Launch Vehicles as Support Subsystems for Communications Satellites

Abstract

Suitable definition of important launch vehicle parameters is necessary to develop and analyze optimum methods of satisfying commercial and government communications satellite systems requirements properly. The launch vehicle is considered a support subsystem whose cost typically amounts to about half of the total space hardware cost. Identification of launch vehicle interface and its capability to furnish the communications spacecraft with electrical power, a suitable environment, structural and dynamic support, and provision for dispensing is important. Launch vehicle performance capability limits the spacecraft permissible weight or number carried per launch for multiple spacecraft launches. Excess performance can be utilized to obtain flexibility in selection of orbit altitudes, apogee kick motor sizing and in extending launch windows. The communications satellite sequencing, guidance, and velocity correction requirements are defined as a result of the launch vehicle's guidance accuracy. Launch vehicle reliability and confidence are major factors in determining program costs. Use of extensive existing ground support capability is important to minimize system cost. Likewise, program-peculiar support requirements should be minimized since expense of launch vehicle development and support modifications can be significant. Suitable program and requirements definition will minimize recurring and non-recurring costs. Launch vehicle costs are also affected by interfaces with existing military and NASA using programs.