(Georgia Institute of Technology, 1998-07)
Way, David Wesley
SCORES (SpaceCraft Object-oriented
Rocket Engine Simulation) is an analysis tool
being developed for conceptual-level spacecraft
and launch vehicle design. Written in C++,
SCORES provides rocket thrust and Isp for
propulsion system trade studies. Common
gateway interface scripts, written in Perl, provide
an interface with the World Wide Web. The
design parameters used in SCORES are mixture
ratio, chamber pressure, throat area, and
expansion ratio, making SCORES effective in
multidisciplinary design optimization. This
paper describes the current status in the
development of SCORES, compares chemical
equilibrium results against accepted equilibrium
codes STANJAN and CEA, compares engine
thrust and Isp predictions against available engine
data for nine rocket engines, and discusses areas
for future work. SCORES accurately predicts
equilibrium mole fractions and adiabatic flame
temperature over a wide range of operating
conditions within 0.5%. Uncorrected errors of
less than 10% within SCORES engine thrust and
specific impulse calculations are within
acceptable tolerances for use in conceptual-level
design. Statistically correcting the performance
predictions reduces these errors appreciably and
provides the designer with additional information,
the confidence interval of the calculations.
(Georgia Institute of Technology, 1997-07)
Way, David Wesley; Olds, John R.
Tremendous growth in the satellite communication market is expected within the next decade. In particular, the market for services based in low earth orbit (LEO) is booming. Large constellations of satellites will soon be deployed with capabilities ranging from modest paging services to high bandwidth, data transfer systems. Constellations in the latter category are referred to as Mega-LEO constellations. Deployment of Mega-LEO constellations will place tremendous demands on international launch capabilities. Current expendable booster capability, reliability, availability, and price are all issues.
This research tests the hypothesis that a new, low cost launch vehicle can be developed specifically to deploy a Mega-LEO constellation and still be economically competitive. A fictitious Mega-LEO constellation called Orion was created to set mission requirements. Aggressive launch cost goals and launch rates were established.
A new two-stage system with a reusable booster was designed to meet the challenge - Sirius. This paper includes the results of the conceptual vehicle design activity including both technical and economic data. Details on the multidisciplinary design optimization methodology employed are also included.