Is there any primary science being done here that a robot couldn't do?

[NNadir]

Beating my favorite dead horse, I'm looking at the "science" connected with the International Space Station, and trying to determine if there's much more to it than the somewhat self-referential study of the effects of being in space are on human beings.

Of course, if one relied on robots to do space work, one would not need to spend so much time studying the effect of space on humans.

http://exploration.nasa.gov/programs/station/list.html

[mr_hat]

1. Developing new recreational drugs?

[Kutjara]

2. Creating the illusion that humanity is a curious...

...intelligent species that wants to personally experience the limits of its environment, instead of just a bloodthirsty mob of clever apes whose fundamental measure of the value of anything (land, wealth, power) is the misery inflicted on others while acquiring it.

I think the real reason why most people think space exploration is pointless is because there's nothing to kill up there. If we do find life elsewhere, particularly life that occupies an environment we want to exploit, we'll be back in business. And using robots to exterminate just isn't as much fun as doing it up close and personal. So manned spaceflight will come in handy one day.

[NNadir]

4. Well the reason I think it pointless is that it diverts limited resources.

I must confess that I am a fan of space science as represented by the planetary missions like Cassini, Galileo, and New Horizons...

One can really do a great deal of science, and assemble vast knowledge if one isn't troubled by life support systems. One wonders how many robotic craft might have been built with the money invested in ISS.

I will also confess to being a huge fan of Hubble, which has relied, and will continue to rely on manned space travel.

But other than Hubble, I don't put much stock in human space travel. One only need spend a few weeks in space to work on that wonderful device. Mostly manned space travel is romance, not science.

[man4allcats]

5. I do think humanity is curious,

but I also agree you are right in asserting there is a selfish motive in our curiosity. It is true we are are a vicious species not much evolved beyond our simian ancestors; so little evolved in fact that we are willing to engage in unwarranted risks such as the 1986 Challenger Disaster and the equally disastrous Shuttle Columbia disintegration in 2003. Both of these disasters were preventable. NASA knew in advance the risks they were taking, and they proceeded nevertheless. As a result, both crews needlessly lost their lives. I used to be a gung ho NASA person, but if they can't or won't do better than this then I think the manned space flight program should be abandoned. NASA needs to get its snap. It's just that simple. I'm more than willing to go where no one has gone before, but only if the "t's" are crossed and the "i's" are dotted. If NASA can't handle that, it's okay. I understand that Houston's Bus Company is hiring.

[lindisfarne]

3. Bush has advocated sending humans to Mars and the moon - a total

waste of funds. Robots can do far far more because they can stay without worry for months or years. Humans back on earth can make virtually the same decisions (or better) that an astronaut could - whatever small costs there might be from not sending humans, they are more than made up for by being able to send many more missions due to the lower costs of sending robots.

[Phoonzang]

6. I think you’re all missing the point....

of manned space flight. We’re not sending people up there just for the sake of pure science. We’re sending humans into space because it fulfills the dreams of humanity to leave the cradle. Many people over the course of history have looked up at the sky and wondered what’s up there. Sure you could send robots out there to take a look, but it lacks the impact of seeing it with your own eyes.

Also, I don’t think that a robot would do a better job exploring a planet than a human would. In the time it takes a robot to slowly crawl along the surface of Mars toward an interesting looking rock, negotiating the terrain so it’s wheels don’t get stuck in some moist sand, a human could have walked over, picked up the rock and taken it back to the lab in the “habitat”. But of course robotic probes are still useful and have so far provided us much more information about space than manned missions. That goes back to the pure science thing…human exploration serves other purposes. It’s not all about efficiency and less cost and blah blah. Well we need to put more money into the space program both manned and unmanned. Know how much you can get done in space for the price of a shiny new B-2 bomber or Aircraft carrier?

I’m sure you all know about Stephen Hawking’s (and others) statement about how we need to leave the Earth or face extinction. Well…if we sit on Earth and send out probes, we’ll make no progress towards this end. When the asteroid comes, or when global warming wipes us out, or when we kill ourselves through nuclear war, that’ll be it, no more human species. We will have left all our eggs in one basket. And I’m sure there are those who’ll say humans shouldn’t leave because we’ll just screw up another planet or take our problems elsewhere. Well fine, stay here and die. Oh, and there’s also the argument that we need to fix our problems on earth before we leave. The absurdity of that is so staggering that I don’t even want to think about it.

