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Travelling to Mars
Hardly a week goes by without some news item about Mars and the
likelihood of manned flight to it. I ask, where is there a cape Canaveral launch facility on the red planet it in order to facilitate a return journey to Earth. Because that's what would be needed given a not dissimilar gravity of the two planets. We are all aware what is need to launch a human into space from earth. It simply cannot be done with the crafts that took off from the moon. Similarly such a craft would not be powerful enough to escape the gravity of Mars. Those people who enthuse about manned spaceflight to mars (curiously enough) never seem to mention this basic problem. Mervo |
#2
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Travelling to Mars
"Mervo" wrote in message
I ask, where is there a cape Canaveral launch facility on the red planet it in order to facilitate a return journey to Earth. Because that's what would be needed given a not dissimilar gravity of the two planets. The acceleration due to gravity on the moon is 1/6 that on earth; on Mars it is roughly 1/3 that on earth. Both of those are dissimilar. We are all aware what is need to launch a human into space from earth. It simply cannot be done with the crafts that took off from the moon. Similarly such a craft would not be powerful enough to escape the gravity of Mars. Nobody is proposing that a lunar module be used on Mars. It would obviously require the design and construction of a new spacecraft. Those people who enthuse about manned spaceflight to mars (curiously enough) never seem to mention this basic problem. What on earth are you talking about? Engineering vehicles to accomplish a Mars mission would not be so much a problem as finding the money to fund it. Jon |
#3
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Travelling to Mars
"Mervo" :
Hardly a week goes by without some news item about Mars and the likelihood of manned flight to it. I ask, where is there a cape Canaveral launch facility on the red planet it in order to facilitate a return journey to Earth. Because that's what would be needed given a not dissimilar gravity of the two planets. We are all aware what is need to launch a human into space from earth. It simply cannot be done with the crafts that took off from the moon. Similarly such a craft would not be powerful enough to escape the gravity of Mars. Those people who enthuse about manned spaceflight to mars (curiously enough) never seem to mention this basic problem. Sorry, but it appears that you did not do much thinking or research before posting here. May I suggest that you spend a little time reading some books in your local library showing some of the past designs planned for a Mars trip. You will find all your problems where addressed decades ago and that is why we don't bother discussing them now. Earl Colby Pottinger -- I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos, SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to the time? http://webhome.idirect.com/~earlcp |
#4
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Travelling to Mars
In article ,
"Jon Berndt" writes: | "Mervo" wrote in message | | I ask, where is there a cape Canaveral launch facility on the red planet | it in order to facilitate a return journey to Earth. Because that's what | would be needed | given a not dissimilar gravity of the two planets. | | The acceleration due to gravity on the moon is 1/6 that on earth; on Mars it | is roughly 1/3 that on earth. Both of those are dissimilar. And it's the potential that matters, anyway, which makes it even easier. | Those people who enthuse about manned spaceflight to mars (curiously | enough) never seem to mention this basic problem. | | What on earth are you talking about? | | Engineering vehicles to accomplish a Mars mission would not be so much a | problem as finding the money to fund it. Well, yes, but the aspect that I notice often gets skimped is the human one. The physiological and psychological problems of such a trip are non-trivial. And one difference between extended sessions in orbit is that they can be cut short in emergency, and a Mars trip couldn't be. The psychological effects of that can't be discounted, either. I don't know what the chances of a serious problem developing would be, but they must be large enough to be a major concern. Back in the days of the comparably stressful sea voyages, there wasn't the same regard for human life and welfare. If a crew member got seriously ill, he died. If one developed a phobia and threatened the ship, he ended up in irons or overboard. And nobody made a fuss about it. I know that people are studying that, but the results are not widely known - at least not to the lay public. What sort of probability of failure would be expected, due to this sort of reason? I don't have a clue, but it won't be zero. Regards, Nick Maclaren. |
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Travelling to Mars
"Jon Berndt" wrote in message ...
