Here's a rebuttal to this article. First I'll respond to his own comments, and then I'll address that article from the NASA page.

According to Frederick Smith, traveling to the stars, perhaps divested of our carnate bodies and turned into gleaming computer-driven machines of stainless steel and plastic, is eminently feasible. It’s right around the corner you feel, if you read his glowing prognosis, which sounds something like Star Wars, which I suppose he saw at least 10 times.

Actually, the basic tech required is either here or right around the corner, yes. “Around the corner” is relative here, of course. I've watched Star Wars more than ten times. But what I propose, and what thinkers on this topic propose, is nothing at all like Star Wars. I wonder if Keyes actually read my article, or just skimmed over it? I clearly said that the chances of living on other planets as they are, of finding “Earth-like” planets that we can just walk around in open air on are virtually zero. Star Wars is good fun, but nothing I proposed involves hyperspace, or zooming from one star to the next in a few hours or minutes. Evolution also tells us that aliens would most likely look nothing like Star Wars aliens, who almost all look like hominids: upright, distinct heads, two arms, two legs, two ears, two eyes, one mouth and so forth.

In other words, serious people are considering interstellar travel and it does no service to anyone to simply link science fiction to science fact and just dismiss it out of hand. Very few Hollywood space movies are actually what's known as “hard sci-fi”. "2001: A Space Oddessey" and "2010: The Year We Make Contact" might qualify in terms of spacecraft.

To hear Smith talk, you’d think it was the easiest thing in the world to get up to a considerable fraction of the speed of light, say 10% or 30,000 kilometers a second, shoot across a gulf of 41 trillion kilometers in a mere 43 years aboard the craft, and set up housekeeping in a biodome on some planet whose existence hasn’t even been established so far.

There are many issues here. First, I never claimed it was easy. It's hard, but so was building the pyramids, an analogy I'll use repeatedly in this rebuttal. Reaching 10% of the speed of light is a problem that's already “solved”, nuclear pulse propulsion allows such speeds. Solved is in quotes because we haven't actually built such a vehicle yet, though the designs we have date from the late 1950's and require nothing exotic. If such a craft can be pushed to that speed, the distance doesn't matter. It will continue to travel that fast indefinitely, so this huge gulf is irrelevant in terms of that speed – they are two different issues. The gulf becomes an issue only in terms of keeping the humans on board alive, which is of course the REAL issue in all things space and in some ways, the only issue.

I did not propose that we build a bio-dome on Gliese 581c, quite the opposite! I suggested that we would have to build one, if we chose to reside there for some reason, but then I gave detailed reasoning for why we probably wouldn't want to do this. Further, whether or not there are “pleasant” oceans on such a world doesn't matter. I used Gliese to make a point. Thomas began his article with a certain disgust about how excitedly astronomers trump their latest findings in newspapers. In any case, we wouldn't be so stupid that we could launch for a destination that might not exist, so this is a moot point. New telescopes are being designed for the express purpose of analyzing extra-solar planets. By the time we are ready, we'll have plenty of targets picked out:

NASA's Space Interferometry Mission (SIM) is headed for launch in 2009, assigned the job of determining the positions and distances of stars several hundred times more accurately than any previous observations. This accuracy will allow SIM to look for the positional (astrometric) wobble of nearby stars induced by orbiting planets. In some cases, planets as small as a few Earth masses should be detectable.

Data from SIM will help establish a catalog of likely targets for another longing-look outward: the NASA Terrestrial Planet Finder, or TPF for short.

With an anticipated launch between 2012-2015, TPF will be capable of detecting and characterizing Earth-like planets around as many as 150 stars up to 45 light-years away. TPF is slated to make 5 years of observations to detect the atmospheric signatures of habitable or even inhabited planets.

