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Space Systems Design Laboratory (SSDL)

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Now showing 1 - 10 of 13
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    Aeroelastic Design Considerations of a Clamped Ballute for Titan Aerocapture
    (Georgia Institute of Technology, 2007-04) Rohrschneider, Reuben R. ; Braun, Robert D.
    The Ballute Aeroelastic Analysis Tool, an in-house tool that loosely couples aerodynamics with structural dynamics, is used to compute static deformed shapes and stresses of a clamped ballute along a Titan Aerocapture trajectory, and to determine if a clamped ballute flutters at the peak dynamic pressure point. Static solutions along a Titan aerocapture trajectory indicate that stress and displacement are correlated to dynamic pressure above 1 Pa. For lower dynamic pressures, the aerodynamic loading is insufficient to fully overcome initial material shape, indicating that spacecraft re-contact is possible, and leading to a recommendation to include supports for the torus. Dynamic analysis of the clamped ballute using a first-order engineering estimate of unsteady aerodynamics indicates that flutter will not be a problem at the peak dynamic pressure point on the trajectory.
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    Ultra Lightweight Ballutes for Return to Earth from the Moon
    (Georgia Institute of Technology, 2006-05) Masciarelli, James P. ; Lin, John K. H. ; Ware, Joanne S. ; Rohrschneider, Reuben R. ; Braun, Robert D. ; Bartels, Robert E. ; Moses, Robert W. ; Hall, Jeffery L.
    Ultra lightweight ballutes offer revolutionary mass and cost benefits along with flexibility in flight system design compared to traditional entry system technologies. Under funding provided by NASA's Exploration Systems Research & Technology program, our team was able to make progress in developing this technology through systems analysis and design, evaluation of materials and construction methods, and development of critical analysis tools. Results show that once this technology is mature, significant launch mass savings, operational simplicity, and mission robustness will be available to help carry out NASA's Vision for Space Exploration.
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    Static Aeroelastic Analysis of a Thin-Film Clamped Ballute for Titan Aerocapture
    (Georgia Institute of Technology, 2006-05) Rohrschneider, Reuben R. ; Braun, Robert D.
    Many authors have shown the potential mass savings that a ballute can offer for both aerocapture and entry. This mass savings could enhance or even enable many scientific and human exploration missions. Prior to flight of a ballute several technical issues need to be addressed, including aeroelastic behavior. This paper begins to address the issue of aeroelastic behavior by developing and validating the Ballute Aeroelastic Analysis Tool (BAAT). The validation effort uses wind tunnel tests of clamped ballute models constructed of Kapton supported by a rigid nose and floating aft ring. Good correlation is obtained using modified Newtonian aerodynamics and non-linear structural analysis with temperature dependent material properties and thermal expansion. BAAT is then used to compute the deformed shape of a clamped ballute for Titan aerocapture in both the continuum and transitional regimes using impact method aerodynamics and direct simulation Monte Carlo.
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    Ultra Lightweight Ballutes for Return to Earth from the Moon
    (Georgia Institute of Technology, 2006-05) Masciarelli, James P. ; Lin, John K. H. ; Ware, Joanne S. ; Rohrschneider, Reuben R. ; Braun, Robert D. ; Bartels, Robert E. ; Moses, Robert W. ; Hall, Jeffery L.
    Ultra lightweight ballutes offer revolutionary mass and cost benefits along with flexibility in flight system design compared to traditional entry system technologies. Under funding provided by NASA's Exploration Systems Research & Technology program, our team was able to make progress in developing this technology through systems analysis and design, evaluation of materials and construction methods, and development of critical analysis tools. Results show that once this technology is mature, significant launch mass savings, operational simplicity, and mission robustness will be available to help carry out NASA's Vision for Space Exploration.
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    Entry System Options for Human Return from the Moon and Mars
    (Georgia Institute of Technology, 2005-08) Putnam, Zachary R. ; Braun, Robert D. ; Rohrschneider, Reuben R. ; Dec, John A.
