Air table experiment system for testing nano-satellite end-of-mission reorbiting device

本实验项目的目的是设计一个能够在模拟零重力空间环境下测试纳米卫星任务末端离轨装置系绳展开机构的气台实验系统。纳米卫星任务结束脱轨器是一种使用电动缆绳（EDT）拖动使纳米卫星脱轨的小型装置。由于它利用被动电磁与地球磁场的相互作用来降低航天器的轨道，因此既不需要推进剂，也不需要动力。因此，它可以在非常低的质量要求下实现纳米卫星的自主脱轨。随着世界上越来越多的大学能够为其教育项目发射纳米卫星，为了保护航天器免受空间碎片的伤害，未来的发射器将任务结束的纳米卫星从空间中移除是非常重要的。自1992年以来，已经进行了几次EDT演示任务。然而，由于工程问题，许多任务过早失败，包括2007年4月最近的MAST任务，系绳未能部署。EDT系统遇到的关键工程问题包括：(1)系索部署；(2)系索系统的稳定性。缆绳将由从主卫星排出的最终质量通过弹簧力或其他机械手段展开。弹簧力不足会因系统阻尼而使展开失败，而弹簧力过大而控制不当则会使系绳松弛或卡住，造成系绳后坐力或端质量反弹，危及主机。拟议的研究计划将通过开发和测试一个高可靠的EDT系统来解决工程问题，该系统使用空气台来模拟零重力的空间环境。发现一些现有理论可能忽略的基本问题，有助于深入了解纳米卫星任务末离轨装置的设计。拟议的设备将训练HQPs设计实验、先进测量和仪器。该提案的结果将加强约克大学的空间工程项目。

The objective of this experimental program is to design an air table experiment system able to test the tether deployment mechanism of a nano-satellite end-of-mission deorbiting device in a simulated space environment of zero gravity.     Nano-satellite end-of-mission deorbitors are small devices that use electrodynamic tether (EDT) drag to deorbit a nano-satellite. Because it uses passive electromagnetic interactions with the Earth's magnetic field to lower the orbit of the spacecraft, it requires neither propellant nor power. Thus, it can achieve autonomous deorbit of a nano-satellite with very low mass requirements. As more and more universities around the world are able to launch nano-satellites for their educational programs, it is important for future launchers to remove the end-of-mission nano-satellites from space in order to safeguard spacecrafts from space debris. Several EDT demonstration missions have flown since 1992. However, many failed prematurely due to ENGINEERING problems including the most recent MAST mission in April 2007, where the tether failed to deploy. The critical engineering problems encountered by the EDT system include: (1) tether deployment, and (2) stability of the tether system. The tether will be deployed by the end mass expelled from the host satellite using either spring force or other mechanical means. Insufficient spring force will fail the deployment due to the system damping, while large spring force without proper control may slack or snag the tether, resulting in the tether recoil or the rebound of end mass to endanger the host. The proposed research program will address the engineering problems by developing and testing a highly reliable EDT system using an air table to simulate space environment of zero gravity. It will help in providing insights into the design of the nano-satellite end-of-mission deorbiting device to discover some fundamental issues which may be overlooked by existing theories. The proposed equipment will train HQPs in the design of experiments, advanced measurements and instruments. The outcome of the proposal will enhance the space engineering program at York University.