There’s also the tremendous amount of raw material out there to make use of. If we were to rope in one of these near earth asteroid (an unmanned operation), mine it. I heard a figure somewhere that one of these rocks of a relatively small size would contain more minerals than have been mined from the beginning of civilization. We’re fighting over dwindling resources down here but there’s all kinds of crap out there just waiting for us. I’m sure we’d find something to fight about out there too, but that’s humans for you…

That being said, the ISS has been a tremendous flop. It had such potential but instead has ended up as an orbiting can where 2 astronauts sit there and twiddle their thumbs. A result of cutbacks and severe lack of vision. Didn’t they ever think that you could move a space station? Anyway, that’s not really relevant to my point.

We should put more money into manned space flight and unmanned space flight; it doesn’t have to be one or the other. And I mean real manned space flight that leads to human habitation of space, not Bush’s anachronistic plans for a photo-op on the moon.

[NNadir]

7. Personally, I think the idea that "we" can escape earth is dangerous

possibly.

Let's be clear. "We" will not escape earth. Those who might escape, a small group of astronauts, all 50 of them, will probably not survive very long in space either. There is no evidence whatsoever that space is hospitable for large organisms. There is no evidence that humanity can survive for eons with limited biodiversity. This is a sci-fi day dream. When I was a boy, there was a movie, 2001 that included colonies on the moon. It didn't happen. There are excellent physical reasons for that, some being the laws of physics and energy involved in reaching the escape velocity. Spacecraft for humans are SUV's on incredible steriods.

I actually think that the best shot we have is to recognize that this planet is what we have. Space technology plays a role in helping us maintain what we have, but I don't believe for a second that it will allow us to escape what we have.

Fundementally, I believe that it is well to extend our vision, to contemplate scientifically the scale and majesty of the universe. But all that terraforming stuff, asteroid capture and so on doesn't really inspire me. If he we can't take care of one planet, there is no reason to suggest that we can take care of many planets.

[qazplm]

9. "we" may not

but our descendants most definitely will.

Mars IS terraformable even with today's technology (would just take millenia currently).

You are right that humans cannot last for eons on just one planet, thus why we need to expand, not only because of limited resources here but also because ELE's like meteors, comets or even several super volcanoes going off at once make our continued existence on here fragile.

There is no reason why we cannot terraform Mars 1000 years from now nor why we couldnt live on the moon 300 years from now. None of those hurdles are insurmountable, they certainly wont be a century from now. When we have computers the size of a calculator 30 years from now, when we figure out fusion, or even matter-antimatter, that will reduce problems with power generation needed to travel amongst the stars.

This idea that we are somehow destroying the planet is a little far fetched. Global Warming is real, but we are slowly but surely working many in our own little way to make it better, certainly better than 10 years ago, much better than 30 years ago. I think your position seems to presuppose that we shall always be as we are now, in all ways. I dont buy it.

And what difference does it make if we are the supreme stewards of "what we have" if 200 years from now a comet comes in and turns the entire surface of the planet to about 500 degrees?

[NNadir]

12. My personal opinion is that you read too much science fiction.

The supposition that Mars is "terraformable" with today's technology doesn't give too many details. I think if you are making such an extraordinary claim, given that no system for supporting a rhodendron - never mind a human being - has ever travelled that far with today's technology, you ought to supply some details.

What elements of today's technology could do this, where would the resources come from, and even more fun, how much would it cost? One element you will need to address is the question of why Mars has a very thin atmosphere today and how, exactly, you might countermand that condition.

[qazplm]

15. Besides being a bit jerkish

your opinion is incorrect. The ability to terraform has nothing to do with "watching too much scifi"

It is about the physical processes required to terraform a planet.

It aint that hard, it just takes a really really really long time with current tech.

Why doesnt Mars have an atmosphere? Several reasons. Lack of geological activity means that gases were not replaced from geological processes like on earth is one big reason. But that happened over millenia. And with a continual terraforming procedure in place you could counteract that.

