PROS Vs CONS. Can Humans goto mars now?

I'm on the pro side for a conversation in class.

I've done a lot of research and i've gotten a good amount of info but not enough.

any pro opinions on why we should go?

--thanks

 

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Yes we can but no one wants to spend the $30-50 billion to do it.
We have basically all the technology just not any money.

Read the book: "The Case of Mars" by Robert Zubrin

Look up on the net:
Mars Direct
Nasa "Reference Mission"

 

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A bit of a daft project?
(thankfully your not on the side of `is the earth flat.`..)
You have probably collected enough stuff off the net.

All i can suggest is to give a bit of thought on the counter arguments.

they will have to stick with moral issues of exploration and conquest...On the technical side there is no argument.

The needs of the many out-weight the needs of the few , or the one.

 

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http://www.marsacademy.com/

This is a good place to get information regarding the mars mission.

Personally I think if we are going to go we should use Ion Engines.

 

Right now?

In short, no. We aren't ready. By that I don't mean spiritually prepared, evolved enough to be trusted or any other gut rot like that. Just simply put, we haven't any vehicles that can reach deep space and we don't have any way of shielding the crew from positive particulate radiation en-route. It's a lengthy mission for astronauts to be subjected to both cosmic and solar space radiation. The only way it could be done in the "foreseeable future" would be with reduced travel time and a small bunker. Cosmic radiation is ok for short periods of time so if we can cut the travel time by half using nuclear power then exposure time is more acceptable a risk. Solar flares on the other hand will fry astronauts. An emergency bunker is the only answer at present. NASA is working on electrostatic shielding to repel radiation but that's not ready "now".

 

To Cthulhu

You did not read anything above did you???
1. We have booster powerful enough
2. Radiation is not as big of a problem as people thinks
3. 6 month travel time is still reasonable

 

I just wrote in another thread that I was leaving Sciforums, but I just have to answer this one.

Ofcourse I read the previous posts. There were only four.

1) The bigger you build a rocket the more complex it is and therefore it becomes increasingly difficult to manage. With current chemical boosters we can achieve around 450 seconds. To reach orbit requires a small mountain of fuel. Around 85% of your mass on the launchpad is fuel. This is because fuel adds to the mass and means more fuel is required to lift the horrendously humongous load. Fuel on fuel on fuel. To save on weight we throw away parts of the vehicle as we go. A three stage rocket for orbit and a five stage rocket for the moon which is only a satellite. Robert Zubrins plan of fueling up from Mars rocks and essentially living off the land seems the most promising for reducing mass. Any other plan would be horribly expensive. Hundreds of billions of dollars. The public won't be sold on it in my opinion. Fifty billion sure but not the entire US budget.

2. Radiation is a big problem. The Apollo Astronauts were very lucky. They didn't know about solar flare danger and the Earth's electromagnetic field offered some protection to them.

3. A six month journey is a one year return trip excluding the stayover period which could be anything from a couple of months to an additional year. Even for cosmic radiation that may be too long a period of exposure. The vehicles would have to be made from materials that don't absorb radiation and then reemit it as dangerous secondary radiation.

A Mars mission would require new technologies we don't presently have. Nothing insurmountable. Mostly engineering challenges rather than scientific ones. Right "now" there is no possibility of an immediate Mars Mission. NASA always plays it cautious. Their zero risk policy dictates a tentative approach. Tests and experimentation are currently underway to assess the true risk from higher radiation exposure. I would agree that the danger has been exaggerated but it still remains an unknown quantity and NASA won't be sending men to other Worlds until it has a handle on this space radiation problem.

A way of answering all these problems would be to build nuclear interplanetary vehicles but then the zero risk factor rears its ugly head again. It would mean more mass for things like bunkers and reduced travel time so less exposure.

 

As for 1 when did I disagree with that?

As for 2 I very much disagree. I said so and why above

As for 3: for a conjunction flight: 180 day or less to get there, 550 days there and 180 back. Total mission time of 940 days. Mission velocity change total is 6km/s. Average mission radiation exposure would be only 52rems and zero gravity exposure of 360 days.

A have nothing against nuclear propulsion and would much like to see it in use, but chemical could do it if we tryed.

sorry to hear your going.

 

Sorry, I didn't see any previous explanation for radiation exposure being acceptable.

There is still a lot we don't know about radiation. I'm one of the most outspoken in downplaying the risks associated. Recent radiation hormesis experiments seem to back up what I have long held to be true. That the old straight line graph in which any level of radiation is harmful just simply isn't correct. Low levels of radiation are in fact beneficial to health and a vital part of the environment around us. DNA repair can only be triggered by radiation. Without a certain level of it, lifeforms grow stunted and sickly. This has a huge bearing on past estimates for deaths from radiation exposure which were all calculated on a straightline graph. This is because the Government has yet to develop a more accurate system.

