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At least 73 records · Page 4

Advanced manned launch system study status

Various concepts for advanced manned launch systems (AMLS) are examined for delivery missions to Space Station and polar orbit. Included are single- and two-stage winged systems with rocket and/or airbreathing propulsion systems. For near-term technologies, two-stage, reusable rocket systems are favored over single-stage rocket or airbreathing/rocket systems. Advanced technologies enable viable single-stage-to-orbit (SSTO) concepts. Although two-stage rocket systems continue to be lighter in dry weight than SSTOs, advantages in simpler operations may make SSTOs more cost-effective over the life cycle. Generally, rocket systems maintain a dry weight advantage over airbreathing systems at advanced technology levels, but to a lesser degree than when near-term technologies are used. More detailed understanding of vehicle systems and associated ground and flight operations requirements and procedures is essential in determining quantitative discrimination between these latter concepts.

Freeman, Delma C., Jr.↗

Dual-Fuel Propulsion in Single-Stage Advanced Manned Launch System Vehicle

As part of the United States Advanced Manned Launch System study to determine a follow-on, or complement, to the Space Shuttle, a reusable single-stage-to-orbit concept utilizing dual-fuel rocket propulsion has been examined. Several dual-fuel propulsion concepts were investigated. These include: a separate-engine concept combining Russian RD-170 kerosene-fueled engines with space shuttle main engine-derivative engines: the kerosene- and hydrogen-fueled Russian RD-701 engine; and a dual-fuel, dual-expander engine. Analysis to determine vehicle weight and size characteristics was performed using conceptual-level design techniques. A response-surface methodology for multidisciplinary design was utilized to optimize the dual-fuel vehicles with respect to several important propulsion-system and vehicle design parameters, in order to achieve minimum empty weight. The tools and methods employed in the analysis process are also summarized. In comparison with a reference hydrogen- fueled single-stage vehicle, results showed that the dual-fuel vehicles were from 10 to 30% lower in empty weight for the same payload capability, with the dual-expander engine types showing the greatest potential.

Lepsch, Roger A., Jr.↗

Electromechanical actuation for thrust vector control applications

At present, actuation systems for the Thrust Vector Control (TVC) for launch vehicles are hydraulic systems. The Advanced Launch System (ALS), a joint initiative between NASA and the Air Force, is a launch vehicle that is designed to be cost effective, highly reliable and operationally efficient with a goal of reducing the cost per pound to orbit. As part of this initiative, an electromechanical actuation system is being developed as an attractive alternative to the hydraulic systems used today. NASA-Lewis is developing and demonstrating an Induction Motor Controller Actuation System with a 40 hp peak rating. The controller will integrate 20 kHz resonant link Power Management and Distribution (PMAD) technology and Pulse Population Modulation (PPM) techniques to implement Field Oriented Vector Control (FOVC) of a new advanced induction motor. Through PPM, multiphase variable frequency, variable voltage waveforms can be synthesized from the 20 kHz source. FOVC shows that varying both the voltage and frequency and their ratio (V/F), permits independent control of both torque and speed while operating at maximum efficiency at any point on the torque-speed curve. The driver and the FOVC will be microprocessor controlled. For increased system reliability, a Built-in Test (BITE) capability will be included. This involves introducing testability into the design of a system such that testing is calibrated and exercised during the design, manufacturing, maintenance and prelaunch activities. An actuator will be integrated with the motor controller for performance testing of the EMA TVC system. The design and fabrication of the motor controller is being done by General Dynamics Space Systems Division. The University of Wisconsin-Madison will assist in the design of the advanced induction motor and in the implementation of the FOVC theory. A 75 hp electronically controlled dynamometer will be used to test the motor controller in all four quadrants of operation using flight type control algorithms. Integrated testing of the controller and actuator will be conducted at a facility yet to be named. The EMA system described above is discussed in detail.

Roth, Mary Ellen↗

Operational efficiency: Automatic ascent flight design

The expected increase in launch vehicle operations to support Space Station Freedom and a Lunar/Mars exploration initiative will require a more efficient approach to ascent flight design and operations. A concept is presented of continuous improvement in ascent flight design through an evolutionary process beginning with today's vehicles and continuing into the next century with the Advanced Launch System (ALS) and Advanced Manned Launch System (AMLS). A pictorial view is given of the improvement path described. The detailed objectives necessary to obtain efficiency improvements are described. The technology milestones along this evolutionary path are outlined and the accomplishments to date are summarized. The technology issues are discussed which must be addressed.

