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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Optical effect of the contamination of infrared windows by the outgassing of materials in outer space

The composition and evaporation rate of the outgassing of a space vehicle thermal control paint as a function of temperature were studied. A contamination chamber was designed, constructed, and tested. Samples of thermal control paint were tested to determine if heating to moderate temperatures causes them to release outgassing products which can be collected on a cooled cesium iodide window for identification by IR analysis. Results showed that outgassing of surfaces other than the sample was a problem. Spectral bands of the deposits collected were compared.

Silberman, E.↗
NASA NTRS1974

Environment of a spacecraft produced by its own outgassing

The effect of material outgassing on the spacecraft internal pressure, on contamination of critical surfaces, on detection of distant weak radiation sources and other problems are discussed. The internal and external outgassing fluxes are examined in relation to their variation with time, temperature, and location. Methods for estimating the total outgassing of a spacecraft are reported. These methods are supported by results obtained in vacuum chamber tests.

Scialdone, J. J.↗
NASA NTRS1972

Vacuum stability testing of Apollo 15 Scientific Instrument Module (SIM) non-metallic materials and reversion of silicone rubber in a motor switch

Vacuum stability screening tests were performed on the Apollo 15 Scientific Instrument Module (SIM) bay nonmetallic materials in accordance with the NASA document SP-R-0022. The testing was necessary to support the evaluation to determine the effect material outgassing contamination would have on the SIM bay optical lenses and sensing devices. The Apollo 15 SIM experiments were highly successful, therefore, it is assumed that contamination due to the outgassing of nonmetallic materials did not affect equipment operation. A related problem, the reversion of a silicone rubber grommet which affected an electrical motor switch operation is also reported.

Clancy, H. M.↗
NASA NTRS2000

International Space Station External Contamination Status

PResentation slides examine external contamination requirements; International Space Station (ISS) external contamination sources; ISS external contamination sensitive surfaces; external contamination control; external contamination control for pre-launch verification; flight experiments and observations; the Space Shuttle Orbiter waste water dump, materials outgassing, active vacuum vents; example of molecular column density profile, modeling and analysis tools; sources of outgassing induced contamination analyzed to date, quiescent sources, observations on optical degradation due to induced external contamination in LEO; examples of typical contaminant and depth profiles; and status of the ISS system, material outgassing, thruster plumes, and optical degradation.

Mikatarian, Ron↗
NASA NTRS2006

Space Shuttle Thermal Protection System Repair Flight Experiment Induced Contamination Impacts

NASA s activities to prepare for Flight LF1 (STS-114) included development of a method to repair the Thermal Protection System (TPS) of the Orbiter s leading edge should it be damaged during ascent by impacts from foam, ice, etc . Reinforced Carbon-Carbon (RCC) is used for the leading edge TPS. The repair material that was developed is named Non- Oxide Adhesive eXperimental (NOAX). NOAX is an uncured adhesive material that acts as an ablative repair material. NOAX completes curing during the Orbiter s descent. The Thermal Protection System (TPS) Detailed Test Objective 848 (DTO 848) performed on Flight LF1 (STS-114) characterized the working life, porosity void size in a micro-gravity environment, and the on-orbit performance of the repairs to pre-damaged samples. DTO 848 is also scheduled for Flight ULF1.1 (STS-121) for further characterization of NOAX on-orbit performance. Due to the high material outgassing rates of the NOAX material and concerns with contamination impacts to optically sensitive surfaces, ASTM E 1559 outgassing tests were performed to determine NOAX condensable outgassing rates as a function of time and temperature. Sensitive surfaces of concern include the Extravehicular Mobility Unit (EMU) visor, cameras, and other sensors in proximity to the experiment during the initial time after application. This paper discusses NOAX outgassing characteristics, how the amount of deposition on optically sensitive surfaces while the NOAX is being manipulated on the pre-damaged RCC samples was determined by analysis, and how flight rules were developed to protect those optically sensitive surfaces from excessive contamination where necessary.

