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interstellaryeller
2008-Oct-26, 11:38 PM
Can astronauts survive a long term spaceflight? Or will exposure to gamma radiation give them brain damage? I heard that they could comeback as a bunch of punch drunks. How true is this?

Ronald Brak
2008-Oct-27, 12:00 AM
Yes humans can survive long term space flight. But they will need adequate protection from radiation. This is doable. Weightlessness is also a problem, however the Soviets demonstrated that humans can survive considerable periods of it, but it does weaken people, but even this can be overcome by making a rotating spacecraft. As our medical knowledge and technology improves it should be possible to oversome some of the negative health effects of spaceflight. For example, drugs might be developed that can help the body repair radiation damage or reverse some of the effects of weightlessness. Or a more extreme solution would be to just send a brain, which would limit the amount of tissue exposed to radiation and would make muscle wasting irrelevant.

Chip
2008-Oct-27, 12:07 AM
Can astronauts survive a long term spaceflight?...

Yes - if the astronauts are extremely well-insulated from longterm radiation as well as micro-(and larger) meteorites, and have artificial gravity created by rotating sections of a very large spaceship. And there is air, water and food and ways of reproducing it on board.

("Long term" in this example equals years in space in a very big ship so its hypothetical but still within present day technology and engineering if we had a good reason to do it.)

PraedSt
2008-Oct-27, 11:45 AM
Can astronauts survive a long term spaceflight? Or will exposure to gamma radiation give them brain damage? I heard that they could comeback as a bunch of punch drunks. How true is this?

Psychological factors might be a bigger problem I think. Unless the crew is big enough.

A bunch of punching drunks, more like :D

Noclevername
2008-Oct-28, 02:51 PM
Mass for shielding, spin for gravity. It's an old solution but a goodie.

showboat
2008-Oct-28, 10:06 PM
Don't need humans.

http://www.urban75.net/vbulletin/showthread.php?p=8024931

Ingemar Joensson of Sweden exposed some 3,000 water bears to 10 days of open-space while aboard a ESA spacecraft in low orbit"

(((Waterbears)))

Actually it transpires that they were in some kind of hibernation state rather than bimbling around '
------------------------------------------------

After germinating on mars the giant water bears [genetically modified to the size of house] can start clawing into mars for opals.

http://www.universetoday.com/2008/10/28/precious-gems-discovered-on-mars/

'The water-based mineral deposits are telltale signs of where and when water was present on ancient Mars. On Earth, opals consist of at least 3-10% water, and Precious Opal, the variety used most often in jewelry, have pockets of spheres that diffract light at various wavelengths, creating colors and a beautiful, if not valuable look. Opal is found in Australia, England and the western US.

On Mars, the hydrated silica has been found around Mars "Grand Canyon". "We see numerous outcrops of opal-like minerals, commonly in thin layers extending for very long distances around the rim of Valles Marineris and sometimes within the canyon system itself," said Ralph Milliken of NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Until now, only two major groups of hydrated minerals, phyllosilicates and hydrated sulfates, had been observed by spacecraft orbiting Mars. Clay-like phyllosilicates formed more than 3.5 billion years ago where igneous rock came into long-term contact with water. During the next several hundred million years, until approximately 3 billion years ago, hydrated sulfates formed from the evaporation of salty and sometimes acidic water.

The newly discovered opaline silicates are the youngest of the three types of hydrated minerals. They formed where liquid water altered materials created by volcanic activity or meteorite impact on the Martian surface. One such location noted by scientists is the large Martian canyon system called Valles Marineris.'
----------------------------------------------

After which they could fart/blast their way off mars into orbit carrying their valuable collection of martian opals in their six arms.

ravens_cry
2008-Oct-29, 04:37 AM
The question is not whether we need humans, it is whether we can go.

Ronald Brak
2008-Oct-29, 04:57 AM
And we can go. We know how much radiation is in space and how to protect against it and we have a good understanding of the effects of long term weightlessness and how to simulate gravity if desired. If people want to discuss the seperate question of if people should go, creating another thread might be appropriate.

Swift
2008-Oct-29, 02:17 PM
Psychological factors might be a bigger problem I think. Unless the crew is big enough.

