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The National Aeronautics and Space Administration (NASA) is interested in characterizing the responses of THOR (test device for human occupant restraint) anthropometric test device (ATD) to representative loading acceleration pulse s. Test conditions were selected both for their applicability to anticipated NASA landing scenarios, and for comparison to human volunteer data previously collected by the United States Air Force (USAF). THOR impact testing was conducted in the fore-to-aft frontal (-x) and in the upward spinal (-z) directions with peak sled accelerations ranging from 8 to 12 G and rise times of 40, 70, and 100ms. Each test condition was paired with historical huma n data sets under similar test conditions that were also conducted on the Horizontal Impulse Accelerator (HIA). A correlation score was calculated for each THOR to human comparison using CORA (CORrelation and Analysis) software.

Meeting radiation protection requirements during EVA is predominantly an operational issue with some potential considerations for temporary shelter. The issue of spacesuit shielding is mainly guided by the potential of accidental exposure when operational and temporary shelter considerations fail to maintain exposures within operational limits. In this case, very high exposure levels are possible which could result in observable health effects and even be life threatening. Under these assumptions, potential spacesuit radiation exposures have been studied using known historical solar particle events to gain insight on the usefulness of modification of spacesuit design in which the control of skin exposure is a critical design issue and reduction of blood forming organ exposure is desirable.

The effects of both the cosmic ray heavy ion exposures and the intense trapped electron exposures are examined with respect to impact on cellular system survival on exterior spacecraft surfaces as well as at interior (shielded) locations for a sample mission to Jupiter’s moons. Radiation transport through shield materials and subsequent exposures are calculated with the established Langley heavy ion and electron deterministic codes. In addition to assessing fractional DNA single and double strand breaks, a variety of cell types are examined that have greatly differing radio-sensitivities. Finally, implications as to shield requirements for controlled biological experiments are discussed.

Special exposure limit recommendations have been designated by the National Council on Radiation Protection (NCRP) for U. S. astronauts in low earth orbit (LEO) operations. These have been established from consideration of a 3% lifetime excess risk of cancer mortality for a 10-yr. active career. The most recent recommendations of the National Council on Radiation Protection and Measurements (NCRP) have incorporated modified procedures for evaluating exposures with accompanying adjustments in career limits. Of special importance are the limit specifications for female exposures, which are approximately 40% less than those for males. Furthermore, radiosensitive organs unique to females require additional attention.

The General Aviation Element of the Aviation Safety Program's Synthetic Vision Systems (SVS) Project is developing technology to eliminate low visibility induced General Aviation (GA) accidents. SVS displays present computer generated 3-dimensional imagery of the surrounding terrain on the Primary Flight Display (PFD) to greatly enhance pilot's situation awareness (SA), reducing or eliminating Controlled Flight into Terrain, as well as Low-Visibility Loss of Control accidents. SVS-conducted research is facilitating development of display concepts that provide the pilot with an unobstructed view of the outside terrain, regardless of weather conditions and time of day. A critical component of SVS displays is the appropriate presentation of terrain to the pilot. An experimental study is being conducted at NASA Langley Research Center (LaRC) to explore and quantify the relationship between the realism of the terrain presentation and resulting enhancements of pilot SA and performance.

An experimental investigation was conducted to study the effectiveness of Synthetic Vision Systems (SVS) flight displays as a means of eliminating Low Visibility Loss of Control (LVLOC) and Controlled Flight Into Terrain (CFIT) accidents by low time general aviation (GA) pilots. A series of basic maneuvers were performed by 18 subject pilots during transition from Visual Meteorological Conditions (VMC) to Instrument Meteorological Conditions (IMC), with continued flight into IMC, employing a fixed-based flight simulator. A total of three display concepts were employed for this evaluation. One display concept, referred to as the Attitude Indicator (AI) replicated instrumentation common in today's General Aviation (GA) aircraft. The second display concept, referred to as the Electronic Attitude Indicator (EAI), featured an enlarged attitude indicator that was more representative of a “glass display” that also included advanced flight symbology, such as a velocity vector.

