In spite of strict limits on outgassing from organic materials, some spacecraft instruments making long-term measurements of solar extreme ultraviolet (EUV) radiation still suffer significant degradation. While such measures have reduced the rate of degradation, they have not completely eliminated it in some cases. For example, in five years, the aluminum filters used in the Extreme Ultraviolet Variability Experiment (EVE) instruments onboard the Solar Dynamics Observatory (SDO) suffered losses exceeding 40% at 30.4 nm. Comparing those losses with the negligible losses of nearby zirconium filters on the same instruments indicated that the problem was not due to carbonization on the Sun-facing side of the filter. To investigate whether the loss was due to carbon deposition on the downstream face of the Al filter, we exposed the backsides of Al and Zr filters to EUV in the presence of a volatile organic solvent in the laboratory and concluded that this could not be the cause. Given that the residual-gas composition in the SDO spacecraft likely has water vapor as well as organics, these findings suggest that the transmission loss in the Al filter originated with oxidation caused by UV-activated adsorbed water.

尽管对有机材料的除气有严格的限制，但一些对太阳极紫外 (EUV) 辐射进行长期测量的航天器仪器仍然遭受严重退化。虽然这些措施降低了降解速度，但在某些情况下并没有完全消除它。例如，在五年内，太阳动力学天文台搭载的极紫外变率实验(EVE) 仪器中使用的铝过滤器(SDO) 在 30.4 nm 处的损耗超过 40%。将这些损失与附近相同仪器上的锆过滤器的可忽略不计的损失进行比较表明问题不是由于过滤器面向太阳的一侧的碳化造成的。为了调查损失是否是由于铝过滤器下游面上的碳沉积造成的，我们在实验室中在挥发性有机溶剂存在的情况下将铝和锆过滤器的背面暴露于 EUV 并得出结论认为这不可能是原因. 鉴于 SDO 航天器中的残余气体成分可能含有水蒸气和有机物，这些发现表明铝过滤器中的传输损失源于由紫外线激活的吸附水引起的氧化。