Long duration Human space missions - Can we survive them?

GCNRevenger · 2005-08-13 01:46:02

My my, such emphasis on "hands on experience..." Well, being that you have no clue at all about the spaceflight concept of specific power, I find it very hard to concede that your "hands on experience" in the field makes you any more informed then I am. I think I said something about this concept in my last post:

"...you have catagorically ignored the real problem with using a nuclear fission reactor to run a VASIMR engine, which is not how many kilowatts is consumes, but rather how much those reactors and their converters weigh per-kilowatt."

Which you haven't answerd, and continue to ignore as it suits you to help berate me from your supposed "position of authority"... It is really a very simple concept, one that seems to have "flown" right over your head: one of the biggest issues with powering VASIMR engines is not building a reliable plant big enough, the problem is building one that produces a great deal of electric power but which also has very little mass.

I am pretty sure that the power plant you have in mind doesn't weigh anything acceptable, and in fact, if it were a derivitive of a submarine plant, it is definatly going to be WAY too heavy. Submarine reactors don't have the requisit cooling systems, you don't get free cooling water in space you know, so you have to lug along one of the biggest mass budget items for space power plants: the huge radiator array. Thanks to the low (by comparison) temperature of your working fluid the tens of megawatts of thermal energy would be EXTREME. This is one of the big reasons why no contemporary reactor arrangement will work, in addition to the mass of the core and its shielding.

I find it kind of odd that you didn't think that this difference with cooling and temperatures might be a problem given how I am sure you know that a nuclear power plant is a classic heat engine, and how there would be no problems with "transplanting a plant" from a submarine with a huge mass budget to a space ship with a very tight one. There are biiig differences in a space based power plant compared to a submarine and besides the basic arrangement of the core they are pretty different animals. To date, no space reactor has ever been flown that reliably even produces ten kilowatts, much less ten thousand.
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"has cause radiation induced cataracts on at least 36% of the entire astronaut corps to date and those astronauts that have been in space for more than five weeks at a time have all complained of suffering from debilitating side effects from prolonged exposure to zero-g for as many as four weeks after returning to earth"

Thirty six percent huh? I don't buy your huge figure, that sounds like a scare number to me... First off, we haven't had many astronauts in space for five weeks or more ever (how did you get a round 36% figure again?). Where did you get this information anyway? Here maybe, that 36 astronauts got cataracts? So many Apollo astronauts got cataracts, who says it was due to radiation? Here is a nice tidbit you forgot to mention: ""Without ever traveling through space, more than half of people older than 65 get cataracts." And, those astronauts only had about 1cm of Aluminum to protect them, while Mars crews will have signifigant shielding for the trip.

Alot of the nastier GCRs (not GCNs) will be blocked by the light nucleii shield that any mission will undoubtably have, which will probobly be alot like the polymer shielding that submariners are probobly familiar with only better, and the crew quarters could be arranged so they sleep inside a double-walled water tank or something. Worst comes to worst and cataracts are a problem, then we just remove them from the astronauts and replace them with nice advanced biocompatible polymers ones. Every member of the the crew ought to have the apendix removed anyway.

And oh no! Unpleasent side effects for a few weeks after a six-month stint in zero-G, how dreadful! Lucky for our Martians, they will be landing on a planet with a third of the gravity... how convienant, no?

If a somewhat increased risk of cataracts and some trouble getting around after landing while you get used to walking again are the price of a trip to Mars, sign me up.
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"...has a real serious need to get out and get real world experience with these technologies... a person can’t just read about them in a book... Every time you post you reveal glaring fundamental errors that indicate how poor your grasp of the technological material really is."

Awwww, somebody has gone and had his feelings hurt it... Every time you post you reveal glaring fundimental errors that indicate how poor your grasp of the technological material concerning the emloyment of nuclear reactors for space electrical power generation really is... Not to mention your complete lack of understanding about fairly simple space travel concepts concening power/mass relatonships and payload fraction... Which I have learned - yes - by reading books and websites.