You dump some lichens and microbial material that dont mind cold weather and love CO2 and they start to grow, turning CO2 into O2. Given a millenia or two and you've got a nice little atmosphere going.

You put soot or another dark material on the ground to soak up heat and warm the planet, you can speed things up.

You can take a comet and aerobrake it into the atmosphere, or since Phobos is already due to crash into the planet soon anyways, you can redirect that to help heat things up. There are many ways to help speed things up but not doable with current tech. Thus why I said that it IS terraformable with today's tech, just over millenia.

With tomorrow's tech, we can do it faster.

Mars was once a planet with a thick atmosphere and water, it is therefore not impossible to recreate conditions to make that happen again.

Before then, there is no reason why large domes could not be constructed while we wait. These things will not happen in my lifetime or my children's lifetime, but they will happen. It is inevitable.

The longer we take to figure out the very basics of manned spaceflight and living on other planets the longer we will take to get there.

[NNadir]

17. An the pressure of CO2 on Mars is what?

The main reason that Mars has an atmosphere that is 1/150th the pressure of earth's atmosphere also involves something called mass. A description of the interrelationship of planetary mass and the retention of an atmosphere can be found in this link: http://cseligman.com/text/planets/retention.htm

Somehow I think it's going to involve a bit more than some lichen.

Maybe you think I'm a jerk, but I think I have an appreciation of the very basic data in the case. If you know of case where people live where the oxygen partial pressure is 1/150th of earth's pressure, I would really be interested to learn about it.

[qazplm]

19. Mars HAD a substantial atmosphere

seeing as how its mass has not changed recently, it is not simply mass that makes it not have an atmosphere.

Titan has much less mass than Mars and yet it has a thicker atmosphere, so thick in fact that a human with 10 foot wings attached could fly using muscle power alone. It aint mass alone that determines how thick an atmosphere is. It is also temperature, the presence of a magnetic field, and outgassing from geological activity.

By the way, from your own link:

"If a planet is fairly small, or a moon of a planet is fairly large, such as Mars and Mercury, or our Moon or Titan, then whether it can hold onto even heavy gases will depend upon the planet's size and escape velocity, and its atmospheric temperature. If it is a larger planet, a little further from the Sun, like Mars, it may be able to hold onto gases, whereas if it is a smaller planet, closer to the Sun, like Mercury, it may not be able to do so."

Even your own link suggests Mars may be able to hold onto gases. And even if it has difficulty holding on to gases, all that means is that once you've achieved a livable volume and quality of gas/air, that you'd have to have some balancing continuity which would replace the gas/air lost. Furthermore, from your own link, this loss does not happen overnight, it happens over millions of years or more.

Somehow, I think that's slow enough to compensate for.

I think your idea of "very basic data" is neither basic nor correct data. Again, you seem to think that because things are a certain way today, thats the only way they can be. No we cant live in a 1/150th of earth pressure, but how about 2/3rds? Emminently doable.

[qazplm]

21. and speaking of CO2...

This from wikipedia on a plan for terraforming Venus:

"Geoffrey A. Landis proposes colonizing the cloud-tops of Venus.<3> Initially, the image of floating cities may seem fanciful, but Landis' proposal points out that a Terran breathable air mixture (21:79 oxygen-nitrogen) is a lifting gas in the Venusian atmosphere. In effect, a gasbag full of human-breathable air would sustain itself and extra weight (such as a colony) in midair. At an altitude of 50 km above Venusian surface, the environment is the most Earthlike in the solar system - a pressure of approximately 1 bar and temperatures in the 0°C-50°C range. Because there is not a significant pressure differential between the inside and the outside of the breathable-air balloon, any rips or tears would diffuse at normal atmospheric mixing rates, not result in an explosive decompression, giving time to repair any such defects.

Such colonies could be constructed at any rate desired, allowing a dynamic approach instead of needing any 'fell swoop' solutions. They could be used to gradually transform the Venusian atmosphere, with their impact directly related to the number of colonies in the atmosphere. As the constructed colonies increased, more solar panels could be used to absorb insolation and thus cool Venus; they could also be used to grow plant matter that would reduce the amount of carbon dioxide in the air. In the beginning, any impact on Venus would be insignificant, but as the number of colonies grew, they could transform Venus more and more rapidly."

