Micrometeorite impacts are one of the main drivers of lunar space weathering and can alter the properties of lunar regolith. However, the details of such processes are not well understood yet. We used transmission electron microscopy to study a micrometeorite impact crater on a glass bead returned by Chang’e-5. We detected Ti-oxide deposits on the crater rim and identified their detailed structure as rutile (TiO₂), trigonal Ti₂O and triclinic Ti₂O. The trigonal Ti₂O and triclinic Ti₂O are newly discovered mineral phases in lunar samples. We show that these Ti-oxide deposits could have formed by vaporization or deposition processes following a high-velocity microimpact on the lunar regolith. We suggest that such Ti minerals are previously overlooked space-weathering products on the Moon. Similar alterations to photocatalytic properties and reflectance spectra of regolith may also happen on other airless planetary bodies in the Solar System.

微陨石撞击是月球空间风化的主要驱动因素之一，可以改变月球风化层的特性。然而，这些过程的细节尚不清楚。我们使用透射电子显微镜研究了嫦娥五号返回的玻璃珠上的微陨石撞击坑。我们在陨石坑边缘检测到钛氧化物沉积物，并确定其详细结构为金红石（TiO ₂）、三方Ti ₂ O和三斜晶Ti ₂ O。三方Ti ₂ O和三斜Ti ₂ O是月球样品中新发现的矿物相。我们表明，这些钛氧化物沉积物可能是在对月球风化层进行高速微撞击后通过蒸发或沉积过程形成的。我们认为，此类钛矿物是以前被忽视的月球上的太空风化产物。风化层光催化特性和反射光谱的类似改变也可能发生在太阳系中其他无空气的行星体上。