Mathematica Packages
The study notebooks are often selfcontained. However, it is sometimes useful to place commonly
used functions or more complex collections of functions into the Mathematica package format. The
study download pages will indicate whether there is a dependency on one of these packages. For Mathematica Version 8,
packages are typically installed at C:\Users\username\AppData\Roaming\Mathematica\Applications\spaceLaunch. This path,
except for the final folder "spaceLaunch" is created when Mathematica is installed. From inside Mathematica, you
can find your default path using the command $UserBaseDirectory.
The packages are of little use if you do not have a full Mathematica license. However, they are in text form so
it is possible to review the equations and functions.

The Chain Dynamic Model was written in order to study long, flexible structures such as tethers, kinetic towers, and earthcircling
cables. The model discretizes a continuous cable or ribbon into a series of connected point masses, and then performs a time integration
to determine the trajectory of the masses. The method allows one to examine the dynamic response and stability of these structures. A modeling
function is provided that will generate a discrete model from a parametric description of the initial cable path, along with functional
descriptions of the stiffness and linear density distributions. A gravity field can be added to the model. Revised on 6/27/2012 to fix
problem with animated outputs persisting after the kernal is closed. 7/17/12 revision changed Integrate to NIntegrate in pathSubdivide.
Integrate was taking too long when a complex function for area was passed. Changed call to FilterRules in chainHistory. Previous version
failed if there were no user options.


Truss Tower Analysis System (TTAS) is a finite element based system for examining tall towers. It provides
basic tools for rapidly building a tower from a user defined repeating unit combined with a functional description
of the tower taper. There is a firstorder optimization function that sizes each of the truss tubes for minimum
weight considering strength, euler buckling, and local buckling constraints. The finite element system provides the
individual tube loads, and computes an overal buckling eigenvalue. The analysis includes a model for wind loads,
including atmospheric density as a function of height.


Provided several functions that can be used to estimate the total mass, and system mass breakdown of a
conventional single or multstage rocket. The functions use the traditional Tsiolkovsky rocket equation to determine
the ratio of intial to final mass. In addition, the user my define mass ratios for the propellant tanks, recovery
systems, and propulsion system. The function use an iterative solution to find a working combination of masses for
a given payload and final velocity. For multstage rockets, the user may either specify the staging velocities,
or there is an optimization function for determining ideal staging velocity.


Major revision of atmoshere.m. The package now includes a direct implementation of the
U.S Standard Atmosphere Model, along with an extended model by Jacchia that may be used for
higher altitudes. The standard model gives the density, pressure, and temperature of the earth's
atmosphere for any altitude, according to "US Standard Atmosphere, 1976" developed jointly by NOAA, NASA,
and the USAF. Package uses the format presented at http://www.atmosculator.com/The%20Standard%20Atmosphere.html.
The 1977 Jacchia gives temperature and density up to 2500km, along with the concentration of various atomic and
molecular species. The implementation is a simple interpolation of the Fortran code J77sri output. Note that
function names have been changed since earlier version of package.


Classical equations for special twobody orbits where one body is much more
massive than the other. Includes a numerical function for determine the orbit parameters that match a specified
velocity and position vector at some point on the orbit path.
Dec 2011 Revision: Addition of timeofflight function. Full package name made compatible with suggested installation path.


This notebook defines functions that will integrate the motion of an abritrary number of bodies under mutual gravitational forces.
It sets up the equations for integration using the builtin NDSolve function (the Mathematica numerical differential equation solver).
User functions are defined within the notebook  this is not a true package. The method is practical for systems on the order of tens of
interacting bodies. Problems can be defined in either two or three dimensions.

NonRocket Propulsion Links
And along the way, some personal commentary
General Interest and Collections
Guns and Ground Accelerators
Tethers
 "Moon & Mars Orbiting Spinning Tether Transport Architecture Study"
NIAC Phase II Final Report by Tethers Unlimited, Aug. 31, 2001.
 Kirk Sorensen, "Hyperbolic Injection Issues for MXER Tethers", AIAA 20035221, 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference
20â€“23 July 2003, Huntsville, Alabama
 Kirk F. Sorensen, "Conceptual Design and Analysis of an MXER Tether Boost Station", AIAA 20013915
 M.L. Cosmo and E.C. Lorenzini, "Tethers in Space Handbook", Third Edition, 1997
 Thomas J. Bogar et al, "Hypersonic Airplane Space Tether Orbital Launch (HASTOL) System: Interim Study Results",
AIAA994802, 9th International Space Planes and Hypersonic Systems and Technologies Conference 15 November 1999, Norfolk, VA USA
Space Elevator
The space elevator is a cable that goes from geosynchronous orbit to the earth's surface. This is currently
the most popular nonrocket concept, and it certainly holds much appeal. Once built, you can simply ride the
cable into space. I don't plan to do any work on this scheme because the conceptual design is already very
mature. Also, after working in composites all my career, I believe that the required materials are many decades
away. The distance from theoretical strength of carbon nanotubes to usable strength of a macroscopic engineering material
is much greater than generally recognized.
Kinetic Structures
I'm using the phrase "kinetic structures" to refer to concepts that use changes in momentum of
a mass stream to support a structure
Atmosphere Harvesting
Other
Some Miscellaneous Space Sites, Blogs, and Forums