This is a pretty brilliant idea, 0-50C range would be comparable to most of the Earth's surface temperature wise, certainly livable, no worries about explosive decompression, and plenty of ready made CO2 for plant life to absorb, all the while slowly but surely blocking the heat and cooling the planet to the point that the clouds start to precipitate out.

The point is, that today is not the end of knowledge, tomorrow will bring new ideas and new methods, and if we can conceive of how it can be done today, that goes a long way towards insuring we will actually do it tomorrow.

[bananas]

23. NASA: "Raising the atmospheric pressure...in a few decades"

I'm not going to bother arguing with Luddites, your mind is made up I won't confuse you with facts, but for other people reading this thread:

NASA: "NASA scientists believe that it is technologically possible at the present time to create considerable global climate changes, allowing humans to live on Mars. But this will not be by any means an easy task. Raising the atmospheric pressure and surface temperature alone could be achieved in a few decades."
http://quest.nasa.gov/mars/background/terra.html

HowStuffWorks.com "Terraforming Mars": http://www.howstuffworks.com/terraforming.htm
"In this edition of How Stuff Will Work, you will find out why Mars is the ideal candidate for colonization, and how we plan to terraform the red planet for human habitation."

Wikipedia: "Terraforming"

Sagan also visualized making Mars habitable for human life in "Planetary Engineering on Mars," a 1973 article published in the journal Icarus.<4> Three years later, NASA officially addressed the issue of planetary engineering in a study, but used the term planetary ecosynthesis instead.<5> The study concluded that there was no known limitation in the ability to alter Mars to support life and be made into a habitable planet. That same year, in 1976, one of the researchers, Joel Levine, organized the first conference session on terraforming, which at the time was called "Planetary Modeling."

In March 1979, NASA engineer and author James Oberg organized the "First Terraforming Colloquium," a special session on terraforming held at the Lunar and Planetary Science Conference in Houston. Oberg popularized the terraforming concepts discussed at the colloquium to the general public in his 1981 book, New Earths.<6> It wasn't until 1982 that the word terraforming was used in the title of a published journal article. Planetologist Christopher McKay wrote "Terraforming Mars," a paper for the Journal of the British Interplanetary Society.<7> The paper discussed the prospects of a self-regulating Martian biosphere, and McKay's use of the word has since become the preferred term. In 1984, James Lovelock and Michael Allaby published The Greening of Mars.<8> Lovelock's book was one of the first books to describe a novel method of warming Mars, where chlorofluorocarbons are added to the atmosphere. Motivated by Lovelock's book, biophysicist Robert Haynes worked behind the scenes to promote terraforming, and contributed the word ecopoiesis to its lexicon.
http://en.wikipedia.org/wiki/Terraforming

Zubrin and McKay, "Technological Requirements for Terraforming Mars"
http://www.users.globalnet.co.uk/~mfogg/zubrin.htm
more at www.MarsSociety.org

[NNadir]

26. The *big* word in your last link is "may."

The planet Mars, while cold and arid today, once possessed a warm and wet climate, as evidenced by extensive fluvial features observable on its surface. It is believed that the warm climate of the primitive Mars was created by a strong greenhouse effect caused by a thick CO2 atmosphere. Mars lost its warm climate when most of the available volatile CO2 was fixed into the form of carbonate rock due to the action of cycling water. It is believed, however, that sufficient CO2 to form a 300 to 600 mb atmosphere may still exist in volatile form, either adsorbed into the regolith or frozen out at the south pole. This CO2 may be released by planetary warming, and as the CO2 atmosphere thickens, positive feedback is produced which can accelerate the warming trend. Thus it is conceivable, that by taking advantage of the positive feedback inherent in Mars' atmosphere/regolith CO2 system, that engineering efforts can produce drastic changes in climate and pressure on a planetary scale.

The bold is mine.

This is of course, in this running advertisement for the manned space program, no estimate of what this grand adventure might cost.