The European Space Agency (ESA) has selected the InfraRed Space Interferometer -- better known as Darwin -- as a mission for its Horizons 2000 program. Selection of a launch date, probably in the 2014-2015 time frame, will be made on cost, science and technology grounds sometime before then, according to ESA. As now envisioned, Darwin will use a flotilla of six space telescopes. Working together, the telescopes are to look for signs of life on Earth-like planets.

Further, the difficulty of a bio-dome or a self-sustaining space habitat is the real challenge, but what does Gliese have to do with it? We would need one to keep us alive for the trip itself (assuming we went as physical humans), so this tech is a prerequisite. This is precisely one of my main points, a point seemingly lost on Keyes. In order to go anywhere in space, we would already have to learn how to live in space. There is probably no reason at all to “settle” on the surface of other planets – space will do fine as long as we have energy and raw materials around.

If most humans who will ever live haven't been born yet, then in all likelihood most will be born in space, far away from Earth. Could the Earth even handle five times our current population? Ten times?

Or better yet, if we have just a little patience, we can go the 193 trillion kilometers to planet Gliese 581c, in a mere 204 years, which should be no problem with our new stainless steel bodies, susceptible of in-flight repairs, upon with Smith predicates his dangerously infectious optimism. Of course, we don’t really know that Gliese 581c is earthling-friendly; it just happens to be in the sort of proximity to its parent star that suggests that it may have liquid water. But no matter, we can always set up a self-contained space station there, even if the water turns out to be ammonia and the temperature is always 200 degrees.

Had Keyes closely ready my article, he would have seen that I proposed that we exist as software, as advanced computer data and programming. In such a state, we wouldn't need water and getting it from the surface of such a heavy planet would be too expensive anyway. The asteroids and comets are loaded with all the water we could ever desire, easily enough to fill the oceans up many times over. Jupiter's moon Europa alone has more water than our whole planet. Surely a target star system would have enough water for our needs floating around in rocks, if we needed water at all in such a non-physical state, whether or not planets are close or far from the star at the center.

I venture to say that no one alive today will live to see Gliese 581c, unless science gets into high gear fast to prolong human longevity. Smith is thirty-something. Will he live to be 225 years old, with or without steel limbs and plastic organs? I surely don’t know why he is so excited? He’s not going to the stars.

Keyes might be right, though I never suggested that I personally wanted to go to the stars. However, if some life extension technology comes along before I die, say in the next 50 years, then I might live as long as humanity will exist. If they can extend my life by, say, another 50 years, surely before that stretch is over technology will have advanced to the point where the next treatment becomes available, and so forth. The first generation that will live greatly extended life-spans will likely be the near-immortal generation. So while I'm not holding my breath or even at all planning to visit other stars, it is possible. If the likes of Ray Kurzweil turn out to be right, in about 50 years I may be scanned into a computer and exist indefinitely as software - who knows?

As for why this excites me, well, therein is the crux of the issue for Thomas. Getting Thomas interested in space exploration is probably more difficult than reaching the nearby-stars ;) It's about learning how common life is, how unique we are, and so forth – about finding an analog to the Earth. The various space agencies spitting out the special planet-finder telescopes that I listed above are equally excited; this isn't the purview of a few lone loons. it is the natural destiny of human kind, if anything is. Keyes once wrote that he considers astrobiology a fake science. It seems Keyes has some sort bias against this kind of thing in general.

It's also about basic survival. Having the whole race on one speck is foolhardy now that we know better. Even if moving masses of the general public off-planet is a long way off, there must be lead-up time as far as the technology goes. Now is the right time to start, this is the lead-up time.

Here's the end of the first part of his article, I'll cover that “NASA” article in a moment:

On a more modest scale, Smith laments the fact that we have not done more to set up housekeeping on the Moon. This is a relatively easy task, he says, talking about recycling modules, spreading solar panels and building a sublunary station far away from cosmic radiation. Yes, I admit that something like that might be in the realm of the possible, but to what purpose?

If we’re so good at tailoring environments, however hostile, to our own needs, why don’t we do it right here on planet earth? If we can build a viable city on Gliese 581c or on the Moon, surely we can build cities in Antarctica, Greenland, the Sahara, the . So what are we ewaiting for?

