space voyages, such as the proposed NASA manned Mars mission
The UCI study indicates that cosmic rays could cause dementia-like symptoms in astronauts on deep-space voyages, such as the proposed NASA manned Mars mission
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The UCI study indicates that cosmic rays could cause dementia-like symptoms in astronauts on deep-space voyages, such as the proposed NASA manned Mars mission
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The UCI study indicates that cosmic rays could cause dementia-like symptoms in astronauts on deep-space voyages, such as the proposed NASA manned Mars mission

If getting to Mars isn't hard enough, scientists at the UC Irvine say that cosmic radiation could cause astronauts on deep space missions to develop symptoms of dementia. Rodent tests indicate that exposure to high-energy particles produce cases of "space brain" marked by long-term neurological damage, cognitive impairment, and diminished judgment.

Radiation has long been recognized as a constant and very real threat to space travelers, which is the reason why crews on the International Space Station (ISS) are legally classed as radiation workers. Prolonged exposure to cosmic rays can result in an increased chance of cancer, impaired immune systems, and even affect the brain and nervous system. The latter is of particular concern because it's already known that patients undergoing radiation therapy to treat brain tumors can suffer severe neurological symptoms, such as problems with cognition and memory.

For astronauts on the ISS, radiation mainly curtails how long and how many visits crews can make in a lifetime. But outside of the protection of Earth's magnetic field, which means any deep space mission, it's another matter. On long missions, including to Mars, galactic cosmic rays become a major hazard. These immensely high energy charged particles that originate outside the Solar System can shoot through spacecraft hulls and passengers as if they aren't even there. However, when the heavier of these particles, such as the nuclei of oxygen and carbon atoms, strike, they can directly or indirectly cause major damage to living tissue.

As part of NASA's Human Research Program, a UCI team under professor of radiation oncology Charles Limoli used the NASA Space Radiation Laboratory at New York's Brookhaven National Laboratory to approximate cosmic rays using an earthbound particle accelerator. Since real cosmic rays are hard to create if one doesn't have a quasar or exploding galaxy handy, the team used fully ionized oxygen and titanium nuclei to approximate the impact of lighter particles of much higher energies.

The radiation generated was used to expose male Wistar rats at dose rates between 0.05 and 0.25 Gy/min. This is equivalent to the doses a human would suffer on a deep-space mission, where 400 to 900 mSv would be absorbed on a typical Mars mission. Since the purpose of the study was to assess damage, no attempt at shielding the animals was made.

The rats were then returned to Limoli's UCI lab, where they were observed over 24 weeks and put through medical and behavioral tests to determine what effects the radiation had. They found that not only was there damage, but it persisted even six months after relatively low exposures.

Physically, the rats suffered from damaged neurons, reduced dendritic complexity causing disrupted nerve transmissions, changes in synaptic protein levels, and elevated neuroinflammation of the brain. This was reflected by the rats developing problems in learning new tasks and impaired memory.

The rats also showed problems with "fear extinction," which is the ability of the brain to handle unpleasant and stressful memories. In other words, it's what helps you get back on the horse again after a fall.

"Deficits in fear extinction could make you prone to anxiety," says Limoli, "which could become problematic over the course of a three-year trip to and from Mars."

Limoli says that the symptoms produced would be like dementia and would manifest themselves within months of leaving Earth. The astronauts would have problems with anxiety, impaired memory, reduced ability to multitask, and poor decision making. Worse, the condition would continue indefinitely.

According to Limoli, these findings are supported by a 2015 study, where he noticed similar effects in brain cancer patients undergoing chemotherapy and cranial irradiation.

Currently, solutions are being sought for the cosmic ray problems, but the amount of shielding needed to protect Mars crews would make any mission too expensive to mount, and the highly energetic particles would still penetrate the hull or cause radiation cascades like a shell turning armor plate into shrapnel. With this in mind, the UCI team is looking at a medical solution using compounds that could scavenge free radicals and protect neurotransmission.

