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A trade study comparing the overall benefits in placing large payloads to GEO with the nuclear electric propulsion option shows superiority of nuclear thermal propulsion. The resulting savings in orbital transfer time and the substantial reduction of overall lift requirement enables the use of low-cost launchers for several near-term military satellite missions. ...An integral space power concept provides both the electrical power and propulsion from a common heat source and offers superior performance capabilities over conventional orbital insertion using chemical propulsion systems. ...An integral space power concept provides both the electrical power and propulsion from a common heat source and offers superior performance capabilities over conventional orbital insertion using chemical propulsion systems. This paper describes a hybrid (bimodal) system concept based on a proven, inherently safe solid fuel form for the high temperature reactor core operation and rugged planar thermionic energy converter for long-life steady state electric power production combined with NERVA-based rocket technology for propulsion.

This paper comments upon the business considerations that depend upon technical predictions of reliability of the SST propulsion system. The necessary scope and timing of such predictions are delineated. Reasons for broadening the concept of reliability are offered.

It has been named the Propulsion Multiplexer (PMUX) System and has been specified for Pratt and Whitney Aircraft and General Electric engines for the Airbus Industrie A310 aircraft.

We analyse 635 set-years of service experience of 147 merchant-marine steam-turbine-gear propulsion sets, finding an MTBF of 23.5 set-years. The sets of one good-sized fleet have 3 times as large an MTBF as the rest of the sample, a fine return on the more conservative attention paid them.

Multiengine vertical takeoff and landing (V/STOL) aircraft have a unique requirement to at least maintain aircraft trim after losing one engine during vertical landing. The most popular scheme by which this is accomplished involves using cross-shafted fans with variable inlet guide vanes. A significantly different approach is described herein whereby cross-ducted fan bleed air is used to obtain roll control and engine out roll trim. The installation of this cross-ducted system in a twin-engine V/STOL aircraft is described in detail along with different options for obtaining pitch control, pitch trim and yaw control. The optimum engine cycle for each configuration is defined based on mission performance results and vertical landing capabilities. The cross-ducted systems were found to offer significant advantages compared to the cross-shafted systems in terms of aircraft performance as well as design simplicity, versatility, reliability, vulnerability, survivability, and safety.

Five requisites are categorized and examined in relation to the propulsion system. Specifically, the needs of reliability, maintainability, operational flexibility, salability, and profitability are discussed and the interplay and accumulative effects are described. ...Goals for the SST propulsion system are compared to the status of today’s operation and data showing historical trends are presented.

Two decades of turboprop technology advances are discussed along with their application to a Prop-Fan propulsion system for modern high-speed commercial aircraft. The Prop-Fan propulsion system features a small diameter, multibladed propulsor geared to an advanced gas turbine engine. ...Several advanced technologies in the airframe and propulsion disciplines have been identified by NASA, with the turboprop being one of these. Two decades of turboprop technology advances are discussed along with their application to a Prop-Fan propulsion system for modern high-speed commercial aircraft.

The reliability and maintenance cost (R&MC) for an advanced turbine engine and prop-fan propulsion system is projected for high speed commercial airline use in the 1990s. The R&MC values are compared with current turboprop values and detailed discussion of the advances necessary to achieve the projected R&MC is provided to substantiate maintenance cost reductions on the order of 50 to 60%.

Requirements for advanced rocket propulsion systems are becoming increasingly more demanding. The use of high temperature capable materials in such systems, including applications in liquid rocket engines and solid rocket motors, offers potential benefits of increased performance and/or efficiency based on the engine operating cycle. ...This approach, when matured, offers the potential for fabrication of lightweight, durable, and cost-effective advanced rocket propulsion components.

Enhancement of aviation fuel supplies at some future date may become necessary due to changing geopolitical conditions or reduced petroleum availability. Use of non-standard fuels may become a necessity on either an emergency or permanent basis. Two engine programs, conducted jointly by the U.S. Navy and GE Aircraft Engines, investigated the effects incurred by using broad specification fuels. Engine component and full-scale engine tests were conducted on the F404-GE-400 turbofan and the T700-GE-701 turboshaft engines. Results have demonstrated that these engines can operate successfully on various alternative fuels. However, there are penalties to engine performance, operability, and durability.

The SST will require considerable advanced technology in several areas of the engine propulsion system. The steps taken by Pratt & Whitney Aircraft to advance the state-of-the-art related to the fulfillment of these requirements are described.

In order to establish a propellant depletion system for propulsion shutdown on the Atlas space launch vehicle, design criteria have been closely examined to meet the unique environmental requirements in this particular application.

One such concept under consideration is Turboelectric Distributed Propulsion (TeDP) featuring a large number of superconducting motors powered by two superconducting generators placed on each wingtip and connected through a DC distribution network.

One concept design proposed is a Turboelectric Distributed Propulsion (TeDP) aircraft that utilises a number of electrically driven propulsors. Such concepts place a new and significant reliance on an aircraft's electrical system for safe and efficient flight.

The Earth-to-Orbit (ETO) Propulsion Program was initiated in 1988 as a major element of NASA's Civil Space Technology Initiative (CSTI), a set of some ten different program elements directed to the revitalization of the U.S.'

A vehicle concept was developed to demonstrate the ability of near term aeromechanics and propulsion technology to support such a system. The vehicle was composed of two stages. The system takes off horizontally and both stages return to a horizontal landing. ...Turbojet, ramjet, and rocket propulsion is used. The sensitivity of the system to thrust, drag, weight, and staging Mach number was examined.

The framework is applicable to a variety of reusable space propulsion systems for existing and future launch vehicles. It provides a “road map” for technology development to enable enhanced engine performance with increased reliability, durability and maintainability. ...The framework hierarchy consists of a mission coordination level, a propulsion system coordination level, and an engine control level. Each level is described in the context of the Space Shuttle Main Engine.

The purpose of this paper is to share how the quantity and quality of data available For propulsion system management greatly increases with the use of digital technology engine monitoring hardware. ...Although referred diagnostic data may not detect all potential engine problems, this available capability, with its artificial intelligence, has demonstrated the ability to identify hidden problems, which greatly enhances propulsion system management. This paper will present details of several current applications to both military and civilian helicopters with the idea that the demonstrated capability to improve operational reliability is potentially essential to maximize flight safety and control operating costs.

The Baseline Space Station Freedom architecture calls for separate and independent water electrolysis subsystems in ECLSS and in Propulsion. A study to assess the potential benefits and impacts of electrolyzer commonality evaluated fifteen sets of ECLSS and Propulsion architectural options with graduated levels of commonality, first by quantifying the electrical power, weight, volume, and heat rejection requirements; and then qualitatively according to safety and redundancy, reliability and maintainability, integration and verification, and assembly. ...A study to assess the potential benefits and impacts of electrolyzer commonality evaluated fifteen sets of ECLSS and Propulsion architectural options with graduated levels of commonality, first by quantifying the electrical power, weight, volume, and heat rejection requirements; and then qualitatively according to safety and redundancy, reliability and maintainability, integration and verification, and assembly.

Evolving aircraft propulsion systems have resulted in more aggressive operational environments, thus providing the impetus to improve the design of the start systems to enhance their durability and aid in improving both dispatch reliability and system responsiveness.