Fly Back Booster Design for Mach 5 Scramjet Launch
- Paper number
IAC-17,D2,7,4,x37687
- Author
Mr. Joseph Chai, University of Queensland, Australia
- Coauthor
Prof. Michael Smart, University of Queensland, Australia
- Coauthor
Mr. Sholto Forbes-Spyratos, University of Queensland, Australia
- Coauthor
Dr. Michael Kearney, University of Queensland, Australia
- Year
2017
- Abstract
Scramjet powered accelerators have the potential to decrease the cost of space access by offering reusability as well as higher specific impulse compared to rockets. The University of Queensland Centre for Hypersonics (CfH) has developed a three stage to orbit, rocket-scramjet-rocket dedicated small payload (100-200kg) launcher concept for LEO and SSO. One of the major hurdles related to scramjet accelerators is the need for high dynamic pressure flight at Mach 5 to begin scramjet ignition. The second stage accelerator, SPARTAN, is designed to be fully reusable. In keeping with reusability, fly back boosters may be designed to boost the launch stack to Mach 5. A great number of fly back booster (FBB) concepts have been developed by organisations such as DLR, SpaceWorks, NASA Langley and CNES. The vast majority of these concepts have featured a delta wing approach and canards for longitudinal stability. Subsonic propulsion varied from turbojet engines to low throttle rockets. Although delta wings are desirable for supersonic flight, they add additional mass as well as increase the ascent drag. A proposed alternative to minimise ascent drag involves a pivot wing approach. The deployable wing has a high aspect ratio (AR = 7-10), which would provide high L/D during flyback. The goal of this study is to investigate the feasibility of utilising a pivot wing, reusable FBB to enable scramjet launch by conducting conceptual design and trade studies. The FBB(s) accelerate the launch stack to Mach 5, q = 50 kPa and 24km altitude before staging and scramjet ignition. After separation, a turning maneuver and high AoA aerobraking is performed. Wings and propellers are deployed when the FBB decelerates to Mach 0.15. Conceptual design has been performed by concurrently assessing requirements related to ascent, glide and fly back. This includes systems packaging, gravimetrics, flight dynamics and aerodynamics. Pseudospectral optimal control is used to optimise the stack ascent trajectory while pseudo 5Dof time stepping simulations are used to model flight dynamics of the turn, aerobraking and flyback trajectories of the FBB. Aerodynamic coefficients were obtained from Cart3D and the reference temperature method. The optimised ascent trajectory and the wing-deployment at Mach 0.15 are used as boundary conditions to investigate the feasibility of several different glide-back strategies for the FBB. Preliminary results have shown that high AoA (20-40$^{\circ}$) aerobraking results in a pull up maneuver and rapid deceleration, demonstrating the feasibility of the concept.- Abstract document
- Manuscript document
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