It's more than in the “realm of possible”. The International Space Station already provides an artificial habitat. We've already landed humans and equipment on the Moon – it takes no imagination to envision a space-station module, something smaller like Skylab or MIR, actually placed on the Moon. The only issue here is will and money, nothing more. I'll agree with Thomas that we might lack the will. If Thomas wants to know why we lack this will, he has only to look in the mirror.

As to his questions about Greenland, what we are waiting for is a reason to build a city in Greenland! All of the reasons for going to the Moon have nothing to do with Earth mountains or frozen wastes. For those who advocate humans in space, no place on Earth will do, though I do of course understand what Keyes is getting at – if humans can't live at the Earth's extremes, how can they live in space? The vacuum of space is a place far more hostile than Antarctica or Greenland and we already have an example of a mini-false biosphere with the ISS. Nuclear submarines can stay under water for months on end, and actually float under the ice-caps. So, the issue is one of motivation and resource allotment, combined with potential returns.

What return could one get from Greenland? High quality ice cubes? Perhaps they could export prefabricated igloos to Minnesota, Buffalo, New York and the upper peninsula of Michigan, not to mention Alaska?

One return-investment from the Moon often used by those who want to sell the idea to politicians is helium-3. My main reason for supporting a base on the Moon has merely to do with humans living someplace else, in two places at once, and to gain the experience needed to live off the “space-land”, to make a stepping stone to the solar system and to nearby stars. I'll get back to helium-3 later on.

Cosmochemist and geochemist Ouyang Ziyuan from the Chinese Academy of Sciences who is now in charge of the Chinese Lunar Exploration Program has already stated on many occasions that one of the main goals of the program would be the mining of helium-3, from where "each year three space shuttle missions could bring enough fuel for all human beings across the world."

And now let me tackle the NASA article that was the bulk of Keye's column. He begins like this:

Here are some informal comments from NASA that seem slightly less enthusiastic than Smith’s almost religious ecstasy:

Informal perhaps, as I shall show – or worse. Is informal the right word though? The more I think about it, the less I think so. NASA, as far as I know, doesn't hold one official view of such things. I've read bits from NASA since the late 1980's, and can tell anyone that it is quite the opposite of a cohesive unit, there is much internal deep philosophical disagreement. Many think that the whole idea of humans in space is foolish, for example, that robotic probes are all we need. Many others are adamantly opposed to this view. NASA is a mash of ironies. On one hand, they have many folks that Keyes might label Star Wars watching "religious" nuts who actually work to improve the long term condition of the human race. On the other hand, NASA seems to mainly produce paper, designs for every kind of vehicle, from those that go a mere 3.3 percent the speed of light, to those that go around 80% light speed using anti-matter, and everything in between.

Anyway, here are some bits from that article that I'd like to address:

Well...it’s still not looking all that good. For a fission rocket you would need a BILLION SUPERTANKER size propellant tanks to get you there, and even with fusion rockets you would still need a THOUSAND SUPERTANKERS!

Even if we look at the best conceivable performance that we could engineer based on today’s knowledge, say an Ion engine or an antimatter rocket whose performance was 100 times better that the shuttle engines, we would need about ten railway tanker sized propellant tanks.

That doesn’t sound too bad, until you consider that we didn’t bring along any propellant to let us stop when we get to the other star system...or if we want to get there quicker than 9 centuries.

THOUSANDS! Wow, and, so what? How many oil tankers have we sent back and forth around our oceans? This isn't impossible, just very expensive, especially given NASA's budget. NASA is forced for no technical or scientific reasons to pull off small miracles, to make ever smaller and cheaper probes within ever tighter budgets. This NASA writer surely must think it a miracle to, in today's environment, fill up 1,000 super tankers worth of nuclear material. Without space infrastructure, even filling up a bathtub of nuclear material and sending it into space is a small miracle. The launch of a space probe is a small miracle, most of that being getting the money from Congress.

