dable 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.
rough propulsion mode transition points, payload mass, etc. A subsequent conceptual performance determination and vehicle sizing exercise was performed by the lead author (then at North Carolina State University) for HRST phase 1. This exercise determined vehicle aerodynamic characteristics, ascent performance, mass properties, heating, propulsion system performance, and final geometric dimensions. Small modifications to the original concept outlined by Escher and Mankins were made as required (e.g. a slight increase in vehicle fineness ratio to reduce drag and a reduction in wing area to save weight). The resultant concept, simply called SERJ RBCC with Maglifter, was presented as a ‘thought starter’ at the HRST Technical Interchange Meeting in July 1995 and is given in Fig. 1. The vehicle was sized to deliver a 20,000 lb. cargo to LEO after making use of an 800 fps launch assist velocity at the end of a sea level, horizontal mag-lev track. The tail rocket was a generic LOX/LH2 staged combustion rocket with a vacuum Isp of 455 sec. The vehicle had no crew cabin and operated autonomously. Transition from the SERJ RBCC engine to the tail rocket occurred at Mach 6 (peak ramjet speed).
Maglifter accelerator RBCC engines LOX tank
implemented during a HRST phase 2 study by the lead author (now at Georgia Tech) and a team of graduate students in the Aerospace Engineering school lead by the second author. This modified concept has been named Argus. Argus has subsequently been evaluated as one of the more promising concepts to emerge from the HRST study .
BASELINE ARGUS CONCEPT Argus System Overview Argus is designed to be a low cost cargo delivery system to LEO. A magnetically-levitated sled (Maglifter) is used to provide an initial ground-based launch assist. LOX/LH2 supercharged ejector ramjet engines provide the main motive power to the vehicle. These engines operate in supercharged ejector, fanramjet, ramjet, and pure rocket modes during ascent and can provide several minut