GCNRevenger · 2005-08-13 02:13:49

I also wouldn't be so hastly to assume that everyone here has regected the use of liquid metal cooled reactors of various types in our planning. We have. In fact not to long ago GCRNevenger and I debated the merits of a nuclear power/vrs solar thermal for powering the extraction of oxygen from moon rocks. I belive he brought up just the system you propose due to it's sacrifice of electric specific power for better thermal specific power. (I still advocate Solar Thermal BTW)

Yes, pretty much spot-on about the specific power problem. Traditional solid-core reactors for power generation are really too heavy, reguardless what arrangement you come up with, because of the low operating temperature of the coolant. You really can't dance around this one with tricks or clever ideas.

For intermediate power generation, I kinda like the old SP-100 reactor... no moving parts at all since it relied on horribly inefficent (5%) thermoelectric conversion (like RTGs), but weapons grade Uranium doesn't weigh that much per-watt, and the thing ran so hot that its radiators were tiny. It would produce massive amounts of waste heat, which would have been lovely for Lunar smelters or whatnot... Very compact too.

The down sides were that it produces gobs more radiation, uses several times the fuel, and would have been tricky to build thanks to its operating temperature. If you were to discount the mass of its very shielding however, the thing would have been relativly light per-watt. Still not really excelent specific power, but not bad. The USAF was pondering a 1MWe version.

Chazbro38 · 2005-08-13 09:14:39

Well in addition to all of your other problems it looks like you have problems with reading and comprehension as well!

I defy anyone to find in my post my statement where I advocated "transplanting" reactors built for submarines directly into a space based applications.

As usual my words were both misquoted and taken out of context (not suprising considering the source). I said that the S4 was the technology which was the most readily adaptable EXISTING reactor technology for the purpose of powering a VASIMR type system.

Oh and speaking of ignorance about reactor technologies, some navy nuclear reactors use not one, not two but THREE water coolant loops in their systems. By the wat, since since ALL nuclear reactors generate radiation require cooling and dense radiation shielding, constantly rehashing those issues in an attempt to pretend you understand the issues is a waste of time. The real issue is which EXISTING reactor technology has the most potential for near term adaptation to space-based propulsion systems.

Anyone who truly understands the issues knows that any and all nuclear reactors are heavy, very hot & require shielding! I defy anyone that can present an EXISTING reactor technology that doesn't! As for radiation shielding from ionizing radiation, NASA has long ago determined that it is less of than a threat than GCR so when they have that problem solved, they will obviously have the radiation shielding for the reator handled as well. Of course, cold soaking in deep space for SIX MONTHS while being exposed to GCR is no solution to anything which is why I will continuously advocate for propulsion systems that have the ability to get people to and from Mars in the least amount of time.

As for how many Astronauts have radiation induced cataracts, all I can tell you is try calling NASA. Thats what I did. I find it very telling that there are people who post on this site and are skeptical of information presented on it and in the same sentance admit that they have not done any actual research themselves. That pretty much says it all. (by the way do ever wonder why Astronauts, many of whom are oh, I don't know PILOTS, freaking test-pilots with 10's of thousands of hours in the air over twenty year careers almost immediately stop flying their own aircraft after they leave NASA? Could it be that they can't pass fight physicals anymore because of vision problems?).

From the previous posting it would appear someone needs a time out followed by some mental health counseling.

Chazbro

Austin Stanley · 2005-08-13 18:20:37

There's no need to throw around personal insults, they are not conductive to good debate.

Again the main issue with you proposition is the issue of specific power. Nuclear reactors offer excelent specific power. Much better than any solar option and competitive with most chemical sources of energy, but of course far superior when you consider the lifetime of a nuclear source. However, they still fall short of what is required to power a energy hungry VASIMR engine. They simply mass to much. The specific power, or the amount of energy per unit of mass is CRITICAL to the performance of any space reactor. You haven't given any details as to how this reactor performs in this crucial catagory, and I am hard pressed to belive that this liquid sodium cooled reactor could achive performance radicaly diffrent than that of any others.

The other issue I'm not sure if you are clear on is the issue of cooling. As I'm sure you know there are only three ways to transfer heat, Conduction, Convection, and Radiation. Terrestrial reactors rely primarily upon conduction and convection to disipate there heat. This is because the Earth is full of matter with high specific heats. Terrestrial reactors are litteraly swimming in it. So it is fairly easy to dump the heat off to the enviroment, even if the temperature gradiate is not as great. Space on the otherhand is as vacuum, so there is nothing to dump the heat off in. Space, despite it's often very cold temperature is a very effective insulator. The only way to lose the heat is to radiate it away. The number of coolent loops betwen the reactor and any turbine doesn't change this fact.

