Survey of advanced booster options for potential Shuttle-derivative vehicles

Abstract

A never-ending major goal for the Space Shuttle program is to continually improve flight safety, as long as this launch system remains in operational service. One of the options to improve system safety and to enhance vehicle performance as well, that has been seriously studied over the past several decades, is to replace the existing strap-on four segment solid rocket boosters (SRB's) with more capable units. A number of booster upgrade options have been studied in some detail, ranging from five segment solids through hybrids and a wide variety of liquid strap-ons (both pressure and pump fed with various propellants); all the way to a completely reusable liquid fly back booster (complete with air breathing engines for controlled landing and return). All of these possibilities appear to offer improvements in varying degrees; and each has their strengths and weaknesses from both programmatic and technical points of view. The most beneficial booster upgrade/design, if the shuttle program were to continue long enough to justify the required investment, would be an approach that greatly increased both vehicle and crew safety. This would be accomplished by increasing the minimum range/minimum altitude envelope that would readily allow abort to orbit (ATO), possibly even to zero/zero, and possibly reduce or eliminate the Return to Launch Site (RTLS) and even the Trans Atlantic Landing (TAL) abort mode requirements. This paper will briefly survey and discuss all of the various booster upgrade options studied previously, and compare their relative attributes. The survey will explicitly discuss, in summary comparative form, options that include: five segment solids; several hybrid possibilities; pressure and/or pump-fed liquids using either LO2/kerosene, H20/kerosene and LOz/Jz, any of which could be either fully expendable, partly or fully reusable; and finally a fully reusable liquid fly back booster system, with a number of propellant and propulsion system options. Performance and configuration comparison illustrations and tables will be included to provide a comprehensive survey for the paper.

Optimal Design of Hybrid Rocket Motors for Microgravity Platform

“…At each instant t, once the tank pressure p t and the motor geometry are known, the propellant flow rates (and their ratio ), c and p c are computed by numerically solving Eqs. (2)(3)(4)(5)(6)(7)(8), while the curve fit for c as a function of is used. Then, the thrust level F p c A t C F is determined by evaluating C F at the actual altitude via Eq.…”

“…All these features make HRMs suitable for relatively simple low-cost applications, such as sounding rockets to be used as microgravity platforms. A large number of papers concerning numerical and experimental HRM investigation can be found in the literature [1][2][3][4][5][6]. In most numerical investigations, a parametric optimization is performed to find the best grain and nozzle geometries as well as the best operating conditions, such as mean mixture ratio and chamber pressure.…”

Design and optimization of variable thrust hybrid rocket motors for sounding rockets

“…Casalino et al studied various oxidizer feeding schemes, optimized the design parameters of HRM, and made numerical optimization researches on its application to sounding rockets [11], the microgravity platform [12], upper stages [13], and the launcher for small satellites [14]. Besides, many researchers carried out pioneering numerical researches on its application to boosters [15,16].…”