Eddy Current Brake to Orbit - Revision history

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2016-09-02T14:48:00Z

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2015-08-09T23:59:44Z

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2015-04-16T08:59:35Z

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2015-04-16T08:39:34Z

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2015-04-16T08:11:36Z

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2015-04-16T07:48:37Z

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2015-03-24T20:54:59Z

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2015-03-24T20:53:16Z

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2015-01-10T02:21:26Z

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2015-01-04T05:21:50Z

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← Older revision		Revision as of 14:48, 2 September 2016
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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 ~~orbit~~ 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.	+	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.

	[[File:Eddy current concept.png]]		[[File:Eddy current concept.png]]

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 ==Motivation==
-Such an orbiting spacecraft carrier ought to be economic in transferring large quantities of cargo from the surface of a celestial body into orbit.  If it is first used successfully in delivering lunar materials for building space based solar power satellites, then it could possibly be developed further to allow mass emigration from Earth and to deliver lunar materials to orbit for building the homes for emigrants.
+Such an orbiting spacecraft carrier ought to be economic in transferring large quantities of cargo from the surface of a celestial body into orbit.  If it is first used successfully in delivering lunar materials for building space based solar power satellites, then it could possibly be developed further to allow mass emigration from Earth and to deliver lunar materials to orbit for building the homes for emigrants, space habitats.
 == Orientational Stability ==

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 == Financial Feasibility ==
-The financial feasibility of the above spacecraft carriers in orbit about Earth is mostly dependent upon the completion of 30 or 40 ten-gigawatt space based solar power satellites from lunar materials.  This would open the door to the construction of a hundred or more additional SBSP satellites and the use of industrial facilities on Luna for other projects.  While it is not a sufficient condition to assure the construction of spacecraft carriers, there is very little chance that spacecraft carriers will be built if the SBSP satellites are not built from lunar materials.  What is needed is a large market for freight and/or passengers from Earth into orbit and dependable access to large amounts of reasonably low cost construction materials.  Developing a program of building SBSP from lunar materials provides both.
+The financial feasibility of the above spacecraft carriers in orbit about Earth is mostly dependent upon the completion of 30 or 40 ten-gigawatt space based solar power satellites from lunar materials.  This would open the door to the construction of a hundred or more additional SBSP satellites and the use of industrial facilities on Luna for other projects.  While it is not a sufficient condition to assure the construction of spacecraft carriers about Earth, there is very little chance that spacecraft carriers will be built if the SBSP satellites are not built from lunar materials.  What is needed is a large market for freight and/or passengers from Earth into orbit and dependable access to large amounts of reasonably low cost construction materials.  Developing a program of building SBSP from lunar materials provides both.
 The cost of emigration from Earth might be borne in part by consortiums that use the population of space habitats as labor for mining and processing operations in the asteroid belt and other places.  These consortiums could profit from using emigrant labor and from using land on Earth for tourist facilities when it is sold by emigrants or their landlords. An emigrant from Earth might have raised the cost of his trip to orbit, sold his property on Earth and bought securities negotiable in extraterrestrial solar space.  The cost of living in a space habitat might be covered by a contract for labor entered into in conjunction with completing a training and evaluation program on Earth.

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 If the orbiting tube imparts velocity to the shuttle at a rate of 30 meters per second per second, then such a tube for Luna should be about 59 kilometers (37 miles) long.  With the same three g acceleration such a spacecraft carrier in orbit about Earth would need to be 1030 kilometers (644 miles) long.  As with other low cost per unit mass systems of launching to orbit, a high mass rate of launch is needed to realize the potential low cost per unit mass.
-The slot shaped opening in the aluminum tube that takes a shuttle to orbit faces down.  A similar tube that can be an extension of the same spacecraft carrier would be on the upper surface of the carrier with the slot facing upward.  This tube would receive incoming shuttles from other celestial bodies and provide deceleration to circular orbit velocity.  If all of the momentum transfers to shuttles taking cargo to cis-lunar space from Luna are balanced by momentum transfers to the spacecraft carrier from shuttles taking cargo to Luna from cis-lunar space; then there is no need to adjust spacecraft carrier momentum with electric thrusters.  In this case the spacecraft carrier would become an electric power generator and excess power could be beamed to Luna by microwave for use there.  There is always likely to be some need for fine adjustment of spacecraft carrier momentum with electric thrusters, limiting the amount of power that can be beamed to Luna.
+The slot shaped opening in the aluminum tube that takes a shuttle to orbit faces down.  A similar tube that can be an extension of the same spacecraft carrier would be on the upper surface of the carrier with the slot facing upward.  This tube would receive incoming shuttles from other celestial bodies and provide deceleration to circular orbit velocity.  If all of the momentum transfers to shuttles taking cargo to cis-lunar space from Luna are balanced by momentum transfers to the spacecraft carrier from shuttles taking cargo to Luna from cis-lunar space; then there is no need to adjust spacecraft carrier momentum with electric thrusters.  In this case the spacecraft carrier would become an electric power generator and excess power could be beamed to Luna by microwave for use there.  In the case in which incoming and outgoing traffic do not cancel their momentum donations to the spacecraft carrier and momentum withdrawals from the spacecraft carrier; there would need to be photovoltaic arrays to generate power for the thrusters that maintain momentum.  There is always likely to be some need for fine adjustment of spacecraft carrier momentum with electric thrusters, limiting the amount of power that can be beamed to Luna.
 A shuttle rising to orbit rises into the slot and extends permanent magnets on struts towards the aluminum to gain lift and acceleration.  Part of the momentum of the spacecraft carrier could be obtained by electrically decelerating shuttles for landing using ancillary equipment.  On the moon incoming shuttles would head for a landing strip with an eddy current braking device.  Shuttles returning to Earth from the spacecraft carrier would use a heat shield that could be a one time use item imported from the moon.  The heat shield could be made of glass sheet and glass fiber.  The slot shaped opening in the aluminum landing tube on the moon's surface faces upward.