This is NASA marketing, the same sort of thing that funded the Apollo mission (actually a cold war game) by talking up the colonies on the moon. Certainly when I was a boy, and first saw Kubricks 2001, I thought they were describing in general terms, what probably would happen, Pan Am flights to the moon! I'm sure NASA was very fond of that movie.

The fact is that there are no plans for terraforming Mars, and no plans for travelling there with settlement in mind. There are very tenuous plans to send a few guys and gals there to, if they make it, wave the flag and pick up some rocks. I note that robots could pick up the rocks as well.

No one has ever considered what might be involved in hauling an ammonia asteroid (if one could find one in fact) to Mars, and then crashing it into the planet. In fact such notions are based wholly on speculation (hence the conditional words and phrases). I have no problem sending robots to find more about Mars, since one can send about a brazillion robots to do what a team of ten very expensive astronauts couldn't possibly do.

I will tell you what my response would be if today someone announced a plan to terraform Mars. I would ask them if they were out of their minds.

[qazplm]

27. good grief

this is not "NASA marketing".

Of course there are currently no plans for terraforming Mars. Just like there are no plans to do a lot of things, even things that should be done. We are still working on getting back to the moon, but we will, and it will be worth every dollar spent.

No one said that today we should start terraforming Mars, what we have said is that the technology already exists to do it over millenia, and that we will do it one day, and like the rest of science, it requires the building of blocks of knowledge, block one being more information on protecting, transporting and taking care of humans in space.

[NNadir]

28. You are making a lot of assumptions.

I don't think that the resources exist to terraform Mars. As before, I make my arguments on the basis of energy. I think that's a big factor in all this handwaving about hauling asteroids conveniently loaded with ammonia.

Simply because one can write a speculative paper, doesn't mean one can actually do it.

I personally don't believe that humans will actually go to Mars, and I'm certainly not in favor of things like the ISS which exist only to answer one question, can humans go one time? As I say, I think robots do a better and safer job.

[Codeine]

29. 800 years or so ago,

you would have been telling folks "Don't sail too far, you'll drop right over the edge!"

50 years ago you'd have been telling people "Don't travel faster than the speed of sound, your head will explode!"

30 years ago you'd have said "Computers in your home? Pfft! What a waste."

Don't worry. Folks with vision, spirit, and the urge to explore will be along shortly to do the heavy lifting. Try not to get in their way.

[qazplm]

31. you are hopeless

energy? To seed the planet with lichen? To drop soot?

The other poster is right, you would have been one of those people who said it was a waste of time to spend money on studying flight.

[NNadir]

33. You are so naive. Bicycle mechanics were able to work on flight.

The Wright Brothers ran a bicycle shop, not a billion dollar space agency.

It did not require 100's of billions of dollars to fly at Kitty Hawk. So your "analogy" is not an analogy at all, so much as it is a red herring.

The fact is that the limited resources of space technology are largely wastes to send a person to wave a flag and pick up rocks. And let's be clear, that's what it's going to come down to. Everything else is just science fiction. There will be no colonization effort in this century or probably the next.

Now, if you can run a bicycle shop and put together a terraforming program, more power to you. If you wish me to support your fantasy to the tune of politically supporting the expenditure of billions on the ISS, to see how long people can live in space, however, and denude useful space programs of funding, I'm sorry, but I'm against it.

[qazplm]

35. naive? No

There were a LOT of scientists at the end of the 19th century who said flight was impossible, you couldnt do it, its a waste of time.

It is the reason two BICYCLE enthusiasts were the ones to finally get it done.

So this is about money then eh? Not about whether we can actually do it as you said before, but now its about money?

So what this really is, is the standard old, we should spend the money here blah blah blah schtick.

Ignoring of course all of the benefits we have already received from the manned space program.

Luddite IS a pretty good word to describe you.

[Name removed]

36. Deleted message

Message removed by moderator. Click here to review the message board rules.

[qazplm]

38. ummmm....

if this is the only reply from you thus far, and it is, then you dont "really" want to discuss any points either.

If you have facts to present, then present them, otherwise drive by posts saying "you appear to be full of shit" arent particularly impressive, even with an emoticon attached to them.

