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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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At least 1,351 records · Page 75
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Heat-transfer tests on the Rockwell International space shuttle orbiter with and without simulated protuberances

Aerothermodynamic tests on the forward half of the Rockwell International Space Shuttle Orbiter Configuration 140C were conducted at Mach number 8. The phase-change paint and thin-skin thermocouple techniques were used to determine the aerodynamic heating rates on the Orbiter models during simulated atmospheric reentry. Smooth 0.04-scale models and models with scaled protuberances and indentations which simulated the windshields, cargo bay door hinges, vents, and thruster nozzles were tested over an angle-of-attack range from 20 to 45 deg at yaw angles from -5 to 5 deg and at Reynolds numbers, based on the total Orbiter scaled length, from 2.15 to 15.9 million. Comparisons of the model heat-transfer rates obtained with a smooth surface and with scaled protuberances are presented.

Carter, L. D.↗
NASA NTRS1975

Results of aerodynamic heat transfer tests of a 0.0175-scale model of the Rockwell International Space Shuttle Orbiter 139 (model number 22-0) in the NASA/Ames 3.5-foot hypersonic wind tunnel (test OH6)

The results of a hypersonic wind tunnel test program conducted using a 0.0175 scale thin-skin thermocouple model of the Space Shuttle Orbiter to obtain aerodynamic heat transfer data on the Orbiter under simulated reentry conditions were presented. The test program was conducted at a Mach number of 7.3 and a freestream Reynolds number ranging between 1.0 and 6.0 million/foot. The model was tested for angles of attack ranging between 10 deg and 30 deg and a sideslip angle of 0 deg. The model was constructed of 15-5 PH stainless steel with the instrumented areas machined to a nominal skin thickness of 0.030 in. The model instrumentation consisted of 288 iron-constantan thermocouples spot welded to the skin inner surface, but only 75 of these were used in this test program. A high-speed, analog-to-digital data acquisition system was used to record data on magnetic tape.

Dye, W. H.↗
NASA NTRS1975

Heat transfer tests on a 0.01-scale Rockwell configuration 3 space shuttle orbiter and tank (37-OT) in the Calspan 48-inch hypersonic shock tunnel (OH12/IH21), volume 1

Model information and data are presented from wind tunnel tests conducted on 0.01-scale models of the space shuttle orbiter and external tank. These tests were conducted in a hypersonic shock tunnel to determine heating rates on ascent and reentry configurations at various Reynolds numbers, Mach numbers, and angles of attack.

Kotch, M.↗
NASA NTRS1976

Zone-forming fungi experiment MA-147

Streptomyces levoris was used as an experimental microorganism during the Apollo Soyuz Test Project to study specific biological considerations that may be influenced by space flight factors. Preflight, inflight, and postflight growth rates of the cultures were compared by photographing the specimens at regular intervals. Preliminary results based on visual comparison of the photographic data indicate that an increased growth rate occurred during space flight in two of eight flight specimens. The increased growth rate continued in the two specimens during the postflight period until termination of the experiment. Radiation effects may be responsible for the absence of spores in two areas of the last spore ring that was formed during the inflight period in one of the flight cultures; however, the radiation studies related to this experiment have not been completed. Distinct morphological differences in spore rings were observed when postflight spore rings were compared with inflight spore rings. Factors that are related to space flight recovery and reentry into earth gravity may have effected these alterations.

Rogers, T. D.↗
NASA NTRS1976

Airborne ballistic camera tracking systems

An operational airborne ballistic camera tracking system was tested for operational and data reduction feasibility. The acquisition and data processing requirements of the system are discussed. Suggestions for future improvements are also noted. A description of the data reduction mathematics is outlined. Results from a successful reentry test mission are tabulated. The test mission indicated that airborne ballistic camera tracking systems are feasible.

Redish, W. L.↗
NASA NTRS1976

Space shuttle digital flight control system

The space shuttle digital, fly by wire, flight control system presents an interesting challenge in avionics system design. In residence in each of four redundant general purpose computers at lift off are the guidance, navigation, and control algorithms for the entire flight. The mission is divided into several flight segments: first stage ascent, second stage ascent; abort to launch site, abort once around; on orbit operations, entry, terminal area energy management; and approach and landing. The FCS is complicated in that it must perform the functions to fly the shuttle as a boost vehicle, as a spacecraft, as a reentry vehicle, and as a conventional aircraft. The crew is provided with both manual and automatic modes of operations in all flight phases including touchdown and rollout.