I suspect that the use of nuclear submarines, which may be isolated for up to six months at a time, has given us a lot of insight on how to keep crews mentally healthy for long periods of time.

PraedSt
2008-Oct-29, 03:07 PM
I suspect that the use of nuclear submarines, which may be isolated for up to six months at a time, has given us a lot of insight on how to keep crews mentally healthy for long periods of time.

Ah, what was the insight I wonder? For >6m: a walk in the park, or avoid like the plague? :)

Swift
2008-Oct-29, 03:24 PM
Ah, what was the insight I wonder? For >6m: a walk in the park, or avoid like the plague? :)
I know you added the smile, but I actually think it is an interesting question. I believe that the six months is because of the mechanical issues of the sub (like how much food they can store), but I don't know that. I suspect the US and Russian Navy have done studies on these issues, but I don't know the results. It would be interesting to get some of the submariners who are on BAUT to comment about this.

PraedSt
2008-Oct-29, 04:14 PM
I suspect the US and Russian Navy have done studies on these issues, but I don't know the results. It would be interesting to get some of the submariners who are on BAUT to comment about this.

I've always found the psychology behind it interesting. You're right about the subs. We've also have Antarctic stations, the Biospheres, and of course the Space Stations.
I found a small overview here (http://www.redcolony.com/art.php?id=0408300).

too many alpha males in a cramped space were likely to display more stress, internal arguments, and problems with ground control :D

It doesn't necessarily have to be completely enclosed spaces either, as one of BigDon's posts (http://www.bautforum.com/1349359-post473.html) shows.
After a month at sea you notice everything is made out of steel and linolium. Two months and you stop and look at a wooden pallet and run your hands across it. Three months at sea and you really understand Columbus' crew wanting to lynch him.

So yeah, think we might have a few problems to solve, especially for very long journeys. Still, I'm sure a solution will be found...one day.

iquestor
2008-Nov-01, 06:59 PM
I know you added the smile, but I actually think it is an interesting question. I believe that the six months is because of the mechanical issues of the sub (like how much food they can store), but I don't know that. I suspect the US and Russian Navy have done studies on these issues, but I don't know the results. It would be interesting to get some of the submariners who are on BAUT to comment about this.

When I was in, we were told that the first limiting factor of how long a modern nuclear sub could stay submerged was largely dependant on the sanity of the crew. Boomers were pretty big, the Tridents larger still. I don't know if actual studies were done, but enough supplies could be kept to allow for several years. I dont think its a secret we made our own oxygen, and were able to bleed out C02 using Amine and other chemicals, so breatheable atmosphere wasnt an issue like it was on earlier subs. Potable water wasnt an issue either. I was given an exact number of years they felt we could stay submerged, but dont remember if that is classified, so I wont post it here.

I did read a science fiction book years ago where the US and russina sub fleets were cut apart and launched into orbit, where they were re-assembled as spacecraft. Very cool idea, but titanium is pretty heavy to be launching into orbit!

Abbadon_2008
2008-Nov-02, 03:51 AM
Well, a few hours trapped in the same car with a group of poeple can produce migranes, high blood pressure, and antisocial thoughts.

Multiply that times one year, without sunlight or rest stops, and BANG! That's what long space flight would be like.

PraedSt
2008-Nov-02, 09:08 AM
Well, a few hours trapped in the same car with a group of poeple can produce migranes, high blood pressure, and antisocial thoughts.

Multiply that times one year, without sunlight or rest stops, and BANG! That's what long space flight would be like.

To continue the topic of psychology: magnetism and maaaaaaadness, on a separate thread (http://www.bautforum.com/life-space/80771-magnetic-hunger.html).

cjameshuff
2008-Nov-03, 07:52 PM
I did read a science fiction book years ago where the US and russina sub fleets were cut apart and launched into orbit, where they were re-assembled as spacecraft. Very cool idea, but titanium is pretty heavy to be launching into orbit!

And vessels made to withstand many atmospheres of external pressure would make rather heavy spacecraft. Especially once you add all the radiators and such needed to run the reactor without cooking the crew with waste heat.

I've seen this idea a few times...people seem to fix on the idea that both subs and spacecraft need to recycle their air and go for long periods without resupply, and ignore all the very many differences that would make subs quite inferior as spacecraft.

