A vertical fishnet tether extends from the Earth to the geostationary orbit and beyond. It is vulnerable to a bomb hidden in its cargo unless the cargo spins about the skyhook and is kept by the centrifugal force away from the skyhook. The tether is curved due to Coriolis force of moving cargo. The minimum mass of a steel skyhook is greater than the mass of the Earth! A structural material of great specific strength is needed to make this idea practicable. Plastic cannot be used because it is vulnerable to space radiation and thermal fatigue. The minimum mass of a buckytube skyhook (for 1-ton cargo) is 104 tons. A short version of the skyhook called orbital elevator is lightweight and less vulnerable than the skyhook.

Science fiction writers sometimes call it Jacob's ladder (after the Bible, Genesis 28 v 12) or beanstalk (after the story of Jack and Beanstalk).

The maximum length of a non-tapered tether that can carry its own weight under a uniform force of one gravity is called characteristic length. The strongest commercial fibers, Zylon and Dyneema have the characteristic length of about 400 km.


Fridrich Arturovich Tsander, "Selected Papers," Zinatne, Riga, 1978, (in Russian; manuscript written in 1910; mentions a tapered tether extending from the Moon toward the Earth).

Yuri Artsutanov, "V Kosmos na Electrovoze (in Russian, Into Space on a Train)," Komsomolskaya Pravda, July 31 1960.

John Isaacs et al, "Satellite Elongation into a True Sky-Hook," Science, Vol. 151, February 11, 1966, pp. 682-683; also Vol. 152, p 800 and Vol. 158, p. 947.

Vladimir Lvov "Sky-Hook: Old Idea," Science, Vol. 158, November 17, 1967, pp. 946-947.

Jerome Pearson, "The orbital tower: a spacecraft launcher using the Earth's rotational energy," Acta Astronautica, Vol. 2, No. 9-10, September-October 1975, pp. 785-99.

G. Polyakov, "Kosmicheskoye "Ozhereye" Zemli (in Russian, A Space "Necklace" about the Earth)," Teknika Molodezhi, No. 4, 1977, pp. 41-43 (English translation: NASA Technical Memorandum TM-75174).

Jerome Pearson, "Anchored Lunar Satellites for Cis-Lunar Transportation and Communication," European Conference on Space Settlements and Space Industries, London, England, September 20, 1977, also in Journal of the Astronautical Sciences 1978.

Jerome Pearson, "Lunar Anchored Satellite Test", AIAA/AAS Astrodynamics Conference, Palo Alto, Ca., August 7-9, 1978, AIAA Paper 78-1427.

Hans Moravec, "Cable Cars in the Sky", 1978.

Arthur C. Clarke, "The Space Elevator: 'Thought Experiment', or Key to the Universe?," Earth Oriented Application of Space Technology, Vol. 1, 1981, pp. 39-48.

Konrad E. Ebisch, "Skyhook: Another Space Construction Project," American Journal of Physics, Vol. 50, No 5, May 1982, pp. 467-469.

Geoffrey A. Landis and Craig Cafarelli, "The Tsiolkovski Tower Reexamined," IAF-95-V.4.07, 46th International Astronautical Congress, October 2-6, 1995, Oslo, Norway.

Bradley C. Edwards, "Design and Deployment of a Space Elevator," Acta Astronautica, Vol. 47, 2000, p. 735.

Skyhook page at NASA.

Skyhook page at Eureka Scientific.

Bradley C. Edwards and Eric A. Westling, The Space Elevator, published by "Bradley C. Edwards & Eric A. Westling" on January 14, 2003.



Skyhook mass

Skyhook mass (reproduced from Landis article)