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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS2006

NASA's J-2X Engine Builds on the Apollo Program for Lunar Return Missions

In January 2006, NASA streamlined its U.S. Vision for Space Exploration hardware development approach for replacing the Space Shuttle after it is retired in 2010. The revised CLV upper stage will use the J-2X engine, a derivative of NASA s Apollo Program Saturn V s S-II and S-IVB main propulsion, which will also serve as the Earth Departure Stage (EDS) engine. This paper gives details of how the J- 2X engine effort mitigates risk by building on the Apollo Program and other lessons learned to deliver a human-rated engine that is on an aggressive development schedule, with first demonstration flight in 2010 and human test flights in 2012. It is well documented that propulsion is historically a high-risk area. NASA s risk reduction strategy for the J-2X engine design, development, test, and evaluation is to build upon heritage hardware and apply valuable experience gained from past development efforts. In addition, NASA and its industry partner, Rocketdyne, which originally built the J-2, have tapped into their extensive databases and are applying lessons conveyed firsthand by Apollo-era veterans of America s first round of Moon missions in the 1960s and 1970s. NASA s development approach for the J-2X engine includes early requirements definition and management; designing-in lessons learned from the 5-2 heritage programs; initiating long-lead procurement items before Preliminary Desi& Review; incorporating design features for anticipated EDS requirements; identifying facilities for sea-level and altitude testing; and starting ground support equipment and logistics planning at an early stage. Other risk reduction strategies include utilizing a proven gas generator cycle with recent development experience; utilizing existing turbomachinery ; applying current and recent main combustion chamber (Integrated Powerhead Demonstrator) and channel wall nozzle (COBRA) advances; and performing rigorous development, qualification, and certification testing of the engine system, with a philosophy of "test what you fly, and fly what you test". These and other active risk management strategies are in place to deliver the J-2X engine for LEO and lunar return missions as outlined in the U.S. Vision for Space Exploration.

Snoddy, Jimmy R.↗
NASA NTRS1972

Hypergol engine restart characteristics.

Several hard restarts and two failures to restart occurred during simulated high-altitude testing of the three Apollo spacecraft primary propulsion engines. Abnormal restarts resulted from flow perturbations by trapped propellants, ignition characteristics of partially frozen propellants, and fuel nitrate retention. Engine restart characteristics are correlated with thermodynamic phenomena that occur after engine shutdown; these include desorption of dissolved pressurant gases and evaporative freezing of propellant residuals. These results are applied to conceptual space shuttle OMS hypergol engines to identify potential restart problems.

Kerkam, B. F.↗
NASA NTRS1973

SMEAT atmosphere trace contaminants.

The atmosphere trace contaminant analysis support provided for the Skylab Medical Experiments Altitude Test (SMEAT) which was conducted from July 26 through September 20, 1972, at the JSC Crew Systems Division facility is discussed. Sample acquisition techniques and analytical instrumentation methodology utilized for identification and quantification of the trace contaminants are described. Emphasis is placed on the contaminants found, their occurrence patterns, and possible sources.

Schornick, J. L.↗
NASA NTRS1973

Program organization

The Skylab medical experiments altitude test plan is outlined. Described are the scope and objectives of the program, the management system under which it would be conducted, requirements for configuration of the test facility, test control documentation, data processing, and detailed test objectives.

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NASA NTRS1973

Facilities

Detailed descriptions are provided for mechanical devices, life support systems, and data handling and communications instrumentation that are connected with the altitude chamber in which the Skylab medical experiments altitude tests were performed.

Battaglia, H. F.↗
NASA NTRS1973

Specimen mass measurement

The Skylab specimen mass measurement device was operated throughout the altitude test in close simulation of the 56-day Skylab mission. It performed operational specimen measurements well until it was passed out of the chamber for replacement of the specimen hold-down and was autoclaved prior to return. Fecal measurements were typically made with less than one percent error.

Thornton, W. E.↗
NASA NTRS1973

Crew background, training, and activities

The brief history of the Skylab altitude test crewmen is followed by an outline of their training in conducting medical experiments, emergency medical procedures, communications, and housekeeping practices during prolonged exposure to the Skylab simulation environment.

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NASA NTRS1974

Biomedical programs operations plans

Operational guidelines for the space shuttle life sciences payloads are presented. An operational assessment of the medical experimental altitude test for Skylab, and Skylab life sciences documentation are discussed along with the operations posture and collection of space shuttle operational planning data.

Walbrecher, H. F.↗
NASA NTRS1975

Microbiological sampling of the spacecraft atmosphere during a simulated Skylab mission

A Skylab Air Sampler (SAS) has been developed for use during Skylab missions. The SAS was used in the Skylab Medical Experiments Altitude Test (SMEAT) to gather baseline data which could be directly compared to data obtained during actual Skylab missions. The results obtained in the SMEAT gave no evidence of consistent change in either concentration or types of microorganisms in the SMEAT atmosphere over the 56-d test. Microorganisms found included some potential pathogens but were largely normal human microflora. Few typical soil microorganisms were found. These findings are related to commonly anticipated effects of long-term spaceflights on environmental microflora and to other closed environment studies.

Brockett, R. M.↗
NASA NTRS1979

Multivariable control altitude demonstration on the F100 turbofan engine

The control system designed under the Multivariable Control Synthesis (MVCS) program for the F100 turbofan engine is described. The MVCS program, applied the linear quadratic regulator (LQR) synthesis methods in the design of a multivariable engine control system to obtain enhanced performance from cross-coupled controls, maximum use of engine variable geometry, and a systematic design procedure that can be applied efficiently to new engine systems. Basic components of the control system, a reference value generator for deriving a desired equilibrium state and an approximate control vector, a transition model to produce compatible reference point trajectories during gross transients, gain schedules for producing feedback terms appropriate to the flight condition, and integral switching logic to produce acceptable steady-state performance without engine operating limit exceedance are described and the details of the F100 implementation presented. The engine altitude test phase of the MVCS program, and engine responses in a variety of test operating points and power transitions are presented.

Lehtinen, B.↗
NASA NTRS1981

Flight test of a full authority Digital Electronic Engine Control system in an F-15 aircraft

The Digital Electronic Engine Control (DEEC) system considered is a relatively low cost digital full authority control system containing selectively redundant components and fault detection logic with capability for accommodating faults to various levels of operational capability. The DEEC digital control system is built around a 16-bit, 1.2 microsecond cycle time, CMOS microprocessor, microcomputer system with approximately 14 K of available memory. Attention is given to the control mode, component bench testing, closed loop bench testing, a failure mode and effects analysis, sea-level engine testing, simulated altitude engine testing, flight testing, the data system, cockpit, and real time display.

Barrett, W. J.↗
NASA NTRS1984

The use of oil for in-flight flow visualization

Oil was used to visualize inflight aerodynamic characteristics such as boundary layer transition, shock wave location, regions of separated flow, and surface flow direction. The technique, which is similar to wind tunnel oil-flow testing, involves an oil mixture to test aircraft before takeoff. After takeoff, the airplane climbs immediately to the test altitude and photographs are taken. The developmental experience is summarized, several examples of inflight oil-flow photographs are presented and discussed, and an approach for potential users of the technique is presented.

Curry, R. E.↗