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Technical Paper

Space Suit Radiator Performance in Lunar and Mars Environments

2007-07-09
2007-01-3275
During an ExtraVehicular Activity (EVA), both the heat generated by the astronaut's metabolism and that produced by the Portable Life Support System (PLSS) must be rejected to space. The heat sources include the heat of adsorption of metabolic CO2, the heat of condensation of water, the heat removed from the body by the liquid cooling garment and the load from the electrical components. Although the sublimator hardware to reject this load weighs only 1.58 kg (3.48 lbm), an additional 3.6 kg (8 lbm) of water are loaded into the unit, most of which is sublimated and lost to space, thus becoming the single largest expendable during an eight-hour EVA. Using a radiator to reject heat from the astronaut during an EVA can reduce the amount of expendable water consumed in the sublimator. Last year we reported on the design and initial operational assessment tests of a novel radiator designated the Radiator And Freeze Tolerant heat eXchanger (RAFT-X).
Technical Paper

A Test Plan for Sensitivity of Hollow Fiber Spacesuit Water Membrane Evaporator Systems to Potable Water Constituents, Contaminants and Air Bubbles

2008-06-29
2008-01-2113
The Spacesuit Water Membrane Evaporator (SWME) is the baseline heat rejection technology selected for development for the Constellation lunar suit. The first SWME prototype, designed, built, and tested at Johnson Space Center in 1999 used a Teflon hydrophobic porous membrane sheet shaped into an annulus to provide cooling to the coolant loop through water evaporation to the vacuum of space. This present study describes the test methodology and planning to compare the test performance of three commercially available hollow fiber materials as alternatives to the sheet membrane prototype for SWME, in particular, a porous hydrophobic polypropylene, and two variants that employ ion exchange through non-porous hydrophilic modified Nafion. Contamination tests will be performed to probe for sensitivities of the candidate SWME elements to ordinary constituents that are expected to be found in the potable water provided by the vehicle, the target feedwater source.
Technical Paper

Lightweight, Flexible, and Freezable Heat Pump/Radiator for EVA Suits

2008-06-29
2008-01-2112
We have completed preliminary tests that show the feasibility of an innovative concept for a spacesuit thermal control system using a lightweight, flexible heat pump/radiator. The heat pump/radiator is part of a regenerable LiCI/water absorption cooling device that absorbs an astronaut's metabolic heat and rejects it to the environment via thermal radiation at a relatively high temperature. We identified key design specifications for the system, demonstrated that it is feasible to fabricate the flexible radiator, measured the heat rejection capability of the radiator, and assessed the effects on overall mass of the PLSS. We specified system design features that will enable the flexible absorber/radiator to operate in a wide range of space exploration environments. The materials used to fabricate the flexible absorber/radiator samples were all found to be low off-gassing and many have already been qualified for use in space.
Technical Paper

First Lunar Outpost Extravehicular Life Support System Evaluation

1993-07-01
932188
A preliminary evaluation of several portable life support system (PLSS) concepts which could be used during the First Lunar Outpost (FLO) mission extravehicular activities (EVA's) has been performed. The weight, volume and consumables characteristics for the various PLSS concepts were estimated. Thermal effects of day and night EVA's on PLSS consumables usage and hardware requirements were evaluated. The benefit of adding a radiator and the total PLSS weight to be carried by the astronaut were also evaluated for each of the concepts. The results of the evaluation were used to provide baseline weight, volume and consumables characteristics of the PLSS to be used on the 45 day FLO mission. The benefit of radiators was shown to be substantial. Considerable consumables savings were predicted for EVA schedules with a high concentration of nighttime EVA's versus daytime EVA's.
Journal Article

A Freezable Heat Exchanger for Space Suit Radiator Systems

2008-06-29
2008-01-2111
During an ExtraVehicular Activity (EVA), both the heat generated by the astronaut's metabolism and that produced by the Portable Life Support System (PLSS) must be rejected to space. The heat sources include the heat of adsorption of metabolic CO2, the heat of condensation of water, the heat removed from the body by the liquid cooling garment, the load from the electrical components and incident radiation. Although the sublimator hardware to reject this load weighs only 1.58 kg (3.48 lbm), an additional 3.6 kg (8 lbm) of water are loaded into the unit, most of which is sublimated and lost to space, thus becoming the single largest expendable during an eight-hour EVA. Using a radiator to reject heat from the astronaut during an EVA can reduce the amount of expendable water consumed in the sublimator. Radiators have no moving parts and are thus simple and highly reliable. However, past freezable radiators have been too heavy.
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