Swift
2008-Nov-03, 08:25 PM
When I was in, we were told that the first limiting factor of how long a modern nuclear sub could stay submerged was largely dependant on the sanity of the crew. Boomers were pretty big, the Tridents larger still. I don't know if actual studies were done, but enough supplies could be kept to allow for several years. I dont think its a secret we made our own oxygen, and were able to bleed out C02 using Amine and other chemicals, so breatheable atmosphere wasnt an issue like it was on earlier subs. Potable water wasnt an issue either. I was given an exact number of years they felt we could stay submerged, but dont remember if that is classified, so I wont post it here.

Thanks iquestor, that exactly the kind of info I was thinking about.

So, are we limited to 6 month missions? How might one increase that? If the problem in subs is lack of windows, spaceships might have a distinct advantage.

As far as breathing atmosphere.... yeah, I kind of figured that out. I think it is pretty public knowledge. Amazing the chemistry you can do if you have a nuclear reactor for power.

ravens_cry
2008-Nov-03, 08:32 PM
Nuclear power completely transformed the concept of a submarine. From what was basically a surface vessel that could submerge to attack and evade detection for a relative short term, to a vessel that could stay underwater for over a year, and say underwater theoretically the entire time, it was nothing short of revolutionary. Now, what could nuclear power do for spacecraft? We have already seen the feats of exploration possible by the space probes sent far into the endless night, such as Voyager 1 & 2 and Pioneer 10 and 11.

Vultur
2008-Nov-04, 09:46 AM
Well, a few hours trapped in the same car with a group of poeple can produce migranes, high blood pressure, and antisocial thoughts.

That's interesting. I never felt that kind of thing on 15+ hour drives. Does it not happen if the people are friends or family members? Or maybe it's just a matter of the type of people.

As for psychological factors, consider the experiences of polar explorers: small groups have spent many months isolated in hostile environments, and generally didn't suffer real psychological damage.

I think it might largely be a matter of picking the right type of people: explorer types, if you will.

PraedSt
2008-Nov-04, 04:09 PM
That's interesting. I never felt that kind of thing on 15+ hour drives. Does it not happen if the people are friends or family members? Or maybe it's just a matter of the type of people.

In my experience it's worse with family members. :)

PraedSt
2008-Nov-04, 04:15 PM
This thread should be in the 'Space Exploration' forum, shouldn't it? Couldn't find it for a minute...

Anyway, some good news regarding the OP.

Can astronauts survive a long term spaceflight? Or will exposure to gamma radiation give them brain damage? I heard that they could comeback as a bunch of punch drunks. How true is this?

New spaceship forcefield makes Mars trip possible (http://www.physorg.com/news145004546.html)

As usual, ignore the headline. Only at research stage.
Space craft visiting the Moon or Mars could maintain some of this protection by taking along their very own portable "mini"-magnetosphere. The idea has been around since the 1960's but it was thought impractical because it was believed that only a very large (more than 100km wide) magnetic bubble could possibly work.
Computer simulations done by a team in Lisbon with scientists at Rutherford Appleton last year showed that theoretically a very much smaller "magnetic bubble" of only several hundred meters across would be enough to protect a spacecraft.

Now this has been confirmed in the laboratory in the UK using apparatus originally built to work on fusion. By recreating in miniature a tiny piece of the Solar Wind, scientists working in the laboratory were able to confirm that a small "hole" in the Solar Wind is all that would be needed to keep the astronauts safe on their journey to our nearest neighbours.

antoniseb
2008-Nov-04, 07:38 PM
We got a request to move this thread to Exploration as opposed to Life in Space. It looks like a toss-up to me, so I'll leave it unless the OP asks.

ToSeek
2008-Nov-04, 08:39 PM
How about Q&A?

mugaliens
2008-Nov-04, 10:49 PM
I suspect that the use of nuclear submarines, which may be isolated for up to six months at a time, has given us a lot of insight on how to keep crews mentally healthy for long periods of time.

As well as physically healthy, mentally and physically fit, hygiene, exercised, fed...

Scrap the Astronaut program! It's time to send the Aquanauts!

Besides, they'll probably feel right at home with water bears.

Edit: I vote for Space Exploration.

kleindoofy
2008-Nov-04, 11:10 PM
Can astronauts survive a long term spaceflight? ...

