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 21

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.
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.
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.
Transforming Aerodynamic Datasets into Parametric Equations for use in Multi-disciplinary Design Optimization

(Georgia Institute of Technology, 1998-10) Scott, Jeffery M. ; Olds, John R.

This paper presents a method of transforming aerodynamic datasets generated in Aerodynamic Preliminary Analysis System (APAS) into parametric equations which may subsequently be used in a multidisciplinary design optimization (MDO) environment for analyzing aerospace vehicles. APAS is an analysis code which allows the user to create a simple geometric model of a vehicle and then calculate the aerodynamic force coefficients of lift, drag, and pitching moment over a wide range of flight conditions. As such, APAS is a very useful tool for conceptual level vehicle designs since it allows the force coefficients for a given design to be calculated relatively quickly and easily. However, APAS suffers from an outdated user interface and, because it is tedious to generate a new dataset during each design iteration, it is quite difficult to integrate into an MDO framework. Hence the desire for a method of transforming the APAS output into a more usable form. The approach taken and described in this paper involves the use of regression analysis techniques and response surface methodology to accomplish the data transformation with two goals in mind. The first goal was to develop a parametric model for calculating the aerodynamic coefficients for a single unique geometry. The second goal was to extend this model to capture the effects of changes in vehicle geometry. This paper presents the results and gives the model developed for analyzing a sample vehicle for both cases.
System Robustness Comparison of Advanced Space Launch Concepts

(Georgia Institute of Technology, 1998-10) McCormick, David Jeremy ; Olds, John R.

This research proposes two methods to investigate the robustness differences between competing types of advanced space launch systems. These methods encompass two different phases of the advanced design process and are used to compare the relative advantages of two concepts in these phases. The first is a Monte Carlo simulation during the conceptual phase of design, where mold lines can be changed to account for uncertainty in weight assumptions. This tests the vehicle weight growth for a fixed mission. Here, the all-rocket single stage to orbit (SSTO) shows a more narrow distribution of dry weight, suggesting higher concept robustness. A study of vehicle mass ratio and mixture ratio combinations for both vehicles show the relative location of the results. The second phase represents the transition to detailed design. An optimization based on length determines the appropriate size for detailed design. This optimization takes into account uncertainties placed on both weight relationships and performance requirements. Both of these analyses utilize Crystal Ball Pro in conjunction with Microsoft Excel. This gives the technique compatibility with commonly used computer platforms. While the all-rocket SSTO does show an advantage in the area of system weight growth, several other factors are important in determining the viability of a reusable launch system, not the least of which is mission flexibility. Here the runway-operated RBCC SSTO has a distinct advantage.
Cross-Platform Computational Techniques for Analysis Code Integration and Optimization

(Georgia Institute of Technology, 1998-09) Olds, John R. ; Steadman, Kimberly B.

Following NASA's lead in Intelligent Synthesis Environments, advanced vehicle design communities are beginning to explore automated distributed computing frameworks for integrating disciplinary analysis tools. These design frameworks allow collaborative design teams to take advantage of distributed expertise and existing legacy codes, while retaining some of the automation and optimization capabilities of monolithic synthesis tools and simple subroutines. A key capability in making these frameworks a reality will be the ability to integrate and access contributing analysis codes running on different computing platforms and in various remote locations. This paper reports a cross-platform technique for integrating Microsoft Excel spreadsheets into UNIX-based computing frameworks. Specifically, a combination of UNIX shell scripts, telnet connections via the Internet, and Applescript is used to remotely execute an Excel spreadsheet hosted on a Macintosh computer and return the results to an executive program running on a UNIX workstation. Sample scripts and integration procedures are outlined. Examples are given in which the technique is used to remotely drive a launch vehicle costing spreadsheet under the control of grid search and genetic algorithm optimization techniques hosted on a UNIX workstation. Advantages and disadvantages of the present technique are discussed.
Multidisciplinary Design Optimization Techniques for Branching Trajectories

(Georgia Institute of Technology, 1998-09) Ledsinger, Laura Anne ; Olds, John R.

Fully reusable two-stage-to-orbit vehicle designs that incorporate ‘branching’ trajectories during their ascent are of current interest in the advanced launch vehicle design community. Unlike expendable vehicle designs, the booster of a reusable system must fly to a designated landing site after staging. Therefore, both the booster return branch and the orbital upper stage branch along with the lower ascent trajectory are of interest after the staging point and must be simultaneously optimized in order to achieve an overall system objective. Current and notable designs in this class include the U. S. Air Force Space Operations Vehicle designs with their ‘pop-up’ trajectories, the Kelly Astroliner, the Kistler K-1, one of the preliminary designs for NASA’s Bantam-X study, and NASA’s proposed liquid flyback booster designs (Space Shuttle solid booster upgrade). The solution to this problem using an industrystandard trajectory optimization code (POST) typically requires at least two separate computer jobs — one for the orbital branch from the ground to orbit and one for the booster branch from the staging point to the landing site. In some cases, three computer jobs may be desired: one from launch to staging, one for the upper stage, and one for the booster flyback. However, these jobs are tightly coupled and their data requirements are interdependent. This paper expounds upon the research necessary to improve the accuracy, computational efficiency, and data consistency with which the branching trajectory problem can be solved. In particular, the proposed methods originate from the field of Multidisciplinary Design Optimization (MDO).