[NNadir]

39. Have you ever done an energy calculation in your life?

You haven't?

What a surprise!

Let me help you here, since you are claiming, in spite of any evidence that your claim is justified, to understand what a "luddite" is.

The Saturn V rocket, which is actually the only device ever to have propelled people to another body in the solar system, contained about 203,000 gallons of refined kerosene, known as RP-1.


The specific gravity of kerosene is about 0.82. It's energy density is about 35 MJ/liter. (Please note that I would take it for granted that anyone with a serious understanding of technology will have no problem converting between metric and English units, although a space craft has crashed because of such a conversion error.)

The second stage contained about 260,000 gallons of liquid hydrogen. We will ignore for a minute the compression energy of that situation and the energy cost of liquefaction. The specific gravity of liquid hydrogen 0.0696. We will ignore all the liquid oxygen this craft contained, pretending for a while that liquid oxygen was not involved in the incident on Apollo 13 or the incident on Apollo 1. The heat of formation for water is about 455 kj/mol.

Let's just forget about the third stage for now.

http://www.apollosaturn.com/s5news/p2-7.htm

Well let's see it big boy. How much energy did the only spacecraft to send people to another planetary body consume? Any idea?

The world's energy demand right now is about 440 exajoules. Maybe you can enlighten us as to how many people we could send to the moon with 440 exajoules. How about 25 times the entire world's energy consumption, including everything used for growing food, transportation, communication and basic commodities like heat and lights?

Any idea?

I didn't think so.

People who make suppositions about technology that are connected to reality generally have a sense of how to do at least freshmen scientific calculations.

Oh, in case you need this number for your calculations, maybe I should inform you about how many people each Saturn rocket carried to the surface of the moon: Two.

I don't know if they have a science fiction forum at DU, but this is the science forum.

[qazplm]

40. You typed a whole lot of crap

to make a ridiculous point.

No one on here is suggesting that next week, we start sending people to the moon.

Nor is anyone on here suggesting that next month, we begin building a moon base.

So stating that we cannot with current technology do either is pretty inane.

I'd suggest you re-read the entire thread quite frankly, but let me sum it up for you.

"Science" moves forward because people actually do things that move it forward. That means to one day get to a "moon base" you start by sending people into space, and, you know, learning stuff.

[Name removed]

41. Deleted sub-thread

Sub-thread removed by moderator. Click here to review the message board rules.

[NickB79]

32. Well, we unintentionally terraformed our own atmosphere in a few centuries

I think that if we survive as a technologically advanced race into the next century (which I'm not so sure we will) we could terraform Mars to the point where genetically altered humans could live on the surface with marginal protection and breathing equipment.

[Dead_Parrot]

37. Depends on the "we"

No-one alive today is going to live on Mars, never mind escape Sol: maybe in 800 years we will. But this is "we" as an in "humankind": Assuming "we" survive what we're doing to own planet, "we" are bound to escape to other worlds. Maybe in 1,000 years, or 100,000, or 100,000,000...

"We" have lots of time. 5,000,000,000 years or so. if we fail, we will die. If we succeed...

...we'll probably still die. But what the fuck, we'll have died trying. :D

[phantom power]

42. I will cite one reason that I think living off-planet is a good goal...

This is what I classify as motivational material:

http://youtube.com/watch?v=00W7TaEr-E8&search=meteorite%20collision

[Codeine]

8. Because it's what humans do!

We explore. We have always wanted to know what's over the next hill, where this river goes, what's across that expanse of ocean, how deep does this cave go, what's at the bottom of this lake, etc. It's our very nature.

I don't want to be part of a culture that says "You can't look there because we still have work to do here." Things were not perfect in Greece when sailors struck out across the Agean and Mediterranean. Doubtless there were problems that the ancient people living in Asia could have solved before striking out across the Bering land bridge. But I'm glad their spirit was exploratory, that the open vistas before them called out "Explore me!" more loudly than the quavering cowards and spiritless among their number could beg them to stay put and not rock the boat.

There will always be problems to solve; we can't await perfection in all things before we look to new knowledge and new places.

[Ready4Change]

10. In my opinion

If there's no reason to have humans in space, then there's no reason to have them on Earth.

