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
 |
Space Elevator Downer
Scientists and science fiction fans alike have big plans for carbon nanotubes; it has been hoped that a cable made of carbon nanotubes would be strong enough to serve as a space elevator. However, recent calculations by Nicola Pugno of the Polytechnic of Turin, Italy, suggest that carbon nanotube cables will not work.
(Looking down a carbon nanotube)
American engineers worked on the problem in the mid-1960's. What type of material would be required to build a space elevator? According to their calculations, the cable would need to be twice as strong as that of any existing material including graphite, quartz, and diamond.
Science fiction writer Arthur C. Clarke recognized the materials problem; his ingenuity was equal to the task of creating just such a material. In his excellent 1978 novel The Fountains of Paradise, he thought up a special form of carbon, something called a "continuous pseudo-one dimensional diamond crystal," to serve as the cable material. To the delight of sf fans and aerospace engineers, Japanese researcher Sumio Iijima (at NEC) discovered carbon nanotubes, which are cylindrical carbon fibers exhibiting strength 100 times greater than that of steel at one sixth the weight, and high strain to failure.
In something of a "downer" for space elevator fans, Pugno has calculated that inevitable defects will greatly reduce the strength of any manufactured nanotubes. Laboratory tests have demonstrated that flawless individual nanotubes can withstand about 100 gigapascals of tension; however, if a nanotube is missing just one carbon atom, it can reduce its strength by as much as thirty percent. Bulk materials made of many connected nanotubes are even weaker, averaging less than 1 gigapascal in strength.
In order to function, a space elevator ribbon would need to withstand at least 62 gigapascals of tension. It therefore appears that the defects described above would eliminate carbon nanotubes as a usable material for a space elevator cable. Pugno will publish his paper in the July edition of Journal of Physics: Condensed Matter. Nanotube enthusiasts counter that ribbons made of close-packed long nanotubes would demonstrate cooperative friction forces that could make up for weaknesses in individual nanotubes.
Read more about Arthur C. Clarke's one-dimensional diamond crystal; in Carbon Nanotube Ribbon for Space Elevator a method of creating meter-long nanotube ribbons is described. A robotic lifter that would traverse a space elevator ribbon has also been tested. Read more about the current controversy at Nature.
Scroll down for more stories in the same category. (Story submitted 5/26/2006)
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 ( 13 )
Related News Stories - (" Space Tech ")
Starship Special Edition For Lunar Shuttle
Love those special edition spaceships.
Capturing Asteroids With Nets
'...the meteor caught and halted just as a small boy catches a swift ball in his cap.' V.E. Thiessen, 1947.
Project Hyperion - Generation Ship Designers Needed!
'We have decided that it shall be but one ship... it must contain everything needed to take us through the generations.' - Judson Reeves, 1930.
Marslink Proposed By SpaceX
'It was the heart of the Solar System's communication line...' - George O. Smith, 1942.
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
Miss Alabama Beauty Contest Offers Different Standards
'...they moved with the ease of dandelion puffs.'
Has Musk Given Up On Full Self Driving (FSD)?
'...some bored drone pusher in a remote driving centre...'
Prufrock-3 'The Monster' Ready To Launch
Just go for it.
Drones In Vast Airborne Grids
'These pods were programmed to hang in space in a hexagonal grid pattern...'
Starship Special Edition For Lunar Shuttle
Love those special edition spaceships.
Capturing Asteroids With Nets
'...the meteor caught and halted just as a small boy catches a swift ball in his cap.'
Project Hyperion - Generation Ship Designers Needed!
'We have decided that it shall be but one ship... it must contain everything needed to take us through the generations.'
AI Welfare Position At Anthropic Filled By Human
'You’re the robopsychologist of the plant, so you’re to study the robot itself...'
Marslink Proposed By SpaceX
'It was the heart of the Solar System's communication line...'
Simple Way To Defeat AI Face Recognition
'... designed to foil facial recognition systems.'
Wood-Panelled LignoSat Launched
'The Consul remembered his first glimpse of the kilometer-long treeship...'
Laser-Beam Welding In Orbital Factories
'His contract with Space Industries required him to work summers in their orbital factory.'
'Iceberg House' Of Travis Kelce Reflects Science Fiction Of Past Century
'The basement was huge... carved deep into the rock that folded up to underlie the ridge...'
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...'
