LAUNCH SYSTEMS Col John Keesee 5 September 2003
LAUNCH SYSTEMS Col. John Keesee 5 September 2003
Outline Launch systems characteristics Launch systems selection process Spacecraft design envelope environments
Outline • Launch systems characteristics • Launch systems selection process • Spacecraft design envelope & environments
Lesson obiectives Each student will Understand launch system characteristics, sizing and trade-offs Estimate launch system sizes. staging requirements Be able to select appropriate launch system for a given mission from available systems Be able to estimate spacecraft requirements driven by launch vehicle induced environments Determine costs of launch systems
Lesson Objectives • Each student will • Understand launch system characteristics, sizing and trade-offs. • Estimate launch system sizes, staging requirements. • Be able to select appropriate launch system for a given mission from available systems. • Be able to estimate spacecraft requirements driven by launch vehicle induced environments. • Determine costs of launch systems
Rocket basics fuel in e Thrust Oxidizer in A Throat Thrust eret Aelpe-p) F=ny Specific impulse SD≡ F mg Isp=K where k depends on y and the engine pressure ratio
Rocket Basics Thrust Specific impulse where K depends on J and the engine pressure ratio ( ) f p ep eA eVe F m M cT Isp K mg Isp F { me Ve Pe Ae fp Fuel in Oxidizer in Thrust pc Throat
Rocket equation F-m isp aFM M,=M.-mt ve ve ve t dmd △=a=p8-dt △V= g Isp nM。M g Ispenyo=g Ispin R propellant Where R- is the mass ratio Assumes zero losses due to drag and gravity
Rocket Equation Where is the mass ratio (Assumes zero losses due to drag and gravity) m t Mo veh g M veh M m Isp veh M a F ' V adt Isp g ³ d m dt dt Mo d m d t t t o t f ³ ¸ ¸ ¹ · ¨ ¨ © § ¸ ¸ ¸ ¸ ¸ ¸ ¸ ¹ · ¨ ¨ ¨ ¨ ¨ ¨ ¨ © § ¸ ¸ ¸ ¸ ¸ ¸ ¸ ¹ · ¨ ¨ ¨ ¨ ¨ ¨ ¨ © § ' g Isp n R f M g Isp n Mo propellant Mo M V g Isp " n Mo " " R Mo Mf