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Space Systems Design Laboratory (SSDL)

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https://hdl.handle.net/1853/70747

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Daniel Guggenheim School of Aerospace Engineering

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https://finding-aids.library.gatech.edu/agents/corporate_entities/1138

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Now showing 1 - 10 of 12

Conceptual Modeling of Supersonic Retropropulsion Flow Interactions and the Relationship to System Performance

(Georgia Institute of Technology, 2012-06) Korzun, Ashley M. ; Braun, Robert D.

Supersonic retropropulsion is an entry, descent, and landing technology applicable to and potentially enabling the high-mass missions to the surface required for advanced robotic and human exploration at Mars. For conceptual design, an initial understanding of the significance of retropropulsion configuration on the vehicle’s static aerodynamic characteristics and the relation of this configuration to other vehicle performance metrics that traditionally determine vehicle configuration is necessary. This work develops an approximate model for the aerodynamic - propulsive flow interaction based on momentum transfer within the flowfield and the geometry of relevant flow structures. This model is used to explore the impact of operating conditions, required propulsion system performance, propulsion system composition, and vehicle configuration on the integrated aerodynamic drag characteristics of full-scale vehicles for Mars entry, descent, and landing. Conclusions are then drawn on the fidelity and effort required to support specific design trades for supersonic retropropulsion.
Supersonic Retropropulsion Flight Test Concepts

(Georgia Institute of Technology, 2011-06) Post, Ethan A. ; Dupzyk, Ian C. ; Korzun, Ashley M. ; Dyakonov, Artem A. ; Tanimoto, Rebekah L. ; Edquist, Karl T.

NASA’s Exploration Technology Development and Demonstration Program has proposed plans for a series of three sub-scale flight tests at Earth for supersonic retropropulsion, a candidate decelerator technology for future, high-mass Mars missions. The first flight test in this series is intended to be a proof-of-concept test, demonstrating successful initiation and operation of supersonic retropropulsion at conditions that replicate the relevant physics of the aerodynamic-propulsive interactions expected in flight. Five sub-scale flight test article concepts, each designed for launch on sounding rockets, have been developed in consideration of this proof-of-concept flight test. Commercial, off-the-shelf components are utilized as much as possible in each concept. The design merits of the concepts are compared along with their predicted performance for a baseline trajectory. The results of a packaging study and performance-based trade studies indicate that a sounding rocket is a viable launch platform for this proof-of-concept test of supersonic retropropulsion.
Application of a Reynolds-Averaged Navier-Stokes Approach to Supersonic Retropropulsion Flowfields

(Georgia Institute of Technology, 2011-06) Korzun, Ashley M. ; Clark, Ian G. ; Braun, Robert D.

Systems analysis efforts have identified supersonic retropropulsion as a candidate decelerator technology for the human exploration of the surface of Mars. These efforts are presently challenged by a lack of available models and are looking to computational fluid dynamics analyses for databases representing the aerodynamic-propulsive interactions inherent to supersonic retropropulsion. This work uses a Reynolds-averaged Navier-Stokes approach to predict the flow field structure, surface pressure distributions, and integrated aerodynamic force coefficients for four configurations recently tested in the NASA Langley Research Center Unitary Plan Wind Tunnel. These configurations have zero, one, three, and four nozzles on the model forebody. Comparisons are made with experimental data for static pressure distributions on the forebody and aft body, and computational schlieren images illustrating the resulting flow fields have also been generated. The results of this work illustrate the applicability of the Reynolds-averaged Navier Stokes equations to this problem through comparison with data from a test series designed explicitly for the validation of computational fluid dynamics tools in simulating supersonic retropropulsion flow fields. The Reynolds-averaged Navier-Stokes approach applied performed well in predicting the surface pressure distribution and flow field structure for supersonic retropropulsion configurations with single and multiple nozzles at zero degrees angle of attack and a thrust coefficient of approximately 2.0. Nomenclature
Comparison of Inviscid Viscous Aerodynamic Predictions of Supersonic Retropropulsion Flowfields

(Georgia Institute of Technology, 2010-06) Korzun, Ashley M. ; Cordell, Christopher E., Jr. ; Braun, Robert D.