I clearly called for space infrastructure in my article. Right now, it costs us about $10,000 per POUND to get something into space via the Space Shuttle, of course getting 1000 of anything up there is a massive (though not at all impossible even with current technology) effort. But if we learn to live off the “space land”, we can get these materials from the Moon and asteroids, where the gravity wells are virtually nonexistent. Once we get over that initial investment, we wouldn't bring up tanker-sized loads from the Earth! If anything, we'd bring tanker sized loads of space goods back down to the Earth instead.

By the way, one wonders at the cost and expense of sending a small ship to nearby stars in any case, if so much fuel was required (something I'm not convinced of, read on). Any humans we send would surely not be coming back, they would set up shop and live there, so we'd have to send a huge amount of material to begin with. Why spend a fortune on anything less?

Building orbital hotels and such would also involve the movement of thousands of large-mass structures around space. And again, living in space for any length of time with any decent population, be it in the solar system or en route to the nearest stars, would also take an enormous amount of material. I can't help but wonder why the writer of this article would focus just on sending a human to the nearby-stars, and assume that this alone would be the project, that none of the other underlying pieces would first be put into place? In other words, if the mass of stuff we need up there is the issue, then building a space hotel is as much of a challenge as reaching the closest stars...

Would the Egyptians start building the Great pyramids without even a stone quarry and without having worked out how to bring the rocks from the quarry to where they're needed? Surely to a pre-stone quarry Egyptian, the idea of a Great pyramid must have seemed equally impossible.

I don't want to hear how difficult it will be to build a city the size of NY in space or how expensive. I already know. I want to hear why such projects are impossible. I want to hear why drilling out the inside of a rock in space and giving it a spin or false gravity is impossible.

We should start now. On the way, we'll find easier and “saner”, less expensive ways to go forward. Folks, we're debating here the validity of ideas developed in the 1960's. Surely by the time we implement any of them, new ideas will present themselves.

Using NASA's current budget and limitations, given our utter lack of space infrastructure, of course it requires a “breakthrough” or even a “miracle”, as this article claims. But are miracle and breakthrough really the right words in a general context? No, not in my view.

Not required: warp drives and hyperspace jumps

Real star travel -- as opposed to "interstellar precursor" missions that just get a little way outside the solar system -- is very hard. But it can be done drawing upon physics we know about today. More good news: Warp drives and hyperspace jumps are not required!

Besides building a Great Pyramid, another analogy might be having to first build Chicago to get the resources to then build the Sears Tower. A massive effort, but not a miracle in the true sense of the word, and, how long did it take to build Chicago, with its miles of underground tunnels big and small and plethora of high buildings? A thousand years? ;) What DID that area of Illinois look like 1,000 years ago?

This quote bothers me from the "NASA" article Keyes copied from:

“To overcome this difficulty, we need either a breakthrough where we can take advantage of the energy in the space vacuum, a breakthrough in energy production physics, or a breakthrough where the laws of kinetic energy don’t apply.”

Of course! If we want the Star Trek/Star Wars notions of zooming to other places and back again versus the one-way tickets that are required to save humanity. Making your own fuel as you go using physics we don't know yet – what a competent and plausible solution (sarcasm intended)! No Wonder NASA does mostly nothing along these lines...

And I'm sure the Egyptians wished that, golly, if they'd just had feather-light bricks that floated into place all on their own yet retained their extreme strength, they could have built 100 times as many pyramids, or perhaps built just one pyramid or temple really high and very wide or built the great pyramids in months rather than DECADES.

Finally, I have some issue with the numbers given in general; they don't seem to sync up. For example, the nuclear pulse propulsion rockets were designed to reach 10% light speed with, I would assume, some payload. If such a craft can reach such a speed, how long it travels at that speed, or how far, doesn't matter. So, if such a design is plausible, then it can get to the nearest stars in 40 years. If not, well, then it can't, obviously. Here's the quip the author used:

Project Orion

The first example is from the 1950’s-60’s, Project Orion - which offered to use nuclear bombs for a constructive purpose -- space travel.