A causal analysis of aviation accidents that involved pilot error is presented. The analysis employs a top-down methodology that investigates the relationship between pilot errors and other causal factors with accidents. The Human Factors Analysis and Classification System (HFACS) framework is utilized to produce a comprehensive causal analysis of accident groups. This analysis will compare and evaluate causal factor patterns for both accidents induced by pilot errors and those where pilot error was a contributor but not the initiating event. Pilot induced accidents are those initiated by an inappropriate action of the aircrew. That is, the National transportation Safety Board (NTSB) report cited pilot error first within its analysis defining accident causes, factors, and findings. Pilot contributed accidents are those that are initiated by some other causal factor (weather, aircraft failure, etc.) and the pilot’s inappropriate action played a part in the outcome.

An experimental investigation of the flow over the rear end of a 0.16 scale notchback automobile configuration has been conducted in the NASA Langley Basic Aerodynamics Research Tunnel (BART). The objective of this work was to investigate the flow separation that occurs behind the backlight and obtain experimental data that can be used to understand the physics and time-averaged structure of the flow field. A three-component laser velocimeter was used to make non-intrusive, velocity measurements in the center plane and in a single cross-flow plane over the decklid. In addition to off-body measurements, flow conditions on the car surface were documented via surface flow visualization, boundary layer measurements, and surface pressures.

The highly inclined orbit of the International Space Station Alpha exhibits significant radiation exposure contributions from the galactic cosmic rays penetrating the earth's magnetic field. In the absence of an accepted method for estimating the corresponding astronaut risk, we examined the attenuation characteristics using conventional LET dependent quality factors (as one means of representing RBE) and a track-structure repair model fit to cell transformation (and inactivation) data in the C3H10T1/2 mouse cell system obtained by T. C. Yang and coworkers for various ion beams. Although the usual aluminum spacecraft shield is effective in reducing dose equivalent with increasing shield thickness, cell transformation rates are increased for thin aluminum shields providing increased risk rather than protection to large shield thickness.

Alternate Environmental Control and Life Support System (ECLSS) technologies were evaluated to reduce Space Station resources and dependence on expendables resupplied from Earth to sustain a multiperson crew in low-Earth orbit. Options were evaluated to close the oxygen (O2) loop by removing carbon dioxide (CO2) from the cabin air, reducing the CO2 to water, and electrolyzing the water to provide metabolic O2 for crew consumption. Options were also evaluated to close the urine/flush, condensate, and hygiene water loops to provide potable water for crew use. Specific evaluation parameters were derived which included weight, power, volume, maintenance, resupply consumables, and technology readiness.

The need for highly accurate measurements of velocity, temperature, pressure and density has required the development of new experimental techniques. While the majority of these development efforts at NASA Langley are focused toward applications for aeronautical programs such as the High-Speed Civil Transport, Advanced Subsonic Transport, and the National Aero-Space Plane, a number are applicable to other fields. The intent of this paper is to review recent instrumentation developments and applications at NASA Langley Research Center that may have applications in automotive testing. Five experimental techniques are described along with recent results obtained in NASA facilities.

Recent findings from NASA Langley tests to define effects of aircraft Type II chemical deicer depositions on aircraft tire friction performance are summarized. The Aircraft Landing Dynamics Facility (ALDF) is described together with the scope of the tire cornering and braking friction tests conducted up to 160 knots ground speed. Some lower speed 32-96 km/hr (20-60 mph) test run data obtained using an Instrumented Tire Test Vehicle (ITTV) to determine effects of tire bearing pressure and transverse grooving on cornering friction performance are also discussed. Recommendations are made concerning which parameters should be evaluated in future testing.

Human factors egress testing of the HL-20 Personnel Launch System, a reusable flight vehicle for Space Station crew rotation, was conducted in both the vertical (launch) and horizontal (landing) positions using a full-scale model. Ingress and egress of 10-person crews were investigated with volunteers representing a range of heights. For both the vertical and horizontal positions, interior structural keels had little impact on egress times which were generally less than 30 seconds. Wearing Shuttle partial pressure suits required somewhat more egress time than when ordinary flight suits were worn due to the larger helmet of the Shuttle suit.

In 1988, a 1067 m long touchdown zone on each end of the Kennedy Space Center (KSC) Shuttle Landing Facility (SLF) was modified from its original heavy-broom finish with transverse grooves configuration to a longitudinal corduroy surface texture with no transverse grooves. The intent of this modification was to reduce the spin-up wear on the Orbiter main gear tires and provide for somewhat higher crosswind capabilities at that site. The modification worked well, so it was proposed that the remainder of the runway be modified as well to permit even higher crosswind landing capability. Tests were conducted at the NASA Langley Aircraft Landing Dynamics Facility (ALDF) to evaluate the merit of such a modification. This paper discusses the results of these tests, and explains why the proposed modification did not provide the expected improvement and thus was not implemented.

