Science Fiction
Dictionary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 |
Emdrive Electromagnetic Drive For Chinese Space Ships?
Tired of those conventional space drives that require some sort of reaction mass? Chinese researchers claim to have confirmed the basic principles behind the Emdrive - an electromagnetic drive concept that converts electrical energy into thrust using microwaves.
The Chinese are currently building a demonstration model to see if it works.
('Emdrive' Electromagnetic Space Drive)
Take a look at the explanation offered on Roger Shawyer's Emdrive website:
The principle of operation is based on the well-known phenomenon of radiation pressure. This relies on Newton’s Second Law where force is defined as the rate of change of momentum. Thus an electromagnetic (EM) wave, travelling at the speed of light has a certain momentum which it will transfer to a reflector, resulting in a tiny force.If the same EM wave is travelling at a fraction of the speed of light, the rate of change of momentum, and hence force, is reduced by that fraction. The propagation velocity of an EM wave, and the resulting force it exerts, can be varied depending on the geometry of a waveguide within which it travels. This was demonstrated by work carried out in the 1950’s. (CULLEN, A.L. ‘Absolute Power Measurements at Microwave Frequencies’ IEE Proceedings Vol 99 Part 1V 1952 P.100)
Thus if the EM wave travelling in a tapered waveguide is bounced between two reflectors, with a large velocity difference at the reflector surfaces, the force difference will give a resultant thrust to the waveguide linking the two reflectors. If the reflectors are separated by a multiple of half the effective wavelength of the EM wave, this thrust will be multiplied by the Q of the resulting resonant cavity.
The inevitable objection raised, is that the apparently closed system produced by this arrangement cannot result in an output force, but will merely produce strain within the waveguide walls. However, this ignores Einstein’s Special Law of Relativity in which separate frames of reference have to be applied at velocities approaching the speed of light. Thus the system of EM wave and waveguide can be regarded as an open system, with the EM wave and the waveguide having separate frames of reference.
The beauty of engineering is that you can actually build something to test it; we'll find out soon enough if Emdrives will power space craft.
In the meantime, you might want to compare the Emdrive explanation with other famous pseudo-scientific science-fictional space drives. See the entries for the spindizzy from James Blish's Cities in Flight and of course the elegant infinite improbability drive from Douglas Adam's Hitchhiker's Guide to the Galaxy .
Via Wired; see also the Emdrive website.
Scroll down for more stories in the same category. (Story submitted 9/29/2008)
Follow this kind of news @Technovelgy.| Email | RSS | Blog It | Stumble | del.icio.us | Digg | Reddit |
Would
you like to contribute a story tip?
It's easy:
Get the URL of the story, and the related sf author, and add
it here.
Comment/Join discussion ( 5 )
Related News Stories - (" Space Tech ")
Sunbird Pulsar Fusion Like Leinster's Space Tug
'It was a pushpot, which could not possibly be called a jet plane because it could not possibly fly. Only it did.' - Murray Leinster, 1953.
Crystalline Structures In Space, You Say?
A massive space borne lifeform from ST:TNG.
Amazing Photonic Crystal Light Sail
'That sail will be twenty thousand miles at the wide part.' - Cordwainer Smith, 1960.
The New Habitable Zones Include Asimov's Ribbon Worlds
'...there's a narrow belt where the climate is moderate.' - Harl Vincent, 1931.
Technovelgy (that's tech-novel-gee!) is devoted to the creative science inventions and ideas of sf authors. Look for the Invention Category that interests you, the Glossary, the Invention Timeline, or see what's New.
Science Fiction
Timeline
1600-1899
1900-1939
1940's 1950's
1960's 1970's
1980's 1990's
2000's 2010's
Current News
Ridiculous 'Ghost Murmur' Tech Still Science Fiction
'...it rears and spreads its fan. It can pick one man out of a crowd.'
Outdoor Video Screens Can Be Arbitrarily Large
The Shape of Things To Come
Infrared Contact Lenses To See In The Dark
'I can see in the dark, Case.'
What'll You Have? Extinct Animals Returned, Or Synthetic Eggshells?
'...a new plastic with the characteristics of an avian eggshell.'
Sunbird Pulsar Fusion Like Leinster's Space Tug
'It was a pushpot, which could not possibly be called a jet plane because it could not possibly fly. Only it did.'
RentAHuman App Lets AI Agents Hire Humans
'She wouldn't stop until Antar had told her everything he knew about whatever it was that she was playing with on her screen.'
Unitree CEO Wang Xingxing Runs With His G1 Robot Army
'Does thinking you're the last sane man on the face of the Earth make you crazy?'
AIs Turn Marxist Under Bad Management
'It was a general strike of the robots...'
Moscow Attacked By Hundreds Of Drones
'It hurtled on down with inconceivable speed until it was visible as thousands of tiny robot planes...'
Nifty Folding Electric Bicycles!
'Separate paths were provided for them...'
FTC: Says Ring Employees Illegally Surveilled Customers
'Then she looked up with a smile and moved closer to the camera.'
Switzerland May Cap Population At Ten Million
'The population of Castle Hagedorn was fixed...'
Project Silica Offers 'Long-Term' Digital Storage
'... folios and tapes and playable discs of platinum alloy.'
Can 'Tactical Umbrellas' Shield One From Drones
'... another corner of his mind began to think about the shields.'
Crystalline Structures In Space, You Say?
A massive space borne lifeform from ST:TNG.
Garçon! A Menu For Artemis II, S'il Vous Plaît
'Michel Ardan, as a Frenchman, was declared chief cook, an important function, which raised no rival.'
