Assessment of Aerospike Nozzle for Single-Stage to Orbit Flight

Single-stage-to-orbit (SSTO) rocket technology offers the potential to substantially reduce launch costs, but is not considered practical for conventional launch vehicles. However, new research in composite propellant tank technology opens the field for reevaluation. One technology that increases the efficiency and feasibility of SSTO flight is an altitude compensating rocket engine nozzle, as opposed to a conventional constant-area, bell nozzle. By implementing an altitude compensation nozzle, such as an aerospike nozzle for inatmosphere flight, the propellant mass fraction (PMF) may be reduced by as much as two percent compared to a conventional rocket engine. In this paper, Optimal Trajectories by Implicit Simulation (OTIS) is used to model SSTO flight trajectories by comparing an aerospike nozzle to a conventional bell nozzle; this includes vacuum thrust, vacuum specific impulse, and nozzle combinations to show that nozzle variability increases the efficiency of SSTO flight through a reduction in PMF. Results suggest that limiting the altitude compensation to lower altitudes further decreases PMF by 0.1-0.2%. Uncertainty estimates suggest that this added benefit is within the range of uncertainty of OTIS, and performs at least as well as the theoretical, infinite nozzle expansion. It is apparent that altitude compensating nozzles outperform conventional bell nozzle designs.

[1]  Howard D. Curtis,et al.  Orbital Mechanics for Engineering Students , 2005 .

[2]  E. L. Houghton,et al.  Aerodynamics for Engineering Students , 1970 .

[4]  J. Hoffman,et al.  Optimization of conical thrust nozzles. , 1967 .

[5]  E. Reske,et al.  Evaluation of altitude compensating nozzle concepts for RLV , 1997 .

[7]  Luca Boccaletto,et al.  High-Performance Rocket Nozzle Concept , 2010 .

[8]  Hong-Gye Sung,et al.  Numerical Study of the Dynamic Characteristics of Pintle Nozzles for Variable Thrust , 2015 .

[9]  S. Kalt,et al.  Conical rocket nozzle performance under flow- separated conditions , 1965 .

[10]  David H. Huang,et al.  Modern Engineering for Design of Liquid Propellant Rocket Engines , 1992 .

[11]  Constant Chamber Pressure Throttling of an Expansion-Deflection Nozzle , 1969 .

[12]  G. A. Hosack,et al.  Performance of the aerobell extendible rocket nozzle , 1969 .

[13]  M. Kutin,et al.  Linear Aerospike SR-71 Experiment (LASRE) rocket engine , 1997 .

[14]  F. J. Hale.  Introduction to space flight , 1993 .

[15]  J. Hoffman,et al.  Effects of base pressure on conical thrust nozzle optimization , 1970 .

[16]  J. Anderson,et al.  Modern Compressible Flow: With Historical Perspective , 1982 .

[17]  George P. Sutton,et al.  History of liquid propellant rocket engines in the United States , 2003 .

[19]  Takuo Onodera,et al.  A study of aerospike-nozzle engines , 1998 .

[20]  D. Munday,et al.  Experimental and Numerical Study of Jets from Elliptic Nozzles with Conic Plug , 2011 .

[21]  Waldy K. Sjauw,et al.  Comparison of Implicit Integration Methods for Solving Aerospace Trajectory Optimization Problems , 2006 .