Apart from the outside dangers, another question is whether a long term, long distance flight can can survive the human error component. Even a tiny glitch in the hardware can have deadly consequences. A spaceship 2/3 of the way to Mars doesn't have a Soyuz capsule for quick re-entry. Even Apollo 13 just barely made it back to Earth, and they were only hours away.

If they keep everything as simple and reliable as possible, things could work out fine, but if they beef it up with new, flashy, complicated tech-bling, as they will, the possibilities for disaster rise exponentially.

timb
2008-Nov-04, 11:45 PM
This thread should be in the 'Space Exploration' forum, shouldn't it? Couldn't find it for a minute...

Anyway, some good news regarding the OP.


New spaceship forcefield makes Mars trip possible (http://www.physorg.com/news145004546.html)

As usual, ignore the headline. Only at research stage.

The paper (http://www.iop.org/EJ/abstract/0741-3335/50/12/124025) makes no mention of solar flares, solar (particle|proton) events, or galactic cosmic radiation, so I'm dubious about its ability to protect against all the radiation hazards long term deep space explorers would face. There are no proven technologies that would keep astronaut exposures within legal safety limits for a six month lunar stay, let alone a three year mission to Mars.

PraedSt
2008-Nov-05, 12:14 AM
The paper (http://www.iop.org/EJ/abstract/0741-3335/50/12/124025) makes no mention of solar flares, solar (particle|proton) events, or galactic cosmic radiation, so I'm dubious about its ability to protect against all the radiation hazards long term deep space explorers would face. There are no proven technologies that would keep astronaut exposures within legal safety limits for a six month lunar stay, let alone a three year mission to Mars.

Yeah, it's only a Mickey Mouse solution. I didn't know about the lunar six-month limit though. Interesting and worrying. Thanks.

Ronald Brak
2008-Nov-05, 12:51 AM
There are no proven technologies that would keep astronaut exposures within legal safety limits for a six month lunar stay, let alone a three year mission to Mars.

Well, except for the very high tech method called a thick layer of dirt or water or polyurethane. No particularly exciting or glamorous, but it works. The old science-fiction idea that everyone can spend huge amounts of time trotting around in just a space suit isn't quite correct, but people won't need to spend vast times on the surface of planets and moons. We have some fairly fancy machines now to do most of the grunt work. (Your arms and legs they got nothing to do, Some machine's doing that for you...)

timb
2008-Nov-05, 01:09 AM
Well, except for the very high tech method called a thick layer of dirt or water or polyurethane. No particularly exciting or glamorous, but it works. The old science-fiction idea that everyone can spend huge amounts of time trotting around in just a space suit isn't quite correct, but people won't need to spend vast times on the surface of planets and moons. We have some fairly fancy machines now to do most of the grunt work. (Your arms and legs they got nothing to do, Some machine's doing that for you...)

For trips to Mars the amount of shielding required in flight is prohibitive, I believe. There is work being done on plastics, but AFAIK this technology has not been proved. Sure you can live in a hole in the ground once on the Moon or Mars analysing samples brought back by robots, but that seems to defeat much of the purpose of going there. You could analyse samples brought back by robots sitting on Earth, and your lab would be much more comfortable and better equipped. The savings on payload you achieve by not lugging all that human junk around would likely more than make up for the required extra fuel for a sample return mission.

So far the demonstrated sample collection and locomotor abilities of robots on Mars does not suggest they are a substitute for human arms and legs.

Ronald Brak
2008-Nov-05, 01:32 AM
For trips to Mars the amount of shielding required in flight is prohibitive, I believe.

Adequate shielding is one reason why long crewed spaceflight will be so expensive, but it's probably only a small slice of the total expense pie, particularly since stuff you need can be used as shielding. And you can easily cut back on shielding by simply careing less about whether or not the crew survive.


There is work being done on plastics, but AFAIK this technology has not been proved.

Um, plastic, cheese, water, old socks, they all stop radiation. It's hard to see how this could get any more proved. And people have been shot into space for a while now, even going as far as the moon.