About 5 bombs per second are dropped out the back and detonated to propel the craft along. A huge shock plate with shock absorbers make up the base of the craft. Experiments using conventional explosives were conducted to demonstrate the viability of this scheme. Although this vehicle was conceived to take a crew to Mars, it can also be considered for sending smaller probes to the stars. This project ended with the nuclear test ban treaty in the 60’s.

It can also be considered for sending probes to the stars? Really? Even though the rest of the article asks us to wait for magical breakthroughs in physics? Hmmm...

Project Daedalus is referred to by the article like this – another project designed to get a payload to nearby stars, and which made no mention of requiring thousands of super-tankers worth of fuel:

In the late 1970’s the British Interplanetary Society revisited the Orion propulsion concept, but at a more reasonable scale and for in-space use only. Project Daedalus was a design study for sending a probe past Barnard’s star with a 50 year trip time. (Barnard’s star is about 6 Light Years away.) In this case it used micro fusion explosions which relied on obtaining the appropriate fuel isotope from Jupiter that it scooped up on its way out of the solar system -- tricky.

“Tricky”, eh? It's tricky?!? What a wonderfully technical dissection of what would be involved! I have no doubt that mining Jupiter would be “tricky”, given our lack of space infrastructure as I've said elsewhere, but I would imagine that this author must have access to the other work from NASA which shows one other place to get the isotope required. That isotope is helium-3, which is found on the Moon which I would assume would be a much easier place to fuel up at than Jupiter.

What else is “tricky” is that we don't actually have working fusion reactors yet. This kind of thing no doubt appeals to Thomas, for if we don't have something today, it must be 1000 years away in some dim future we know nothing about. Many of the experts predict that within 30-50 years we will have fusion – good enough for me. Far from being pie in the sky, there is an international consortium spending big bucks to build a commercial nuclear fusion reactor. Time to pretend like we will have it for sure - if fusion ends up being a fizzle, the money wouldn't have been wasted. More human activity in space is positive and other ideas will come along. The pyramid builders failed a few times too. There's nothing magical about the fusion process after all, it happens in stars all the time...

Thomas ends like this:

Does Frederick Smith have the breakthroughs all planned out? Or does he doubt NASA’s authority? I mentioned these to him months ago, in other articles.

Thomas has indeed mentioned these “problems” to me months ago, and months ago, I responded to him to my satisfaction as well. In fact, I've responded to his "nope, can't do it, impossible" claims several times since my stay here at UK. Call me when anything required to get us to the stars breaks the laws of physics. Call me when climbing a mountain is no longer attempted because it takes too much work. If you want to tell me that a group of people are standing at the base of that mountain waiting for a breakthrough, perhaps for the mountain to extrude steps up its shallower slopes so that the climbers can just walk up, then I'm not interested. Or, let me know when the comments of the author (which are not those of the entire organization of NASA) about the billions or thousands of tankers worth of nuke-stuff is matched up with the quips used for the Orion and the Daedalus, designed to send probes to nearby stars with existing or near-term technology in decades rather than 900+ year time spans associated with those many large tanks...

Finally, this quote from the article referred to several times above makes this very clear. Recall that this article also called human flight to nearby systems a “miracle”. It seems that the miracle has mostly to do with money and perhaps limited imaginations or ambitions:

"Most people don't realize how ambitious interstellar flight is," said Raymond Halyard, an engineer with United Space Alliance in Houston, Texas. The 4.3 light-years to Alpha Centauri equate to approximately 25 trillion miles. That's about 100 million times the quarter million miles to the Moon," he noted.

Halyard is a rocket propulsion engineer, with years under his belt working at NASA's Johnson Space Center in Houston, Texas on the Apollo/Saturn 5 booster engines, as well as on space shuttle propulsion systems. He is conducting his own independent research on Inertial Confinement Fusion propulsion.