Supersonic retropropulsion, or the initiation of a retropropulsion phase at supersonic freestream conditions, is an enabling decelerator technology for high-mass planetary entries at Mars. The current knowledge on supersonic retropropulsion is largely derived from exploratory development efforts prior to the Viking missions in the 1960s and early 1970s, predominantly sub-scale wind tunnel testing. Little literature exists on analytical and computational modeling approaches for supersonic aerodynamic-propulsive interactions at moderate thrust levels and flight-relevant conditions. This investigation presents a discussion of the relevant flow physics to provide insight into the effectiveness of inviscid and viscous computational analysis approaches in consistently and accurately capturing the relevant flow physics. Preliminary computational results for a blunt body with two retropropulsion configurations are compared with experimental data for the location of prominent flow features and surface pressure distributions. This work is intended to provide an initial discussion of the challenges facing the computational simulation of supersonic retropropulsion flowfields.
Development of Supersonic Retro-Propulsion for Future Mars Entry Descent Landing Systems

(Georgia Institute of Technology, 2010-06) Edquist, Karl T. ; Dyakonov, Artem A. ; Korzun, Ashley M. ; Shidner, Jeremy D. ; Studak, Joseph W. ; Tigges, Michael A. ; Kipp, Devin M. ; Prakash, Ravi ; Trumble, Kerry A. ; Dupzyk, Ian C.

Recent studies have concluded that Viking-era entry system technologies are reaching their practical limits and must be succeeded by new methods capable of delivering large payloads (> 10 metric tons) required for human exploration of Mars. One such technology, termed Supersonic Retropropulsion, has been proposed as an enabling deceleration technique. However, in order to be considered for future NASA flight projects, this technology will require significant maturation beyond its current state. This paper proposes a roadmap for advancing the component technologies to a point where Supersonic Retropropulsion can be reliably used on future Mars missions to land much larger payloads than are currently possible using Viking-based systems. The development roadmap includes technology gates that are achieved through testing and/or analysis, culminating with subscale flight tests in Earth atmosphere that demonstrate stable and controlled flight. The component technologies requiring advancement include large engines capable of throttling, computational models for entry vehicle aerodynamic/propulsive force and moment interactions, aerothermodynamic environments modeling, entry vehicle stability and control methods, integrated systems engineering and analyses, and high-fidelity six degree-of freedom trajectory simulations. Quantifiable metrics are also proposed as a means to gage the technical progress of Supersonic Retropropulsion. Finally, an aggressive schedule is proposed for advancing the technology through sub-scale flight tests at Earth by 2016.
High Mass Mars Entry, Descent, and Landing Architecture Assessment

(Georgia Institute of Technology, 2009-09) Steinfeldt, Bradley A. ; Theisinger, John E. ; Korzun, Ashley M. ; Clark, Ian G. ; Grant, Michael J. ; Braun, Robert D.

As the nation sets its sight on returning humans to the Moon and going onward to Mars, landing high mass payloads (>/= 2 t) on the Mars surface becomes a critical technological need. Viking heritage technologies (e.g., 70degrees sphere-cone aeroshell, SLA-561V thermal protection system, and supersonic disk-gap-band parachutes) that have been the mainstay of the United States' robotic Mars exploration program do not provide sufficient capability to land such large payload masses. In this investigation, a parametric study of the Mars entry, descent, and landing design space has been conducted. Entry velocity, entry vehicle configuration, entry vehicle mass, and the approach to supersonic deceleration were varied. Particular focus is given to the entry vehicle shape and the supersonic deceleration technology trades. Slender bodied vehicles with a lift-to-drag ratio (L=D) of 0.68 are examined alongside blunt bodies with L=D = 0.30. Results demonstrated that while the increased L=D of a slender entry configuration allows for more favorable terminal descent staging conditions, the greater structural efficiencies of blunt body systems along with the reduced acreage required for the thermal protection system affords an inherently lighter vehicle. The supersonic deceleration technology trade focuses on inflatable aerodynamic decelerators (IAD) and supersonic retropropulsion, as supersonic parachute systems are shown to be excessively large for further consideration. While entry masses (the total mass at the top of the Mars atmosphere) between 20 and 100 t are considered, a maximum payload capability of 37.3 t results. Of particular note, as entry mass increases, the gain in payload mass diminishes. It is shown that blunt body vehicles provide sufficient vertical L=D to decelerate all entry masses considered through the Mars atmosphere with adequate staging conditions for the propulsive terminal descent. A payload mass fraction penalty of approximately 0.3 exists for the use of slender bodied vehicles. Another observation of this investigation is that the increased aerothermal and aerodynamic loads induced from a direct entry trajectory (velocity ~6.75 km/s) reduce the payload mass fraction by approximately 15% compared to entry from orbital velocity (~4 km/s). It should be noted that while both IADs and supersonic retropropulsion were evaluated for each of the entry masses, configurations, and velocities, the IAD proved to be more mass-efficient in all instances. The sensitivity of these results to modeling assumptions was also examined. The payload mass of slender body vehicles was observed to be approximately four times more sensitive to modeling assumptions and uncertainty than blunt bodies.
Performance Characterization of Supersonic Retropropulsion for Application to High-Mass Mars Entry, Descent, and Landing

(Georgia Institute of Technology, 2009-08) Korzun, Ashley M. ; Braun, Robert D.

