Search Results

NIRSpec is a near-infra-red spectrometer and one of the four instruments onboard the James Webb Space Telescope (JWST). The JWST observatory will be placed at the second Lagrange point (L2). The instrument will be operated at about 30 Kelvin. Temperature stability and controlled heat rejection to dedicated JWST radiators are important issues of the NIRSpec thermal design. Besides thermal insulation, the NIRSpec Optical Assembly Cover also has to provide light tightness and stray light suppression to prevent unwanted light entering the instrument. Air tightness is needed to allow a controlled purge gas flow for contamination prevention while allowing proper air venting during launch. Because of mass constraints a cover employing two-foil Kapton blankets supported by aluminum posts and a wire tent was chosen. Failure tolerance and cleanliness are other important design drivers. This paper describes the design solutions established to fulfil the contrary requirements

The baseline hygiene water reclamation system for Space Station Freedom has been changed from Reverse Osmosis with Multifiltration post-treatment to stand-alone Multifiltration. The Multifiltration concept offers increased system reliability, a decrease in power consumption, and essentially 100% water recovery. Multifiltration is based on well documented sorption technology for removal of contaminant species. System complexity is minimal. Moving parts are limited to one pump and simple valving. Reliable microbial control is obtained by heat sterilization and by the use of iodine as a bactericide. Iodine addition is accomplished in the Unibeds with an iodinated resin which is also used in the Microbial Check Valve (MCV). Microbial Check Valves have proven reliable and effective on board the Space Shuttle since the beginning of the Shuttle program. Power consumption is primarily attributed to heat sterilization. The energy required for the pump and controls is relatively low.

Long duration space flights will require an on-board clothes laundering facility to reduce the logistic requirement of resupplying clean clothing. The concept investigated and discussed in this paper addresses two major problems associated with all microgravity clothes laundering facilities to date: high energy consumption and two-phase air/water waste streams. Foam and air bubbles decrease the efficiency of pumps, storage vessels, and water reclamation systems. This problem was overcome by eliminating all air additions during the wash/rinse cycles. Energy consumption is minimized by use of microwave energy for drying.

The ability to aseptically remove samples and products, and the capability for addition of materials to sterile or otherwise microbially susceptible systems have always been compromised by the lack of a reliable means of sterilizing the mating fixtures. Cultures of mammalian cells are particularly vulnerable to microbial contamination due to the complexity of nutrient media and the lengthy periods required for cell growth. The Microwave Sterilizable Access Port has been developed to overcome this limitation. The system consists of three primary components: a microwave power source, a combined sterilization chamber/in-line valve port assembly, and a specimen transfer interface. Microwave energy is transmitted via coaxial cable to a small pressurized chamber that serves as a sterile transition between the surrounding environment and the system during transfer of materials.

A microgravity whole body shower and waste water recovery system were evaluated in three separate closed loop tests at NASA/JSC. These tests covered a period from August 1985 to June 1987 in which shower waste water was reclaimed and reused for showering. Test persons showered in a preprototype whole body shower following a protocol similar to that anticipated for the Space Station. Each test was performed by using different water recovery system technologies which included phase change distillation and two separate reverse osmosis processes. These were integrated with post-treatment for the final purification of the reclaimed water. The phase change, a preprototype Thermoelectric Hollow Fiber Membrane Evaporation Subsystem was used for the initial test with chemical pretreatment of the shower waste water input. A reverse osmosis dynamic membrane system was used for the second test and a 2-stage ultrafiltration/reverse osmosis system for the third test.

A microgravity whole body shower (WBS) and a waste water recovery system (WWRS) were used in a closed loop test at the Johnson Space Center. The WWRS process involved chemical pretreatment, phase change distillation and post-treatment. A preprototype Thermoelectric Integrated Hollow Fiber Membrane Evaporation Subsystem (TIMES) was used for distillation after pretreatment and the post-treatment was accomplished with activated carbon, mixed ion exchange resin beds and microbial check valve (MCV) iodine bactericide dispensing units. The purposes of this test were to evaluate a NASA approved Shuttle soap for whole body showering comfort; evaluate the effects of the shower water on the WBS and the TIMES; and evaluate purification qualities of the recovered water in a closed loop operation.

A shower test was conducted recently at NASA-JSC in which waste water was reclaimed and reused. Test subjects showered in a prototype whole body shower following a protocol similar to that anticipated for Space Station. The waste water was purified using reverse osmosis followed by filtration through activated carbon and ion exchange resin beds. The reclaimed waste water was maintained free of microorganisms by using both heat and iodine. This paper discusses the test results, including the limited effectiveness of using iodine as a disinfectant and the evaluation of a Space Station candidate soap for showering. In addition, results are presented on chemical and microbial impurity content of water samples obtained from various locations in the water recovery process.

The development of a spectrophotometric analyzer for use on water samples in microgravity environments is discussed. The instrument is constructed around a commercial spectrophotometer, the Hewlett-Packard HP8453, with a separate turbidimetric analyzer, here a modified Hach 2100P ratio turbidimeter. Flow-through sample cells were constructed for each instrument to support microgravity use and sample deaeration. Spectrophotometric analyses on aqueous samples on orbit are sensitive to the presence of undissolved gases in the samples. In a micro-g environment, free gas in samples can and does remain suspended, clouding the mixture and interfering with spectral optical density measurements. This paper discusses the design of a spectrophotometric analyzer, with particular emphasis on the merits of two approaches to eliminating free gas interferences in on-orbit water analyses: hyperbaric gas redissolution and deaeration across a hydrophobic membrane.

Iodine is the disinfectant used in U.S. spacecraft potable water systems. Recent long-term testing on human subjects has raised concerns about excessive iodine consumption. Efforts to reduce iodine consumption by Shuttle crews were initiated on STS-87, using hardware originally designed to deiodinate Shuttle water prior to transfer to the Mir Space Station. This hardware has several negative aspects when used for Shuttle galley operations, and efforts to develop a practical alternative were initiated under a compressed development schedule. The alternative Low Iodine Residual System (LIRS) was flown as a Detailed Test Objective on STS-95. On-orbit, the LIRS imparted an adverse taste to the water due to the presence of trialkylamines that had not been detected during development and certification testing. A post-flight investigation revealed that the trialkylamines were released during gamma sterilization of the LIRS resin materials.