Sure you can live in a hole in the ground once on the Moon or Mars analysing samples brought back by robots, but that seems to defeat much of the purpose of going there. You could analyse samples brought back by robots sitting on Earth, and your lab would be much more comfortable and better equipped. The savings on payload you achieve by not lugging all that human junk around would likely more than make up for the required extra fuel for a sample return mission.

It does seem a bit odd, doesn't it? But whether or not it is worth it is a seperate issue from whether or not it can be done.


So far the demonstrated sample collection and locomotor abilities of robots on Mars does not suggest they are a substitute for human arms and legs.

Okay. And so far the demonstrated collection and locomotor abilites of human arms and legs on earth does not suggest they are a good substitute for bulldozers in rich countries because of the high cost of labour. As the cost of human labour is likely to be extremely high on mars, my guess is that a capital intensive approach is likely to be taken with reguards to production.

JonClarke
2008-Nov-05, 09:11 AM
As well as physically healthy, mentally and physically fit, hygiene, exercised, fed...

Scrap the Astronaut program! It's time to send the Aquanauts!



Submariners provide useful analogues to long duration space travellers, as do polar expeditioners. But there are also many differences.

Compared to astroauts submariners a younger, more male dominated, almost exclusively military, less educated, have minimal scientific training, live in much larger groups (typically a nuclear submarine as a crew of ~100 or more),lessvolumeper person, and have much less contact with the outside world.

Oddly enough, the best population to learn from regarding long duration spacecraft are.... astronauts. A considerable number have space flight experience equivalent to at least the shorter trips to Mars.

For example:

Sergei Krikalev 804 days (six flights, three long duration)
Sergei Avdeyev 748 days (three long duration flights, one more than a year)
Valeriy Polyakov 679 days (two long duration flights, one 14 months)
Anatoly Solovyev 651 days (four flights, three long duration)
Alexandr Kaleri 610 days (four long duration flights)
Viktor Afanasyev 556 days (three long duration flights)
Yuri Usachev 553 days (four flights, three long duration)
Musa Manarov 541 days (two long duration flights, one more than a year)
Yuri Malenchenko 515 days (three long duration flights)
Alexander Viktorenko 489 days (four long duration flights)
Nikolai Budarin 444 days (three long duration flights)
Yuri Romanenko 431 days (three flights, two long duration)
Alexander Volkov 391 days (three flights, two long duration)
Yuri Onufrienko 389 days (two long duration flights)
Vladimir Titov 387 days (five flights, (two long duration)
Gennady Padalka 387 days (two long duration flights, third scheduled)
Vasili Tsibliyev 382 days (two long duration flights)
Valery Korzun 386 days (two long duration flights)
Pavel Vinogradov 381 days (two long duration flights)
Peggy Whiston 377 days (two long duration flights)
Leonid Kizim 375 days (three flights, two long duration)
Michael Foale 373 days (five flights, two long duration)
Aleksandr Serebrov 373 days (four flights, two long duration)
Valeri Ryumin 372 days (five flights, two long duration, 8 months apart)

Where long duration = >4 months (the shortest feasible flight to Mars)

Jon

JonClarke
2008-Nov-05, 09:14 AM
Apart from the outside dangers, another question is whether a long term, long distance flight can can survive the human error component. Even a tiny glitch in the hardware can have deadly consequences. A spaceship 2/3 of the way to Mars doesn't have a Soyuz capsule for quick re-entry. Even Apollo 13 just barely made it back to Earth, and they were only hours away.

If they keep everything as simple and reliable as possible, things could work out fine, but if they beef it up with new, flashy, complicated tech-bling, as they will, the possibilities for disaster rise exponentially.

Actuaally the human component will be what makes large sophisticated, high performance mission possible.

People often point to the considerable number of Mars missions that have failed on route or at encounter. Very few of these would have failed had their been humans on boards, as they were almost all due to trivial software or navigation errors.

Humans will not be the weakest leak, but the strongest.

Jon

JonClarke
2008-Nov-05, 09:17 AM
Well, a few hours trapped in the same car with a group of poeple can produce migranes, high blood pressure, and antisocial thoughts.

Multiply that times one year, without sunlight or rest stops, and BANG! That's what long space flight would be like.

Why no sunlight? Spacecraft have windows.

Astronauts are also not your average car traveller.

People have flown missions of more than a year without problems.