According to your calculations, astronauts would be exposed for 940 days. Mars offers no protection.

Even 52 rems is quite a lot. It's generally measured in millirems.

Radiation Trivia.

About 450 rem is a lethal dose if no treatment is recieved and its given to the entire body in a short period of time. 100 rem causes radiation sickness in similar circumstances. Ionizing radiation can penetrate cells and create ions in the cell contents. These, in turn, can cause permanent alterations in DNA; that is, mutations.

This includes.

X rays
gamma rays
neutrons
electrons ("beta" particles)
alpha particles (helium nuclei)

The general public gets about roughly 100-200 millirems(thousanths of a rem) a year from natural background levels. An additional 7 millirem if they live in a brick house. An additional 0.1 - 0.6 millirems if they spend a year standing at the fence of a nuclear plant. About 0.2 - 1.5 to the gonads from TV sets. Average airline passenger (10 flights/year) can add 3 millirems. Annual dose to each person in the U. S. population from fallout (former weapons testing plus Chernobyl) is 0.06 millirems. About 9.4 millirems is received by the bone marrow during a set of dental x rays.

About 27% of our annual exposure to radiation is from background radiation:

cosmic radiation (27 mrem). The value increases with altitude, so the dose for people in Denver, Colorado is about 50 mrem.

rocks and soil (28 mrem). This value varies with the geology of a region: people in Louisiana get as little as 15 mrem/yr; people on the Colorado plateau (incl. Denver!) get 140 mrem/yr.

from within the body (40 mrem). Most of this comes from potassium-40. About 0.02% of the potassium in nature is in the form of the radioactive isotope 40K. Living tissue cannot discriminate between radioactive and nonradioactive versions, so the same 0.02% (about 2.7 g in a 70-kg person) is radioactive.


I changed my mind about leaving.

 

Got to agree with Cthulhu, especially on the radiation stuff. We have theoretical stuff on radiation protection, most promising is the plasma shield, but right now the only tested method we have it ordinary mass shielding. Heavy. The Apollo missions could abort if a flare was detected...a Mars journey would require protection, because of the length of time. They will have flares during the journey.

We haven't even touched on humans and duration in zero G. Have we done any actual research into artificial gravity yet? What about nutrition, self sufficiency? Lots of questions that we are working on right now, but aren't sure on the answers yet.

And there's the question of why we're going. What will we do when we get there. Plant a flag, grab some rocks, take some pictures? I hope when we go there's much more than that planned. Which means we have to be more knowledgeable on long term survival in hostile areas. Wouldn't it make more sense to try this out on the Moon first, so if something bad happens, Earth is right there to escape to, or to send help?

I'm not going to touch on the propulsion issue...I'm for waiting for nuclear development, just to help some of the above, but I have no doubt chemical could do it if we had to. It's the above arguments that hold me back in supporting a Mars mission right now.

Zubrin's great...and if I recall from reading his stuff, he's in agreement with all this.

Let's go to Mars...prepared.

 

hehe you mean 100rem in one sec causes radiation sickness. we are talking 52 rems over 2 years! that has been proven to have no effect!

 

People normally recieve about half a rem a year. It varies. Background radiation in some places like India is over 100 times the norm for the US. No sign of harmful affect on fauna or flora has been measured. According to hormesis studies a tripling of the background level world wide might actually increase our health. These are all new studies however. Don't get me wrong. I'm all for a manned mission to Mars and I poo poo government estimates for deaths from radiation every chance I get. We must accept that an unknown quantity of risk does exist though. High levels such as 100 rem from a massive x-ray or close proximity to a nuclear detonation can kill. We are still defining the limits for safe dosages. Fifty two rem over two years is about 50 times the normal exposure. It shouldn't take long to discover whether this is a safe tolerance level. I would imagine it would increase cancer risks to an unacceptable degree and if so we'll have to work around this problem. The question was whether we are ready to send men now. I don't think we are but NASA seems to be taking the preparatory measures necessary to ensure we make the attempt some day. About time too. I'm sick of watching shuttles go around and around.

Robert Zubrin occasionally emails me and we post his articles at http://www.nuclearspace.com every chance we get. He sent the members there a personal thankyou for all the hard work they have done in supporting nuclear power for spaceflight. He's written quite a bit about the advantages of nuclear propulsion. In particular the decreased radiation risk. Ironic isn't it. Using a nuclear reactor to power your vehicle would reduce not increase your crews exposure to radiation.

