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Martin, James A.

Publications and source records attributed to Martin, James A..

33 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Integrated launch and emergency entry vehicle concept

This paper describes the design of an integrated launch and emergency entry vehicle (EEV) that can satisfy the need for an advanced manned vehicle, a heavy-lift launch vehicle, and the Space Station. It is pointed out that, because only one small entry vehicle would need to be developed, the development costs should be relatively low. The EEV would have reasonable operating costs because its expendable tank would be smaller than that of the Space Shuttle and all expensive parts would be reusable. Schematic diagrams are included.

Martin, James A.↗
NASA NTRS1989

Two-stage reusable launch system utilizing a winged core vehicle and glideback boosters

A near-term technology launch system is described in which Space Shuttle main engines are used on a manned orbiter and also on twin strap-on unmanned boosters. The orbiter has a circular body and clipped delta wings. The twin strap-on boosters have a circular body and deployable oblique wings for a glideback recovery. The dry and gross weights of the system, capable of delivering 70klb of cargo to orbit, are compared with a similar system with hydrocarbon-fueled boosters and with the current Shuttle.

Macconochie, Ian O.↗
NASA NTRS1989

Optimization of the propulsion cycles for advanced shuttles. I - Propulsion mass model methodology

During the past year NASA and DLR computer codes were combined in order to analyze and optimize advanced rocket launcher systems. Previous optimization results led to relatively low chamber pressures and nozzle area ratios for the different cycles. Additional effort has been made to improve the verification of propulsive parameters such as chamber pressure, nozzle extension, kind of cycle, tripropellant systems, variable mixture ratio rocket motors, new technology effects, etc. The emphasis of this paper is to describe the methodology of the improved propulsion mass model.

Manski, Detlef↗
NASA NTRS1989

Variable-mixture-ratio and other rocket engines for advanced shuttles

Previous computer models of rocket engines and single-stage-to-orbit vehicles have been extended to include variable-mixture-ratio engines. The model has been applied to study a vertical-takeoff, horizontal-landing, winged, manned, fully-reusable vehicle with a payload of 13.6 Mg and which is launched to low-earth orbit. Both single-stage and two-stage vehicles are considered, with special attention given to hydrogen, methane, and propane engines with staged-combustion cycles. Results are presented for the optimum nozzle exit pressure, thrust split between the booster and orbiter, chamber pressure, and mixture ratio.

Martin, James A.↗
NASA NTRS1989

Rocket nozzle expansion ratio analysis for dual-fuel earth-to-orbit vehicles

Results are reported from a recent study of the effects of Space Shuttle Main Engine expansion ratio modifications, in the cases of both single-stage and two-stage systems. Two-position nozzles were employed; after varying the lower expansion ratio while the higher was held constant at 120, the lower expansion ratio was held constant at 40 or 60 while the higher expansion ratio was varied. The expansion ratios for minimum vehicle dry mass are different for single-stage and two-stage systems. For two-stage systems, a single expansion ratio of 77.5 provides a lower dry mass than any two-position nozzle.

Martin, James A.↗
NASA NTRS1989

Dual-fuel, dual-mode rocket engine

The invention relates to a dual fuel, dual mode rocket engine designed to improve the performance of earth-to-orbit vehicles. For any vehicle that operates from the earth's surface to earth orbit, it is advantageous to use two different fuels during its ascent. A high density impulse fuel, such as kerosene, is most efficient during the first half of the trajectory. A high specific impulse fuel, such as hydrogen, is most efficient during the second half of the trajectory. The invention allows both fuels to be used with a single rocket engine. It does so by adding a minimum number of state-of-the-art components to baseline single made rocket engines, and is therefore relatively easy to develop for near term applications. The novelty of this invention resides in the mixing of fuels before exhaust nozzle cooling. This allows all of the engine fuel to cool the exhaust nozzle, and allows the ratio of fuels used throughout the flight depend solely on performance requirements, not cooling requirements.

