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Space Elevator Rebuttal From LiftPort Founder
TropicalCoder is the reader who submitted the story about the possible demise of LiftPort a couple of weeks back. The resulting discussion was mostly negative about the feasibility of building a space elevator. TropicalCoder writes: "At one point during the discussion, LiftPort founder Michael J. Laine personally entered the discussion, but for the most part remained invisible since he hadn't logged in. I responded to his comment that if he would like a chance to rebut the criticisms, he should contact me and I would undertake to interview him and post the resulting story on Slashdot." Read below for the story of how Mr. Laine's detailed reply and rebuttal to that Slashdot discussion came about. TropicalCoder asks, "After reading LiftPort's rebuttal to Slashdot critics, do any of you now feel your pessimism somewhat dispelled?"
Michael Laine called me long distance via cell phone that very day from his back yard near Seattle, and spoke with me for over an hour. Michael came across as a rather sober, likable fellow, not at all like the crackpot image one would conjure up from reading many of the Slashdot comments. He was clearly wounded by the stinging criticisms in the Slashdot discussion, and I couldn't help empathizing with him. Here was man who had put his money where his mouth was, risking everything on his dream, perhaps suffering his darkest hour, and enduring ridicule on top of that.
At no point during the conversation did I get any impression of a huckster who would sell you the Brooklyn Bridge, something that I was on the lookout for. It was clear to me that he sincerely believes in what he is doing. Whether he succeeds in the end or not, I would prefer to call him a "visionary." After all, for every great visionary you can recall from history, there must have been a thousand others who tried and failed, but are no less visionary because of that. The jury is still out on LiftPort, and rumors of their death would be premature. They continue their research, and as I write are preparing for the "Tethered Towers" demo on Thursday June 28.
At the end of the conversation it was agreed that I would summarize the Slashdot discussion for him and offer him an opportunity for point-by-point rebuttal. I completed this summary (in which many Slashdot readers will recognize their own words), and sent it off to him the next day. He acknowledged receipt and promised an answer shortly. A few weeks passed, and I imagined that he must have decided in the end that the criticisms were so severe, perhaps it would be best just to try to forget it. It was a total surprise to me when a thoroughly detailed response arrived in my mailbox today, demonstrating that the people at LiftPort at least are still convinced that building a space elevator is possible.
Space elevator themes have been celebrated in science fiction and many Slashdot readers have shared the dream, only to become disillusioned with the apparent pending demise of LiftPort. After reading LiftPort's rebuttal to Slashdot critics, do any of you now feel your pessimism somewhat dispelled?"
Michael Laine called me long distance via cell phone that very day from his back yard near Seattle, and spoke with me for over an hour. Michael came across as a rather sober, likable fellow, not at all like the crackpot image one would conjure up from reading many of the Slashdot comments. He was clearly wounded by the stinging criticisms in the Slashdot discussion, and I couldn't help empathizing with him. Here was man who had put his money where his mouth was, risking everything on his dream, perhaps suffering his darkest hour, and enduring ridicule on top of that.
At no point during the conversation did I get any impression of a huckster who would sell you the Brooklyn Bridge, something that I was on the lookout for. It was clear to me that he sincerely believes in what he is doing. Whether he succeeds in the end or not, I would prefer to call him a "visionary." After all, for every great visionary you can recall from history, there must have been a thousand others who tried and failed, but are no less visionary because of that. The jury is still out on LiftPort, and rumors of their death would be premature. They continue their research, and as I write are preparing for the "Tethered Towers" demo on Thursday June 28.
At the end of the conversation it was agreed that I would summarize the Slashdot discussion for him and offer him an opportunity for point-by-point rebuttal. I completed this summary (in which many Slashdot readers will recognize their own words), and sent it off to him the next day. He acknowledged receipt and promised an answer shortly. A few weeks passed, and I imagined that he must have decided in the end that the criticisms were so severe, perhaps it would be best just to try to forget it. It was a total surprise to me when a thoroughly detailed response arrived in my mailbox today, demonstrating that the people at LiftPort at least are still convinced that building a space elevator is possible.