"Mervo" wrote in message I ask, where is there a cape Canaveral launch facility on the red planet it in order to facilitate a return journey to Earth. Because that's what would be needed given a not dissimilar gravity of the two planets. The acceleration due to gravity on the moon is 1/6 that on earth; on Mars it is roughly 1/3 that on earth. Both of those are dissimilar. What really matters is the Delta V involved. As it happens, the delta V from Mars to escape velocity is much less than even from Earth to low Earth orbit (~5.2 km/s vs. ~8.5km/s). So much so, in fact, that Single Stage to Escape Velocity rocketry from Mars is *easy*. Several first stages for launch vehicles currently in production could be changed to launch vehicles with *significant* paylod to escape velocity from the Martian surface with ease. The point is that the technology for getting off Mars with a rocket is well in hand, the engines, fuels, and structures we have today are much more than up to the job, the trick is getting the vehicles and all the fuel where you need it. We are all aware what is need to launch a human into space from earth. It simply cannot be done with the crafts that took off from the moon. Similarly such a craft would not be powerful enough to escape the gravity of Mars. Nobody is proposing that a lunar module be used on Mars. It would obviously require the design and construction of a new spacecraft. Those people who enthuse about manned spaceflight to mars (curiously enough) never seem to mention this basic problem. What on earth are you talking about? I think I've figured out what he's getting at. He's trying to imply that the Moon is a much different place than Earth and Mars, and that in rocketry Mars is more like the Earth than the Moon. Specifically, he thinks, I believe, that a full launch pad and gantry would be needed for launching from Mars, instead of the simple setup for leaving the Moon. He is, as it turns out, quite completely wrong. Mars is not the Moon, but it is not Earth either. More importantly, even on Earth a full launch gantry and pad are not necessary for launch, there are other ways to do it. For Earth gettng to orbit is such a close thing with the technology we have that it's better to not hamper the performance of the launch vehicle by putting the mass burden on it instead of on a gantry and pad. But for Mars there's quite enough margin available so that designing a rocket that doesn't need a gantry and pad won't result in a huge mass penalty and will still have substantial payload to orbit or to escape velocity. Note that the Delta V needed to launch from Mars to escape velocity is less than that achieved by top of the line ballistic missiles, some of which are fired from submarines or mobile trucks. The mass of the "launch facilities" for those missiles is very much less than for a conventional gantry, and even if launching from Mars required a similar mass penalty, it would not pose a great engineering challenge. As for people considering manned spaceflight to Mars, they *have*, in fact, thought of all of this, and worked it into their plans. Sometimes with enormous detail. That the solutions to the problem required much less massive structures than a full launch gantry and pad probably caused him to overlook their very existence. Engineering vehicles to accomplish a Mars mission would not be so much a problem as finding the money to fund it. Yup. |
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Travelling to Mars
Attitude toward loss of lives is not the only difference between the
sailing exploration voyages and a Mars trip. I think a good background book would be, Patrick O'Brian, The Golden Ocean (1956) based upon a voyage made before a remedy was found for scurvy. Note much use made of locally available materials for shipbuilding and resupplying. Copying knowhow abstractions from the sailing days into a Mars trip is a good idea, but it's going to be hard to do. Re The Golden Ocean. Clear a couple of hours before you start it. Once you're in it you won't be stopping til the end. Cheers -- Martha Adams |
#7
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Travelling to Mars
Christopher M. Jones wrote:
What really matters is the Delta V involved. As it happens, the delta V from Mars to escape velocity is much less than even from Earth to low Earth orbit (~5.2 km/s vs. ~8.5km/s). Plus the Martian atmosphere is much thinner. I'd think this would also make the Martian launch easier. -- Hop David http://clowder.net/hop/index.html |
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Travelling to Mars
from the Martian surface with ease. The point is that the
technology for getting off Mars with a rocket is well in hand, the engines, fuels, and structures we have today are much more than up to the job, the trick is getting the vehicles and all the fuel where you need it. The 'Mars Direct' plan as advocated by Robert Zubrin calls for staging and testing the return vehicles in advance of sending the manned vehicles to Mars and also for the production of rocket fuel from CO2 on Mars itself with a small starter batch of hydrogen, as demonstrated in his experiments here on earth. A lot of details are described in his books and on the Mars Society web pages. B. Debic. |
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