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===<!--[[Image:red_ring.png|15px|left]]-->Featured article: [[Volatiles]]===
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===<!--[[Image:red_ring.png|15px|left]]-->Featured article: [[Eddy Current Brake to Orbit]] | 24 October 2019===
[[Image:Apollo11Soil.jpg|160px|left]] The primary resource of value to humans on the Moon is the volatile components found in the [[regolith]]. These are all the components that are gases at room temperature. Most of the volatiles have been deposited in the top layers of the Moon's surface by the [[solar wind]] over geologic time. A notable exception to this is [[Argon]]. the concentration of Argon in lunar soil is much higher than found in the solar wind, so must come from a different source. Especially, the isotope Argon-40. It is presently believed that the Argon-40 comes from radioactive decay of [[Potassium]] and/or [[Krypton]] deep within the lunar mantle or core, and that the Argon-40 seeps out to the surface via fissures. This vented Argon enter the lunar atmosphere; then the Argon is implanted into the regolith by([[Volatiles|read more]])
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[[File:Eddy current concept.png|160px|left]]
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This device is the central feature of a spacecraft carrier that receives spacecraft into orbit as an aircraft carrier receives aircraft that land on its deck. It works by having a long slotted aluminum tube in orbit and having the shuttle vehicle that is launched to orbital altitude enter this slot while the tube is moving by at orbital speed. The shuttle only needs to reach orbital altitude to enter the eddy current brake tube. That can be 10 kilometers on Luna at the perilune, an altitude that can be reached with 188 meters per second mission delta v, including gravity loss, a few seconds maneuvering fuel, and a small safety margin. Magnetic flux from permanent magnets deployed by the shuttle is directed at the walls of the tube causing a repulsive force and a retarding force.<ref>[http://en.wikipedia.org/wiki/Eddy_current_brake ''Eddy current brake'' at Wikipedia]</ref><ref>[https://en.wikipedia.org/wiki/Inductrack ''Inductrack'' at Wikipedia]</ref> By reducing the speed of the shuttle relative to the orbiting aluminum tube, the shuttle is brought up to near orbital speed. Since eddy current braking loses effectiveness at low relative speeds, friction braking is used to give the shuttle the last 18 meters per second to reach orbital speed and match velocity with the aluminum tube. During all the time that the relative speed of the shuttle and the aluminum tube is greater than 18 meters per second, there is no contact between the material of the shuttle and the material of the aluminum tube. ...([[Eddy Current Brake to Orbit|read more]])
 
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Latest revision as of 04:46, 24 October 2019

Featured article: Eddy Current Brake to Orbit | 24 October 2019

Eddy current concept.png

This device is the central feature of a spacecraft carrier that receives spacecraft into orbit as an aircraft carrier receives aircraft that land on its deck. It works by having a long slotted aluminum tube in orbit and having the shuttle vehicle that is launched to orbital altitude enter this slot while the tube is moving by at orbital speed. The shuttle only needs to reach orbital altitude to enter the eddy current brake tube. That can be 10 kilometers on Luna at the perilune, an altitude that can be reached with 188 meters per second mission delta v, including gravity loss, a few seconds maneuvering fuel, and a small safety margin. Magnetic flux from permanent magnets deployed by the shuttle is directed at the walls of the tube causing a repulsive force and a retarding force.[1][2] By reducing the speed of the shuttle relative to the orbiting aluminum tube, the shuttle is brought up to near orbital speed. Since eddy current braking loses effectiveness at low relative speeds, friction braking is used to give the shuttle the last 18 meters per second to reach orbital speed and match velocity with the aluminum tube. During all the time that the relative speed of the shuttle and the aluminum tube is greater than 18 meters per second, there is no contact between the material of the shuttle and the material of the aluminum tube. ...(read more)

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