Space elevator themes have been celebrated in science fiction and many Slashdot readers have shared the dream, only to become disillusioned with the apparent pending demise of LiftPort. After reading LiftPort's rebuttal to Slashdot critics, do any of you now feel your pessimism somewhat dispelled?"
I really enjoyed the writeup and the interview. I thought that it covered the points in a very concise fashion while also outlining all the points that had been raised in aa very negative manner. I look forward to following this project and its future directions.
No Coffee, No Workee
How we know is more important than what we know.
Not at all. If anything my pessism has increased when I read the spin, handwaving, misdirection, and evasions in Mr Laine's 'rebuttal'.
For example, this little gem:
Q: Business model is predicated on a technology that not only does not exist but you are incapable of inventing.
A: That's true for the president of Boeing too. There's no way he could engineer the likes of the 777 with just the top level executives. He hires the right people to design, test and build these wonders of technology. Rather than waste our investors money on hiring full time engineers that could not succeed within the timeframe allowed by the dollars available, we subcontract. Outsourcing is not a new concept, and it saves companies quite a bit of money and time.
Notice the answer completely unrelated to the question and the 'spin'.
Or this one:
Q: Perhaps should have been managed by a more highly qualified individual, such as a professional engineer with advanced engineering management degrees
Because all engineers make good business administrators? Engineers are (and this is a generalization, I admit) generally too cautious. Innovators are risk takers. Entrepeneurs are risk takers. Engineers want triple redundancy and safety factors. To run a company for 4 years off a $200,000 investment takes talent. Granted, much more was invested by Mr. Laine himself, from his personal income, to keep this business running.
More spin - and the fantastic claim that running a business for $200k for four years implies some kind of 'talent'. Heck, I could run a business for two *centuries* with that kind of investment. (It wouldn't produce a profit - but it would be 'run' and about as effective as LiftPort.)
Q: You'll never see a fully functional space elevator on earth. The requirements are too close to the edge of what is even theoretically possible.
If it weren't for the costs, we could build one this year.
To put it bluntly - this is an outright lie. Period. if it were true - why is LiftPort spending money on R&D rather than production?
Q: Even if the materials science isn't the problem, we have never made 36,000 miles of ANYTHING before.
Roads? Railroads? The SMW3 fiber optic cable is 39,000km long. That's over a third of the 100,000km necessary to build the Elevator to Space (not 36,000 miles).
The SMW3 fiber optic cable isn't a unitary and (for all practical purposes) flawless carbon nanotube fiber. Roads and railroads aren't unitary either. Micheal is either very disingenuous or very clueless.
Q: You need a material approximately 3 times the strength of a (perfect) carbon nanotube in order to be a relatively safe civil/space engineering construction.
That goes back to my statement earlier about engineers. No. You're not going to be able to have triple redundancy, and safety factors. You will have safety margins, and one of our first cargoes would be the second space elevator. We should be able to build that with half the strength of "perfect" SWNTs. We will employ standards of safety. We're sure the international legal community would see to that. About half the team grew up near the Tacoma Narrows Bridge. The failure of this bridge is a standard lesson in how NOT to engineer something for most engineering schools. We understand what is at stake.
I too live near the Tacoma Narrows Bridge - and no, that is not how the bridge collapse is taught in engineering schools. Because in fact, the basic engineering of the bridge was quite sound - they failed however to take into account the effects of the winds. Numerous b
Let me preface this by saying I work with carbon nanotubes (as an "innovator," not an engineer).
Where these guys are right on is that building a CNT factory would generate the kind of money they need to get going, especially if they can reliably grow high quality tubes. They are absolutely right that spin off technologies could more than make up for their current investments. But, as they recently found out, nanotubes are very hard to grow in large amounts, and they grow very slowly... hence the current high cost.
That leads to where they went wrong: They had "contractors" working on nanotube growth. It's not easy to grow CNTs, and it's not well understood. It's very difficult to reproduce published work on CNT growth unless you really, really know what you're doing. They need to form partnerships with the people working with nanotubes who are on the cutting edge of growth research. While they've tried and failed to build a factory, Iijima's group has made major breakthroughs in growing nanotubes in bulk, and he's the obvious person to start off trying to get on board with this (as a well known Nobel laureate working with nanotubes). If not his group, then any number of dedicated CNT-growth research groups in the US.
