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Technical Paper

Space Station ATCS Performance During Orbiter Berthing

This paper documents the Space Station Freedom (SSF) Active Thermal Control System (ATCS) performance during approach/departure, berthing, and deberthing operations. Recommended fixed radiator orientations and radiator orientations as a function of the (β angle were used for SSF flights MB5 through UF-1. Radiator rotation restrictions impacting ATCS performance included plume loads during proximity operations, minimum clearances from the Shuttle post-mating, visual cues required for mating and/or SSF remote manipulator system, attitude perturbations, number of Orbital Replacement Units (ORUs) deployed and thermal radiator rotation joint bending moment response. Three thermal models (TEA, ALPHA and TAURUS) performed the analyses on the MB5 through UF-1 mission builds. The study was divided into three parts pertaining to approach/departure, berthing, and deberthing.
Technical Paper

Space Station ATCS Radiator Rotation Profiles in LVLH TEA/LVLH, Arrow and Gravity Gradient Mode

This study assessed Active Thermal Control System Central Thermal Bus radiator rotation profiles for the Space Station Freedom in Local Vertical/Local Horizontal, two Torque Equilibrium Attitudes (MB11 and MB17), Arrow and Gravity Gradient modes while maintaining radiator angular velocities and accelerations under 45 degree/minute and 0.01 degree/sec2, respectively. To determine the thermal influence of the Flex Hose Coupler (FHC), cases ran with the ±105° radiator orientation restriction as imposed by the coupler. The study used hot thermal environments and End-Of-Life panel properties. The model used was structured to produce radiator profiles that are as close as possible to an instantaneous and local minimum environment without violating the maximum angular rotation imposed. The results from all the investigated cases indicate that the radiator should be allowed to rotate between -167° (Gravity Gradient mode) and 207° (Arrow mode).
Technical Paper

Development of an Air-Bearing Fan for Space Extravehicular Activity (EVA) Suit Ventilation

AiResearch has demonstrated a high-speed axial fan that can be used for space extravehicular activity (EVA) suit ventilation. The fan provides variable flow for the suit in a lightweight, compact design. It combines fine-scale aerodynamics with air bearings and a two-pole toothless permanent magnet motor. The fan has demonstrated quiet, vibration-free operation satisfying performance requirements in a small package: 0.31 l (18.9 cu in.) in volume, 7.8 cm (7 in.) in length, with a weight under 0.9 kg (1.98 lb). This paper describes the fan and control design and discusses test results. The fan accommodates desired changes in the ventilation flow rate by allowing the astronaut to vary fan speed, achieving over a two-to-one range in flow rate. The development program tested the fan at flow rates ranging from 99 to 225 l/min (3.5 to 8 acfm) at operating pressures from 0.414 to 1.586 bar (6.0 to 23 psia) with pressure rises of 0.5 to 2.49 kPa (2.0 to 10 in. H2O).
Technical Paper

ASDA - Advanced Suit Design Analyzer Computer Program

ASDA was developed to evaluate the heat and mass transfer characteristics of advanced pressurized suit design concepts for use in low pressure or vacuum planetary environments. The model incorporates a generalized 3-layer suit, constructed with the Systems Integrated Numerical Differencing Analyzer '85 (SINDA '85), with a 41- node FORTRAN routine that simulates the transient heat transfer and respiratory processes of a human body in a suited environment. User options for the suit include a liquid cooled garment, a removable jacket, a CO2/H2O permeable layer and a phase change layer. The model also has an option to isolate flowing oxygen in the helmet from stagnant or flowing gas in the torso and limbs. Options for the environment include free and forced convection with a user input atmosphere, incident solar/infrared fluxes, radiation to a background sink and radiation and conduction to a surface. Results from a study of Mars suit concepts will also be presented.
Technical Paper

Shuttle Launch Entry Suit Liquid Cooling System Thermal Performance

A thermoelectric liquid cooling system recently developed at the Johnson Space Center was evaluated in manned and unmanned ground tests as an alternative to the Space Shuttle launch and entry suit personal fan. The liquid cooling system provided superior cooling in environments simulating flight deck conditions during launch and postlanding.