"This is not positive news for astronauts deployed on a two-to-three-year round trip to Mars," says Limoli. "The space environment poses unique hazards to astronauts. Exposure to these particles can lead to a range of potential central nervous system complications that can occur during and persist long after actual space travel – such as various performance decrements, memory deficits, anxiety, depression and impaired decision-making. Many of these adverse consequences to cognition may continue and progress throughout life."

The research is published in the Nature Research Journal Scientific Reports.

Source: UCI

13 comments
Green_Grasshopper
It is all well to come up with the doom and it cant be done scenarios, but why aren't these supposedly smart people working on ways to reduce the danger instead of constantly knocking the future of space travel.
DouglasNelson
And we are expected to still believe they went to the moon. At some point they need to be honest... they landed the stuff there... maybe... but people never actually went. There should be extremely high res photos possible but ... nope.. nothing
Rocky Stefano
@Green_Grasshopper, I'm sure they have, however, as noted, nothing that we have today is likely good enough to stop the highest energy bursts from penetrating the hull. Unless we can come up with Star Trek "type" shields I very much doubt you can guarantee any level of safety for an astronaut. Those types of shields require energy sources we simply do not have today.
Bob
The radiation has been known for years but this hasn't stopped the space travel fans from hyping a trip to Mars in the near future. This also highlights the earth's incredible shielding that makes it habitable for us. It also implies the high probability that Mars is sterile despite once having abundant water. Any trip to Mars will likely be one way and colonization fairly short.
CharlieSeattle
Unless lead can be mined on the moon, water is the next best shield to use to block out cosmic radiation. That is available on the moon. A spacecraft with a circular rotating torus section, like that shown in the movie, "Mission to Mars" with water in the outer walls to provide the protection from cosmic radiation. The rotation also provides artificial gravity. http://www.sharecg.com/images/medium/132557.jpg%3C/a%3E%3C/div%3E%3Cdiv%20class=
bobcat4424
The author has missed an extremely important part of the equation. For the two most serious issues --- cosmic radiation damage and muscle and bone atrophy from weightlessness --- good solutions already exist. But these solutions are heavy and very expensive to launch into space. The easy solution for cosmic radiation is to use water as a shield for radiation and replace it with human waste. Water (or any hydrogen-based molecule) is an excellent cosmic radiation shield and could also be drank and used as a source of fuel and oxygen. Its problem is its weight. Weightlessness can be handled by using a revolving structure that substitutes centrifugal force for gravity. This structure would be both heavy and complex, but worthwhile. Neither of these is new, but what has changed is that SpaceX has dramatically lowered (by almost 90% for high-velocity launches) with reusability and weight is no longer as intimidating as in the past.
Pelham
The article is fascinating, but CharlieSeattle's comment is even better. And that's because instead of just identifying a seemingly insurmountable problem, it proposes a solution. Beyond that, going to Mars appears to be the only possible space mission of any sort that really gets the blood stirring. But what about after that? Pretty much nothing. Oh, robotic probes here and there are still worthwhile, but this is fairly minor stuff. What we need to be working on is the technology that would take us far beyond our the neighborhood of our Sun, that would make us truly interstellar, able to travel between star systems in moments rather than centuries or millennia. And with no ill effects. But so far as I'm aware, the main roadblock to anything of the sort is our own scientific community, which insists that no such possibility exists. And perhaps they're right. But there's at least a slim chance that they're wrong, and I believe it would actually be worth spending billions or even trillions of dollars to find out, even if it all ends up being a waste. In this regard, those dreamers berated as wearers of tinfoil hats are worthier of honor than those who insist on limitations as defined by this moment in human history.
RobertAGlazer
Get there faster! This would limit exposure time. Make the trip in weeks and not in years. Robert Glazer.
Jan Garber
I wonder if there is anything that attracts this radiation? Maybe something that could be used like a lightening rod.
JamesDemello
This kind of research is great because it can be done here on Earth relatively cheap. Unlike what NASA does on the ISS that costs crazy amounts of money and returns little concrete scientific results. That is probably why they do so many PR stunts as they don't have much science to talk about. I say get rid of the ISS (lower Earth orbit is an unrealistic environment to research space travel anyway) and give that money to research projects like this one and other robotic efforts that actually have an objective and give back substantial results. Tired of the monkeys in space doing low gravity somersaults.