With the rapid evolution of space-borne capabilities, space edge computing (SEC) is becoming a new computation paradigm for future integrated space and terrestrial networks. Satellite edges adopt advanced on-board hardware, which not only enables new opportunities to perform complex intelligent tasks in orbit, but also involves new challenges due to the additional energy consumption in power-constrained space environment. In this paper, we present PHOENIX, an energy-efficient task scheduling framework for emerging SEC networks. PHOENIX exploits a key insight that in the SEC network, there always exist a number of sunlit edges which are illuminated during the entire orbital period and have sufficient energy supplement from the sun. PHOENIX accomplishes energy-efficient in-orbit computing by judiciously offloading space tasks to "sunlight-sufficient" edges or to the ground. Specifically, PHOENIX first formulates the SEC battery energy optimizing (SBEO) problem which aims at minimizing the average battery energy consumption while satisfying various task completion constraints. Then PHOENIX incorporates a sunlight-aware scheduling mechanism to solve the SBEO problem and schedule SEC tasks efficiently. Finally, we implement a PHOENIX prototype and build an SEC testbed. Extensive data-driven evaluations demonstrate that as compared to other state-of-the-art solutions, PHOENIX can effectively reduce up to 54.8% SEC battery energy consumption and prolong battery lifetime to 2.9$\times$ while still completing tasks on time.

翻译：随着星载能力的快速发展，空间边缘计算正成为未来空天地一体化网络的新型计算范式。卫星边缘节点采用先进星载硬件，不仅为在轨执行复杂智能任务提供了新机遇，同时也因功耗受限的空间环境中额外的能源消耗带来了新挑战。本文提出PHOENIX——一种面向新兴空间边缘计算网络的节能任务调度框架。PHOENIX基于一个关键洞见：在空间边缘计算网络中，始终存在若干在整个轨道周期内持续受日照且能从太阳获得充足能量补充的"日光充足"边缘节点。PHOENIX通过审慎地将空间任务卸载至"日光充足"边缘节点或地面，实现节能的在轨计算。具体而言，PHOENIX首先构建了空间边缘计算电池能量优化问题，该问题旨在满足各类任务完成约束的同时最小化平均电池能耗。随后PHOENIX引入日光感知调度机制来求解该优化问题并高效调度空间边缘计算任务。最后，我们实现了PHOENIX原型系统并搭建了空间边缘计算测试平台。大量数据驱动实验表明，相较于现有先进方案，PHOENIX能有效降低高达54.8%的空间边缘计算电池能耗，将电池寿命延长至2.9$\times$，同时仍能保证任务按时完成。