Organizational Unit:

Space Systems Design Laboratory (SSDL)

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

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Organizational Unit

Daniel Guggenheim School of Aerospace Engineering

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

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Publication Search Results

Now showing 1 - 10 of 34

Validation of APAS Aerodynamic Predictions with a Navier-Stokes CFD Analysis of a Hankey-Wedge Forebody

(Georgia Institute of Technology, 1999-12-09) Sorensen, Kirk

While in the conceptual design phase of launch vehicles, aerodynamic data is often obtained through the use of a simple analytic program called APAS (Aerodynamic Preliminary Analysis System). While suffering from an archaic and temperamental interface, APAS yields results swiftly for simple geometries at a variety of angles of attack and Mach numbers. The results from APAS are compared to those obtained through the analysis of the same vehicle shape using a sophisticated CFD program called GASP (General Aerodynamic Simulation Program). The comparison is made on the forebody for the Stargazer Bantam launch vehicle, which is based on a Hankey-wedge design. Significant differences are noted and techniques to improve the accuracy of APAS output data are suggested
Hyperion: An SSTO Vision Vehicle Concept Utilizing Rocket-Based Combined Cycle Propulsion

(Georgia Institute of Technology, 1999-11) Olds, John R. ; Bradford, John Edward ; Charania, Ashraf ; Ledsinger, Laura Anne ; McCormick, David Jeremy ; Sorensen, Kirk

This paper reports the findings of a conceptual launch vehicle design study performed by members of the Space Systems Design Laboratory at Georgia Tech. Hyperion is a conceptual design for an advanced reusable launch vehicle in the Vision Vehicle class. It is a horizontal takeoff, horizontal landing SSTO vehicle utilizing LOX/LH2 ejector scramjet rocket-based combined cycle (RBCC) propulsion. Hyperion is designed to deliver 20,000 lb. to LEO from the Kennedy Space Center. Gross weight is estimated to be 800,700 lb. and dry weight is estimated to be 123,250 lb. for this mission. Preliminary analysis suggests that, with sufficient launch traffic, Hyperion recurring launch costs will be under 200 dollars per lb. of payload delivered to LEO. However, nonrecurring costs, including development cost and acquisition of three airframes, is expected to be nearly 10.7B dollars. The internal rate of return is only expected to be 8.24 percent. Details of the concept design including external and internal configuration, mass properties, engine performance, trajectory analysis, aeroheating results, and concept cost assessment are given. Highlights of the distributed, collaborative design approach and a summary of trade study results are also provided.
Stargazer: A TSTO Bantam-X Vehicle Concept Utilizing Rocket-Based Combined Cycle Propulsion

(Georgia Institute of Technology, 1999-11) Olds, John R. ; Ledsinger, Laura Anne ; Bradford, John Edward ; Charania, Ashraf ; McCormick, David Jeremy ; Komar, D. R.

This paper presents a new conceptual launch vehicle design in the Bantam-X payload class. The new design is called Stargazer. Stargazer is a two-stage-to-orbit (TSTO) vehicle with a reusable flyback booster and an expendable LOX/RP upper stage. Its payload is 300 lbs. to low earth orbit. The Hankey wedge- shaped booster is powered by four LOX/LH2 ejector scramjet rocket-based combined-cycle engines. Advanced technologies are also used in the booster structures, thermal protection system, and other subsystems. Details of the concept design are given including external and internal configuration, mass properties, engine performance, trajectory analysis, aeroheating results, and a concept cost assessment. The final design was determined to have a gross mass of 115,450 lb. with a booster length of 99 ft. Recurring price per flight was estimated to be $3.49M. The overall conceptual design process and the individual tools and processes used for each discipline are outlined. A summary of trade study results is also given.
Integrating Aeroheating and TPS into Conceptual RLV Design

(Georgia Institute of Technology, 1999-11) Cowart, Karl K. ; Olds, John R.

The purpose of this study is to develop the Thermal Calculation Analysis Tool (TCAT) that will enable Aeroheating and Thermal Protection System (TPS) sizing to be, an on-line, automated process. This process is described as dynamic on-line TPS sizing. It enables the assumptions made about the vehicle TPS to be updated through out the iteration-process. This method is faster and more accurate than a static offline process where the assumptions of the vehicle TPS are held constant during the vehicle design procedure. TCAT will work in conjunction with other engineering disciplines in a Design Structure Matrix (DSM). The unsteady, one dimensional heat diffusion equation was discretized, and resulted in a tridiagonal system of non-linear algebraic equations. This system was implicitly solved using the iterative Newton-Raphson technique at each time level. This technique was conducted for both steady-state and transient conditions that predicted the temperature profiles, and in-depth conduction histories for several TPS material test cases. Also, this was performed on several disparate TPS materials layered together at one time. Finally; comparative benchmark solutions of the TCAT transient analyses were conducted using the commercial software code SINDA/G. Results show that TCAT performed as predicted, and will satisfy the requirement of lowering the amount of time required to conduct TPS sizing for a reusable launch vehicle. Future work will consist of adding temperature dependent material properties to TCAT, coupling TCAT to an optimizer, and creating a web-interface that will enable cross-platform operation of TCAT.
The Bimese Concept: A Study of Mission and Economic Options

