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
 |
Moon's Huge Lava Tubes Perfect For Heinlein's Bat Wings
Lava tubes on Earth, in California, Hawaii and Iceland, result when underground rivers of molten rock empty out, leaving channels up to 30 meters across. Planetary geophysicist Dave Blair of Purdue University in West Lafayette, Indiana and colleagues estimate that lunar caves could exist that are up to 5 kilometers across!
(Thurston Lava Tube, Hawaii)
Mounting evidence from the SELENE, LRO, and GRAIL spacecraft suggests the presence of vacant lava tubes under the surface of the Moon. GRAIL evidence, in particular, suggests that some may be more than a kilometer in width. Such large sublunarean structures would be of great benefit to future human exploration of the Moon, providing shelter from the harsh environment at the surface—but could empty lava tubes of this size be stable under lunar conditions? And what is the largest size at which they could remain structurally sound?We address these questions by creating elasto-plastic finite element models of lava tubes using the Abaqus modeling software and examining where there is local material failure in the tube's roof. We assess the strength of the rock body using the Geological Strength Index method with values appropriate to the Moon, assign it a basaltic density derived from a modern re-analysis of lunar samples, and assume a 3:1 width-to-height ratio for the lava tube. Our results show that the stability of a lava tube depends on its width, its roof thickness, and whether the rock comprising the structure begins in a lithostatic or Poisson stress state.
With a roof two meters thick, lava tubes a kilometer or more in width can remain stable, supporting inferences from GRAIL observations. The theoretical maximum size of a lunar lava tube depends on a variety of factors, but given sufficient burial depth (500 m) and an initial lithostatic stress state, our results show that lava tubes up to five kilometers wide may be able to remain structurally stable.
Fans of science fiction Grandmaster Robert A. Heinlein find themselves nodding sagely, since reading all about such structures in his 1957 novel Menace from Earth:
Most of the stuff written about Bats' Cave gives a wrong impression. It's the air storage tank for the city, just like all the colonies have - the place where the scavenger pumps, deep down, deliver the air until it's needed. We just happen to be lucky enough to have one big enough to fly in. But it never was built, or anything like that; it's just a big volcanic bubble, two miles across, and if it had broken through, way back when, it would have been a crater.
Never one to neglect the adventuresome spirit of American youth, Heinlein obligingly provided lunar colonists with Storer-Gulls Wings for recreational use of lunar lava tubes.
Via The structural stability of lunar lava tubes.
Scroll down for more stories in the same category. (Story submitted 12/15/2016)
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 ( 0 )
Related News Stories - (" Space Tech ")
SpaceX EVA Spacesuit Tested By Polaris Dawn Crew
'Now, except for weight and heat, the same conditions prevail in this chamber as in space.' - Otto Willi Gail, 1929.
ESA To Build Moon Bases Brick By Printed LEGO Brick
'We made a crude , small cell and were delighted - and, I admit, somewhat surprised - to find it worked.' - John W. Campbell, 1950.
FLOAT Levitating Train On The Moon ala Clarke
'The low-slung monorail car, straddling its single track, bored through the shadows on a slowly rising course.' - Arthur C. Clarke, 1955.
SpaceX Intros Extravehicular Activity Suit
'Provision had been made to meet the terrific cold which we knew would be encountered the moment we had passed beyond the atmosphere.' - Garrett P. Serviss, 1898.
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
Chaffeur Robot Musashi Will Drive Your Regular Car
'What would you do,' Eric asked the robot cabdriver, 'if your wife had turned to stone, your best friend were a toad, and you had lost your job?'
Space Exporers! Now, You Can Drink Your Own Urine
'those suits they wear -- call them 'stillsuits' -- that reclaim the body's own water...'
SpaceX EVA Spacesuit Tested By Polaris Dawn Crew
'Now, except for weight and heat, the same conditions prevail in this chamber as in space.'
Automatic Bot Traffic Is 38 Percent Of HTTP Requests
'there were so many worms and counterworms loose in the data-net...'
Shanghai Guidelines For Humanoid Robots
'Now, look, let's start with the three fundamental Rules of Robotics...'
Desktop TARS Robot From Interstellar
What's YOUR sarcasm setting?
Robots Can Now Have Smiling Faces With Human Skin
'I am a cybernetic organism...'
Virtual Rat Predicts Actual Rat Neural Activity
'..the synthetic intellects at the Place of Knowledge had far outstripped the minds of men.'
GoSun EV Solar Charger Drapes Onto Your Car
'...six square yards of sunpower screens.'
Rizon 4 Ironing Robot
'But after washing and drying clothes had to be smooth - free from fine lines and wrinkles ...'
Cognify - A Prison Of The Mind We've Seen Before In SF
'So I serve a hundred years in one day...'
Robot With Human Brain Organoid - 'A Thrilling Story Of Mechanistic Progress'
'A human brain snugly encased in a transparent skull-shaped receptacle.'
Goodness Gracious Me! Google Tries Face Recognition Security
'The actuating mechanism that should have operated by the imprint of her image on the telephoto cell...'
With Mycotecture, We'll Just Grow The Space Habitats We Need
'The only real cost was in the plastic balloon that guided the growth of the coral and enclosed the coral's special air-borne food.'
Can A Swarm Of Deadly Drones Take Out An Aircraft Carrier?
'The border was defended by... a swarm of quasi-independent aerostats.'
WiFi and AI Team Up To See Through Walls
'The pitiless M rays pierced Earth and steel and densest concrete as if they were so much transparent glass...'