At some point, it would not be a bad idea to let a scientist into the upper management of a space elevator company. Just as a smart inventor will let go of some control of a company to a business person, these business people would have been wise to let a scientist make some of their decisions.
By (publicly, at least) focusing on robotics, they missed the boat on one key technology they needed which would have also provided them with the funds to keep everything else going. Hopefully whoever takes over leadership of the space elevator community has more luck.
More accurately, it's like asking Intel to release their trade-secret research on building 10 GHz chips, because you don't believe they're possible.
Look, the guy said they could do it with existing technology, given the funds for 100s of heavy lift rockets (Delta-V maybe?) and A LOT of Honeywell Spectra fibre. Think for a second how much 100s of heavy lift rockets would cost, even if they could have that many made within a production timespan - that's crazy money for most anyone. But if a group of BIG companies got together (Japanese style) I reckon it's almost feasible.
OTOH, and relating back to our Mars story, IF this cat can show big investors a serious engineering proposal for a project with existing technology, we just got our first "train station".
Forget thrust, drag, lift and weight. Airplanes fly because of money.
But if we end up with a "bipolar" cold war world, then you're right. Obiviously if one block starts to build an elevator, the other block has no option but to start building one as well, and certainly US will still exist and be in one of the blocks by the time we can practically build one. Of course there's no guarantee that the block with US would get their elevator finished first, but I don't think that really matters as long as both blocks would get their elevators working in the same decade or so. Considering the possible problems that won't be discovered until the elevator is finished, it might even be desirable to be the 2nd, a few years behind, so that there's still time to alter the design if some unforeseen problem is discovered by the 1st.
Well, just saw this
EuroSpaceward was just awarded funding by The National Research Fund of Luxembourg to hold a workshop on space elevator climber and tether design primarily focusing on systems for entry in the US and German competitions. The tentative dates are Nov. 14-16, 2007 and the workshop will be held in a yet to be announced venue in Luxembourg.
found at http://www.spaceelevator.com/
So it does seem there is still some interest outside US, albeit for entering a NASA based competition. I think that the immigration problems in the US for foreign students will quickly have some negative effect on innovation in the US in the long term. Innovation in the US has always been due to it's courting of students world wide to study and then contribute.
"If the King's English was good enough for Jesus, it's good enough for me!" -- "Ma" Ferguson, Governor of Texas (circa
He specifically mentioned Honeywell Spectra Fiber which is billed to be "pound for pound 10 times stronger that steel"
We need to translate that statement first. They don't mention what KIND of steel. Steel can have a tensile strength of 0.3 GPa to 1.88 GPa depending on type. That gives SF2K a tensile strength between 3.0 GPa to 18.8 GPa. (Wikipedia apparently agrees with this assessment...)
Using Wikipedia as firther source, "A space elevator can be made relatively economically feasible if a cable with a density similar to graphite and a tensile strength of ~65-120 GPa can be mass-produced at a reasonable price." Graphite has a density of 140 lbs/cu.ft, so this imaginary material needs a minimum strength/density ratio of 65/140 = 0.46.
SF2K has a specific gravity of 0.097, which translates to 97 kg per cubic meter (6.055 lbs/cu.ft.) That puts the strength/density ratio at 0.50 to 3.13 - Higher than our theoretical required material, so it should be strong enough.
SF2K also has "High resistance to chemicals, water, and UV light" and "good resistance to abrasion and flex fatigue." These are all desirable qualities.
He mentioned the ribbon would likely be "15 feet wide and less than the thickness of a human hair". Average human hair is about 4 mil (0.004 inches or 0.00033 feet). That's a theoretical cross-sectional area of 0.00495 feet. At that thickness, one pound of material will stretch just over 200 feet. They need about 62,000 miles (327,360,000 ft)of the stuff, so that's only about 820 tons. 820 really isn't THAT much in the grand scheme of things... imagine 28 standard shipping containers, that'll hold 820 tons of cargo.
So as far as the cable itself goes - yeah, that's "doable" right now if you've got the cash.
=Smidge=
Postulate for a moment a limitless supply of raw materials, and a limitless space to put waste materials in. In that environment, what, exactly, is wrong with a "consume all" mentality?