Martin, James A.↗
NASA NTRS1989

Automated power distribution system hardware

An automated power distribution system testbed for the space station common modules has been developed. It incorporates automated control and monitoring of a utility-type power system. Automated power system switchgear, control and sensor hardware requirements, hardware design, test results, and potential applications are discussed. The system is designed so that the automated control and monitoring of the power system is compatible with both a 208-V, 20-kHz single-phase AC system and a high-voltage (120 to 150 V) DC system.

Anderson, Paul M.↗
NASA NTRS1988

Space transportation main engines for two-stage shuttles

Current studies are examining two-stage fully reusable vehicles, heavy-lift vehicles, and rocket engines for these vehicles. A previous study showed that several advanced engine designs could reduce the dry mass of a single-stage vehicle relative to designs with the baseline hydrocarbon and hydrogen engines. This paper reports the results of a similar study for two-stage vehicles. The results indicate that the advanced engines can reduce the dry mass of two-stage vehicles, and that the same engine can be used for both stages.

Martin, James A.↗
NASA NTRS1988

Evaluation of innovative rocket engines for single-stage earth-to-orbit vehicles

Computer models of rocket engines and single-stage-to-orbit vehicles that were developed by the authors at DFVLR and NASA have been combined. The resulting code consists of engine mass, performance, trajectory and vehicle sizing models. The engine mass model includes equations for each subsystem and describes their dependences on various propulsion parameters. The engine performance model consists of multidimensional sets of theoretical propulsion properties and a complete thermodynamic analysis of the engine cycle. The vehicle analyses include an optimized trajectory analysis, mass estimation, and vehicle sizing. A vertical-takeoff, horizontal-landing, single-stage, winged, manned, fully reusable vehicle with a payload capability of 13.6 Mg (30,000 lb) to low earth orbit was selected. Hydrogen, methane, propane, and dual-fuel engines were studied with staged-combustion, gas-generator, dual bell, and the dual-expander cycles. Mixture ratio, chamber pressure, nozzle exit pressure liftoff acceleration, and dual fuel propulsive parameters were optimized.

Manski, Detlef↗
NASA NTRS1988

Comparing hydrogen and hydrocarbon booster fuels

The present evaluation of the consequences of hydrogen and hydrocarbon fuels as the basis of launch vehicle booster rocket-stage performance notes that hydrocarbon fuels lead to lower vehicle dry mass, for low-velocity requirements, while hydrogen fuel furnishes lower dry mass. Vehicles employing both types of fuel attempt to take advantage of the low intercept and slope of hydrocarbon fuel at low velocity, and subsequently, of the slope of the hydrogen curves at higher velocities.

Martin, James A.↗
NASA NTRS1987

Space transportation main engines for single-stage vehicles

Studies are currently being conducted that could lead to the development of new hydrocarbon booster and hydrogen upper-stage engines. More advanced engines are also being considered which could be developed instead of the baseline designs if the vehicle programs allow time. This paper describes results of the analyses of the advanced engines on single-stage-to-orbit vehicles. The results show that the vehicle dry mass can be reduced about 20 percent with advanced engines when compared to the baseline engines. Some of the advanced engines may not require much extra development time.

Martin, James A.↗
NASA NTRS1987

The Orbit-on-Demand and Shuttle II Studies at NASA Langley

This paper reviews advanced space transportation studies that have been conducted at the Langley Research Center recently. The Orbit-on-Demand Vehicle Study focused on concepts capable of rapid launch. The Shuttle II Study considered concepts with the potential to reduce the cost of transportation to orbit for payloads in the Shuttle class or less.

Martin, James A.↗
NASA NTRS1986

Comparison of methane and propane rockets

Martin (1983) compared methane and propane fuels for a single-stage-to-orbit vehicle, demonstrating a significant advantage for propane. Attention is presently given to the ways that this comparison changes when both methane and propane vehicles are optimized. It is found that while the difference is slightly reduced, propane remains the better hydrocarbon fuel for dry mass minimization.

Martin, James A.↗