The Stardust sample return capsule will return to Earth in January 2006 with primitive debris collected from Comet 81P/Wild-2 during the fly-by encounter in 2004. In addition to the cometary particles embedded in low-density silica aerogel, there will be microcraters preserved in the Al foils (1100 series; 100 micrometers thick) that are wrapped around the sample tray assembly. Soda lime spheres (approximately 49 m in diameter) have been accelerated with a light-gas-gun into flight-grade Al foils at 6.35 km s(sup -1) to simulate the potential capture of cometary debris. The preserved crater penetrations have been analyzed using scanning electron microscopy (SEM) and x-ray energy dispersive spectroscopy (EDX) to locate and characterize remnants of the projectile material remaining within the craters. In addition, ion beam induced secondary electron imaging has proven particularly useful in identifying areas within the craters that contain residue material. Finally, high-precision focused ion beam (FIB) milling has been used to isolate and then extract an individual melt residue droplet from the interior wall of an impact penetration. This enabled further detailed elemental characterization, free from the background contamination of the Al foil substrate. The ability to recover pure melt residues using FIB will significantly extend the interpretations of the residue chemistry preserved in the Al foils returned by Stardust.
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机译：“星尘”样本返回舱将于2006年1月返回，携带2004年飞越时从81P / Wild-2彗星收集的原始碎片。除嵌入低密度硅胶气凝胶中的彗星颗粒外，还将有微陨石坑。保存在包裹样品托盘组件的铝箔（1100系列； 100微米厚）中。用轻气枪将苏打石灰球（直径约49 m）加速到飞行级铝箔中，其速度为6.35 km s（sup -1），以模拟捕获彗星碎片的可能性。已使用扫描电子显微镜（SEM）和X射线能量色散谱（EDX）对保留的弹坑穿透进行了分析，以定位和表征弹坑内残留的弹丸材料的残留物。此外，离子束感应的二次电子成像已被证明在识别陨石坑内含有残留物质的区域特别有用。最后，高精度聚焦离子束（FIB）铣削已被用于隔离，然后从冲击穿透的内壁中提取出单个的熔渣残滴。这使得能够进行更详细的元素表征，而不受Al箔基材的背景污染。使用FIB回收纯熔体残留物的能力将大大扩展对Stardust返回的铝箔中保留的残留物化学成分的解释。
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