Yang Fan Yang, Nelson Bron, Aziz Jonathan, Carlino Roberto, Perez Andres Dono, Faber Nicolas, Foster Cyrus, Frost Chad, Henze Chris, Karacalıoğlu Arif Göktuğ, Levit Creon, Marshall William, Mason James, O'Toole Conor, Swenson Jason, Worden Simon P, Stupl Jan
MEI/NASA Ames Research Center, United States.
Computer Sciences Corporation/NASA Ames Research Center, United States.
Acta Astronaut. 2016 Sep;126:411-423. doi: 10.1016/j.actaastro.2016.04.032. Epub 2016 May 10.
This work provides an efficiency analysis of the LightForce space debris collision avoidance scheme in the current debris environment and describes a simulation approach to assess its impact on the long-term evolution of the space debris environment. LightForce aims to provide just-in-time collision avoidance by utilizing photon pressure from ground-based industrial lasers. These ground stations impart minimal accelerations to increase the miss distance for a predicted conjunction between two objects. In the first part of this paper we will present research that investigates the short-term effect of a few systems consisting of 20 kW class lasers directed by 1.5 m diameter telescopes using adaptive optics. The results found such a network of ground stations to mitigate more than 85 percent of conjunctions and could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. While these are impressive numbers that indicate LightForce's utility in the short-term, the remaining 15 % of possible collisions contain (among others) conjunctions between two massive objects that would add large amount of debris if they collide. Still, conjunctions between massive objects and smaller objects can be mitigated. Hence, we choose to expand the capabilities of the simulation software to investigate the overall effect of a network of LightForce stations on the long-term debris evolution. In the second part of this paper, we will present the planned simulation approach for that effort. For the efficiency analysis of collision avoidance in the current debris environment, we utilize a simulation approach that uses the entire Two Line Element (TLE) catalog in LEO for a given day as initial input. These objects are propagated for one year and an all-on-all conjunction analysis is performed. For conjunctions that fall below a range threshold, we calculate the probability of collision and record those values. To assess efficiency, we compare a baseline (without collision avoidance) conjunction analysis with an analysis where LightForce is active. Using that approach, we take into account that collision avoidance maneuvers could have effects on third objects. Performing all-on-all conjunction analyses for extended period of time requires significant computer resources; hence we implemented this simulation utilizing a highly parallel approach on the NASA Pleiades supercomputer.
这项工作对当前碎片环境下的LightForce太空碎片碰撞避免方案进行了效率分析，并描述了一种模拟方法，以评估其对太空碎片环境长期演变的影响。LightForce旨在通过利用地面工业激光器的光子压力提供即时碰撞避免。这些地面站施加最小的加速度以增加两个物体预测交会时的错过距离。在本文的第一部分，我们将展示研究成果，该研究调查了由1.5米直径望远镜使用自适应光学系统引导的20千瓦级激光器组成的几个系统的短期效果。结果发现这样的地面站网络能够缓解超过85%的交会情况，并能将低地球轨道（LEO）的预期碰撞次数降低一个数量级。虽然这些数字令人印象深刻，表明LightForce在短期内的效用，但其余15%的可能碰撞情况（其中包括）两个大质量物体之间的交会，如果它们碰撞将会产生大量碎片。不过，大质量物体与较小物体之间的交会情况仍可缓解。因此，我们选择扩展模拟软件的功能，以研究LightForce站网络对碎片长期演变的总体影响。在本文的第二部分，我们将展示为此项工作计划的模拟方法。对于当前碎片环境下碰撞避免的效率分析，我们采用一种模拟方法，该方法使用给定日期低地球轨道中的整个两行轨道根数（TLE）目录作为初始输入。这些物体被传播一年，并进行全对全的交会分析。对于低于距离阈值的交会情况，我们计算碰撞概率并记录这些值。为了评估效率，我们将基线（无碰撞避免）交会分析与LightForce激活时的分析进行比较。使用这种方法，我们考虑到碰撞避免机动可能会对第三个物体产生影响。长时间进行全对全的交会分析需要大量计算机资源；因此我们在NASA昴宿星超级计算机上采用高度并行的方法实现了此模拟。