Smith, Kendall A.↗
NASA NTRS1984

Improved materials characterization for spacecraft applications

A material outgassing test consists of an effusion cell, mass spectrometer, and thermally controlled quartz crystal microbalance (TQCM). The material sample is placed in the effusion cell at a predetermined temperature, and the sample is outgassed in a vacuum of 0.000001 torr range. The total outgassing mass as a function of time is determined with the TQCM which is cooled to LN2 temperatures. Based on the view factor of the TQCM, the total outgassed mass can be determined. The technique can be verified by comparing the results to the actual mass loss of the sample which is determined by hanging the diffusion cell from the Cohn microbalance. The mass spectrometer can be used to determine if there are any low molecular weight components outgassing, such a nitrogen which does not condense on the TQCM. After the material outgasses to a point of saturation, the effusion cell is closed off, and the TQCM is slowly heated to allow the condensed film to be broken down into its components. As the temperature is increased, the components evaporate from the surface at a different rate and can be detected with the mass spectrometer. The relative amount of each component is found by the change in frequency of the TQCM as the component evaporates. Hence, from this test, not only is isothermal kinetic data obtained, but the primary components can also be identified in terms of their molecular weight.

Cull, R.↗
NASA NTRS1994

ASTM E 1559 method for measuring material outgassing/deposition kinetics has applications to aerospace, electronics, and semiconductor industries

The American Society for Testing and Materials has published a new standard test method for characterizing time and temperature-dependence of material outgassing kinetics and the deposition kinetics of outgassed species on surfaces at various temperatures. This new ASTM standard, E 1559(1), uses the quartz crystal microbalance (QCM) collection measurement approach. The test method was originally developed under a program sponsored by the United States Air Force Materials Laboratory (AFML) to create a standard test method for obtaining outgassing and deposition kinetics data for spacecraft materials. Standardization by ASTM recognizes that the method has applications beyond aerospace. In particular, the method will provide data of use to the electronics, semiconductor, and high vacuum industries. In ASTM E 1559 the material sample is held in vacuum in a temperature-controlled effusion cell, while its outgassing flux impinges on several QCM's which view the orifice of the effusion cell. Sample isothermal total mass loss (TML) is measured as a function of time from the mass collected on one of the QCM's which is cooled by liquid nitrogen, and the view factor from this QCM to the cell. The amount of outgassed volatile condensable material (VCM) on surfaces at higher temperatures is measured as a function of time during the isothermal outgassing test by controlling the temperatures of the remaining QCM's to selected values. The VCM on surfaces at temperatures in between those of the collector QCM's is determined at the end of the isothermal test by heating the QCM's at a controlled rate and measuring the mass loss from the end of the QCM's as a function of time and temperature. This reevaporation of the deposit collected on the QCM's is referred to as QCM thermogravimetric analysis. Isothermal outgassing and deposition rates can be determined by differentiating the isothermal TML and VCM data, respectively, while the evaporation rates of the species can be obtained as a function of temperature by differentiating the QCM thermogravimetric analysis data.

Garrett, J. W.↗
NASA NTRSDate not supplied

Overview of the Lunar Gateway External Contamination Environment

As a part of the Artemis mission, Gateway will be a long duration space station in a near rectilinear halo orbit around the Moon. Gateway will be exposed to a variety of external contamination sources, which can degrade external hardware / surfaces and impact science utilization objectives. Requirements and methodologies addressing material outgassing, chemical and electric thruster plumes, vacuum venting, and visiting vehicle interactions have been developed by the Gateway Induced Environments team to ensure vehicle performance and mission success. The external contamination requirements and integration process are described along with required data deliverables. Integrated external contamination analyses are conducted by the Gateway Environments Team to assess compliance with external contamination requirements. This paper provides a current status of integration activities and analysis results, as well as future plans to improve external contamination characterization.