Why are we here at all? The Earth and it's environment did fine for billions of years before us. If we were to disappear it will be fine without us. Really, we're not needed here.

I could also say, why is there anyone on the American continents? Our species didn't develop here. Why did we walk out of our original terrain? Rather than continue increasing our population and seeking new resources, we should have just sat down, maintained our "original" numbers, and learned to get by with what we had.

So, should we be boxed into a single continent? A single planet? A single solar system? A single galaxy? What size box should we limit ourselves to?

[NNadir]

13. The laws of physics seem to have some bearing on the galaxy question.

The nearest star is 4 light years away.

Let us imagine that one could propel space craft to very high velocity, suppose with a highly efficient ion propulsion engine, say one quarter the speed of light. Ignoring relativistic corrections, how much energy would be involved? How much mass would need to be converted to energy in order to accelerate a system that could be biologically closed. Next, consider the question of acceleration. Suppose the people on the spacecraft all were on Arnold Schwarzenegger brand steroids and agreed to live at a constant acceleration of 1.5 g. How long would they be required to do this?

What would be the momentum of dust particles that might encounter the shock front of this space craft? From what kind of structural materials would the spacecraft be constructed to maintain integrity with dust particles?

The density of granite is about 2700 kg-m^-3. A sphere of granite with a radius of 1 mm, quite literally a grain of sand, as I calculate it including the relativistic correction, having a volume of about 4 billionths of a cubic meter would have a kinetic energy of about 100 billion joules. Before you dismiss this concern, let me tell you that it is already very much a concern of NASA's in earth orbit at much lower velocities.

I would submit that many of these same considerations would apply for a trip to Mars, even a single trip, never mind a trip to a nearby star. The Voyager craft have been traveling since the 1970's and have not even reached the heliopause.

Almost always, when you ask these questions, you hear about fanciful laws of physics that have never been demonstrated, worm-hole travel and that sort of thing. However appealing to the known laws of physics, the question of long distance space travel becomes far more problematic.

I know I am about to be informed about all of Steven Hawkings recent remarks about space colonization, which are very cool, I'm sure. Someone will tell me that Hawkings said this should be done, and therefore it must be possible. But one asks whether Hawkings has also supplied any answers to these obvious questions. I wonder to what extent he has actually thought this through.

[salvorhardin]

14. I would argue

That the benefits come as a side effect of trying. Better, more efficient technology, medical discoveries as a result of trying to support human life in space, some pure science, etc. You're correct in that no one can make an economic case for human space flight yet. The thing is, we don't know if human space flight will be worth it or just go down in the history books as a distraction. It's a gamble. I tend to think it's a gamble that will pay off, you don't. And let's face it, part of the reason we have the very real concerns with global warming today is because we took an unthinking risk in using fossil fuels and then ignored the warning signs for far too long. But in the long run, I'd hate to see a human race that has become so risk avoidant that it no longer gambles on the long shots.

As far as what I'd do if I were made king? I'd defund as much of the military black budget as possible and rechannel the spending into two new Apollo style programs -- One program to put a continuous sizable human presence into space and the other to fund energy research and development, particularly into nuclear technologies. Both those programs would have an enormous economic benefit just in terms of jobs creation alone. And really I see both programs as being synchronistic.

[qazplm]

16. you could do it

with a solar sail which would get you there if done right in less than a generation.

A fusion or antimater/matter engine could certainly generate enough power to do it.
Even an ion engine could do it.

All you need is a constant acceleration and eventually and quicker than you might think, you've reached enough of the speed of light to make that 4 light year trip into an 8-12 year trip for the occupants of the craft.

The problem with getting to nearby stars is not so much a problem of gaining the appropriate speed as it is building the shield necessary to protect the crew from obstacles the size of grains of sand going at that speed.

However, even now we can consider ways of doing it...

a shield of water works surprisingly well, or we could create a literal "deflector shield" of EM energy which would sweep them out of our way.

The bottom line is, we can already conceive of how to do it, and history has CLEARLY shown that once we can conceive of ways of doing something, that something more likely than not gets done.