Again. What matters here is MASS. How much the reactor weighs. As far as I know no reactor to date, be it cooled by water, heavy water, sodium, or even CO2 achives quite the specific power necessary to make a realy outstanding VASMIR type system possible. Some sort of next generation system, be it fusion, GCNR, or perhapce lead cooled reactor will be necessary.

GCNRevenger · 2005-08-13 20:02:19

You said you were a submariner, and then you go on to say that exsisting technologies could be used to power VASIMR. As liquid-metal cooled reactors have been used to power submarines, it seemed to imply that you wanted to take a submarine reactor - which you stated has the needed power output - and put it on a VASIMR rocket. And your notion about using an S4 type power plant doesn't make much sense, since such a technology won't work very well with its low temperatures because of its massive radiator arrays would be entirely impractical.

"The real issue is which EXISTING reactor technology has the most potential for near term adaptation to space-based propulsion systems. "

Yes, which as Mr. Stanley has pointed out and I have reiterated several times now, that the measure of its practicality is specific power and not power output, but you continue to ignore the only relevent measure of performance.

"all I can tell you is try calling NASA. Thats what I did"

Oh really... how convienant that the information given to you isn't readily available by independant (IE not from you) means, and then there is the "you must have talked to a different NASA guy" excuse. Being critical of other peoples' ideas is something called "peer review," which is kinda how modern science works... In a peer review, the burden of proof is on the party presenting the information, not the reviewers. Proving your statement is your problem, not mine to disprove, thats how peer review works. Since your "proof" is immaterial and not corroborated, I don't buy it.

"From the previous posting it would appear someone needs a time out followed by some mental health counseling."

Ahhhh yes, because I disagree and challenge the ideas of a "bonefied expert" who doesn't understand the trouble with simple things like specific power, heat rejection, or whatnot I am mentally unwell.

Edit: I would like to re-emphasize the difference between specific energy and specific power, that the former is the energy available per mass from a particular source, whereas the latter is the energy per time per mass.

Chazbro38 · 2005-08-13 20:56:32

Sadly it appears that any and all of GCN Avengers responses are both incoherent & irrational, and his critical thinking skills are all but non existant given the content of his posts.

He is left in his own world of delusion where he is happy substituting his feverous suppositions of what I meant as opposed to dealing with what I have said. Now he thinks this website is subject to the standards of peer review. How sad! If it were how would he have ever been allowed to post? But I digress.

Its disturbing that he clearly doesn't have the proper intellectual skill set to do proper research, acquire and validate facts or properly pursue a line of inquiry (skills that I personally acquired early in grade school) or maybe its just that he's too lazy to do the required work so that he feels that if someone doesn't do it for him he feels that its appropriate to ignore information provided to him.

That it appears obvious that he has no technical experise whatsoever I can not allow myelf to be drawn into wasting time picking his posts apart because they are so invalid... speaking only for myself I have a life. GCN Avenger may want to get out sometime and get one of his own but first, it appears he need his dosage adjusted...preferrably upwards.

P.S.
I don't know what the "you must have talked to a different NASA guy" excuse. is even supposed to mean except that maybe GCN Avenger might want to add electroshock to his treatments.

Chazbro

GCNRevenger · 2005-08-13 21:06:21

Best case senario I can think of for a solid-core space power reactor for propulsion... a high-temperature (>1400C+) lithium cooled one like the SP-100, only bigger, except instead of a thermoelectric converter use MHD to get a bit higher efficency (say, 10%?). Then, using the nice magnetic pumps, pump the liquid metal directly through high-temp radiators to complete the coolant loop. You'll need a massive amount of heat energy to make much power, but adding Uranium and bulking up the reactor vessel is easier then adding low-temp radiators, extra cooling loops/pumps, heat exchangers, turbines/generators, and so on.

Even then, the old SP-100 only hoped to achieve a specific power of 370W/kg thermal and 18W/kg electric. With a hypra-advanced MHD generator with much higher efficency and slightly increased operating temperature you might increase this figure by four or five times to maybe 100W/kg or something, but really high figures like 1,000W/kg are not happening.

