Tether deployment and trajectory modeling for space plasma science missions

Certain space plasma science missions employ a research payload that comprises two subpayloads that are connected by an electrically conductive tether of up to 1200 m in length. The missions are conducted in suborbital trajectory attained with a small multistage launch vehicle; A reel-type deployer is used, and subpayload separation is achieved mainly by thrusters on one of the, subpayloads. The focus is on modeling the deployment phases and the orientation of the configuration in space. The subpayloads are modeled as mass points in inertial space in the Earth's gravity field. Approximate solutions are derived that provide functional relationships that are useful for mission design. Results from simulation and the approximate formulas are shown to compare well with flight dynamics measurements made with a tether force sensor and star cameras during a mission in November 1995.