Astronaut Muscles Waste in Space: Safety for Future Mars Missions Questioned

[n2doc]

ScienceDaily (Aug. 18, 2010) — Astronaut muscles waste away on long space flights reducing their capacity for physical work by more than 40%, according to research published online in the Journal of Physiology.

This is the equivalent of a 30- to 50-year-old crew member's muscles deteriorating to that of an 80-year-old. The destructive effects of extended weightlessness to skeletal muscle -- despite in-flight exercise -- pose a significant safety risk for future human missions to Mars and elsewhere in the Universe.

An American study, led by Robert Fitts of Marquette University (Milwaukee, Wisconsin), was recently published online by the Journal of Physiology and will be in the September printed issue. It comes at a time of renewed interest in Mars and increased evidence of early life on the planet. NASA currently estimates it would take a crew 10 months to reach Mars, with a 1 year stay, or a total mission of approximately 3 years.

Fitts, Chair and Professor of Biological Sciences at Marquette, believes if astronauts were to travel to Mars today their ability to perform work would be compromised and, with the most affected muscles such as the calf, the decline could approach 50%. Crew members would fatigue more rapidly and have difficulty performing even routine work in a space suit. Even more dangerous would be their return to Earth, where they'd be physically incapable of evacuating quickly in case of an emergency landing.

http://www.sciencedaily.com/releases/2010/08/100817212011.htm

[ixion]

1. simulating gravity is the key

and the lack of it is why exercise isn't working.

[kestrel91316]

3. Good luck with that.

[ixion]

6. You speak like it can't be done...

why?

[Orsino]

14. Well, it hasn't been done yet.

I'm pretty sure, too, that centrifugal simulation of gravity would be all that's needed...but we haven't really tried it out yet. One rotating section of a spacecraft might be all that's needed, but it would suck to find out otherwise one year into a three-year mission.

However, even a 50% reduction in work capacity might not be so bad in Mars' 0.3g.

[Posteritatis]

21. Any child with a merry-go-round and most fairgrounds have done it.

It's not exactly complex.

[Orsino]

22. Our spacecraft are already far more complex...

...but they represent the limit of what can be achieved with current budgets and know-how. Adding rotating sections to the craft we're developing means more money, time and chance of failure.

It is simple, yes, but doing it in space is not. We have not often had the luxury of adding on whole new rooms. Astronauts today have to be more concerned with staying alive in the short term than with their long-term health.

[jailthecrooks]

7. You never saw 2001: A Space Odyssey

Artificial, faux, simulated, rotational gravity would keep muscles, bodies and minds in tip top shape. A nuclear powered VASIMIR rocket would shorten the journey and reduce the amount of supplies and food needed to be hauled up into orbit during construction.

Magnetically levitated rail gun systems could shoot almost all the components up to LEO where it could be ferried into higher orbit by solar sail, VASIMIR, or other method.

I vote for zero shuttle flights and not even astronauts should go up on rockets.

The escape velocity at the Earth's surface is about 11.2 kilometers per second (25,000 miles per hour); the escape velocity on the Moon's surface is 2.4 kilometers per second (5,300 miles per hour)"

http://www.thefreedictionary.com/escape+velocity

"Magnetic levitation is a promising technology for future space transportation," Yang told PhysOrg.com. "The most expensive part of space missions to low-Earth orbit is the first few seconds—getting off the ground."

In their model of a test vehicle on a seven-meter-long track, Yang's group used a suspension system based on bulk high temperature superconductors, which achieve highly stable levitation due to their diamagnetic and flux pinning properties. The researchers used an arrangement of YBCO bulk superconductors, which achieve their remarkable property of zero resistance at 77 K. When the superconductors were cooled to this temperature, the test vehicle levitated freely over the track.

"The maglev launch assist benefits from the large levitation ability for heavy loads and a linear motor's acceleration technology, as in the maglev train," Yang explained. "In this investigation on the feasibility of the PM-HTS maglev technology, the test vehicle weighed 40kg and was moved on the 7-meter-long track. A running velocity of 5m/s was achieved with an acceleration of 1.2g"

http://www.physorg.com/news91272157.html

A back of the napkin analysis says that ramping up the small scale test track to 9.4 miles long would put a payload into space, or an astronaut as 1.2 g's is less than race cars accelerate. Actually it would be much shorter. Increasing acceleration beyond what a human could tolerate would further shorten the length of the track.