The high 200W/kg figure for a scaled down version of the S4 that Mr. Stanley mentioned does not take into account the cooling systems needed for space use that aren't needed for Earthly use, and I am sure will be much lower when such changes are factored in...

Anyway, point being, that specific power for traditional solid-core space reactors isn't going to have the order-of-magnetude improvement needed to make a high-payload/short-transit VASIMR ship possible. High payload OR short transit maybe, but not both.

GCNRevenger · 2005-08-13 21:43:11

Sadly it appears that any and all of GCN Avengers responses are both incoherent & irrational, and his critical thinking skills are all but non existant given the content of his posts.
He is left in his own world of delusion where he is happy substituting his feverous suppositions of what I meant as opposed to dealing with what I have said. Now he thinks this website is subject to the standards of peer review. How sad! If it were how would he have ever been allowed to post? But I digress.
Its disturbing that he clearly doesn't have the proper intellectual skill set to do proper research, acquire and validate facts or properly pursue a line of inquiry (skills that I personally acquired early in grade school) or maybe its just that he's too lazy to do the required work so that he feels that if someone doesn't do it for him he feels that its appropriate to ignore information provided to him.
That it appears obvious that he has no technical experise whatsoever I can not allow myelf to be drawn into wasting time picking his posts apart because they are so invalid... speaking only for myself I have a life. GCN Avenger may want to get out sometime and get one of his own but first, it appears he need his dosage adjusted...preferrably upwards.
P.S.
I don't know what the "you must have talked to a different NASA guy" excuse. is even supposed to mean except that maybe GCN Avenger might want to add electroshock to his treatments.
Chazbro

I think that is quite enough... your post really doesn't contain a single relevent thing other then snide attacks against me. Since your posting has contained less and less material relevent to the topic and continues to be conspicuously absent of any commentary or expression of your supposed expertise about the problem in question - low specific power - that it seems quite clear that you are either unwilling or unable to discuss or debate the matter that you yourself have brought up...

...So I think that trying to talk to you further in this thread is a bit, well, pointless.

GCNRevenger · 2005-08-14 00:56:47

Lets see here... you really haven't said anything. Basically you claim that contemporary reactor technology will reach an impossibly high level of performance through "R & D," even though it has been explained to you why this is not going to happen, based on fundimental principles of heat engines which you don't seem to understand the importance of. Not so good on the resume for a nuclear operator?

And "disturbing" that I won't do my own research? When you make a (fairly outlandish) statement, it is not at all unreasonable to demand that you back up your statement. You have failed to do this, and have not provided any evidence other then empty assurance that your "hands on expertise" with nuclear technology makes your opinion of the feasability of your statement beyond reproach, even when confronted with facts to the contrary. Peer review as a concept is perfectly valid, that if you can't support what you say then nobody has any reason to take it seriously. If the statement is yours, it is therefore on you to support it; I challenged you to present your supporting material, and you did not do so.

...the rest is just personal assaults ("doesn't have a life") other then that last bit, which should be pretty obvious if you thought about it: that was basically a jab that you never actually made any phone call to NASA, stating that you did to lend credance to your baseless assertions which could not be verified except by your word.

Generally speaking, given how you stoop to such a level of childishness in the personal insults against me combined with the total lack of any evidence of your supposed specialty, I think it liky you made up the story that you are or ever were a USN submarine reactor operator.

A minimally civil debate about the merits and applicability of a nuclear/VASIMR propelled spacecraft would have been nice...

Chazbro38 · 2005-08-14 09:27:24

Did you ever notice that your posts are full of things you claim that I said but when you, oh you know actually read my posts then mysteriously it turns out that I never said any of them? Its not very healthy from a mental stand point that these are the very issues that you obssess about the most.

Then you said "Basically you claim that contemporary reactor technology will reach an impossibly high level of performance through "R & D," I dare you to prove that I ever in my life said that. Hey what happens to authors that present falsified data as fact. (by the way, thanks for further validating my assessment of your alleged research issues.....just keep on posting now....show everybody what you've got!).

Although it is possible that this level of quality is what passes for rearearch in whatever world you live in (outlandish assertion, take my dare and then decide for yourself!