"I've worked on Inertial Confinement Fusion propulsion designs for years," Halyard said. The best Alpha Centauri flyby design has a terminal velocity of 1/10^th the speed of light and a flight time of 50 years. The cost of the effort would be approximately $100 billion, roughly the price tag of the Apollo program corrected for inflation, he said.

What's this!? Can this be correct? His technical issue is fusion, which as I said isn't a reality yet. We have thus far produced no self-sustaining fusion reactions in any form. But, forgetting that “tricky” bit for a moment, how can he come up with such a LOW price? Where do his calculations include the hauling up to space those thousand super-tankers worth of fuel?

To summarize all of this, let's call the NASA article that Thomas quoted a worst case scenario. If such missions require such enormous amounts of fuel, they represent massive efforts. Not really hard in terms of science and technology, just very difficult in terms of logistics, like building a great temple by hand with few tools. Those estimates don't really jive with the existing designs for fast rockets, the Daedalus and the Orion, at least it seems so from a cursory comparison, but even if an Orion had to be wrapped up in 1000 supertankers worth of fuel to reach the nearest star, isn't it amazing that we are rather confident of just exactly how to go about something like this, this early in our space-tech?

The elephant in the room isn't city-sized spacecraft or long distances, the elephant in the room is our lack of space infrastructure.

There are a whole series of technologies that I didn't delve into, human hibernation and seed ships, as well as solar sail craft, each viable in their own way, each also requiring a healthy and robust space infrastructure, each also a massive effort, none requiring any magical new understanding of physics from the next Einstein. I also didn't mention anti-matter. The article tells us that using anti-matter is “bad” because it means having to have 8 box-cars full of the stuff, but it doesn't tell us why that's bad. The ISS is already bigger than 8 box-cars – it's bad because the stuff, right now, costs a lot. In fact, it's the most expensive substance known to mankind. We need particle accelerators to make anti-matter, and there are just a few of those around. Of course, we could build solar-powered accelerators in space by the hundreds eventually and dedicate them to this purpose – right now, accelerator time is expensive and has to be divvied up between scientists the world over...

Yup, my views are ambitions, like the views of the pyramid builders. But I can confidently say that the range Keyes offers, somewhere between 1000 years and infinity, is ludicrous. What did humans accomplish over the last 1000 years? Even assuming very few new advances and no major physics space-warp breakthroughs, and assuming a worst case, rocket by rocket hauling of material from Earth to orbit, I expect an interstellar craft ready long before then. Heck, once we have a space infrastructure established, I'd expect 1000 super-tanker sized vehicles moving about the Moon/Earth system DAILY, the same as our current ocean shipping lanes and other cargo venues down here. After all, don't we routinely move that much material around on Earth for other reasons as well, to make dams like Hoover and Three Gorges, or perhaps the dirt that used to occupy the Chunnel?

But, even if the sucker has to CRAWL to the stars:

"Reasonable time" is of course a matter of opinion, Kare quickly added. "If you're willing to take a thousand years to go a few light years, ordinary nuclear fission power and ion thrusters will get you there. That's the 'generation ship' approach that has appeared in science fiction many times [books, not Hollywood, at least not any movie I've seen and certainly not Star Wars – Fred Smith]. Given a good enough reason, such as finding out that the Sun will explode on Jan. 1, 2100, we could start building interstellar ships today," he said.

Finally, it's unfair of me to suggest that Thomas Keyes has no imagination - I've read some of his fiction stories. If one of his books gets published, perhaps someone will love it enough to read it 10 times. I rather think Keyes would like that. He just seems to lack the ability to stretch that imagination to this topic, perhaps because he's lived through so much hope and good ideas, few of which have actually been implemented. My arguments are not based on human motivations and apathy, which are far greater issues than technology, I instead argue from feasibility and need.

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