    Earth entry system options for human return missions from the Moon and Mars were analyzed and compared to identify trends among the configurations and trajectory options and to facilitate informed decision making at the exploration architecture level. Entry system options included ballistic, lifting capsule, biconic, and lifting body configurations with direct entry and aerocapture trajectories. For each configuration and trajectory option, the thermal environment, deceleration environment, crossrange and downrange performance, and entry corridor were assessed. In addition, the feasibility of a common vehicle for lunar and Mars return was investigated. The results show that a low lift-to-drag ratio (L/D = 0.3) vehicle provides sufficient performance for both lunar and Mars return missions while providing the following benefits: excellent packaging efficiency, low structural and TPS mass fraction, ease of launch vehicle integration, and system elegance and simplicity. Numerous configuration options exist that achieve this L/D.
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    Tempest: Crew Exploration Vehicle Concept
    (Georgia Institute of Technology, 2005-07) Hutchinson, Virgil L., Jr. ; Olds, John R. ; Alemany, Kristina ; Christian, John A., III ; Clark, Ian G. ; Crowley, John ; Krevor, Zachary C. ; Rohrschneider, Reuben R. ; Thompson, Robert W. ; Young, David Anthony ; Young, James J.
    Tempest is a reusable crew exploration vehicle (CEV) for transferring crew from the Earth to the lunar surface and back. Tempest serves as a crew transfer module that supports a 4-person crew for a mission duration of 18 days, which consists of 8 days total transit duration and 10-day surface duration. Primary electrical power generation and on-orbit maneuvering for Tempest is provided by an attached Power and Propulsion Module (PPM). Hydrogen (H2)/oxygen (O2) fuel cells and a high energy-density matter (HEDM)/liquid oxygen (LOX) propellant reaction control system (RCS) provide power and reaction control respectively during Tempest’s separation from the PPM. Tempest is designed for a lifting entry and is equipped with parachutes for a soft landing. Tempest is part of an overall lunar transportation architecture. The 60,731 lbs combination of Tempest and the PPM are launched atop the notional Centurion C-1 heavylift launch vehicle (HLLV) and delivered to a 162 nmi, 28.5º circular orbit. After separating from the C-1 upper stage, the Tempest/PPM autonomously rendezvous with Manticore, an expendable trans-lunar injection (TLI) stage pre-positioned in the current orbit, and transfer to a lunar trajectory. After entering a 54 nmi polar circular lunar orbit, the Tempest/PPM separate from Manticore. Tempest separates from the PPM and is ferried to/from the lunar surface by Artemis, a reusable lunar lander. Upon return from the lunar surface, Tempest reconnects with the PPM, and the PPM provides the trans-earth injection (TEI) burn required to return to low earth orbit (LEO). Prior to atmospheric entry, Tempest separates from the PPM and subsequently executes a lifting entry trajectory. Crushable thermal foam attached to the lower surface of Tempest serves as an ablative thermal protection system (TPS) and the impact absorber of the parachute landing. Details of the conceptual design process used for Tempest are included in this paper. The disciplines used in the design include: configuration, aerodynamics, propulsion, trajectory, mass properties, environmental control life support system (ECLSS), entry aeroheating and TPS, terminal landing system (TLS), cost, operations, and reliability & safety. Each of these disciplines was computed using a conceptual design tool similar to that used in industry. These disciplines were then combined and optimized for the minimum gross weight of the Tempest CEV. The total development cost including the design, development, testing and evaluation (DDT&E) cost was determined to be $2.9 B FY’04. The theoretical first unit (TFU) cost for the Tempest CEV was $479 M FY’04. A summary of design disciplines as well as the economic results are included.
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    A Survey of Ballute Technology for Aerocapture
    (Georgia Institute of Technology, 2005-06) Rohrschneider, Reuben R. ; Braun, Robert D.
    Ballute aerodynamic decelerators have been studied since early in the space age (1960’s), being proposed for aerocapture in the early 1980’s. Significant technology advances in fabric and polymer materials as well as analysis capabilities lend credibility to the potential of ballute aerocapture. The concept of the thin-film ballute for aerocapture shows the potential for large mass savings over propulsive orbit insertion or rigid aeroshell aerocapture. The mass savings of this concept enables a number of high value science missions. Current studies of ballute aerocapture at Titan and Earth may lead to flight test of one or more ballute concepts within the next five years. This paper provides a survey of the literature with application to ballute aerocapture. Special attention is paid to advances in trajectory analysis, hypersonic aerothermodynamics, structural analysis, coupled analysis, and flight tests. Advances anticipated over the next 5 years are summarized.
