近日，美国哈佛大学Joost J. Vlassak团队研究了近空间条件下穿孔结构的光致飞行。相关论文于2025年8月13日发表在《自然》杂志上。

轻质纳米结构可以在近太空中光致发射有效载荷。提出的结构范围从微尺度的工程气溶胶，到具有表面调节系数变化的厘米尺度薄盘，到纳米尺度厚度4的三明治结构，可能扩展到米尺度宽度。定量了解结构和表面性质如何决定光致发光力是开发实用飞行装置所必需的。

研究组将重点放在热蒸腾上，认为这是最有前景的大型装置的光致发光机制，并提出了一个由两个间隔一小段距离的穿孔膜组成的结构上的光致发光力的混合分析-数值模型。他们确定了最佳的结构参数，包括装置尺寸、膜穿孔密度和连接两个膜的垂直韧带的分布，每一个都是大气高度的函数。针对这些最佳参数，他们制造了具有异质韧带分布的结构，有效地折衷了结构刚度和光致性能。

研究组测量了这些结构产生的抬升力如何依赖于三种不同分子量气体的压力。在26.7帕气压条件下，用750瓦/平方米的光照强度（相当于太阳光强度的55%）照射时，研究组观测到1厘米宽的结构体发生光泳悬浮现象。最后，研究组描述了一个半径为3厘米的装置初步设计，该装置在75公里高度具有10毫克的有效载荷能力，可进行水平运动控制，过夜沉降，以及在气候传感，通信和火星探测中的应用。

附：英文原文

Title: Photophoretic flight of perforated structures in near-space conditions

Author: Schafer, Benjamin C., Kim, Jong-hyoung, Sharipov, Felix, Hwang, Gyeong-Seok, Vlassak, Joost J., Keith, David W.

Issue&Volume: 2025-08-13

Abstract: Lightweight nanofabricated structures could photophoretically loft payloads in near-space. Proposed structures range from microscale engineered aerosols1, to centimetre-scale thin disks with variations in surface accommodation coefficients2,3, to sandwich structures with nanoscale thickness4,5 that might be extended to metre-scale width6,7. Quantitative understanding of how structural and surface properties determine photophoretic lofting forces is necessary to develop a practical flying device. Here we focus on thermal transpiration as the most promising photophoretic mechanism for lofting large devices8 and present a hybrid analytical–numerical model of the lofting force on a structure that consists of two perforated membranes spaced a small distance apart. We identify optimal structural parameters, including device size, membrane perforation density and distribution of the vertical ligaments that connect the two membranes, each as a function of atmospheric altitude. Targeting these optimal parameters, we fabricate structures with a heterogeneous ligament distribution, which efficiently compromises between structural rigidity and photophoretic performance. We measure how lofting forces generated by these structures depend on pressure using gases with three different molecular weights. We observed photophoretic levitation of a 1-cm-wide structure at an air pressure of 26.7Pa when illuminated by 750Wm2, about 55% the intensity of sunlight. Lastly, we describe the preliminary design of a 3-cm-radius device with 10-mg payload capacity at 75-km altitudes and discuss horizontal motion control, overnight settling, and applications in climate sensing, communications and Martian exploration.

DOI: 10.1038/s41586-025-09281-8

Source: https://www.nature.com/articles/s41586-025-09281-8