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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

Natural Hazards of the Space Environment

Spacecraft in Low Earth Orbit (LEO) are subject to numerous environmental hazards. Here I'll briefly discuss three environment factors that pose acute threats to the survival of spacecraft systems and crew: atmospheric drag, impacts by meteoroids and orbital debris, and ionizing radiation. Atmospheric drag continuously opposes the orbital motion of a satellite, causing the orbit to decay. This decay will lead to reentry if not countered by reboost maneuvers. Orbital debris is a by-product of man's activities in space, and consists of objects ranging in size from miniscule paint chips to spent rocket stages and dead satellites. Ionizing radiation experienced in LEO has several components: geomagnetically trapped protons and electrons (Van Allen belts); energetic solar particles; galactic cosmic rays; and albedo neutrons. These particles can have several types of prompt harmful effects on equipment and crew, from single-event upsets, latchup, and burnout of electronics, to lethal doses to crew.All three types of prompt threat show some dependence on the solar activity cycle. Atmospheric drag mitigation and large debris avoidance require propulsive maneuvers. M/OD and ionizing radiation require some form of shielding for crew and sensitive equipment. Limiting exposure time is a mitigation technique for ionizing radiation and meteor streams.

Evans, Steven W.↗
NASA NTRS2019

Durability of Polymers in the Space Environment

Spacecraft in low Earth orbit (LEO) are subjected to harsh environmental conditions, including radiation (cosmic rays, ultraviolet, x-ray, and charged particle radiation), micrometeoroids and orbital debris, temperature extremes, thermal cycling, and atomic oxygen (AO). These environmental exposures can result in erosion, embrittlement and optical property degradation, threatening spacecraft performance and durability. While all of these environmental exposures can cause degradation to spacecraft components, AO is a particularly serious structural, thermal, and optical threat, to exterior oxidizable spacecraft materials, such as polymers. To further our understanding of AO erosion and radiation embrittlement of spacecraft materials, NASA Glenn Research Center has developed and flown a series of experiments as part of the Materials International Space Station Experiment (MISSE) missions on the exterior of the International Space Station (ISS). In continuing these studies, three new Glenn experiments have accepted for flight on the new ISS MISSE-Flight Facility (MISSE-FF). The Polymers and Composites Experiment (PCE) is being flown as part of the MISSE-9 inaugural mission of MISSE-FF. The Polymers and Composites Experiment-2 (PCE-2) and Polymers and Composites-3 Experiment (PCE-3) are being flown as part of the MISSE-10 and MISSE-12 missions, respectively. This presentation provides an overview of the Glenn's three MISSE-FF flight experiments including the objectives and initial spaceflight results.

spaceflight↗
NASA NTRS2006

Overview of Space Environment Effects on Materials and GRC's Test Capabilities

The Electro-Physics Branch at NASA Glenn Research Center has been involved with evaluating the durability of materials and understanding environment interactions for over 20 years. A combination of flight experiments, ground based exposure facilities, and environmental modeling provide a well rounded approach to material durability evaluation and prediction for future missions. Ground based testing includes atomic oxygen exposure facilities (large and small area thermal facilities and directed atomic oxygen with and without VUV radiation, VUV and NUV exposure facility, and thermal cycling facility with and without UV radiation. A lunar dust exposure facility is also being brought on-line. Material reactions in these facilities is compared to that observed in space.

Banks, Bruce A.↗
NASA NTRS2005

Simulated Space Environment Effects on Tether Materials with Protective Coatings

Atomic oxygen (AO) erodes most organic materials. and ultraviolet radiation embrittles polymers. A previous study indicated untreated polymers such as ultra-high molecular weight polyethylene (UHMWPE) are severely degraded when exposed to AO. This test series was performed to determine the effect of AO and UV on the mechanical integrity of tether materials that were treated with AO-protective coatings. Three coating systems were evaluated for their ability to protect the underlying material from AO erosion. The first coating system is the Photosil surface modification process which incorporates silicon-containing functional groups into the top micron of an organic material. The Photosil process has had favorable results with polyurethane- and epoxy-based thermal control coatings . The second coating system is metallization, in this case nickel. The third coating system is silsesquioxane. The Marshall Space Flight Center Atomic Oxygen Beam Facility (AOBF) was used to simulate low Earth orbit AO of 5 eV energy. In addition, some tether samples were exposed to ultraviolet radiation then evaluated for any changes in mechanical strength. Tether missions, such as a momentum-exchange/electrodynamic reboost (MXER) tether, may benefit from this research.

Finckenor, Miria M.↗
NASA NTRS2019

Summary of Space Environment Magnetometer and Particle Replacement Experiment (SEMPRE) Study

As part of the GOES-R series follow on architecture study following the NOAA Satellite Observing System Architecture (NSOSA) study, a study team evaluated the feasibility of accommodating the GOES in-situ instruments (Magnetometer and Particle Detectors) on a dedicated spacecraft with no impact to the overall baseline mission cost assuming two large observatories. The accommodations cost on a primary operational type observatory are non-negligible requiring: a large non-magnetic boom to reduce the impact of the spacecraft interference on the magnetometer; and strict contamination control and magnetic cleanliness to prevent magnetic contamination near the magnetometers. These, along with the additional interface complexities greatly increase the cost of larger spacecraft by extending integration time with a large marching army. By contrast, a dedicated mission provides flexibility in location and refresh rate not afforded when these sensors are launched as secondary payloads. This study performed an informal industry survey of small form-factor instruments currently flying or in process of being developed. The study identified three potential particle detector suites and multiple magnetometers that will satisfy the requirements while having low enough volume and mass to allow accommodation on a rideshare class spacecraft. Using the largest of the identified particle detector suites, the Goddard Space Flight Center Mission Design Lab developed a design for a rideshare spacecraft that will accommodate the particle detector suite and magnetometer. The cost of the spacecraft, based on multiple cost models, is comparable to the cost of accommodating the magnetometer and particle detector suite on two (East and West) larger main observatories.

Todirita, Monica↗