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The effectiveness of a proposed concept for shielding a manned Mars vehicle using a confined magnetic field configuration is evaluated by computing estimated crew radiation exposures resulting from galactic cosmic rays and a large solar flare event. In the study the incident radiation spectra are transported through the spacecraft structure/magnetic shield using the deterministic space radiation transport computer codes developed at Langley Research Center. The calculated exposures unequivocally demonstrate that magnetic shielding could provide an effective barrier against solar flare protons but is virtually transparent to the more energetic galactic cosmic rays. It is then demonstrated that through proper selection of materials and shield configuration, adequate and reliable bulk material shielding can be provided for the same total mass as needed to generate and support the more risky magnetic field configuration.

Tests of the Space Shuttle Orbiter nose-gear tire have been completed at NASA Langley's Aircraft Landing Dynamics Facility. The purpose of these tests was to determine the cornering and wear characteristics of the Space Shuttle Orbiter nose-gear tire under realistic operating conditions. The tire was tested on a simulated Kennedy Space Center runway surface at speeds from 100 to 180 kts. The results of these tests defined the cornering characteristics which included side forces and associated side force friction coefficient over a range of yaw angles from 0° to 12°. Wear characteristics were defined by tire tread and cord wear over a yaw angle range of 0° to 4° under dry and wet runway conditions. Wear characteristics were also defined for a 15 kt crosswind landing with two blown right main-gear tires and nose-gear steering engaged.

Tests with specially instrumented NASA B-737 and B-727 aircraft together with several different ground friction measuring devices have been conducted for a variety of runway surface types and wetness conditions. This effort is part of the Joint FAA/NASA Aircraft/Ground Vehicle Runway Friction Program aimed at obtaining a better understanding of aircraft ground handling performance under adverse weather conditions and defining relationships between aircraft and ground vehicle tire friction measurements. Aircraft braking performance on dry, wet, snow-, and ice-covered runway conditions is discussed together with ground vehicle friction data obtained under similar runway conditions. For a given contaminated runway surface condition, the relationship between ground vehicles and aircraft friction data is identified. The influence of major test parameters on friction measurements such as speed, test tire characteristics, and surface contaminant type are discussed.

One of the factors needed to describe the wear behavior of the Space Shuttle Orbiter main gear tires is their behavior during the spin-up process. An experimental investigation of tire spin-up processes was conducted at the NASA Langley Research Center's Aircraft Landing Dynamics Facility (ALDF). During the investigation, the influence of various parameters such as forward speed and sink speed on tire spin-up forces were evaluated. A mathematical model was developed to estimate drag forces and spin-up times and is presented. The effect of prerotation was explored and is discussed. Also included is a means of determining the sink speed of the orbiter at touchdown based upon the appearance of the rubber deposits left on the runway during spinup.

Joining advanced composite materials is one of the greatest obstacles to proliferating their use in aerospace structures. Another hindrance is the high cost of manufacturing advanced composite structures using conventional methods. The present trend in both the automotive and aerospace industries is lighter weight, energy efficient structures. In the aerospace community, the use of advanced composite structures has the potential for weight reductions of 35 to 40 percent as compared with the use of conventional aluminum alloys. However, this advantage is offset by the higher cost of manufacturing in using conventional composite technology. This paper identifies pultrusion and induction bonding as potential methods for manufacturing lightweight high-strength advanced composite structures.

Large space structures will be a key element of our future space activities. They will include spacecraft such as the planned Space Station and large antenna/reflector structures for communications and observations. These large structures will exceed 100 m in length or 30 m in diameter. Concepts for construction of these spacecraft on orbit and their materials of construction provide some unique research challenges. This paper will provide an overview of our research in space construction of large structures including erectable and deployable concepts. Also, an approach to automated, on-orbit construction will be presented. Materials research for space applications focuses on high stiffness, low expansion composite materials that provide adequate durability in the space environment. The status of these materials research activities will be discussed.

The LIDAR In-Space Technology Experiment (LITE) will employ LIDAR techniques to study the atmosphere from space. The LITE instrument will be flown in the Space Shuttle Payload Bay with an earth directed orientation. The experiment thermal control incorporates both active and passive techniques. The Laser Transmitter Module (LTM) and the System Electronics will be actively cooled through the shuttle pallet coolant loop. The Receiver System and Experiment Platform will be passively controlled through the use of insulation and component surface properties. This paper explains the thermal control techniques used and the analysis results, with primary focus on the Receiver System.

Seventeen Environmental Control and Life Support System technology options to provide metabolic oxygen and water to sustain a multiperson crew on Space Station missions have been evaluated. The options included state-of-the-art technologies as well as advanced technologies that offer the potential for improvements in Environmental Control and Life Support Systems performance. The methodology for candidate technology recommendations was based upon specific assessment criteria as functions of prelaunch development activities and postlaunch operational considerations. The electrochemical depolarized cell option for carbon dioxide concentration, the sabatier option for carbon dioxide reduction, the static feed water electrolysis option for metabolic oxygen recovery, and vapor compression distillation and multifiltration options for waste water recovery were recommended.

The Toroid Joining Gun is a low cost, self-contained, portable low powered (100-400 watts) thermoplastic welding system developed at Langley Research Center for joining plastic and composite parts using an induction heating technique. The device developed for use in the fabrication of large space structures (LSST Program) can be used in any atmosphere or in a vacuum. Components can be joined in situ, whether on earth or on a space platform. The expanded application of this welding gun is in the joining of thermoplastic composites, thermosetting composites, metals, and combinations of these materials. Its low-power requirements, light weight, rapid response, low cost, portability, and effective joining make it a candidate for solving many varied and unique bonding tasks.

A description is given of a computer program developed at the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) for the assessment of manned space station environmental control and life support systems (ECLSS) technology. The program methodology along with the data base and mission model variables are given for 17 candidate technologies that show potential for supplying metabolic oxygen and water on manned space missions. The data base includes metabolic design loads associated with crew activity, engineering design parameters for each technology option, and cost data required for candidate life cycle cost comparisons. The method for ranking the candidate options in order to provide recommendations for space station application or subsequent development is presented.