How many scientists said we couldnt fly, split the atom, break the sound barrier?
Even now we have real physical models for travelling faster than the speed of light.

You seem to be of the belief that if we cant do it right now, today, cheaply, then it cant be done ever.

[Ready4Change]

18. No need to build boats.

There's nothing across that ocean. So why bother building boats? We're having problems feeding all our people as it is.

There are always demands to spend resources in other ways. There are always people who don't see the reasons why others may be interested. Indeed, often, people who don't see a reason far outnumber those who feel compelled to peek over the next horizon.

That's me talking romantically, I admit. But then, if we cast aside such romance I see no reason for us to continue existing at all.

However, while I'm a huge sci-fi fan, I acknowlege that the technical difficulties of interplanetary travel are on the verge of insurmountable, except perhaps for limited, Apollo style dart'n'grabs. And interstellar travel? All but unimaginable.

But then, the world used to end just over the horizon, almost no one could swim, and but a few had ever ridden in anything more than a rowboat. The idea of floating cities racing about oceans and launching great noisy birds that carried men in their bellys would have seemed madness.

[qazplm]

20. The beauty of interplanetary travel

is that with a universe that should last at least another 50 billion years give or take, that you have a very very long time in which to traverse even a whole galaxy, with little "dart n grabs".

Of course the reality is we only have about 3 billion years before we collide with Andromeda, and that could create conditions that scrub most life from both universes.

Even so, imagine doing a dart and grab every hundred years to a new star system 4, 5 or 6 light years away. You could do that conceivably. In a thousand years you've covered 50 light years. In 100 thousand you've covered 5,000. In 1 million years you've covered 50,000. In 2 billion you'd cover more than the diameter of our galaxy.

[Odin2005]

11. Humans are natural explorers.

images from a robotic probes doesn't cut it, we want to actually go there and see it with our own eyes.


Another reason manned space flight is needed is to prepare for colonizing other planets.

[Dead_Parrot]

22. No, but so what?

Having mulled this question over for a few days, here's my answer...

Probably not. If we, as a species, had shoveled the resources we've put into manned space flight over the last 30 years into robotic development, we'd have some incredibly adaptable robotics. The stuff coming out of the Japanese labs is mind boggling as is, and given a bit more impetus would be quite capable of replacing a HST camera.

But consider, for a moment, the inspiration value of manned space flight: I grew up on the Apollo missions, and until the Challenger disaster I wanted to be "a spaceman". Now, there's a chance that NASA don't want overweight thirty-something alcoholic smokers, so I may have missed the bus. But it was enough to kindle an interest in astronomy and astrophysics that still endures: And even though I've never done any really useful research in the field, there must be thousands of kids watching Fossum dick about with a spanner while watching an orbital sunrise thinking "Cor, I wanna do that".

Most of them will never make it to orbit. But maybe they'll grow up to be the next generation of engineers at JPL, NASA, the ESA or the RSA, and will push the boundaries for another 20 years.

I doubt it's worth the lives claimed by the space programs. But it's certainly worth the money, unless you want to put a dollar value on wisdom. (Which I doubt you do!).

I'll bet that the current flock of NASA astronauts & flight crew were more inspired by Armstrong than Voyager.

If can do it safely, we should certainly do it.

[benburch]

24. Almost no science at all is on on the ISS.

Station keeping duties take up all of the crew's time.

[Beelzebud]

25. Evolution did not end with our thumbs.

Our destiny is in space.

[Codeine]

30. NO, no, no!

Stay here. It's comfy, and look -- things aren't perfect yet. We can't do anything until everything here is just right. That's it, sit back and relax, have some Soma. :evilgrin:

[YankeyMCC]

34. We need to learn to live out there

life - particularly human life since I'm partial to my own race - survives best by expanding. We can't really expand on Earth any more and even if we could there's much more "space" off Earth than on of course.

There are beneficial feedbacks from human presences in space of course and those count. But the real point is expansion of life, continued evolution of our civilization if not our physical and intellectual existence.

It's not about 'escaping' either because that will never be at all a practical solution to any of Earth's problems but it is about keeping humanity vitally engaged in the universe. WE must continue to strive to expand our existence or stagnate and fade.