Preliminary braking, steering, and tread wear performance results from testing of 26 x 6.6 and 40 x 14 radial-belted and bias-ply aircraft tires at NASA Langley's Aircraft Landing Dynamics Facility (ALDF) are reviewed. These tire tests are part of a larger, ongoing joint NASA/FAA/Industry Surface Traction And Radial Tire (START) Program involving these two different tire sizes as well as an H46 x 18-20 tire size which has not yet been evaluated. Both dry and wet surface conditions were evaluated on two different test surfaces - nongrooved Portland cement concrete and specially constructed, hexagonal-shaped concrete paver blocks. Use of paver blocks at airport facilities has been limited to ramp and taxiway areas and the industry needs a tire friction evaluation of this paving material prior to additional airport pavement installations.

Aerodynamic effects induced from vectoring an exhaust jet are investigated using a well established thin-layer Reynolds averaged Navier-Stokes code. This multiple block code has been modified to allow for the specification of jet properties at a block face. The applicability of the resulting code for thrust vectoring applications is verified by comparing numerically and experimentally determined pressure coefficient distributions for a jet-wing afterbody configuration with a thrust-vectoring 2-D nozzle. Induced effects on the body and nearby wing from thrust vectoring are graphically illustrated.

An investigation was conducted at the NASA Langley Research Center's Aircraft Landing Dynamics Facility (ALDF) to define the post-tire failure drag characteristics of the Space Shuttle Orbiter main tire and wheel assembly. Skid tests on various materials were also conducted to define their friction and wear rate characteristics under higher speed and bearing pressures than any previous tests. The skid tests were conducted to support a feasibility study of adding a skid to the orbiter strut between the main tires to protect an intact tire from failure due to overload should one of the tires fail. Roll-on-rim tests were conducted to define the ability of a standard and a modified orbiter main wheel to roll without a tire. Results of the investigation are combined into a generic model of strut drag versus time under failure conditions for inclusion into rollout simulators used to train the shuttle astronauts.

A model scaled test apparatus has been designed and assembled to simulate supersonic plume/aircraft structure Interaction for the cruise configuration. Preliminary results have been obtained to demonstrate the severity of the associated acoustic fatigue loads. Two rectangular supersonic nozzles with aspect ratios of 7 and 7.7 ware fabricated with internal convergent-divergent contours designed for Mach numbers of 1.35 and 2.00. A large flat plate was located beneath each nozzle at various nozzle height separations. The plate was instrumented to measure surface dynamic pressure and mean wall temperature. Phase averaged schliern measurements revealed the presence of high intensity acoustic emission from the supersonic plume above the plate and directed upstream. This radiation can be associated with the shock noise generation mechanism. Narrow band spectra of wall dynamic pressure show spectral peaks with amplitude levels as high as 1 PSI.

One of the factors needed to describe the handling characteristics of the Space Shuttle Orbiter during the landing rollout is the response of the vehicle's tires to variations in load and yaw angle. An experimental investigation of the cornering characteristics of the Orbiter main gear tires was conducted at the NASA Langley Research Center Aircraft Landing Dynamics Facility. This investigation compliments earlier work done to define the Orbiter nose tire cornering characteristics. In the investigation, the effects of load and yaw angle were evaluated by measuring parameters such as side load and drag load, and obtaining measurements of aligning torque. Because the tire must operate on an extremely rough runway at the Shuttle Landing Facility at Kennedy Space Center (KSC), tests were also conducted to describe the wear behavior of the tire under various conditions on a simulated KSC runway surface. Mathematical models for both the cornering and the wear behavior are discussed.

An investigation was conducted to determine the static mechanical characteristics of 30 × 11.5 - 14.5 bias-ply and radial aircraft tires. The tires were subjected to vertical and lateral loads and mass moment of inertia tests were conducted. Static load deflection curves, spring rates, hysteresis losses, and inertia data are presented along with a discussion of the advantages and disadvantages of one tire over the other.