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  (Source: TriStar Pictures)
NASA already responded to the results, saying it will conduct studies of its own

Astronauts have the ability to see planets and other space-related beings in ways most of us never will, but new research shows that astronauts could potentially lose their vision completely by living out this profession.

The University of Texas Medical School at Houston recently performed tests on astronauts who had spent more than one month in space, and found that they had eyeball and brain tissue damage.

Texas researchers studied 27 astronauts who had participated in long-duration NASA missions. Out of the 27, nine had an expansion of the cerebral spinal fluid space surrounding the optic nerve; six of them had a flattening of the rear of the eyeball; four of them had a bulging of the optic nerve, and three of them had changes in their pituitary gland and its connection to the brain.

All of the astronauts studied spent an average of 108 days in space, either on a space shuttle mission or spending time on the International Space Station (ISS). The researchers found that the issues these astronauts have are similar to those caused by intracranial hypertension, where pressure in the brain presses against the eye sockets and skull.

"Microgravity-induced intracranial hypertension represents a hypothetical risk factor and a potential limitation to long-duration space travel," said Professor Larry Kramer, leader of the study at the University of Texas Medical School. "Consider the possible impact on proposed manned missions to Mars or even the concept of space tourism. Can risks be eventually mitigated? Can abnormalities detected be completely reversed?

"The next step is confirming the findings, defining causation and working towards a solution based on solid evidence."

The study has already grabbed NASA's attention. While no astronauts are being pulled from any programs at this point, the space agency plans to look further into these results.

"NASA has placed this problem high on its list of human risks, has initiated a comprehensive programme to study its mechanisms and implications, and will continue to closely monitor the situation," said William Tarver, head of flight medicine at NASA's Johnson Space Centre in Houston, Texas.

If these results were proven true, it could throw a wrench in many space plans such as SpaceX's idea to develop a reusable launch system for cheap spaceflight and Mars settlement. There are also plans to send an astronaut to an asteroid by 2025 and another to Mars by 2030.

Sources: Phyorg.com, ABC News, The Pioneer



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RE: Well.
By MrBlastman on 3/14/2012 10:55:31 AM , Rating: 4
Good points yes but I think there are others to consider also. What we have here is a study with results and a proposed causative source inducing a less than desirable effect on the human body. The easiest answer here is we need artificial gravity... on paper.

One other idea to consider is this. The study mentions that hypertension is causing these changes in the optic nerve/eyeball etc. But why? Why would it do this? Well, think about it. Strap your ankles to a coatrack and hang there for some time. I can assure you that pressure will build up in your head and eventually you might pass out.

What we see here is how gravity helps us regulate the pressure in our skull. Man is accustomed to being upright or laying down, constantly being effected by gravity. When we are sleeping it is not so much an issue as our blood pressure naturally drops when gravity is not pulling as much blood to our feet (thus reducing pressure in our head), so, it counterbalances our waking hours.

When awake and active, gravity acts on the blood and keeps it from traveling to our heads with as much force versus our feet. When a fighter pilot, for instance, pulls extreme G's, they black out because too little goes to their brain, thus the inception of G-suits and 30-degree reclining seats to assist in preventing this.

When man is in space... there is no gravity to act upon the body and bloodflow, thus, pressure is not regulated by this natural mechanism--increasing total pressure in the brain. You see, as it seems (with limited data) that a short-term, more elegant solution would be... blood pressure medication! I believe the studies should continue by having astronauts pop beta blockers and other drugs to help reduce pressure while in space so we can see if there is any benefit to this. I theorize that there will be... and in the short-term, alleviates the need for artificial gravity (which with our current technology... is very primitive in potential).

Going to Mars... I'm not so worried about. Put the ship in a 1 G burn, orient the cabin layouts to have astronaut feet on the "ground" of this and it will seem like they are on earth... fuel is an issue, though...


