Difference between revisions of "Template:Featured article"

From Lunarpedia
Jump to: navigation, search
 
(4 intermediate revisions by one other user not shown)
Line 1: Line 1:
===<!--[[Image:red_ring.png|15px|left]]-->Featured article: [[Geologic Processes on the Moon/Cratering on the Moon|Cratering on the Moon]]===
+
===<!--[[Image:red_ring.png|15px|left]]-->Featured article: [[Eddy Current Brake to Orbit]] | 24 October 2019===
[[Image:GP1Fig_3.jpg|160px|left]] Craters cover the surface of the moon and are the result of hyper-velocity impacts by meteorites. The velocity of meteorites upon impact varies, but is generally between 10 and 40 km/sec. This number is a combination of the ‘approach velocity’ and the ‘escape velocity.’ The approach velocity of objects refers to the velocity of the object with respect to the moon. This varies with the type of object (for example, long period comets generally have a higher approach velocity than short period comets) and the direction with which it approaches the moon (for example, if it approaching the moon ‘head on,’ it will have a higher approach velocity than...([[Geologic Processes on the Moon/Cratering on the Moon|read more]])
+
[[File:Eddy current concept.png|160px|left]]
 +
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]])
 
<DIV style="text-align:right">
 
<DIV style="text-align:right">
 
<SMALL><STRONG>[[Featured articles|See all featured articles]]</STRONG> | [[Talk:Featured_articles|Nominate!]]</SMALL>
 
<SMALL><STRONG>[[Featured articles|See all featured articles]]</STRONG> | [[Talk:Featured_articles|Nominate!]]</SMALL>

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)

See all featured articles | Nominate!