thruster plumes↗
NASA NTRSDate not supplied

Gateway Induced Environments Overview

Gateway will be a long duration space station orbiting the Moon in support of NASA’s Artemis campaign. Over its lifetime, Gateway will be exposed to a variety of induced environments, including materials outgassing, chemical and electric thruster plumes, vacuum vents, and lunar dust transport (from the Human Lander System, HLS). Induced Environments can impact vehicle performance and mission success. The multidisciplinary Gateway Induced Environments Team has developed requirements and methodologies to address the complex challenge of integrating multiple elements and visiting vehicles while maintaining the Gateway induced environments within prescribed limits. The Gateway Induced Environments requirements are summarized along with the integration / verification process and preliminary system analysis results.

Gateway↗
NASA NTRSDate not supplied

Gateway Induced Environments Overview

Gateway will be a long duration space station orbiting the Moon in support of NASA’s Artemis campaign. Over its lifetime, Gateway will be exposed to a variety of induced environments, including materials outgassing, chemical and electric thruster plumes, vacuum vents, and lunar dust transport (from the Human Lander System, HLS). Induced Environments can impact vehicle performance and mission success. The multidisciplinary Gateway Induced Environments Team has developed requirements and methodologies to address the complex challenge of integrating multiple elements and visiting vehicles while maintaining the Gateway induced environments within prescribed limits. The Gateway Induced Environments requirements are summarized along with the integration / verification process and preliminary system analysis results.

Gateway↗
NASA NTRSDate not supplied

Small Space Craft Materials Evaluation of Commercial Off The Shelf (COTS) Parts

The proliferation of inexpensive small spacecraft involves increasing use of Commercial Off The Shelf (COTS) parts. Often the composition, origin, provenance and/or properties of these parts are unspecified.The use of these materials complicates the evaluation of component suitability for low outgassing, material properties and even functionality. These problems will drive: a) the development of a sequence of gateway acceptability tests that can be used to reject parts before contaminating the usual Thermal Vacuum Chamber (TVAC) and other test equipment; b)the creation of a database for COTS parts that are acceptable for spacecraft use; c) a course of flight hardware training for novice spacecraft builders to limit the recurrence of common mistakes; d)fostering a more experienced, mature and sophisticated community of spacecraft developers that can determine if a proposed approach or material use is appropriate.An especially common spacecraft material issue involves the appropriate and inappropriate use of silicones. This presentation will provide examples of strategic methods used to mitigate the risks of COTS parts.

Small Spacecraft↗
NASA NTRS1975

Analytical study of spacecraft deposition contamination by internal reflection spectroscopy

The in-situ vacuum chamber designed around the IRE was tested under vacuum. The contamination analyzer system was tested using two liquid contaminant materials. The analysis of the contaminants on the SL-4 rendezvous window shows that the material has methyl silicone, hydroxyl, and carbonyl radicals. The analysis of the outgassing material from Shuttle TPS shows silicone as the primary product.

Mookherji, T. K.↗
NASA NTRS2026

Outgassing Characterization of Common Trash Items for Disposal By Nanoracks Airlock on the International Space Station

The arrival of the Nanoracks Airlock to the International Space Station (ISS) has provided the ISS program the capability to dispose of common trash items. The concept of operations involved the crew bagging up those items into a trash bag and then utilizing the robotic arm and the airlock to jettison the trash bag. Because of the unknown thermal vacuum stability of some of the items, a molecular contamination concern was raised by the ISS program as the trash is exposed to vacuum upon the evacuation of air from the airlock and the robotic arm moving the airlock to its jettison location. In order to characterize the representative outgassing rates for ISS trash, thermal vacuum testing was performed at White Sands Test Facility. Trash was sorted into a “lower” outgassing bag and a “mixed” bag. The “mixed” trash bag contained more items that were suspected to be not vacuum stable. Load cells were chosen as the primary means for measuring mass loss. A sharp decay in the outgassing rate was observed in the first 30 minutes followed by a slower decay. As expected, the “mixed” bag lost more mass. While Quartz Crystal Microbalances (QCMs) are often utilized to measure long term outgassing rates and the sticking coefficients of contaminants at different operating temperatures for vacuum stable materials, these measurements proved difficult due to the amount and the inclusion of materials with suspect thermal vacuum stability. Because of high rates of material outgassing, the facility was unable to maintain the CQCM temperature setpoint of 80 K QCMs.. The QCMs operating at the warmer temperatures also saturated on occasion due to high levels of condensed matter. Though testing was able to confirm high risk of outgassing contamination for the program, true sticking coefficients could not be determined, available measurements are provided herein.

