Nanoscale spacecrafts have shed light on an audacious but promising vision for interstellar travel to neighboring planets beyond the solar system. The nanocrafts can be accelerated to a significant fraction of light speed, which leads to the possibility of completing the otherwise millennia space missions using the current rocket propulsion technology in several decades. However, electrical energy is a severe challenge for long-term interstellar travel. Mechanical energy metamaterials have been proposed as a promising technology integrated multiscale architected structures with energy materials, which have opened an exciting venue for energy harvesting under extreme conditions such as the cosmic environment. Mechanical energy metamaterials are envisioned as an alternative energy solution to address the power issue of nanocrafts in interstellar travel. Here, this article comprehensively overviews the debut and development of mechanical energy metamaterials and discusses the potential and application paradigm for energy harvesting in the cosmic environment. We first clarify the main feature and functionality of mechanical metamaterials and summarize the recent findings on typical mechanical energy metamaterials. Next, we identify the characteristics and challenges of the cosmic environment, deliberate the fundamental energy issue of interstellar travel, and examine the stringent criteria to design mechanical energy metamaterial nanosails for electrical power. Discussion indicates that kinetic energy resulted in cosmic dust grains collision and photovoltaic energy from starlight can be the main energy sources for mechanical energy metamaterials. In the end, we propose the applications of mechanical energy metamaterial nanosails in the nano space energy systems (nano-SES) to address the energy challenges in interstellar travel by generating electrical power from the kinetic and photovoltaic energies.

纳米级航天器揭示了一个大胆但充满希望的愿景，即星际旅行到太阳系以外的邻近行星。纳米飞行器可以加速到光速的很大一部分，这使得有可能在几十年内使用当前的火箭推进技术完成千年的太空任务。然而，电能对于长期的星际旅行来说是一个严峻的挑战。机械能超材料已被提议作为一种有前途的技术，将多尺度建筑结构与能源材料集成在一起，为在宇宙环境等极端条件下收集能量开辟了一个令人兴奋的场所。机械能超材料被设想为替代能源解决方案，以解决星际旅行中纳米飞行器的电力问题。在此，本文全面概述了机械能超材料的出现和发展，并讨论了在宇宙环境中收集能量的潜力和应用范式。我们首先阐明了机械超材料的主要特征和功能，并总结了典型机械能超材料的最新发现。接下来，我们确定宇宙环境的特征和挑战，审议星际旅行的基本能源问题，并检查设计用于电力的机械能超材料纳米帆的严格标准。讨论表明，宇宙尘埃颗粒碰撞产生的动能和星光的光伏能可以成为机械能超材料的主要能源。最后，我们提出了机械能超材料纳米帆在纳米空间能源系统 (nano-SES) 中的应用，通过利用动能和光伏能发电来解决星际旅行中的能源挑战。