Jon

JonClarke
2008-Nov-05, 09:25 AM
The paper (http://www.iop.org/EJ/abstract/0741-3335/50/12/124025) makes no mention of solar flares, solar (particle|proton) events, or galactic cosmic radiation, so I'm dubious about its ability to protect against all the radiation hazards long term deep space explorers would face. There are no proven technologies that would keep astronaut exposures within legal safety limits for a six month lunar stay, let alone a three year mission to Mars.

As a matter of fact a conjunction class mission with modest shielding will stay inside the astronaut limits if the crew are older rather than younger.

The uncertainies on that limit mean that the standard diviations do fall outside the limits however. But as knowledge increases those limits will be narrowed. Plus there are so many ways that radiation exposures can be reduced at minimum cost below what mant studies assume.

Good spacecraft design, placing as much equipment, consumables and waste round the periphery as possible, can give 10-20 g/cm2 shielding with no penality. Turning the spacecraft in the event of a SPE so thatpropulsion stage is between the crew and the sun will increasing effective shielding to kg/cm2.

On the martian surface the average shielding given by the atmosphere is 16 g/cm2 at the zenith, on top of the shielding provided by the spacecraft hull. A low altitude location will provide even more.

For permanent stations you can bury the habitat structures with regolith or use local water as shielding.

Looked at operationaally, radiation is a manageable issue.

Jon

timb
2008-Nov-05, 11:19 AM
Asa matter of fact a conjunction class mission with modest shielding will stay inside the astronaut limits if the crew are older rather than younger.

The uncertainies on that limit mean that the standard diviations do fall outside the limits however. But as knowledge increases those limits will be narrowed. Plus there are so many ways that radiation exposures can be reduced at minimum cost below what mant studies assume.

Good spacecraft design, placing as much equipment, consumables and waste round the periphery as possible, can give 10-20 g/cm2 shielding with no penality. Turning the spacecraft in the event of a SPE so thatpropulsion stage is between the crew and the sun will increasing effective shielding to kg/cm2.

On the martian surface the average shielding given by the atmosphere is 16 g/cm2 at the zenith, on top of the shielding provided by the spacecraft hull. A low altitue location will provide even more.

For permanent stations you can bury the habitat structures with regolith or use local water as shielding.

Looked at operationaally, radiation is a manageable issue.

Jon

I think you mean latitude (or maybe altitude). The sources I looked at, eg space.com (http://www.space.com/missionlaunches/080331-radiation-shielding.html), were less positive than you.

I was slightly dubious about the idea of using consumables as shielding. Once you've consumed it, it's not shielding. However, it's a matter (at least as far as the dosimeter is concerned) of integrating radiation intensity over time that the crew are exposed. A higher level of exposure towards the end of the mission is acceptable so long as the cumulative dose is within acceptable limits, which the consumables helped you achieve.

JonClarke
2008-Nov-05, 10:26 PM
I think you mean latitude (or maybe altitude). The sources I looked at, eg space.com (http://www.space.com/missionlaunches/080331-radiation-shielding.html), were less positive than you.

Altitude is correct, thank you. new stories won't be as positive as me. Saying the problem is manageable is never as news worthy as saying it is one.

I have a pragmatic approach to these things. We can always lear more and do it better. But if we know that people can survive and do useful work, then that is enough to say that we can go. The improveents will come with time.



I was slightly dubious about the idea of using consumables as shielding. Once you've consumed it, it's not shielding.

I agree. So it has to be carefully balanced. That is why I include waste in there. You use the waste to replace some of the shielding you can consumed. Plus with water there will always be an operational reserve. And of course propellant and water tanks are of very solid construction, and will provide shielding even when empty.


However, it's a matter (at least as far as the dosimeter is concerned) of integrating radiation intensity over time that the crew are exposed. A higher level of exposure towards the end of the mission is acceptable so long as the cumulative dose is within acceptable limits, which the consumables helped you achieve.

Agreed, it is a very complex equation. Age is also important, the older the better as far as radiation risk is concerned.

Jon

kleindoofy
2008-Nov-05, 10:39 PM
Actuaally the human component will be what makes large sophisticated, high performance mission possible.

People often point to the considerable number of Mars missions that have failed on route or at encounter. Very few of these would have failed had their been humans on boards, as they were almost all due to trivial software or navigation errors.