Source record↗

An advanced manned launch system concept

A two-stage fully reusable rocked powered concept is defined and analyzed in detail for the Advanced Manned Launch System missions. The concept elements include a Mach 3 staging unmanned glideback booster and a 149-ft long winged orbiter with an external payload canister with a 15-ft diameter and 30-ft long payload bay. The booster and orbiter main propulsion system is a lightweight derivative of the current Space Shuttle Main Engine. The primary mission is the Space Station Freedom logistics mission, 40,000-lb payload with two crew members and eight passengers. The structural design and material selection, the thermal protection system, the integral cryogenic tanks and insulation, the propulsion system, and the modular payload canister system are described. The ground and flight operations approach analysis, the manufacturing and certification plan, and the technology development requirements are also discussed.

Stone, H. W.↗

Advanced Recovery Systems for Advanced Launch Vehicles (ARS) phase 1 study results

The paper documents the work completed during the Advanced Recovery Systems for Advanced Launch Vehicles phase 1 study. Particular attention is given to the definition of the design of a single recovery system for the most likely near-term payload, a propulsion/avionic module (P/AM). A P/AM recovery system for phase 2 demonstration was designed which offers low cost, extremely low weight, good performance, potential for pinpoint loading, and operational flexibility.

Wailes, William K.↗

Systems integration and demonstration of advanced reusable structure for ALS

The objective was to investigate the potential of advanced material to achieve life cycle cost (LCC) benefits for reusable structure on the advanced launch system. Three structural elements were investigated - all components of an Advanced Launch System reusable propulsion/avionics module. Leading aeroshell configurations included sandwich structure using titanium, graphite/polyimide (Gr/PI), or high-temperature aluminum (HTA) face sheets. Thrust structure truss concepts used titanium, graphite/epoxy, or silicon carbide/aluminum struts. Leading aft bulkhead concepts employed graphite epoxy and aluminum. The technical effort focused on the aeroshell because the greatest benefits were expected there. Thermal analyses show the structural temperature profiles during operation. Finite element analyses show stresses during splash-down. Weight statements and manufacturing cost estimates were prepared for calculation of LCC for each design. The Gr/PI aeroshell showed the lowest potential LCC, but the HTA aeroshell was judged to be lower risk. A technology development plan was prepared to validate the applicable structural technology.

Gibbins, Martin N.↗

Aerodynamic predictions and experimental results for an Advanced Manned Launch System orbiter configuration

The results from a series of wind-tunnel tests are presented along with predictions of the aerodynamic characteristics for a proposed Advanced Manned Launch System orbiter configuration. The predicted characteristics were made using the Aerodynamic Preliminary Analysis System (APAS), and were shown to be of sufficient accuracy for use in preliminary configuration analysis. Various methods of analysis were used in the APAS system, and the results of each were compared with the wind-tunnel dam. The accuracy of the predicted data varied over the Mach range studied. The best agreement between the wind-tunnel data and the APAS predictions occurr4ed in the low subsonic and the high supersonic regimes, while the low supersonic predictions resulted in only fair agreement. The APAS paneled-body analysis method (low speed) and the HABP impact analysis method (high speed) gave the most accurate results when compared against the experimental data.

Engelund, Walter C.↗

Advanced Crew Rescue Vehicle/Personnel Launch System

The Advanced Crew Rescue Vehicle (ACRV) will be an essential element of the Space Station to respond to three specific missions, all of which have occurred during the history space exploration by the U.S. and the Soviets: (1) Mission DRM-1: Return of disabled crew members during medical emergencies; (2) Mission DRM-2: Return of crew members from accidents or as a result of failures of Space Station systems; and (3) Mission DRM-3: Return of crew members during interruption of Space Shuttle launches. The ACRV will have the ability to transport up to eight astronauts during a 24-hour mission. Not only would the ACRV serve as a lifeboat to provide transportation back to Earth, but it would also be available as a immediately available safe refuge in case the Space Station were severely damaged by space debris or other catastrophe. Upon return to Earth, existing world-wide search and rescue assets operated by the Coast Guard and Department of Defense would be able to retrieve personnel returned to Earth via the ACRV. The operational approach proposed for the ACRV is tailored to satisfying mission requirements for simplicity of operation (no piloting skills or specially trained personnel are required), continuous availability, high reliability and affordability. By using proven systems as the basis for many critical ACRV systems, the ACRV program is more likely to achieve each of these mission requirements. Nonetheless, the need for the ACRV to operate reliably with little preflight preparation after, perhaps, 5 to 10 years in orbit imposes challenges not faced by any previous space system of this complexity. Specific concerns exist regarding micrometeoroid impacts, battery life, and degradation of recovery parachutes while in storage.

