I have no problem with the Boeing report but its conclusion is for tether lengths that are much longer than the ones that are being discussed in this article This is where your lack of knowledge about engineering is a problem The mass of a space tether goes up with length Assuming it could take the thermal environment you can build a space tether out of kite string But there is a limit on how long this space tether could be made based on the strength to weight ratio of the string This is where designers start making tapered lines that have more cross sectional area in the middle than at the ends Even with this there are still limits on the length based on cost and total mass You can make an Earth surface to geostationary orbit space elevator using kite string but it will be larger than the Earth hence not practical That doesn t mean that you still can t use that kite string to fly a kite obviously you can The difference is in the length The space elevator is 100 000 km long Your kite string is only a few hundred feet at most The same applies to skyhooks You could build a 100 000 km long space elevator out of T1000 GB carbon fibers but it would have near planetary mass and as a result isn t practical But like the much shorter kite string for flying a kite a skyhook made of carbon fibers in the 200 km to 4 000 km range is possible As to the references not all being open source on the internet there is not much I can do about that You will need to either pay for them or go to a university library that pays for access to them and have them downloaded References 7 18 and 19 are open source Reference 19 is only for the part of that paper that covers non rotating skyhooks and does not include the entire paper If you want to see the entire paper do a search using the title on google it is open source Quite simply the information is out there but you will have to do a little digging or pay for it You will also need a basic understanding of engineering and orbital mechanics in regards to space tethers For that I recommend the Tether in Space Handbook it is also open source on the internet see reference 7 You could also just read the abstracts for the non open source papers and you will get an idea that this is a workable concept Or you could just notice who is writing these reports NASA reference 19 Lockheed Martin references 5 8 9 and 10 and Smithsonian Astrophysical Observatory reference 7 Do you really think these organizations would be wasting their time and money on a lie To conclude with the Boeing report The Boeing report says 1 His analysis showed that because a hanging tether must be tapered to support its lower end in the gravitational field of the Earth achieving a HyperSkyhook tether tip rendezvous with a 5 0 km s 16 kft s or Mach 16 airplane would require a HyperSkyhook tether mass of 25 times the payload mass 5 0 km s is 64 of low Earth orbit velocity A tether mass of 25 times payload mass can be built I have no argument with this 2 Trying to lower the tether tip speed to 4 0 km s 13 kft s or Mach 13 would require a HyperSkyhook tether mass greater than 200 times the payload mass 4 0 km s is 51 of low Earth orbit velocity A tether mass of 200 times payload mass sounds about right and it is highly unlikely that such a tether length would be economic Again no disagreement The tether tip speeds for the non rotating skyhook examples in this article and in all the references I have listed start at 96 of low Earth orbit velocity and go to approximately 70 of low Earth orbit velocity There is no reason to go any lower As a result the final line of the Boeing quote In general the non spinning tether HyperSkyhook concept does not look competitive with the spinning tether concepts does not apply for two reasons 1 It doesn t apply to the skyhook lengths in the article and 2 it is an unfounded over generalization that falls under the category of sales BS that is promoting rotating skyhooks Do you now understand how the Boeing quote that you are so fond of does not apply to the non rotating skyhooks in this article PS The reference numbers are for the article as I have written it Since you keep deleting references with your changes the reference numbers keep changing hence you will need to use the article as I have written it if you want the reference numbers quoted here to mean anything So please read this until you understand it and do your research to confirm what I and many others are saying If you run into any problems that you can not resolve easily write me here and I will do what I can to assist you