I'll admit that you are right when you say that peer review is 100% valid as a
process. I enjoy it and have made use of it many times myself. I just think that you might want to submit your own posts to it (a little introspection is good for the soul).

Personally, if I were the one proposing Gas Core Nuclear reactor technology as a viable alternative to well, anything at all, I wouldn't feel comfortable calling other peoples posts into question. Your advocacy of gas core technology certainly validates your ability to do reasearch?????? Speaking of someone backing up their claims, why don't you post some objective, third party, verifiable information on the existance, engineering specifications, known performance specifications and operating history of say one or more gas core reactor that have been built......ever.

Enough said, about whether or not you are qualified to question anyone about anything, anywhere. ever.

Dude, you clearly have some sort of a problem. Thats OK though, I would suggest that you take a short break from posting in this forum and relax, take it easy maybe get a head C-T or something. I'm sure inthe long run everything will stabilize and you'll be OK....someday.

Chazbro

GCNRevenger · 2005-08-14 12:09:00

This is growing quite tiresome really, if you aren't willing to apologize for your attacks against me and act with the dignity of a supposed elite member of the USN, then I do believe our conversation is at an end.

Both myself and Mr Stanley have pointed out to you that the key to a fast transit with high payload for a reasonably sized VASIMR ship to Mars is the specific power of the power plant. You then proceeded to insist that contemporary low/mid temperature liquid metal cooled plants could be employed to meet the (rather high) minimum performance for effective VASIMR operation. Both myself and Mr Stanley contest that no exsisting technology of any kind current or future has a high enough performance. But, you have continually insisted otherwise, despite being challenged with facts about comperable power plants and the physics that limits said performance.

Mr Stanley found actual specific power figures for a similar power plant, which were an order of magnetude too low, but you asserted that it could have been made light enough anyway without a reason. I have pointed out to you on this and your duplicate thread that the cooling requirements are a real problem that makes the proposition for contemporary nuclear technologies even worse.

You said this in your duplicate thread, which I am pretty sure that you made while alive:

"Power/Mass density issues will just have to handled through ongoing R & D"

Which is where that came from... I pointed out that the only real way to radically increase the performance of a plant is to increase the temperature it operated at, consistant with principles of elementary thermodynamics.

Since reactors flown and proposed for space use already operate at temperatures near the practical limit for core materials, I stated that there is not going to be a needed order-of-magnetude performance improvement because operating temperatures cannot be increased. I challenged you that your assertion is probobly untrue, but you have not yet given a single fact or principle to support it.

I reiterate, that specific power is the yard stick which makes or breaks ultrahigh performance VASIMR propulsion, but you didn't even acknolage this simple concept until myself and Mr Stanley pressed you about it repeatedly. You continue to stonewall about how this problem is to be overcome using the power plant type that you insist will work, and instead harp about your alleged "experience" makes your assertion beyond reproach by us "mentally unstable" folk.

In fact, you haven't even really honestly admitted there is a problem, where you have stated on more then one occasion that a multimegawatt plant is "going to be heavy", which is precisely the very thing that it cannot be. The mass of contemporary power plants is simply too high as has been pointed out to you with rough estimates of propulsion system mass earlier in the thread. If your power plant is too heavy, then the VASIMR ship will either have to give up its payload or give up its short travel time, and maybe both.
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I have already once explained my reasoning and principles as to why a gas-core (also called vapor core) reactor is probobly nessesarry to attain such high performance levels. The reason why GCRs are so superior is that they operate at comparitively high temperatures (hot enough to vaporize alkali metals like sodium), which means that you need to produce fewer watts of heat per watt of electricity with the higher temperature delta (Carnot cycle ring a bell?) and piping the vapor directly to the radiators radically reduces their size per-watt of heat rejection. It also gets a boost with MHD generators, since the vapor is partially ionized due to the high temperature and the ionizing radiation.

Such a power plant would be extremely advanced and also extremely expensive to develop, and to date it exsists only as a concept. However, its theoretical performance would meet the electrical need for a VASIMR engine consistant with established principles of thermodynamics. It works, on paper.

Chazbro38 · 2005-08-14 16:30:25

Everything you just posted has validated everything I have already posted while continuing to discredit all of your own arguements. The sad part is your so clueless you will never understand why this is true. Evidently, you don't even know what the content of your own prior posts are. (By the valid on paper is the same as worthless) It appears that you resort to presenting your delusional interpretation of what I have said as fact when the "information" you post is shown to be worthless and or invalid...which evidently is about as much as we can expect from you. Fair enough.