Minott, G. M.↗
NASA NTRS1975

Solution of an optimal control lifting body entry problem by an improved method of perturbation functions

This paper presents a solution to a complex lifting reentry three-degree-of-freedom problem by using the calculus of variations to minimize the integral of the sum of the aerodynamics loads and heat rate input to the vehicle. The entry problem considered does not have state and/or control constraints along the trajectory. The calculus of variations method applied to this problem gives rise to a set of necessary conditions which are used to formulate a two point boundary value (TPBV) problem. This TPBV problem is then numerically solved by an improved method of perturbation functions (IMPF) using several starting co-state vectors. These vectors were chosen so that each one had a larger norm with respect to show how the envelope of convergence is significantly increased using this method and cases are presented to point this out.

Garcia, F., Jr.↗
NASA NTRS1976

Pulmonary function evaluation during the Skylab and Apollo-Soyuz missions

Previous experience during Apollo postflight exercise testing indicated no major changes in pulmonary function. Pulmonary function has been studied in detail following exposure to hypoxic and hyperoxic normal gravity environments, but no previous study has reported on men exposed to an environment that was both normoxic at 258 torr total pressure and at null gravity as encountered in Skylab. Forced vital capacity (FVC) was measured during the preflight and postflight periods of the Skylab 2 mission. Inflight measurements of vital capacity (VC) were obtained during the last 2 weeks of the second manned mission (Skylab 3). More detailed pulmonary function screening was accomplished during the Skylab 4 mission. The primary measurements made during Skylab 4 testing included residual volume determination (RV), closing volume (CV), VC, FVC and its derivatives. In addition, VC was measured in flight at regular intervals during the Skylab 4 mission. Vital capacity was decreased slightly (-10%) in flight in all Skylab 4 crewmen. No major preflight-to-postflight changes were observed. The Apollo-Soyuz Test Project (ASTP) crewmen were studied using equipment and procedures similar to those employed during Skylab 4. Postflight evaluation of the ASTP crewmen was complicated by their inadvertent exposure to nitrogen tetroxide gas fumes upon reentry.

Sawin, C. F.↗
NASA NTRS1976

Results from a convective heat transfer rate distribution test on a 0.0175 scale model (22-0) of the Rockwell International vehicle 4 space shuttle configuration in the AEDC-VKF tunnel B (OH49B), volume 1

The tests were conducted in a hypersonic wind tunnel at Mach number 8 to investigate reentry mode convective heat--transfer rates to the vehicle 4 shuttle orbiter. The thin skin thermocouple technique was used to obtain the heat transfer rate measurements. A complete set of tabulated data is presented.

Herrera, B. J.↗
NASA NTRS1976

Nonelastomeric Rod Seals for Advanced Hydraulic Systems

Advanced high temperature hydraulic system rod sealing requirements can be met by using seals made of nonelastomeric (plastic) materials in applications where elastomers do not have adequate life. Exploratory seal designs were optimized for advanced applications using machinable polyimide materials. These seals demonstrated equivalent flight hour lives of 12,500 at 350 F and 9,875 at 400 F in advanced hydraulic system simulation. Successful operation was also attained under simulated space shuttle applications; 96 reentry thermal cycles and 1,438 hours of vacuum storage. Tests of less expensive molded plastic seals indicated a need for improved materials to provide equivalent performance to the machined seals.

Hady, W. F.↗
NASA NTRS1976

An investigation of the aerodynamic characteristics of a 0.00548 scale model (model no. 486) of the space shuttle 146-inch diameter solid rocket booster at angels of attack from 113 deg to 180 deg in the AEDC PWT 4-foot transonic wind tunnel (SA16F)

An experimental investigation (SA16F) was conducted in the AEDC PWT 4T to determine the entry static stability of a 0.00548 scale space shuttle solid rocket booster (SRB). The primary objective was to improve the definition of the aerodynamic characteristics in the angle of attack range beyond 90 deg in the vicinity of the entry trim point. The SRB scale model consisted of the reentry configuration with all major protuberances. A simulated heat shield around the engine nozzle was also included. Data were obtained for a 60 deg side mounted sting and a straight nose mounted sting. The angle of attack range for the side mounted sting was 113 deg to 147 deg and for the nose mounted sting 152 deg to 187 deg. The Mach number range consisted of 0.4 to 1.2 at roll angles of 0 and 90 deg. The resulting 6-component aerodynamic force data was presented as the variation of coefficients with angle of attack for each Mach number and roll angle.