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    Flight System Options for a Long Duration Mars Airplane
    (Georgia Institute of Technology, 2004-09) Rohrschneider, Reuben R. ; Olds, John R. ; Kuhl, Christopher A. ; Braun, Robert D. ; Steffes, Stephen R. ; Hutchinson, Virgil L., Jr.
    The goal of this study was to explore the flight system options for the design of a long endurance Mars airplane mission. The mission model was built in the design framework ModelCenter and a combination of a hybrid and user-driven fixed point iteration optimization method was used to determine the maximum endurance solution of each configuration. Five different propulsion systems were examined: a bipropellant rocket, a battery powered propeller, a direct methanol fuel cell powered propeller, and beamed solar and microwave powered propeller systems. Five airplane configurations were also studied. The best configuration has a straight wing with two vertical tails. The direct methanol fuel cell proved to be the best onboard power system for a long endurance airplane and the solar beamed power system showed potential for indefinite flight. The combination of the best configuration and the methanol fuel cell resulted in an airplane capable of cruising for 17.8 hours on Mars.
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    Modeling Approach for Analysis and Optimization of a Long-Duration Mars Airplane
    (Georgia Institute of Technology, 2004-05) Rohrschneider, Reuben R. ; Olds, John R. ; Braun, Robert D. ; Hutchinson, Virgil L., Jr. ; Kuhl, Christopher A. ; Steffes, Stephen R.
    The goal of this study was to determine the best system level modeling tool for the design of a long endurance Mars airplane mission, and to use this tool to determine the best configuration for the aircraft. The mission model was built in the design framework ModelCenter. User-driven fixed point iteration (FPI), optimizer based decomposition (OBD) and a hybrid method were implemented. Convergence difficulties were discovered in the OBD and hybrid methods. The user-driven FPI method produced the most reliable results, but required the most time. A combination of the hybrid and user-driven FPI methods were used to perform a technology study in which five different propulsion systems were examined: a bipropellant rocket, a battery powered propeller, a direct methanol fuel cell powered propeller, and beamed solar and microwave powered propeller systems. The direct methanol fuel cell proved to be the best onboard power system for a long endurance airplane and the solar beamed power system showed potential for indefinite flight.
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    Tanker Argus: Re-supply for a LEO Cryogenic Propellant Depot
    (Georgia Institute of Technology, 2002-10) St. Germain, Brad David ; Kokan, Timothy Salim ; Marcus, Leland R. ; Miller, Jeff ; Rohrschneider, Reuben R. ; Staton, Eric ; Olds, John R.
    The Argus reusable launch vehicle (RLV) concept is a single-stage-to-orbit (SSTO) conical, wingedbodied vehicle powered by two liquid hydrogen (LH2)/liquid oxygen (LOX) supercharged ejector ramjets (SERJ). The 3rd generation Argus launch vehicle utilizes advanced vehicle technologies along with a magnetic levitation (Maglev) launch assist track. A tanker version of the Argus RLV is envisioned to provide an economical means of providing liquid fuel and oxidizer to an orbiting low Earth orbit (LEO) propellant depot. This depot could then provide propellant to various spacecraft, including reusable orbital transfer vehicles used to ferry space solar power (SSP) satellites to geo-stationary orbit. Two different tanker Argus configurations were analyzed. The first simply places additional propellant tanks inside the payload bay of an existing Argus reusable launch vehicle. The second concept is a modified pure tanker version of the Argus RLV in which the payload bay is removed and the vehicle propellant tanks are extended to hold additional propellant. An economic analysis was performed for this study that involved the calculation of the design/development and recurring costs of each vehicle. The goal of this analysis was to determine at what flight rate it would be economically beneficial to spend additional development funds to change an existing, sunk cost, payload bay tanker vehicle into a pure tanker design. The results show that for yearly flight rates greater than ~50 flts/yr it is cheaper, on a $/lb basis , to develop and operate a dedicated tanker.