Drag augmentation via supersonic retropropulsion for atmospheric deceleration [electronic resource]
- Noël Mojgan Bakhtian.
- Physical description
- 1 online resource.
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|3781 2012 B||In-library use|
- With sample-return and manned missions on the horizon for Mars exploration, the ability to decelerate high-mass systems upon arrival at a planet's surface has become a research priority. Mars' thin atmosphere necessitates the use of advanced entry, descent, and landing (EDL) systems to aid in deceleration to sufficiently low terminal descent velocities, and the limits of current state-of-the-art Mars EDL technologies are being challenged by evolving mission requirements. Supersonic retropropulsion (SRP), the application of jets facing into the freestream during the supersonic portion of flight, has been proposed as a candidate enabling technology for future high-mass Mars missions. Moving beyond the current "jets as thrust" paradigm, this work explores augmentation of the decelerative forces experienced during Mars entry through a flow control approach which increases aerodynamic drag through SRP jet manipulation of the bow shock. A drag augmentation model is developed based upon attainable shock physics seen in high-fidelity simulations of SRP jets. This flow model uses SRP jet manipulation to recover shock losses normally associated with the strong high-Mach number bow shock on the entry vehicle. Flow control through SRP allows for partial recovery of stagnation pressure and thus significant deceleration without the burden of substantial fuel mass, increasing both the mass of deliverable payloads and the payload mass fraction. To quantify maximum achievable benefits, an analytical study determines the upper limit on drag coefficients for probable jet-induced cascading shock structures (oblique shocks followed by a normal shock). Subsequent trajectory studies reveal a tremendous potential for aerodynamic drag generation which is substantial even if only a modicum of the stagnation pressure losses can be recovered through SRP shock manipulation. Finally, attainable drag coefficient values and candidate configurations are presented based on well-validated CFD simulations of modeled jets and the resulting shock structures, establishing this novel SRP-based flow control concept as a technology capable of increasing the deliverable payload mass for future Mars missions.
- Publication date
- Submitted to the Department of Aeronautics and Astronautics.
- Ph.D. Stanford University 2012
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