Session
Session IX: From Earth to Orbit
Abstract
Stellar-J trade studies were undertaken to determine minimum performance requirements to launch small satellite constellation units (e.g., CICERO) or alleviate ascent load concerns of airframe manufacturers. Studies assumed vehicle total take-off weight of 35 tons, similar to a Gulfstream-3, with capability to carry an NK-31/39 class reusable rocket engine. Burn durations were reduced from a 135-sec vehicle baseline to 70-sec in 5-sec increments. Trajectories characterized 6, 3 and 2-ton total separation weight expendable stage designs marking orbital injection weights. Payload weights were based on 4 assumed mass fractions (l =0.85, 0.875, 0.9 , 0.9 2). Overall trajectory results and propellant assumptions derived stage dimensions, and tank volumes. Effects of 4 hydrocarbon fuels (RP1, C3H8, CH4 and ethanol) on propulsion and performance for the last of the two expendable stages (IIB) were examined, holding the first expendable stage (IIA) fixed. Inherent higher ISP of low carbon fuels benefited the smallest mass payloads due to the high final stage DVs, but pressurization system design effects on l were more telling. High dry weights and precision steering for orbital insertion seemed issues for use of simple sounding rockets. Examining thrust vector control (gimbals) and attitude thrusters, we reviewed classical control approaches to time varying gains and slosh problems. Results indicate that a 2-ton expendable upper stage on lowered performance Stellar-J trajectories (70-75 second ascent burns) provides a means to launch single or double CICERO satellite units. Advantages include low cost, responsiveness and dedication to the needs of this or other potential small satellite users.
Presentation Slides
The Stellar-J: A Partially Reusable Horizontal Take-Off Launch System Designed for Small Satellite and Low Startup Cost
Stellar-J trade studies were undertaken to determine minimum performance requirements to launch small satellite constellation units (e.g., CICERO) or alleviate ascent load concerns of airframe manufacturers. Studies assumed vehicle total take-off weight of 35 tons, similar to a Gulfstream-3, with capability to carry an NK-31/39 class reusable rocket engine. Burn durations were reduced from a 135-sec vehicle baseline to 70-sec in 5-sec increments. Trajectories characterized 6, 3 and 2-ton total separation weight expendable stage designs marking orbital injection weights. Payload weights were based on 4 assumed mass fractions (l =0.85, 0.875, 0.9 , 0.9 2). Overall trajectory results and propellant assumptions derived stage dimensions, and tank volumes. Effects of 4 hydrocarbon fuels (RP1, C3H8, CH4 and ethanol) on propulsion and performance for the last of the two expendable stages (IIB) were examined, holding the first expendable stage (IIA) fixed. Inherent higher ISP of low carbon fuels benefited the smallest mass payloads due to the high final stage DVs, but pressurization system design effects on l were more telling. High dry weights and precision steering for orbital insertion seemed issues for use of simple sounding rockets. Examining thrust vector control (gimbals) and attitude thrusters, we reviewed classical control approaches to time varying gains and slosh problems. Results indicate that a 2-ton expendable upper stage on lowered performance Stellar-J trajectories (70-75 second ascent burns) provides a means to launch single or double CICERO satellite units. Advantages include low cost, responsiveness and dedication to the needs of this or other potential small satellite users.