RE: Well.
By ppardee on 3/14/2012 2:52:44 PM , Rating: 2
While I appreciate your desire to find a simpler solution, drugs aren't the answer, especially for long-term trips. Hypertension medication has side-effects. Trying to fix one problem by introducing another is not advisable. Secondly, having the crew take drugs every day means you have to have the drugs on board. This means a higher launch weight, greater inertia (lower maneuverability) and less space on the ship. Related to that, what happens when you run out of the medication?

Gravity can be simulated via centrifugal force. A cylindrical capsule can be spun, creating "downward" force against the sides of the capsule. The down side here is that it limits the design. The upside is varying gravity is as easy as spinning up/down the capsule, and maintaining gravity should require little/no power since there is little/no drag on the capsule itself. Have the crew sit on the end of the capsule for launch (so they are upright on Earth) then once they've had enough of weightlessness, they can spin up the capsule. This would also have the benefit of offsetting the atrophy associated with long-term weightlessness.


RE: Well.
By MrBlastman on 3/15/2012 1:05:04 AM , Rating: 2
You're missing a few things... I'll elaborate. :)

quote:
Hypertension medication has side-effects.


They are small. Have you ever been on beta blockers? I am and not for high blood pressure.

quote:
This means a higher launch weight, greater inertia (lower maneuverability) and less space on the ship.


Not that much. We're talking pills here. Beta blockers are quite light weight, I can assure you that. As for inertia... minimal effect at best and not even worth mentioning.

quote:
maintaining gravity should require little/no power since there is little/no drag on the capsule itself.


Nope. You forget this little thing called the people inside touching the walls and manipulating objects within. For every action there is an equal and opposite reaction. While it might be small, it is parasitic to a degree. Some form of maintenance of the speed is required.

Also, many studies have been done on the coriolis effects of rotational artificial gravity and they can be significant. The RPM of the rotation can not exceed 2 RPM thus requiring a 735 ft radius of rotation--a LARGE ship! This problem is costly and complicated to solve by just saying, "hey, lets do artifical gravity!" The cost of materials to put a craft/parts into orbit to accommodate these needs far outweigh the costs to put some pills into orbit.


RE: Well.
By niva on 3/14/2012 6:49:20 PM , Rating: 2
A sustained 1G burn to Mars would get us there in days... Obviously somewhere halfway through you'll have to turn this around and start breaking at a sustained 1G, but what I'm trying to say is that right now with our technology this is not feasible at all.

Assuming 9.8 m/s^2 acceleration within a day (86400 seconds) starting from 0 velocity you would have traveled well over 300k km.

http://www.wolframalpha.com/input/?i=integrate+9.8...

At a sustained acceleration of 1G at the end of 1 day you're moving at ~8000 km/s which is faster than any human has moved up to this point in history that we know of relative to the position of our planet.

We have no such energy source available in space right now, to accelerate a massive spacecraft filled with people, so that we could produce such long term acceleration.

So 1G acceleration is ludicrous to talk about at this stage. Artificial gravity is also ludicrous because we cannot yet build such big structures in space that would make this possible unless we stop all wars and dedicate ourselves towards conquering our solar system at least.


RE: Well.
By MrBlastman on 3/15/2012 12:56:48 AM , Rating: 2
Hence why,

quote:
fuel is an issue, though...


The information is in the details. I choose my words carefully and deliberately so it is easy to overlook things I say. ;)

This gets back to my first point--beta blockers and blood pressure medication. It might just work as a holdover to better solutions.


RE: Well.
By JediJeb on 3/15/2012 4:04:35 PM , Rating: 3
I have been on beta blockers in the past and am on blood pressure medicine currently, and not all of them would relieve this problem. Beta blockers work by controlling heart rate, which probably would not fix the problem mentioned in the article. Also the article talks about hypertension within the brain cavity, not the entire circulatory system. This problem arises from the fact that in a weightless environment the body's internal fluids tend to flow up into the upper body. Think of how sitting for long periods no earth can cause swelling in the feet and legs, in space it is the opposite effect, your chest and head "swells" or fill with fluid. To remedy the problem we need to find a way to keep things like lymphatic fluids and blood lower in the body under weightless conditions. I'm not sure we have drugs yet that can accomplish this.


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