Craig, Jerry W.↗

Evaluation of advanced propulsion options for the next manned transportation system: Propulsion evolution study

The objectives were to examine launch vehicle applications and propulsion requirements for potential future manned space transportation systems and to support planning toward the evolution of Space Shuttle Main Engine (SSME) and Space Transportation Main Engine (STME) engines beyond their current or initial launch vehicle applications. As a basis for examinations of potential future manned launch vehicle applications, we used three classes of manned space transportation concepts currently under study: Space Transportation System Evolution, Personal Launch System (PLS), and Advanced Manned Launch System (AMLS). Tasks included studies of launch vehicle applications and requirements for hydrogen-oxygen rocket engines; the development of suggestions for STME engine evolution beyond the mid-1990's; the development of suggestions for STME evolution beyond the Advanced Launch System (ALS) application; the study of booster propulsion options, including LOX-Hydrocarbon options; the analysis of the prospects and requirements for utilization of a single engine configuration over the full range of vehicle applications, including manned vehicles plus ALS and Shuttle C; and a brief review of on-going and planned LOX-Hydrogen propulsion technology activities.

Spears, L. T.↗

Advanced Manned Launch System (AMLS) study

To assure national leadership in space operations and exploration in the future, NASA must be able to provide cost effective and operationally efficient space transportation. Several NASA studies and the joint NASA/DoD Space Transportation Architecture Studies (STAS) have shown the need for a multi-vehicle space transportation system with designs driven by enhanced operations and low costs. NASA is currently studying an advanced manned launch system (AMLS) approach to transport crew and cargo to the Space Station Freedom. Several single and multiple stage systems from air-breathing to all-rocket concepts are being examined in a series of studies potential replacements for the Space Shuttle launch system in the 2000-2010 time frame. Rockwell International Corporation, under contract to the NASA Langley Research Center, has analyzed a two-stage all-rocket concept to determine whether this class of vehicles is appropriate for the AMLS function. The results of the pre-phase A study are discussed.

Ehrlich, Carl F., Jr.↗

Advanced Information Processing System (AIPS)-based fault tolerant avionics architecture for launch vehicles

An avionics architecture for the advanced launch system (ALS) that uses validated hardware and software building blocks developed under the advanced information processing system program is presented. The AIPS for ALS architecture defined is preliminary, and reliability requirements can be met by the AIPS hardware and software building blocks that are built using the state-of-the-art technology available in the 1992-93 time frame. The level of detail in the architecture definition reflects the level of detail available in the ALS requirements. As the avionics requirements are refined, the architecture can also be refined and defined in greater detail with the help of analysis and simulation tools. A useful methodology is demonstrated for investigating the impact of the avionics suite to the recurring cost of the ALS. It is shown that allowing the vehicle to launch with selected detected failures can potentially reduce the recurring launch costs. A comparative analysis shows that validated fault-tolerant avionics built out of Class B parts can result in lower life-cycle-cost in comparison to simplex avionics built out of Class S parts or other redundant architectures.

Lala, Jaynarayan H.↗

Structural and loads analysis of a two-stage fully reusable Advanced Manned Launch System

The conceptual design of a rocket-powered, two-stage fully reusable launch vehicle has been performed as a part of NASA's Advanced Manned Launch System (AMLS) study. This paper summarizes the structural design and loads analysis of this two-stage fully reusable launch vehicle. The method used to determine the structural weights consists of generating a finite-element model for each vehicle, selecting a set of critical loading conditions, determining the loads on the model caused by those conditions, determining the model response and changing the sizes of individual elements to obtain a safe structure. The integrated loads on the two-stage vehicle were obtained from a three-degrees-of-freedom trajectory analysis.