Ramsey, P. E.↗
NASA NTRS1977

Research study on neutral thermodynamic atmospheric model

The Global Reference Atmospheric Model is used along with the revised perturbation statistics to evaluate and computer graph various atmospheric statistics along a space shuttle reference mission and abort trajectory. The trajectory plots are height vs. ground range, with height from ground level to 155 km and ground range along the reentry trajectory. Cross sectional plots, height vs. latitude or longitude, are also generated for 80 deg longitude, with heights from 30 km to 90 km and latitude from -90 deg to +90 deg, and for 45 deg latitude, with heights from 30 km to 90 km and longitudes from 180 deg E to 180 deg W. The variables plotted are monthly average pressure, density, temperature, wind components, and wind speed and standard deviations and 99th inter-percentile range for each of these variables.

Hargraves, W. R.↗
NASA NTRS1975

Effects of Control Hysteresis on the Space Shuttle Orbiter's Entry

There are six degree-of-freedom simulations of the space shuttle orbiter entry with aerodynamic control hysteresis conducted on the NASA Langley Research Center interactive simulator known as the Automatic Reentry Flight Dynamics Simulator. These were performed to determine if the presence of aerodynamic control hysteresis would endanger the mission, either by making the vehicle unable to maintain proper attitude for a safe entry, or by increasing the amount of the reaction control system's fuel consumption beyond that carried.

Powell, R. W.↗
NASA NTRS1977

Aerothermal and structural performance of a cobalt-base superalloy thermal protection system at Mach 6.6

A flightweight, metallic thermal protection system (TPS) applicable to reentry and hypersonic vehicles was subjected to multiple cycles of both radiant and aerothermal heating in order to evaluate its aerothermal performance and structural integrity. Good structural integrity and thermal performance were demonstrated by the TPS under both a radiant and aerothermal heating environment typical of a shuttle entry. The shingle-slip joints effectively allowed for thermal expansion of the panel without allowing any appreciable hot gas flow into the TPS cavity. The TPS also demonstrated good structural ruggedness.

Sawyer, J. W.↗
NASA NTRS1977

Aileron roll hysteresis effects on entry of space shuttle orbiter

Six-degree-of-freedom simulations of the space shuttle orbiter entry with control hysteresis were conducted on the NASA Langley Research Center interactive simulator known as the automatic reentry flight dynamics simulator. These simulations revealed that the vehicle can tolerate control hysteresis producing a + or - 50 percent change in the nominal aileron roll characteristics and an offset in the nominal characteristics equivalent to a + or - 5 deg aileron deflection with little increase in the reaction control system's fuel consumption.

Powell, R. W.↗
NASA NTRS1977

Hematology and immunology studies

A coordinated series of experiments were conducted to evaluate immunologic and hemotologic system responses of Skylab crewmen to prolonged space flights. A reduced PHA responsiveness was observed on recovery, together with a reduced number of T-cells, with both values returning to normal 3 to 5 days postflight. Subnormal red cell count, hemoglobin concentration, and hematocrit values also returned gradually to preflight limits. Most pronounced changes were found in the shape of red blood cells during extended space missions with a rapid reversal of these changes upon reentry into a normal gravitational environment.

Kimzey, S. L.↗
NASA NTRS1977

Validation of a Flexible Aircraft TakeOff and Landing Analysis /FATOLA/ computer program using flight landing data

A multiple-degree-of-freedom takeoff and landing analysis, Flexible Aircraft TakeOff and Landing Analysis computer program (FATOLA), was used to predict the landing behavior of a rigid-body X-24B reentry research vehicle and of a flexible-body modified-delta-wing supersonic YF-12 research aircraft. The analytical predictions were compared with flight test data for both research vehicles. Predicted time histories of vehicle motion and attitude, landing-gear strut stroke, and axial force transmitted from the landing gear to the airframe during the landing impact and rollout compared well with the actual time histories. Based on the comparisons presented, the versatility and validity of the FATOLA program for predicting landing dynamics of aircraft has been demonstrated.

Carden, H. D.↗