The headaches I get from trying to figure out if your posts are the product of some sort of untreated bipolar disorder or just plain ignorance is more than enough justification for ceasing this conversation.

Chazbro

John Creighton · 2005-08-14 17:39:42

Everything you just posted has validated everything I have already posted while continuing to discredit all of your own arguements. The sad part is your so clueless you will never understand why this is true. Evidently, you don't even know what the content of your own prior posts are. (By the valid on paper is the same as worthless) It appears that you resort to presenting your delusional interpretation of what I have said as fact when the "information" you post is shown to be worthless and or invalid...which evidently is about as much as we can expect from you. Fair enough.
The headaches I get from trying to figure out if your posts are the product of some sort of untreated bipolar disorder or just plain ignorance is more than enough justification for ceasing this conversation.
Chazbro

Well, if that is what you believe start doing the math to prove him wrong.

John Creighton · 2005-08-14 18:01:10

Did you ever notice that your posts are full of things you claim that I said but when you, oh you know actually read my posts then mysteriously it turns out that I never said any of them? Its not very healthy from a mental stand point that these are the very issues that you obssess about the most.
Then you said "Basically you claim that contemporary reactor technology will reach an impossibly high level of performance through "R & D," I dare you to prove that I ever in my life said that. Hey what happens to authors that present falsified data as fact. (by the way, thanks for further validating my assessment of your alleged research issues.....just keep on posting now....show everybody what you've got!).

Ever here of paraphrasing, dude? Of course GCNRevenger doesn’t claim that you said that. Obviously if you believed a level of performance could be achieved then you wouldn’t think it was impossible. Duh :rol:

What GCNRevenger claims is that the level of performance that you think can be obtained from solid core nuclear reactors is impossible. I am sure he has papers to back this up but if you don’t believe him start doing some calculations to prove him wrong.

I’ll give you a starting point, the maximum possible efficiency that can be obtained form any heat engine is the carnot cycle. If you are serious about proving him wrong I’ll get you the equations later. To calculate the efficiency of the carnot cycle you are going to need a thermal reservoir (the nuclear reactor) and a sink (the radiators). The heat dissipated from the radiaters will depend on temperature. The hotter they are the more heat they can dissipate per mass but this will mean that the heat sink will be warmer and the heat engine will not be as efficient. Consequently there is a tradeoff between power and efficiency and the only way you can increase both power and efficiency while keeping the radiators the same size is to increase the temperature of the thermal reservoir (the nuclear reactor).

Therefore, it is clear that the only way to get more power per weight is to run the reactor hotter.

GCNRevenger · 2005-08-14 22:58:57

Well, it looks like things have finally reached zero, with Chazbro's latest post containing not one single specific thing in it about the topic nor the discussion of the topic concerning nuclear power use in space... I mean, there is really nothing there at all, no specific accusation of taking statements out of context, nothing about the problem of specific power, and nothing about how comperable plant types are no where near good enough... Just particularly vitriholic and childish attacks against me, completly devoid of any substance or dignity.

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Back on topic... say we want to build a high-capacity, inexpensive, and reliable nuclear power plant for propulsion or for operating Moon/Mars bases but aren't aiming to achieve the ultrahigh performance for a GCR or something, what is the best arrangement?

There are two and a half basic routes that have been historically used for space power reactors:

-Trade reduced radiator mass and fewer moving parts for increased reactor mass and radiation hazard with a high-output reactor using a low efficency converter system (thermoelectric or MHD).

-Trade reduced reactor mass and radiation hazard for increased radiator size by maximizing efficency using dynamic (turbine/piston, gas driven) systems with their low maximum coolant temperatures.

-A combination or hybrid of the two... such as reactors with gas as a primary coolant for driving a turbine at intermediate temperatures, or plants that use both MHD and dynamic systems with one or more coolant loops.

Pros and cons abound... I lean closer to the former then the latter, because the plant will be simpler, more compact, more reliable, and generates more waste heat that you might use for Moon/Mars chemical processing or base heating. Shielding mass might be a concern though since it would generate gobs more then the latter case.