The space elevator - or rather, a technology which gives efficient, low-cost access to space - has the potential to make that scenario a reality. We've got near-earth asteroids, the moon, and the entire asteroid belt full of metals. We've got moons and an Oort Cloud full of CHON - carbon, hydrogen, oxygen, nitrogen: the building blocks of all our food. And we've got all of space to discard waste products into. The resources exist in this solar system to keep us in consumables for a long, long time if we can just get out hands on them.
An important - not, of course, the only, or even the hardest, but an important - step towards this is a cheap, high-volume way of ferrying material out of and into Earth's gravity well.
Reality has a conservative bias: it conserves mass, energy, momentum...
Beyond only being useful for cargo that can withstand thousands of g's of acceleration, you also have a couple of other problems. First, you have to account for atmospheric drag with your initial velocities. That means you have to be traveling at a speed higher than orbital velocity.
But the real problem is this. We have a term for hitting Earth's atmosphere at orbital velocities. It's called re-entry. It's problematic for normal space vehicles which will bleed off speed in the thinner upper atmosphere at orbital velocities. Now what happens when you launch a payload in the thicker part of Earth's atmosphere, at speeds greater than orbital velocity? I'm guessing a fiery ball of death.
Spectra is a mere 3.5G GPa UTS and *950* kg per cubic meter. You converted g/cm to kg/m^3 wrong. It's not even within an order of magnitude of what is needed. Furthermore, you represented SWNTs wrong. They're SWNTs, not graphite; it's a completely different form that just happens to use the same SP2 bonding structure. Their density is about 1300 kg/m^3.
Furthermore, while it's possible to build a space elevator with a nanotube cable that's only 65 GPa tensile, it's not realistic. It's also possible to build a space elevator out of kevlar. Your taper factor is just preposterous. LiftPort's numbers call for a SWNT fiber with strength 100-120 GPa, yet a total system cost in the tens of billions. You really can't get much lower of a strength and still have a remotely feasible business plan.
Now, the sad truth that Laine refused to address. Early after the discovery of SWNTs, there were all sorts of wild numbers for their strength produced, most around 120 GPa. That's not the reality of the situation. Modern calculations are only for 50-60 GPa, and that matches well what has been tested by using microscopic probes to break nanotubes. But it gets worse! The tubes cluster into ropes by pi bonding and vdw, and these aren't some sort of "reverse-wrap" ropes. Their strengths are only 3.6 += 0.4 GPa. Now, this can probably be improved, but it's obviously never going to surpass, and probably never even approach, the strength of the individual tubes. However, even ropes aren't the end of the story -- then you have to produce an *affordable fabric of an indefinite length* out of them, which puts yet another strength bottleneck into play.
Come on, Laine -- why didn't you address this? It's not like it hasn't been raised.
I think Liftport's development process can best be summed up as:
"In other news, my Teleporation Shoes are performing extremely well in tests. The shoelaces have survived twelve straight tying tests, including one "bunny ears" test conducted by a young child. Sole durability tests are also holding up well. Teleporation will be tested at some time in the future."
"99 dead duelists of Dios on the wall. 99 dead duelists of Dios! Take one's ring, pass it around..."
It's *possible* for a spectra elevator to exist, but that doesn't mean anything. Plugging Spectra's strength and density (3.5e9 N/m^2 and 950 kg/m^3) into Spelsim, using a payload mass of two tonnes and a safety factor of only 2, we get an elevator mass of 9.8745e17 kg. That's 987,450,000,000,000,000 kg: just about a quadrillion metric tonnes. By comparison, Mars's largest moon (Phobos) is about 1/10th that mass. I've seen the mass of Mount Everest cited as about 1e14kg (1/10000th the mass), all living organisms at 1e15kg (1/1000th the mass), the water in the atmosphere and the total biomass aboveground at 1e16kg (1/100th the mass), all of the surface freshwater at 1e17 kg (1/10th the mass), and the entire stratosphere at 1e18kg (same mass)
Think you can launch that?
"99 dead duelists of Dios on the wall. 99 dead duelists of Dios! Take one's ring, pass it around..."