来自阴影相机的沙克尔顿坑

2023年5月5日

Shackleton from ShadowCam
Image Credit: NASA, ShadowCam, Korea Aerospace Research Institute, Arizona State University

Explanation: Shackleton crater lies at the lunar south pole. Peaks along the 21 kilometer diameter are in sunlight, but Shackleton’s floor is in dark permanent shadow. Still, this image of the shadowed rim wall and floor of Shackleton crater was captured from NASA’s ShadowCam, an instrument on board the Korea Pathfinder Lunar Orbiter (KPLO) launched in August 2022. About 200 times more sensitive than, for example, the Lunar Reconnaissance Orbiter’s Narrow Angle Camera, ShadowCam was designed image the permanently shadowed regions of the lunar surface. Avoiding direct sunlight, those regions are expected to be reservoirs of water-ice and other volatiles deposited by ancient cometary impacts and useful to future Moon missions. Of course, the permanently shadowed regions are still illuminated by reflections of sunlight from nearby lunar terrain. In this stunningly detailed ShadowCam image, an arrow marks the track made by a single boulder rolling down Shackleton crater’s wall. The image scale is indicated at the bottom of the frame.

Tomorrow’s picture: twilight in a flower

来自阴影相机的沙克尔顿坑
影像提供: NASA, ShadowCam, Korea Aerospace Research Institute, Arizona State University

说明: 沙克尔顿坑位于月球的南极。沿着21公里直径沙克尔顿撞击坑缘的山峰沐浴在阳光中，然而其坑底却位于黝黑的永恒阴影里。尽管如此，2022年8月发射的韩国探路者号月球轨道船（KPLO）上、由美国国家航空航天局建造的阴影相机，仍然能为沙克尔顿坑的坑墙及坑底拍下了这幅影像。主要用来拍摄月表永夜区的阴影相机，其灵敏度比月球探勘号轨道船的窄视角相机要高200倍左右。由于避开了阳光的直射，这些永夜区预期会是远古彗星撞击后遗留下来的水冰和其他挥发性物质的储存库，因此对未来的探月任务非常有用。当然，永夜区仍然会受到从邻近月表反射的阳光之照射。在这张极为细致的阴影相机影像里，泛白箭头标示的线形结构，是一颗巨石从沙克尔顿坑的坑墙滚落的轨迹。影像的比例尺标示在底缘。 （Shackleton crater 沙克尔顿坑； ShadowCam 阴影相机）

明日的图片: twilight in a flower