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 ==Landing on Luna==
-Setting down on the lunar surface by eddy current braking has some advantages over using tethers. With a rotating tether, for example one that rotates four times while orbiting the moon once, each end of the tether touches down on the moon three times per orbit.  There are six opportunities for momentum exchange launch to orbit.  A vehicle to land must achieve the correct orbital speed at the correct position at the correct time to rendezvous with the tether and be dropped to the moon.  The tether provides both launching to orbit and landing from orbit, but both must be scheduled with matching masses for every launch.  There might be some fill-in cargo that is sent when other cargo does not match the incoming mass, like bricks or fiber glass.  With the eddy current braking device, the vehicle to be landed only requires the correct position and correct direction of movement with respect to the slotted aluminum tube to properly enter the eddy current braking device and brake to a stop. It is much like landing an airplane on a runway. The differences are that an airplane does not have such a high relative speed to the runway, the runway is somewhat wider than the eddy current braking slot, and the airplane must contend with varying wind conditions which would not affect eddy current braking on Luna. Also for an eddy braking slot there is no requirement for super strong structural materials as for a tether.  There is no mass matching requirement for incoming and outgoing cargo.  Unused cargo capacity on any particular shuttle would still be likely to be filled with bulk cargo being sent at a lower freight rate.  A tether fastened to the lunar surface and extending up through L2 would be a nice way to handle cargo and would not require matching incoming and outgoing cargo mass, but it would be well in excess of  64500 kilometers long.  It would be a major engineering project that would not be the first thing undertaken by industry on Luna.
+Setting down on the lunar surface by eddy current braking has some advantages over using tethers. With a rotating tether, for example one that rotates four times while orbiting the moon once, each end of the tether touches down on the moon three times per orbit.  There are six opportunities for momentum exchange launch to orbit.  A vehicle to land must achieve the correct orbital speed at the correct position at the correct time to rendezvous with the tether and be dropped to the moon.  The tether provides both launching to orbit and landing from orbit, but both must be scheduled with matching masses for every launch.  There might be some fill-in cargo that is sent when other cargo does not match the incoming mass, such as bricks or fiber glass.  With the eddy current braking device, the vehicle to be landed only requires the correct position and correct direction of movement with respect to the slotted aluminum tube to properly enter the eddy current braking device and brake to a stop. It is much like landing an airplane on a runway. The differences are that an airplane does not have such a high relative speed to the runway, the runway is somewhat wider than the eddy current braking slot, and the airplane must contend with varying wind conditions which would not affect eddy current braking on Luna. Also for an eddy braking slot there is no requirement for super strong structural materials as for a tether.  There is no mass matching requirement for incoming and outgoing cargo.  Unused cargo capacity on any particular shuttle would still be likely to be filled with bulk cargo being sent at a lower freight rate.  A tether fastened to the lunar surface and extending up through L2 would be a nice way to handle cargo and would not require matching incoming and outgoing cargo mass, but it would be well in excess of  64500 kilometers long.  It would be a major engineering project that would not be the first thing undertaken by industry on Luna.
 ==Potential for Future Expansion==

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 [[File:Eddy current concept.png]]
-In the illustration of the Eddy Current Brake Device, the rectangle and dot to the left represent the spacecraft carrier and shuttle approaching rendezvous The dot and rectangle to the right are the spacecraft carrier and shuttle and moving off together.
+In the illustration of the Eddy Current Brake Device, the rectangle and dot to the left represent the spacecraft carrier and shuttle approaching rendezvous The dot and rectangle to the right are the spacecraft carrier and shuttle moving off together.
 ==Motivation==

← Older revision		Revision as of 20:53, 24 March 2015
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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 orbit 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.	+	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 orbit 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.
		+
		+	[[
		+
		+	File:Eddy current concept.png ]]
		+
		+	In the illustration of the Eddy Current Brake Device, the rectangle and dot to the left represent the spacecraft carrier and shuttle approaching rendezvous The dot and rectangle to the right are the spacecraft carrier and shuttle and moving off together.

	==Motivation==		==Motivation==

← Older revision		Revision as of 02:21, 10 January 2015
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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 orbit 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.		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 orbit 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.
		+
		+	==Motivation==
		+	Such an orbiting spacecraft carrier ought to be economic in transferring large quantities of cargo from the surface of a celestial body into orbit. If it is first used successfully in delivering lunar materials for building space based solar power satellites, then it could possibly be developed further to allow mass emigration from Earth and to deliver lunar materials to orbit for building the homes for emigrants.

	== Orientational Stability ==		== Orientational Stability ==