Moon & Mars Orbiting Spinning Tether Transport - Tethers Unlimited

Tethers Unlimited, Inc.Appendixm M: TetherSim where h is the altitude and T ex is the average exospheric temperature, 1100K.MSISE 90 Model:For more detailed simulations, such as the simulation of the aerodynamic drag and heating on thetethers in the Hypersonic Airplane Space Tether Orbital Launch (HASTOL) architecture, the code canutilize an aero drag and heating model developed by Stuart Bowman and Professor Mark Lewis of theUniversity of Maryland, which uses the MSISE 90 model to calculate the atmospheric density.Tether Reeling and DeploymentIn order to study the dynamics of tether deployment and reeling maneuvers, the code has beenextended to include the capability to model these behaviors. The tether can be deployed/reeled byeither endmass. Currently, the code has models for:• Free deployment (with deployment tension depending upon deployment rate)• Deployment at a controlled tension• Deployment at a controlled rate or rate program• Tether retraction at controlled tension• Tether retraction at controlled rate or rate programThese models have been used to model the deployment of a Terminator Tether and spin-up of theTORQUE experiment.Endmass DynamicsTetherSim can model the attitude dynamics of spacecraft attached to the tether. The attitudedynamics propagation algorithm is based upon standard quaternion methods.M-5