The surfaces of airless bodies, such as the Moon and asteroids, are subject to space weathering, which alters the mineralogy of the upper tens of nanometers of grain surfaces. Atom probe tomography (APT) has the appropriate 3‐D spatial resolution and analytical sensitivity to investigate such features at the nanometer scale. Here, we demonstrate that APT can be successfully used to characterize the composition and texture of space weathering products in ilmenite from Apollo 17 sample 71501 at near‐atomic resolution. Two of the studied nanotips sampled the top surface of the space‐weathered grain, while another nanotip sampled the ilmenite at about 50 nm below the surface. These nanotips contain small nanophase Fe particles (~3 to 10 nm diameter), with these particles becoming less frequent with depth. One of the nanotips contains a sequence of space weathering products, compositional zoning, and a void space (~15 nm in diameter) which we interpret as a vesicle generated by solar wind irradiation. No noble gases were detected in this vesicle, although there is evidence for ⁴He elsewhere in the nanotip. This lunar soil grain exhibits the same space weathering features that have been well documented in transmission electron microscope studies of lunar and Itokawa asteroidal regolith grains.

中文翻译：

---

空间风化月钛铁矿颗粒表面的原子探针层析成像

诸如月球和小行星之类的无气物体的表面会受到空间风化的影响，这会改变上几十纳米晶粒表面的矿物学。原子探针层析成像（APT）具有适当的3D空间分辨率和分析灵敏度，可在纳米级上研究此类特征。在这里，我们证明了APT可以成功地以近原子分辨率表征来自Apollo 17样品71501的钛铁矿中的空间风化产物的组成和质地。所研究的两个纳米尖端对经过风化风化的谷物的顶表面进行了采样，而另一个纳米尖端则在表面以下约50 nm处对钛铁矿进行了采样。这些纳米尖端包含小的纳米相Fe颗粒（直径约3至10 nm），随着深度的增加，这些颗粒变得越来越少。纳米尖端之一包含一系列空间风化产物，成分分区和一个空隙空间（直径约15 nm），我们将其解释为由太阳风辐射产生的囊泡。尽管有证据表明在该囊泡中未检测到稀有气体⁴他在nanotip的其他地方。这种月球土壤颗粒表现出与在月球和伊藤川小行星硬粒硅谷粒的透射电子显微镜研究中充分证明的相同的空间风化特征。