Lazarus: A SSTO Hypersonic Vehicle Concept Utilizing RBCC and HEDM Propulsion Technologies

Abstract

Lazarus is an unmanned single stage reusable launch vehicle concept utilizing advanced propulsion concepts such as rocket based combined cycle engine (RBCC) and high energy density material (HEDM) propellants. These advanced propulsion elements make the Lazarus launch vehicle both feasible and viable in today's highly competitive market. The Lazarus concept is powered by six rocket based combined cycle engines. These engines are designed to operate with HEDM fuel and liquid oxygen (LOX). During atmospheric flight the LOX is augmented by air traveling through the engines and the resulting propellant mass fractions make single stage to orbit (SSTO) possible. A typical hindrance to SSTO vehicles are the large wings and landing gear necessary for takeoff of a fully fueled vehicle. The Lazarus concept addresses this problem by using a sled to take off horizontally. This sled accelerates the vehicle to over 500 mph using the launch vehicle engines and a propellant cross feed system. This propellant feed system allows the vehicle to accelerate using its own propulsion system without carrying the necessary fuel required while it is attached to the sled. Lazarus is designed to deliver 5,000 lbs of payload to a 100 nmi x 100 nmi x 28.5° orbit due East out of Kennedy Space Center (KSC). This mission design allows for rapid redeployment of small orbital assets with little launch preparation. Lazarus is also designed for a secondary strike mission. The high speed and long range inherent in a SSTO launch vehicle make it an ideal global strike platform. Details of the conceptual design process used for Lazarus are included in this paper. The disciplines used in the design include aerodynamics, configuration, propulsion design, trajectory, mass properties, cost, operations, reliability and safety. Each of these disciplines was computed using a conceptual design tool similar to that used in industry. These disciplines were then combined into an integrated design process and used to minimize the gross weight of the Lazarus design. Nomenclature α = angle-of-attack, ° AFRSI = Advanced Flexible Reusable Surface Insulation CAD = computer aided design CER = cost estimating relationship c L = coefficient of lift DDT&E = design, development, test, & evaluation DoD = Department of Defense DSM = Design Structure Matrix EMA = electro-mechanical actuators

Trajectory Optimisation of a Partially-Reusable Rocket-Scramjet-Rocket Small Satellite Launch System

“…The ascent trajectories of SSTO airbreathing launch vehicles are significantly different from allrocket launch systems, due to their airbeathing engines requiring atmosphere to operate, necessitating the launch vehicle spending a large amount of time flying close to horizontal. Most SSTO airbreathing systems are designed to be horizontally launched, under turbojet or rocket-assisted power [16,20,21,28,[74][75][76][77]. The exception to this is the GTX, which launches vertically under rocket power [17,18] .…”

“…These various propulsion systems may all be integrated into a single-stage-to-orbit spaceplane that is capable of launching, placing payload in orbit, reentering, and returning to a suitable landing site [15][16][17][18][19][20][21][22]. Single-stage-to-orbit launch vehicles are fully-reusable, and have the potential to be extremely cost-efficient, if they are able to be reused for many missions [23].…”

“…Single-stage-to-orbit launch vehicles are fully-reusable, and have the potential to be extremely cost-efficient, if they are able to be reused for many missions [23]. However, their development cost is likely to be very high, and they are generally suited for launching large amounts of payload-to-orbit [15][16][17][18][19][20][21][22], a market which is now extremely competitive thanks to the relatively recent advent of large, partially reusable, rocket-based launch systems. Alternatively, the launcher may be separated into multiple stages, similarly to typical, fully rocket-based launch systems [24][25][26][27][28][29][30][31][32][33].…”

“…There are as of yet no airbreathing launch systems that have progressed past the research and very early design stages [15][16][17][18][19][20][21][22][24][25][26][27][28][29][30][31][32][33]. The development and analysis of trajectories is a crucial part of this early design process, and it is a complex task to ensure that an airbreathing launch system is able to survive launch and fly with maximum efficacy.…”

“…For single-stage-to-orbit airbreathing launch systems, trajectories have been developed and studied in detail [15][16][17][18][19][20][21][22], in particular due to a multitude of studies in the 1980s and 90s, the most prominent of which was the National Aerospace Plane (NASP), which led, in part, to the Hyper-X program and the X-43 flight experiment [23]. These studies show complex trade-offs that occur in maximum efficiency airbreathing vehicle trajectories, including trade-offs between the operational efficiencies of the various engine modes.…”