MHD for power conversion could make a signifigant difference in reducing the reactor mass in the former case, which makes a substantial difference since the high output reactor constitutes the majority of the total plant mass. I don't know much more then the basics, does anyone (civil) know much about it? Efficency ranges? Temperature dependance? Ideal coolants?

idiom · 2005-08-14 23:02:46

I have to agree with Chazbro. There is no way current technology could be effectively used in space applications to achieve a rapid high payload transport system. All his arguments very clearly point to this conclusion.

The more energy a system puts out the larger it is given the same level of technology. But even technology has its limit based on material physics. This is basic chemistry GCNR, why can't you understand this?

GCNRevenger · 2005-08-14 23:10:37

I have to agree with Chazbro. There is no way current technology could be effectively used in space applications to achieve a rapid high payload transport system. All his arguments very clearly point to this conclusion.
The more energy a system puts out the larger it is given the same level of technology. But even technology has its limit based on material physics. This is basic chemistry GCNR, why can't you understand this?

Um, what? You aren't making any sense... might you be confused about which post is which?

idiom · 2005-08-14 23:16:01

I just assumed nobody was taking this thread seriously anymore and tried to join in the light hearted banter with some ironic mishashing of the thread.

I was following the technical debate, such that it maybe, as carefully as possible earlier though.

GCNRevenger · 2005-08-14 23:29:51

Ahhh okay... Since I am a huge nuclear fan boy, it would be nice if the topic were to continue though.

SpaceNut · 2005-09-15 10:13:29

We know that the muscle lose and so do the very bones to which are there under laying strength over time in 0 g . But what if there were a way though exercise...

Space Cycle tests artificial gravity as solution to muscle loss

A bike-like centrifuge that creates artificial gravity may help astronauts combat muscle atrophy in space. Through a study at the University of California, Irvine, the National Space Biomedical Research Institute (NSBRI) is exploring the concept of a Space Cycle for inflight resistance-training exercise.

SpaceNut · 2005-10-03 12:58:01

I guess not only along with the duration question comes the first question which is are we fit enough for space flight in the first place.

Well here is a quiz, open book of course.
Are you fit for space?

There's no age limit for the “Right Stuff,” as John Glenn proved in 1998 when he flew into space at the age of 77. But there are medical and physical standards that astronauts have to meet. Take our quiz to see if you meet some of the standards for NASA space flight. Remember, this is for fun and educational purposes only. You must answer each question for the results to be valid.

My response to the quiz

Congratulations: You appear to be fit for travel in space. But before you stock up on Tang, note that you must still undergo an examination by a qualified air surgeon. He or she would ensure that you don’t suffer from any disease, defect or medical treatment that would render you unable to perform your duties safely.

WHoHoo now if I only had a spare 20million for the seat....

Commodore · 2005-10-03 13:03:21

Dam my bad eyes.

EuroLauncher · 2005-10-21 12:57:23

We know that the muscle lose and so do the very bones to which are there under laying strength over time in 0 g . But what if there were a way though exercise...
Space Cycle tests artificial gravity as solution to muscle loss
A bike-like centrifuge that creates artificial gravity may help astronauts combat muscle atrophy in space. Through a study at the University of California, Irvine, the National Space Biomedical Research Institute (NSBRI) is exploring the concept of a Space Cycle for inflight resistance-training exercise.

nice link there !

SpaceNut · 2005-11-01 08:14:54

There have been several bed rest studies here and abroad in an effort to simulate the conditions of 0g effects on the body.

[url=http://www.cleveland.com/news/plaindealer/index.ssf?/base/news/1130841383112770.xml&coll=2]Easy does it after long bed-rest test
12 weeks off feet in space exercise study leaves man wobbly [/url]

Well 12 weeks are far short of a mars mission and not even close to ISS typical missions.

The goal of the study is to determine whether zero-gravity exercise will prevent bone loss and muscle atrophy. If it does, it could be used in long-distance space travel.

SpaceNut · 2005-11-14 07:47:20

With the budget cuts going on I thought that most life science for duration of exposure to space had stopped but that appears to not be the case.

Indiana University Cyclotron to study long missions in space

little is known about how radiation from solar storms might affect space travelers whose bodies have been weakened by months at zero gravity.

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