(Georgia Institute of Technology, 1999-08-01) Tooley, Jeffrey

The ideal NASA space transportation system of the future consists of a fleet of low cost vehicles that can provide a wide variety of payload options while leveraging future commercial launch markets. The Bimese concept, a NASA Langley design for a reusable Earth-to-orbit space transportation system, tries to fill this future by attempting to, "provide the broadest range of payload and mission capabilities with the minimum number of architectural developments (Talay)." Creating a vehicle that meets this requirement can minimize development costs because the same vehicle design (and hence the same development cost) can be used to support various missions. Such a transportation system can also result in a more efficient operational and manufacturing scenario by creating a learning curve effect on these processes. A vehicle that can perform various missions also has the advantage of early initial operating capability because it can be phased in over time with early missions consisting of the simplest configurations. These characteristics of the Bimese space transportation system make it a candidate for a future NASA supported launch vehicle. The intent of this paper is to analyze the performance and economics of the Bimese space transportation system in terms of trying to fulfill NASA’s ideal future
An Evaluation of Two Alternate Propulsion Concepts for Bantam-Argus: Deeply-Cooled Turbojet+Rocket and Pulsed Detonation Rocket+Ramjet

(Georgia Institute of Technology, 1999-06) St. Germain, Brad David ; Olds, John R.

The Bantam-Argus reusable launch vehicle concept is a smaller version of the original Argus single-stage-to-orbit launch vehicle design. Like the original Argus, Bantam-Argus uses a Maglifter launch assist system to provide an initial horizontal launch velocity. Bantam-Argus is designed to deliver 300 lb. payloads to low earth orbit and, like the full sized Argus, the baseline Bantam-Argus concept utilizes two liquid oxygen/liquid hydrogen supercharged ejector ramjets as prime motive power. This paper presents the results of an investigation of two alternate propulsion systems for the Bantam-Argus launch vehicle. First, a thermally integrated combined- cycle system consisting of two deeply-cooled turbojets and two liquid rocket engines was evaluated. Second, a combination propulsion system utilizing two pulsed detonation rocket engines and two standalone ramjets was evaluated. The results show that both alternate propulsion systems have the potential to reduce both the dry weight and gross weight of the baseline Bantam-Argus concept (when resizing the vehicle while holding mission payload constant). The pulsed detonation rocket engine option is particularly attractive. However, these results must be treated with caution given the relative immaturity of the supporting propulsion data available for both alternatives. Trade studies on key performance parameters were performed to bound the potential gains to be expected from either alternative.
SCORES: Web-Based Rocket Propulsion Analysis Tool for Space Transportation System Design

(Georgia Institute of Technology, 1999-06) Way, David Wesley ; Olds, John R.
SCCREAM v.5: A Web-Based Airbreathing Propulsion Analysis Tool

(Georgia Institute of Technology, 1999-06) Bradford, John Edward ; Olds, John R.

To properly assess the advantages and disadvantages of various RBCC design options at the conceptual vehicle level, an engine performance analysis tool is required. This tool must be capable of modeling engine performance effects that will subsequently be propagated throughout the conceptual design process via trajectory analysis, weight assessment, fuel balance calculations, thermal environment, life cycle cost, etc. For a given engine configuration, the tool will need to generate engine thrust and Isp as a function of altitude and Mach number for each operating mode of an RBCC engine. A project to create a new computer program for the analysis of RBCC engines has already been initiated. Called SCCREAM, for Simulated Combined-Cycle Rocket Engine Analysis Module, it is intended for use in the conceptual phase of airbreathing launch vehicle design. This paper will detail the capabilities of the latest version of SCCREAM and present the results of validation efforts. Combustor thermodynamic properties and overall engine performance for a sample engine will be compared with industry standard codes. Results from the new scram-rocket mode will be discussed. Ejector mode performance plots generated over the web will also be presented.
Demonstration of CLIPS as an Intelligent Front-End for POST

(Georgia Institute of Technology, 1999-01) Budianto, Irene Arianti ; Olds, John R. ; Baker, Nelson C.

Most of the analysis codes used in the design of aerospace systems are complex, requiring some expertise to set up and execute. Usually the Program to Optimize Simulated Trajectories (POST) fails to converge when its control variables are given a bad set of initial guesses, causing the trajectory to remain in the infeasible design region throughout the computations. The user then analyzes the output produced and relies on a set of heuristics, typically gained from experience with the program, to determine the appropriate modification to the problem setup that will guide POST in finding a feasible region and eventually converge to a solution. The potential benefits of employing knowledge-based system within a design environment have long been well known. Various methods of utilization have been identified. As a postprocessing guide, an expert system can distill information obtained from an analysis code, such as POST, into knowledge. The system then can emulate the human analyst's decision-making capability based on this collected knowledge. This paper describes the implementation of POST expertise in a knowledge-based system called CLIPS and demonstrates the feasibility of utilizing this integrated system as a design tool.
Economic Uncertainty of Weight and Market Parameters for Advanced Space Launch Vehicles

(Georgia Institute of Technology, 1998-10) Whitfield, Jeff A. ; Olds, John R.

This paper reports the results of a study that evaluated the economic risk inherent in market variability and the uncertainty of developing weight estimates for an advanced space launch vehicle program. The purpose of this study was to determine the sensitivity of a business case for advanced space flight design with respect to the changing nature of market conditions and the complexity of determining accurate weight estimations during the conceptual design phase. The expected uncertainty associated with these two factors drives the economic risk of the overall program. The study incorporates Monte Carlo simulation techniques to determine the probability of attaining specific levels of economic performance when the market and weight parameters are allowed to vary. This structured approach toward uncertainties allows the assessment of risks associated with a launch vehicle program's economic performance. This results in the determination of the value of the additional risk placed on the project by these two factors.