Humans will not be the weakest leak, but the strongest.

Jon

I should have been more clear: I meant the humans on Earth, not the astronauts. The construction, the systems, the hardware. True, the Apollo 13 astronauts got home because they could react and correct. However, Apollo 13's problem was caused on Earth, months before the flight. One stupid little faulty cable. But that one cable almost caused three deaths, within short order. The astronauts had luck.

A long term manned space flight has so many variables, so many chances for mechanical failure, systemic failure, etc. Sure, many things can be jerry-ridged on site, but there's a limit to that. It only takes one faulty cable ... Things can go very wrong very quickly out there.

I still think that is potentially more dangerous than the radiation.

JonClarke
2008-Nov-06, 12:52 AM
I should have been more clear: I meant the humans on Earth, not the astronauts. The construction, the systems, the hardware. True, the Apollo 13 astronauts got home because they could react and correct. However, Apollo 13's problem was caused on Earth, months before the flight. One stupid little faulty cable. But that one cable almost caused three deaths, within short order. The astronauts had luck.

A long term manned space flight has so many variables, so many chances for mechanical failure, systemic failure, etc. Sure, many things can be jerry-ridged on site, but there's a limit to that. It only takes one faulty cable ... Things can go very wrong very quickly out there.

I still think that is potentially more dangerous than the radiation.

I think you are right, that the biggest risk, apart from catastrophic failure in ascent or descent, is something complete unexpected.

However, if we look at space station operations - and we have decades of experience with them - we can see that there has not been a single case when a failure or accident has lead to mission loss. We have had fire, collision, loss of pressure, power failure, guidance system malfunction, collapse of every aspect of life support, the list is very long. Provided there is redundancy in the systems and spares, people have been able to repair them work round them. A Mars mission will need to carry more spares and more extensive workshop facilities than a space station because you are further from Earth, but this should not be a problem.

Apollo 13 was a sortie mission. Limited redunancy, very limited reserves, and no repair capability. Very different to how a Mars mission would be structured.

Jon

JohnD
2008-Nov-06, 10:56 AM
Yes, the Rutherford Appleton experiment was very early work, but why rubbish it?
For a video see a BBC report: http://news.bbc.co.uk/1/hi/sci/tech/7706844.stm
Before anyone else notices, the journalist's blurb confabulates 'cosmic rays' and the solar wind, but then even the Earth's magnetosphere and atmosphere cannot deflect some cosmic rays.

And if you go to the original paper's abstract ( http://www.iop.org/EJ/abstract/0741-3335/50/12/124025 ) you can still register and log on for a complete pdf download of the whole paper. There you will find the (apparent) simplicity of the experimental system - a permanent magnet at 0.2T and "a pulsed system formed from a 10 turn solenoid with a maximum current of 3.5 kA/turn," that produced 2T.

This gave a magnetic bubble 120mm across (Fig.7) in which the ion density fell immensly. Only 5 inches, and a high current solenoid, but worth more work, surely?

John

PraedSt
2008-Nov-11, 05:28 PM
Bump!

Looks like we'll have some more psychological data soon.

ESA: Mars isolation tests (http://www.physorg.com/news145539743.html)

European scientists said they had selected a shortlist of eight men Monday willing to take part in a 105-day isolation experiment to further knowledge about the stress of a manned trip to Mars.

Six of the eight candidates will be chosen to live, eat, sleep and work inside a sealed laboratory in Moscow that will simulate a Martian mission, the European Space Agency (ESA) said.

Their stay, starting in March, is a precursor to a longer study later in 2009 in which another six-member crew will experience 520 days together.

The extreme experiments are aimed at seeing how long-term confinement acts on mood, morale, hormone regulation and the effectiveness of dietary supplements.

The final eight candidates for the 105-day test are all male, aged between 28 and 39, and hail from Denmark, Sweden, Germany (2), France (3) and Belgium, ESA said in a press release.

mugaliens
2008-Nov-11, 11:48 PM
Bump!

Looks like we'll have some more psychological data soon.

ESA: Mars isolation tests (http://www.physorg.com/news145539743.html)

I seem to do just fine with the reply delays I experience on BAUT.

Perhaps they ought to send message-boarders?