 |
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
")
Japan's LignoSat Space Wood Satellite And Dan Simmons' Treeship
'The Consul remembered his first glimpse of the kilometer-long treeship...' - Dan Simmons, 1989.
Is It Time For Lunar Farside Telescopes?
'Mount Ambarzumian Observatory, on Farside.' - Poul Anderson, 1958.
Spaceflight Vertigo Solved By NASA Releasing The Kraken
"I threw up in my helmet."
Lunar Pogo Stick - Retro Technovelgy From 1968
'Lucky touched the leap knob...' - Isaac Asimov, 1954.
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
Japan's LignoSat Space Wood Satellite And Dan Simmons' Treeship
'The Consul remembered his first glimpse of the kilometer-long treeship...'
Skyline Robotics Instantiates Heinlein's 'Window Willie' Skyscraper Robot
'Do you know what window washing used to cost by the hour?'
Drone Bombings In Moscow Foreseen 100 Years Ago
'Once the target is confirmed, it uses an IR laser to send a coded signal back to the parent, clearing it to attack.'
I Didn't Know You Can Already Buy Flesh Putty
'I filled your bullet hole with flesh putty and the lattice.'
'A Sign in Space' Gives Practice In Decoding ET Messages
'... it will be easy to form an alphabet which shall enable us to converse with the inhabitants of the moon.'
Melting Permafrost Endangers Infrastructure
'From the tower's huge octagonal base radiate wide silvery strips...'
EELS Exobiology Extant Life Surveyor For Enceladus
'It was about five feet long... a black bullet head and red camera eyes.'
Lazy Lawyer's Trust In ChatGPT Misplaced
'The Law Society has strict rules on the use of pseudo-intelligent software...'
Paradromics Implant FDA 'Breakthrough Device'
'I used my implant to tell MILLIE what we wanted...'
Mice, At Least, Can Sober Up Quickly
'Then draw some aldodote-vitamin pills from the medic.'
Is It Time For Lunar Farside Telescopes?
'Mount Ambarzumian Observatory, on Farside.'
Spaceflight Vertigo Solved By NASA Releasing The Kraken
"I threw up in my helmet."
TM-62 Loitering Ground Landmine
Runaway movie comes to life!
Helpful Robots In Science Fiction
'If you douse me again... I'm donating you to a city college.'
Lunar Pogo Stick - Retro Technovelgy From 1968
'Lucky touched the leap knob...'
MIT And Rice Create Blade Runner Photo Analysis
Rick Deckard, your photo analysis is ready.
More SF in the News Stories
More Beyond Technovelgy science news stories
|
 |