The physics of the space elevator

Aravind, P. K.

doi:10.1119/1.2404957

Cited by 29 publications

(17 citation statements)

References 5 publications

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“…Photon has linear dispersion. Graphene atoms are act same like a photon atoms but at lower speed [17][18][19]. It is properties of quantum electrodynamics where relativity effect can be observe without need to accelerate the particle to close speed of light.…”

Section: Unique Linear Energy Dispersionmentioning

confidence: 99%

Universality of Graphene as 2-D Material

Ketansinh¹

2016

J Material Sci Eng

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Section: Unique Linear Energy Dispersionmentioning

confidence: 99%

Universality of Graphene as 2-D Material

Ketansinh¹

2016

J Material Sci Eng

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“…Target orbit(s) Size or mass required Reference Space Elevator ~GEO 52 x 10 3 kg (> 3.3 m) (Aravind, 2007) Geo-engineering: Dust ring LEO ~LEO 2.3 x 10 12 kg (> 1190 m) (Pearson et al, 2006) Geo-engineering: Dust cloud L 1 Sun-Earth L 1 1.9 x 10 11 kg (> 515 m) (Bewick et al, 2012) Geo-engineering:…”

Section: Projectmentioning

confidence: 99%

Opportunities for Asteroid Retrieval Missions

2013

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Asteroids and comets are of strategic importance for science in an effort to uncover the formation, evolution and composition of the Solar System. Near-Earth Objects (NEOs) are of particular interest because of their accessibility from Earth, but also because of their speculated wealth of material resources. The exploitation of these resources has long been discussed as a means to lower the cost of future space endeavours. In this chapter, we analyze the possibility of retrieving entire objects from accessible heliocentric orbits and moving them into the Earth's neighbourhood. The asteroid retrieval transfers are sought from the continuum of low energy transfers enabled by the dynamics of invariant manifolds; specifically, the retrieval transfers target planar, vertical Lyapunov and halo orbit families associated with the collinear equilibrium points of the Sun-Earth Circular Restricted Three Body problem. The judicious use of these dynamical features provides the best opportunity to find extremely low energy transfers for asteroidal material. With the objective to minimise transfer costs, a global search of impulsive transfers connecting the unperturbed asteroid's orbit with the stable manifold phase of the transfer is performed. A catalogue of asteroid retrieval opportunities of currently known NEOs is presented here. Despite the highly incomplete census of very small asteroids, the catalogue can already be populated with 12 different objects retrievable with less than 500 m/s of v. All, but one, of these objects have an expected size in the range that can be met by current propulsion technologies. Moreover, the methodology proposed represents a robust search for future retrieval candidates that can be automatically applied to a growing survey of NEOs.

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“…In the rotating frame of the Earth’s surface, the tether is freestanding—that is, it exerts no force on the ground—if its weight and outward centrifugal force are in balance, thus maintaining it under lengthwise tension. Using the notation in [ 11 ], figure 1 b shows that each small, horizontal element of the tether experiences four forces: its weight , the outward centrifugal force and upward/downward forces and , owing to the part of the cable above/below the element (and a potential counterweight placed above geosynchronous height to reduce the cable length needed). A balanced tether implies that, each segment is in equilibrium in the aforementioned rotating frame of reference, that is, .…”

Section: Introductionmentioning

confidence: 99%

Building the space elevator: lessons from biological design

Popescu

Sun

2018

J. R. Soc. Interface.

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One of the biggest perceived challenges in building megastructures, such as the space elevator, is the unavailability of materials with sufficient tensile strength. The presumed necessity of very strong materials stems from a design paradigm which requires structures to operate at a small fraction of their maximum tensile strength (usually, 50% or less). This criterion limits the probability of failure by giving structures sufficient leeway in handling stochastic components, such as variability in material strength and/or external forces. While reasonable for typical engineering structures, low working stress ratios—defined as operating stress as a fraction of ultimate tensile strength—in the case of megastructures are both too stringent and unable to adequately control the failure probability. We draw inspiration from natural biological structures, such as bones, tendons and ligaments, which are made up of smaller substructures and exhibit self-repair, and suggest a design that requires structures to operate at significantly higher stress ratios, while maintaining reliability through a continuous repair mechanism. We outline a mathematical framework for analysing the reliability of structures with components exhibiting probabilistic rupture and repair that depend on their time-in-use (age). Further, we predict time-to-failure distributions for the overall structure. We then apply this framework to the space elevator and find that a high degree of reliability is achievable using currently existing materials, provided it operates at sufficiently high working stress ratios, sustained through an autonomous repair mechanism, implemented via, e.g. robots.

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The physics of the space elevator

Cited by 29 publications

References 5 publications

Universality of Graphene as 2-D Material

Universality of Graphene as 2-D Material

Opportunities for Asteroid Retrieval Missions

Building the space elevator: lessons from biological design

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