[caraher]

9. Scaling up is challenging to say the least

Cooling miles of YBCO to liquid nitrogen temperature is one challenge. You almost certainly want to run at more like 3 g for acceleration with astronauts (and yes, you could go much higher if launching cargo). Getting rid of the need to carry a lot of reaction mass does help a lot, but when you're accelerating a test payload to only a few m/s you don't have to deal with aerodynamic drag or the thermal problems that come with moving at near-orbital speeds in the thick air close to Earth.

You might also check your napkin math. The book I use for my non-science major's class discusses electromagnetic launch systems and calculates that at 3g to reach a typical orbital speed of 8 km/s would require 1000 km of track.

v^2=v0^2 + 2ax Since v0=0, we get x=(v^2)/2a = <(8000 m/s)^2>/<2 (30 m/s^2)>=1067 km.

[txlibdem]

12. I must have different math than you

Since we're talking about putting a payload into low earth orbit I did overestimate the speed required to put a payload into orbit. My figure would have shot each of the space ship components off into the void. I'll take your 8 kilometers per second figure. The article I based my 1.2g calculation on was way off, too. Thanks for pointing that out. It looks like humans will still have to ascend to orbit using rockets for the time being.

The launch ring would be very similar to the particle accelerators used for physics experiments, with superconducting magnets placed around a 2-kilometre-wide ring.

Anything launched in this way would have to be able to survive enormous accelerations - more than 2000 times the acceleration due to gravity (2000g).

http://www.newscientist.com/article/dn10180-huge-launch-ring-to-fling-satellites-into-orbit.html

It looks like a perfect system to lift all the components of a mars-mission spacecraft or space station because it reduces the cost to put a payload into orbit by 100 to 1.

[bananas]

16. Are you jailthecrooks ?

You're not supposed to use sockpuppets here.

[RaleighNCDUer]

4. And that is why we should have put a colony on the moon years ago

instead of wasting so much time in LEO space stations. Until we have the capacity to build ships and stations which can simulate gravity we will be limited to mere close orbit tourism.

This was known decades ago, from the first Soyuz station, and was predicted by science writers (and science fiction writers) decades before that.

Only problem is, it's impractical to put bomb platforms on the moon, which is what our space program has been all about since the 80s.

[Peace Patriot]

5. You nailed it, RaleighNCDUer! War won. Science lost.

"Only problem is, it's impractical to put bomb platforms on the moon, which is what our space program has been all about since the 80s."

It could have been otherwise. That's the saddest part.

[kestrel91316]

2. Humans evolved in an environment with constant gravity. Why we would

think we could survive long-term without it, any more than we could survive without oxygen, is utterly beyond me.

[jailthecrooks]

8. Werner Von Braun

did a whole series of articles about space stations that rotated to provide artificial gravity.

Shaped like a wheel with two spokes, von Braun's space station would spin like a carnival ride to create centrifugal force that would act as a false gravity. Inside the wheel, three decks would provide room for the communications equipment, earth observatories, military control centers, weather forecasting centers, navigational equipment, living space and mercury-vapor power generating turbines that would facilitate the many functions that von Braun imagined the station would perform.

http://science.nasa.gov/science-news/science-at-nasa/2000/ast26may_1m/

Some more background and cool pics at http://home.flash.net/~aajiv/bd/colliers.html

[kestrel91316]

10. We lack the resources to build it, even if it would work.

[txlibdem]

13. If we're talking about limited resources

there is no point discussing human space travel at all. We don't have the resources to be in space right now at all if we're using that diversion.

But the question of how much would it cost to build it can be compared to the cost of NOT building it, just as a value exercise. With muscle and bone loss due to lack of gravity this sets an upper limit on the amount of time an astronaut can stay in space without being completely incapacitated once he reaches his destination. For a Mars mission an astronaut will have to be in pretty much top shape upon arrival.

[tinrobot]

20. But what about when they get to Mars?

The gravity on Mars is a little more than 1/3 that of Earth. I suspect that the significantly lower gravity will not be kind to an explorer's muscles, either.

[laconicsax]

11. Magnets!

Make the floor into a big electomagnet and make everyone wear dorky magnetic jumpsuits.

Sure the prolonged exposure would wreak havoc with equipment and probably cause other health problems, but isn't it fun to play with bar magnets?

[Orrex]

15. What if the astronauts try to walk past each other?

They'll either get stuck together for the rest of the trip or else repel each other backwards against the walls!

[laconicsax]

17. Like I said, it's fun to play with bar magnets. n/t

[Orrex]

18. You fool! You'll kill us all!

[Avalux]

19. But if gravity doesn't exist.....

:shrug:

Kidding aside, the earth's living organisms and gravity go together like popcorn and cholula. It's not just restricted to humans; all living organisms.