GTOSS is a tether simulation code developed by David Lang to study the dynamics of a wide variety of tethered object configurations, both terrestrial and in space. This code was first used for flight certification of the Shuttle TSS experiments, and is capable of simulating many aspects of the space elevator system dynamics. The source has been made freely available to those interested and capable of pursuing similar studies. You can learn more about GTOSS's general attributes at the GTOSS description web site.
The code is made available via a source sharing facility http://sharesource.org and is based on the Mercurial source management software system; Make sure you have Mercurial and relevant fortran compilers, etc. installed. Using a Unix or Linux type shell-terminal interface (say "Terminal" on Mac OSX or Ubuntu, etc),
hg clone http://hg.sharesource.org/gtoss
Note: Inside the "SE Dynamics Exploration Runs" directory there are 35 GTOSS input-run streams that produce a wide variety of space elevator analyses.
Getting started documentation is here: File:Getting Started with GTOSS.pdf
Full Docs are located here: http://keithcu.com/GTOSS%20Reference%20Docs.zip
The space elevator is a challenging dynamics problem. It reaches through a gravity well, has a very unique aspect ratio, is in an environment with wind, passing gravity wells, solar wind pressure, ascending climbers and a moving anchor. An extensive study was undertaken by David Lang to simulate the system from deployment through operation. Some results of those studies are shown below.
General GTOSS Simulation Results
A Handbook of Various Dynamic Attributes of the Space Elevator
This handbook covers many of the dynamic attributes and responses of the space elevator, however the papers listed below, also expand upon and extend the contents of the handbook.
File:Dyn HB Final pdf.pdf: Large compilation of David Lang's Space Elevator dynamics work. (10.2Meg PDF) - This document will be split and referenced.
Selected GTOSS Simulation Animations
The animations shown below represent but a few examples that typify the larger body of GTOSS space elevator work that has been done. Following these is a list of papers which includes a more extensive selection of animations pertaining to, and elucidating on, the specific subject matter of each paper.
Important Note: In ALL animations below, Deflection-Distances are generally MAGNIFIED & time is ACCELERATED
Selected Atmospheric Wind Response Animations
NOTE: these winds are very high, and are not typical of the space elevator geographical location
File:Lang Movie Low.avi: AVI movie: Stop-time animation with Low altitude view and atmospheric density depiction
File:Lang Movie Full.avi: AVI movie: Stop-time animation of entire elevator length (with horizontal response scale greatly magnified)
Selected Wave Propagation Animations Viewed at Ribbon High Above Earth
NOTE: this wave originates at the ground in response to a planned base-movement
: QUICKTIME movie, Horizontal scale is greatly magnified
Note: the above QT movie was made using the application SpaceAnimator, created by Paul Snow
(you can contact Paul in the Seattle area at "email@example.com", phone: 425 466-1405)
Papers and Related Explanatory Animations
Note: Following each paper below is a link to a page that presents animations of GTOSS simulations of the paper's subject; these animations will clarify, supplement and expand upon the contents of each paper.
1. Paper on Aerodynamic Response to Atmospheric Wind (PDF) File:Paper Lang Aero.pdf
See animations pertaining to Aerodynamic Response
2. Paper on Dynamic Response to Climber Transits (PDF) File:Paper Lang Climber Transit.pdf
See animations pertaining to Climber Dynamics Response
3. Paper on the Dynamics of GEO-Based Construction Deployment (PDF) File:Paper Lang GEO Deploy.pdf
See animations pertaining to Construction Deployment
For those interested in working with GTOSS please contact David Lang. The GTOSS program is being added to this site and will be made available to individuals with the background knowledge to use it. The code is extremely complex as are the input parameters and interpretation of the output results.