 

Robert Zubrin say in his book "the Case For Mars"

He quete anoterh study and I'm not into typing so I'm going to just give you the results strait:
Chronic radiation doses Totaling 100 rem Probability of fatal cancer in 30 years:

Leukemia .30%

Breast .45%

Lung .40%

GI track .30%

Bone .06%

All others .3%

Total 1.81%

 

Personally, I like those odds and would be happy to go to Mars on their value.

If I didn't tend to throw up on Roller Coaster rides that is.

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I created a category at NS devoted entirely to 'radiation myths' but it was later merged with 'opposition groups' and 'snake oil'.

It does my heart good to see that others don't see radiation as a huge obstacle. Unfortunately though, it is. Radiation itself is increasingly looking less of a serious risk, but the publics perception of it is still a major obstacle. One of the major reasons I started NS in the first place. Countering half a century of B-grade hollywood movie propaganda is quite a challenge. I think it's happening though. People will accept the truth if presented with it in a readily understood fashion. I think that very soon we will have overwhelming professional support from academia. That will force a rewrite of the gutter science still being taught in schools and people will gradually shift away from the "any amount of radiation is death" mentality. We just have to keep preaching the truth.

Until then the radiation bogeyman is going to remain a thorn in our side.

 

I think a funded Mars mission would help research into active radiation protection, and strengthen the case in going.

Again the big question is what are we doing when we get there? That's a long way, especially by chemical rocket, to just stay a bit...if we go, we should go as we should have gone to the Moon, to stay there permanently. Fusion will aid both Moon and Mars in setting up colonies, because you can move more faster, and if problems arise, actually plan for rescues. I know many Mars supporters would go on a slow boat, assuming all radiation, emergency, and stranded colony risks happily. But wouldn't you rather given a choice, take the fast route that has backups for problems?

I've looked into the plasma shields, as well as the others...anyone have a clue how effective they would be with solar flares, or is a flare always going to be a "duck into the central leaded room" deal?

 

Whenever I hear mention of controlled fusion I have to suppress a snigger. Sorry. It's just that I don't believe we can bottle the sun. Everybody is quick to point out how creative humans are and how far we've come. Sure, fusion research is light years ahead of where it was. Yet, in 70 odd years of trying, we still can't get more energy out than we put in. The equipment is not cheap to build or maintain. To become competitive with other forms of energy it must deliver a sizable return on energy put in.

Back in our grandparents day everyone was saying that useful fusion was "just around the corner". I suspect our great grandchildren will be saying the same thing. Realistically, it's nuclear or nothing for a Mars mission. It might be possible to get there by chemical means but its incredibly impractical. Like powering a plane with coal. We'd need to build landing strips every 5 km. Assuming the things ever got off the ground. Space rockets run on chemical essentially "cruise" most of the trip.

 

Bah, who wants the sun's fusion. There are better ones, that don't throw out all sorts of nasties.

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I never said we should wait on fusion. Fission will work for me until then. Chemical if need be, but I'd prefer a constant thrust through the mission as well. Having to push your fuel that's heavier than the rest of the ship is so....20th century.

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Thermonuclear fusion would be ok. It's fusion but pulsed. We've had that technology for decades. Even small ones would need a big ship but that's what we need for interplanetary flight.

Fission is the way to go now. Americium-242m is an interesting possibility but it's so shortlived and expensive to make. Still, if we could get around the problems we would be looking at a two week trip to Mars. People could go to the moon for weekends. A ferry to orbit and then a super fast transit to another lunar ferry at the other end.

Ion drives are great for steady lengthy burns but we humans like to get to places in a hurry.

 

Watch out people might laugh at you someday like we laugh at all those people that thought flight impossible... but I do agree that electric propulsion using nuclear power is much more developed and a perfect choose for now. With a isp of as high as 30,000 a VASIMR would be 66 times more efficient then the most efficient chemical rocker engine.

 

30,000???

Are you sure? That seems a bit high. Did you mean 3,000 Isp.

Controlled fusion might be practical one day but I'm not even convinced of that. It looks like a farflung future possibility. Like warpdrives. Fun to talk about but not taking us anywhere anytime shortly. I'm a strong believer in hands on engineering going hand in hand with theoretical research. We didn't go from steam engine to ferarri purely with chalk on a blackboard. It was sweat and blood. Trial and error. We already have new technologies waiting for active work. I firmly believe that the fastest way to harnessing fusion, anti-matter and all other futuristic propulsion is through working what is actually available to us. Nuclear propulsion can be a stepping stone to even better technologies. If we choose to stop sitting on our hands and do something about it. Reactors are essential for interplanetary manned exploration. Whether for Vasimr or even newer more radical proposals.