Prior high-mass Mars EDL systems studies have neglected aerodynamic-propulsive interactions and performance impacts during the supersonic phase of descent. The goal of this investigation is to accurately evaluate the performance of supersonic retropropulsion with increasing vehicle ballistic coefficient across a range of initiation conditions relevant for future high-mass Mars landed systems. Past experimental work has established supersonic retropropulsion trends in static aerodynamics as a function of retropropulsion configuration, freestream conditions, and thrust. From this experimental database, an aerodynamic-propulsive interactions model is created. EDL system performance results are developed with the potential aerodynamic drag preservation included and excluded during this phase of flight for comparison against prior studies. The results of this investigation demonstrate the significance of aerodynamic drag preservation as a function of retropropulsion initiation conditions, characterize mass optimal trajectories utilizing supersonic retropropulsion, and compare propulsion system requirements with existing propulsion systems and systems under development for future exploration missions.
A Concept for the Entry, Descent, and Landing of High-Mass Payloads at Mars

(Georgia Institute of Technology, 2008-09) Korzun, Ashley M. ; Stahl, Benjamin A. ; Dubos, Gregory F. ; Quicksall, John J. ; Iwata, Curtis K.

The architecture concepts and aggressive science objectives for the next phases of Mars exploration will require landed masses an order of magnitude or greater than any Mars mission previously planned or flown. Additional studies have shown the requirements for missions more ambitious than the 2009 Mars Science Laboratory (~ 900 kg payload mass) to extend beyond the capabilities of Viking-heritage entry, descent, and landing (EDL) technologies, namely blunt-body aeroshells, supersonic disk-gap-band parachutes, and existing TPS materials. This study details a concept for Mars entry, descent, and landing capable of delivering a 20 t payload within 1 km of a target landing site at 0 km MOLA. The concept presented here explores potentially enabling EDL technologies for the continued robotic and eventual human exploration of Mars, moving beyond the Viking-heritage systems relied upon for the past 30 years of Mars exploration. These technologies address the challenges of hypersonic guidance, supersonic deceleration, precision landing, and surface hazard avoidance. Without support for the development of these enabling technologies in the near term, the timeline for the successful advanced exploration of Mars will likely extend indefinitely.
Entry, Descent, and Landing System Design for the Mars Gravity Biosatellite

(Georgia Institute of Technology, 2008-06) Korzun, Ashley M. ; Smith, Brandon P. ; Hartzell, Christine M. ; Yu, Chi-Yau ; Place, Laura A. ; Martinelli, Scott K. ; Braun, Robert D. ; Hott, Kyle B.

Execution of a full entry, descent, and landing (EDL) from low Earth orbit is a rare requirement among university class spacecraft. Successful completion of the Mars Gravity Biosatellite mission requires the recovery of a mammalian payload for post-flight analysis of the effects of partial gravity. The EDL design for the Mars Gravity Biosatellite is driven by requirements on the allowable deceleration profile for a payload of deconditioned mice and maximum allowable recovery time. The 260 kg entry vehicle follows a ballistic trajectory from low Earth orbit to a target recovery site at the Utah Test and Training Range. Reflecting an emphasis on design simplicity and the use of heritage technology, the entry vehicle uses the Discoverer aeroshell geometry and leverages aerodynamic decelerators for mid-air recovery and operations originally developed for the Genesis mission. This paper presents the student-developed EDL design for the Mars Gravity Biosatellite, with emphasis on trajectory design, dispersion analysis, and mechanical design and performance analysis of the thermal protection and parachute systems. Also included is discussion on EDL event sequencing and triggers, the de-orbit of the spacecraft bus, plans for further work, and the educational impact of the Mars Gravity Biosatellite program.
Supersonic Retropropulsion Technology for Application to High Mass Mars Entry, Descent, and Landing

(Georgia Institute of Technology, 2008-04-30) Korzun, Ashley M.

As vehicle masses continue to increase for missions involving atmospheric entry, supersonic deceleration is challenging the qualifications and capabilities of Viking-heritage entry, descent, and landing (EDL) technology. At Mars, high entry masses and insufficient atmospheric density often result in unacceptable parachute deployment and operating conditions, requiring the exploration of alternative approaches to supersonic deceleration. Supersonic retropropulsion, the initiation of a retropropulsion phase while the vehicle is still traveling supersonically, may be an enabling technology for systems with high ballistic coefficients operating in thin atmospheres such as at Mars. The relevance of this technology to the feasibility of Mars EDL has been shown to increase with ballistic coefficient to the point that it is likely required for human Mars exploration. In conjunction with a literature review of supersonic retropropulsion technology as it applies to blunt body entry vehicles, a systems study was performed to assess the impact of supersonic retropropulsion on high mass Mars EDL. This investigation addresses the applicability, limitations, and performance implications of supersonic retropropulsion technology in the context of future human and robotic Mars exploration missions.