Alvin Y Huang↗
NASA NTRS1981

Absorption spectra of typical space materials in the vacuum ultraviolet

In order to develop a data base for potential optical degradation of space vacuum ultraviolet instruments, the collected volatile condensed material (CVCM) transmittance was measured in the wavelength region from 115 nm to 300 nm. The parent outgassing materials included: the adhesives, Ablebond 36-2, Trabond BB-2116, EA-9309, and Scotchweld 2216; the paints, Chemglaze Z-306, Z-306 over 9922 primer, Z-306 over AP-131 primer, Cat-A-Lac 463-3-8, 463-3-8 over primer, 3M Nextel 401-C10, and 401-C10 over 901-P1 primer; the resins, Fiberite 934, Solithane 113/C113-300 Formulation no. 1, and 113/C113-300 Formulation no. 8; the lubricants, Lube-Lok 4306 and RT/Duroid 5813; and the double-sided adhesive tape 3M-415. The effect of thermal vacuum conditioning of selected materials was also studied. The transmittance measurements were used to calculate the absorption coefficient for each of 28 different source materials versus wavelength.

Muscari, J. A.↗
NASA NTRS1974

The outgassing and pressures in a spacecraft

The parameters that affect the internal pressure, i.e., the effective flow conductances of the internal volumes, their time constants and outgassing sources are examined. The objectives are to estimate the internal pressure of the spacecraft during the first several days after launch and to evaluate the responses of the volume to external pressure variations. The general approach followed is to (1) establish the various flow paths from a compartment to the low pressure regions; (2) calculate the conductances and combined effective conductances for these paths; (3) estimate the material outgassing rates in each volume from a general knowledge of materials used in the spacecraft; and (4) establish the pressure vs time in these compartments. The results of these techniques have been compared with experimental results obtained during thermal vacuum test of the spacecraft.

Scialdone, J. J.↗
NASA NTRS1991

LDEF post-retrieval evaluation of exobiology interests

Cursory examination of the Long Duration Exposure Facility (LDEF) shows the existence of thousands of impact craters of which less than 1/3 exceed 0.3 mm in diameter; the largest crater is 5.5 mm. Few craters show oblique impact morphology and, surprisingly, only a low number of craters have recognizable impact debris. Study of this debris could be of interest to exobiology in terms of C content and carbonaceous materials. All craters greater that 0.3 mm have been imaged and recorded into a data base by the preliminary examination team. Various portions of the LDEF surfaces are contaminated by outgassed materials from experimenters trays, in addition to the LDEF autocontamination and impact with orbital debris not of extraterrestrial origin. Because interplanetary dust particles (IDP's) nominally impacted the LDEF at velocities greater than 3 km/s, the potential for intact survival of carbonaceous compounds is mostly unknown for hypervelocity impacts. Calculations show that for solid phthalic acid (a test impactor), molecular dissociation would not necessarily occur below 3 km/s, if all of the impact energy was directed at breaking molecular bonds, which is not the case. Hypervelocity impact experiments (LDEF analogs) were performed using the Ames Vertical Gun Facility. Grains of phthalic acid and the Murchison meteorite (grain diameter = 0.2 for both) were fired into an Al plate at 2.1 and 4.1 km/s respectively. The results of the study are presented, and it is concluded that meaningful biogenic elemental and compound information can be obtained from IDP impacts on the LDEF.

Bunch, T. E.↗