Argus, a Highly Reusable SSTO Rocket-Based Combined Cycle Launch Vehicle with Maglifter Launch Assist
John R. Olds† Peter X. Bellini†† Space Systems Design Laboratory School of Aerospace Engineering Georgia Institute of Technology, Atlanta, GA 30332-0150
ABSTRACT This paper summarizes the results of a conceptual design study that was performed in support of NASA’s recent Highly Reusable Space Transportation study. The Argus concept uses a Maglifter magneticlevitation sled launch assist system to accelerate it to a takeoff ground speed of 800 fps on its way to delivering a payload of 20,000 lb. to low earth orbit. Main propulsion is provided by two supercharged ejector rocket engines. The vehicle is autonomous and is fully reusable. A conceptual design exercise determined the vehicle gross weight to be approximately 597,250 lb. and the dry weight to be 75,500 lb. Aggressive weight and operations cost assumptions were used throughout the design process consistent with a second-generation reusable system that might be deployed in 10 - 15 years. Drawings, geometry, and weights of the concept are included. Preliminary development, production, and operations costs along with a business scenario assuming a price-elastic payload market are also included. A fleet of three Argus launch vehicles flying a total of 149 flights per year is shown to have a financial internal rate of return of 28%. At $169/lb., the recurring cost of Argus is shown to meet the study goal of $100/lb. - $200/lb., but optimum market price results in only a factor of two to five reduction compared to today’s launch systems.
NOMENCLATURE g Isp ∆V acceleration of gravity (32.2 ft/sec2) specific impulse (sec.) velocity change, ‘delta V’ (ft/sec.)
BACKGROUND In an effort to identify technologies and vehicle concepts that have the potential to significantly reduce the high cost of access to space, NASA recently conducted the Highly Reusable Space Transportation (HRST) study [1, 2]. The study investigated a number of near-term, far-term, and very far-term launch vehicle concepts with the goal of identifying a technology development path that could reduce the recurring costs of launching 20,000 lb. – 40,000 lb. payloads to low earth orbit (LEO) for under $200/lb. The HRST study was conducted in two phases from 1995 to 1997. Among the concepts investigated were all-rocket single-stage-to-orbit (SSTO) concepts, concepts with launch assist, rocket-based combined cycle (RBCC) concepts, advanced expendable vehicles, and more far term ground-based laser powered launchers . The Argus concept outlined in this paper was one of the concepts proposed. The notion of an advanced HRST-class launch vehicle using a magnetic-levitation track for launch assist and employing two supercharged ejector ramjet (SERJ) engines and a single LOX/LH2 tail rocket for main propulsion was first suggested to the lead author by Mr. Bill Escher and Mr. John Mankins of NASA Headquarters. At a private meeting at NASA – Langley during the spring of 1995, Escher and Mankins outlined the concept with a simple sketch and an overall notion of how the vehicle would be flown,
- Assistant Professor, School of Aerospace Engineering, senior member AIAA. †† - Graduate Research Assistant, School of Aerospace Engineering, student member AIAA. Copyright ©1998 by John R. Olds and Peter X. Bellini. Published by the American Institute of Aeronautics and Astronautics, Inc. with permission.