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 ")
Mechazilla Arms Catch A Falling Starship, But Check Out SF Landing-ARMS
'...the rocket’s landing-arms automatically unfolded.' - Edmond Hamilton, 1931
Solar-Powered Space Trains On The Moon
'The low-slung monorail car, straddling its single track, bored through the shadows on a slowly rising course.' - Arthur C. Clarke, 1955.
JWST Finds Bucking Centaur 29P/Schwassmann-Wachmann 1
'... the glittering little rocket bolted to the black iron behind him.' - Jack Williamson, 1933.
First Trips To Mars Announced By Elon Musk
'I had determined that my first attempt should be a visit to Mars.' Percy Greg, 1880.
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
Mechazilla Arms Catch A Falling Starship, But Check Out SF Landing-ARMS
'...the rocket’s landing-arms automatically unfolded.'
A System To Defeat AI Face Recognition
'...points and patches of light... sliding all over their faces in a programmed manner that had been designed to foil facial recognition systems.'
Robot Hand Separate From Robot
'The crawling, exploring object was V-Stephen's surgeon-hand...'
Hybrid Wind Solar Devices
'...the combined Wind-Suncatcher, like a spray of tulips mounted fanwise.'
Is Optimus Autonomous Or Teleoperated?
'I went to the control room where the three other men were manipulating their mechanical men.'
Robot Masseuse Rubs People The Right Way
'The automatic massager began to fumble gently...'
Solar-Powered Space Trains On The Moon
'The low-slung monorail car, straddling its single track, bored through the shadows on a slowly rising course.'
Drone Deliveries Instead Of Waiters In Restaurants?
'It was a smooth ovoid floating a few inches from the floor...'
Optimus Robot Can Charge Itself
'... he thrust in his charging arm to replenish his store of energy.'
Skip Movewear Arc'teryx AI Pants
'...the terrible Jovian gravity that made each movement an effort.'
'Robovan' Name Already Taken - Elon, Try These
There are alternative names that are probably in the public domain by now.
How Old Are Tesla Designs?
You be the judge.
Is Your Autonomous Tractor Safe?
'The field-minder finished turning the top-soil of a two-thousand-acre field.'
Smart TVs Are Listening!
'You had to live -- did live, from habit that became instinct -- in the assumption that every sound you made was overheard...'
Police Drones In China Would Like To Have A Word With You
''OVERRIDE,' the City Fathers said suddenly, without being asked anything at all.'
Oh Great (Part 2), Fence-Climbing Robots
Please, no stingers.
