| タイトル | Characterization of Candidate Solar Sail Materials Subjected to Electron Radiation |
| 著者（英） | Hubbs, Whitney; Edwards, David; Semmel, Charles; Hollerman, Andy; Stanaland, Tesia |
| 著者所属（英） | NASA Marshall Space Flight Center |
| 発行日 | 2003-01-01 |
| 言語 | eng |
| 内容記述 | The National Aeronautics and Space Administration's Marshall Space Flight Center (MSFC) is concentrating research into the utilization of ultra lightweight materials for spacecraft propulsion. The Space Environmental Effects Team at MSFC is actively characterizing candidate solar sail material to evaluate the thermo-optical and mechanical properties after exposure to space environmental effects. Radiation, from a variety of sources, exists in the space environment with low energy electrons primarily dominating the distribution. Practical sails must be resistant to the effects of long duration electron exposure. For this reason, research was initiated using a 95 keV electron source to determine the hardness of several candidate sail materials. Hardness in this context is defined as the amount of electron fluence (electrons/area) required to cause the sail material to fail. Solar sails are generally composed of a highly reflective metallic front layer, a thin polymeric substrate, and occasionally a highly emissive back surface, State-of-the-art candidate solar sail materials are generally composed of a polymeric substrate that is 2 to 3 microns thick. This polymeric film is coated with a thin metallic layer, usually aluminum. A typical thickness for this metallic layer is 50 nm. Two candidate solar sail materials, aluminized Mylar(trademark) and aluminized Kapton(trademark) were characterized. A radiation dose versus material depth profile was generated for each candidate sail material. This dose-depth profile was used to determine the relationship between the 95 keV electron fluence and radiation dose in the sail material. The focus of this investigation was to determine the effect of a uniform dose of 95 keV electron radiation on the sail material mechanical properties. Candidate sail materials were loaded, in tension, and stress relaxation as a function of time was recorded in vacuum. Stress relaxation data was obtained for sail materials that were exposed to 95 keV electron radiation and also for sail materials not exposed to radiation. The radiation dose levels for both materials exceeded 600 Megarads (Mrads). The results of this investigation indicate the aluminized Mylar(trademark) experienced a noticeable degree of mechanical property degradation. The aluminized Kapton(trademark) appears to have a higher tolerance to electron radiation exposure. Additional research using more mission specific electron environments will be completed in the future. This paper will discuss the preliminary results of this research. |
| NASA分類 | Spacecraft Propulsion and Power |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/333120 |
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