Robinson, James C.↗

Atomic hydrogen as a launch vehicle propellant

An analysis of several atomic hydrogen launch vehicles was conducted. A discussion of the facilities and the technologies that would be needed for these vehicles is also presented. The Gross Liftoff Weights (GLOW) for two systems were estimated; their specific impulses (I sub sp) were 750 and 1500 lb (sub f)/s/lb(sub m). The atomic hydrogen launch vehicles were also compared to the currently planned Advanced Launch System design concepts. Very significant GLOW reductions of 52 to 58 percent are possible over the Advanced Launch System designs. Applying atomic hydrogen propellants to upper stages was also considered. Very high I(sub sp) (greater than 750 1b(sub f)/s/lb(sub m) is needed to enable a mass savings over advanced oxygen/hydrogen propulsion. Associated with the potential benefits of high I(sub sp) atomic hydrogen are several challenging problems. Very high magnetic fields are required to maintain the atomic hydrogen in a solid kilogauss (3 Tesla). Also the storage temperature of the propellant is 4 K. This very low temperature will require a large refrigeration facility for the launch vehicle. The design considerations for a very high recombination rate for the propellant are also discussed. A recombination rate of 210 cm/s is predicted for atomic hydrogen. This high recombination rate can produce very high acceleration for the launch vehicle. Unique insulation or segmentation to inhibit the propellant may be needed to reduce its recombination rate.

Palaszewski, Bryan A.↗

Atomic hydrogen as a launch vehicle propellant

An analysis of several atomic hydrogen launch vehicles was conducted. A discussion of the facilities and the technologies that would be needed for these vehicles is also presented. The Gross Liftoff Weights (GLOW) for two systems were estimated; their specific impulses (I sub sp) were 750 and 1500 lb(sub f)/s/lb(sub m). The atomic hydrogen launch vehicles were also compared to the currently planned Advanced Launch System design concepts. Very significant GLOW reductions of 52 to 58 percent are possible over the Advanced Launch System designs. Applying atomic hydrogen propellants to upper stages was also considered. Very high I(sub sp) (greater than 750 lb(sub f)/s/lb(sub m)) is needed to enable a mass savings over advanced oxygen/hydrogen propulsion. Associated with the potential benefits of high I(sub sp) atomic hydrogen are several challenging problems. Very high magnetic fields are required to maintain the atomic hydrogen in a solid hydrogen matrix. The magnetic field strength was estimated to be 30 kilogauss (3 Tesla). Also the storage temperature of the propellant is 4 K. This very low temperature will require a large refrigeration facility for the launch vehicle. The design considerations for a very high recombination rate for the propellant are also discussed. A recombination rate of 210 cm/s is predicted for atomic hydrogen. This high recombination rate can produce very high acceleration for the launch vehicle. Unique insulation or segmentation to inhibit the propellant may be needed to reduce its recombination rate.

Palaszewski, Bryan A.↗

ALS engine controller system

This report summarizes analysis and design done on the controller system for the Advanced Launch System (ALS) main engine.

Payne, Roger↗

Liquid Rocket Booster (LRB) for the Space Transportation System (STS) systems study. Volume 2: Addendum 1

The potential of a common Liquid Rocket Booster (LRB) design was evaluated for use with both the Space Transportation System (STS) and the Advanced Launch System (ALS). A goal is to have a common Liquid Oxygen/Liquid Hydrogen (LO2/LH2) engine developed for both the ALS booster and the core stage. The LO2/LH2 option for the STS was evaluated to identify potential LRB program cost reductions. The objective was to identify the structural impacts to the external tank (ET), and to determine if any significant ET re-development costs are required as a result of the larger LO2/LH2 LRB. The potential ET impacts evaluated are presented.

Source record↗

Propulsion studies for advanced manned launch systems

The topics covered include the following: (1) the next manned space transportation system; (2) development of a new hydrogen booster engine (like the Space Transportation Booster Engine); (3) development of a new hydrogen engine (like the Space Transportation Main Engine); and (4) an increase in oxidizer to fuel ratio from the current Space Shuttle Main Engine level. This document is presented in viewgraph form.

Freeman, D.↗