Orbital and surface risks from rocket bodies: Physical challenges, interdisciplinary solutions

2021年4月，全世界的目光都聚焦在中国长征五号乙火箭本体不受控制的再入。超过20吨的火箭体的特殊尺寸引发了安全问题，美国宇航局局长指责中国未能达到负责任的太空飞行标准。但中国否认有任何不当行为。它指出，人员伤亡的风险很低，并指责美国宇航局虚伪，因为不受控制的火箭重返大气层的情况很常见。事实上，就在一个月前，SpaceX猎鹰9号（SpaceX Falcon 9）的火箭主体在太平洋西北部上空失控再入，引起了相当大的关注，在华盛顿州发现了一些碎片。中国说得对，失控再入很常见--这就是问题所在。发射国长期以来一直认为，地球的表面积是如此之大，以至于不受控制的重返对人类构成的风险微乎其微。这一假设反过来又导致各国和各公司把重点放在降低进入太空的成本上，包括通过最低限度的监管和一次性设备，没有一个国家或公司在太空运营是真正安全的。虽然有些国家在减少不受控制的重返大气层的百分比或限制不受控制的物体的质量方面比其他国家做得更好，但所有国家都在赌航天器的一部分是否会造成损害或伤亡。此外，发射国采取或允许这些关于世界全体人口安全的赌博--而不让世界其他国家有发言权。更糟糕的是，我们的初步研究表明，全球南部国家的出口风险不成比例地下降了福尔斯。该项目将调查不受控制的火箭体重返大气层的历史、目前和预计伤亡风险，以了解发射国如何在全球范围内出口风险，并确定这些出口的趋势。这包括通过全球灾害地图为政策制定者提供可视化信息，传达伤亡风险的全球特征，并使用模拟来说明这些风险的低概率/高后果特征。该项目还将确定国内和国际空间法律和政策的变化，这些变化可能会抑制在轨道上丢弃大型物体，同时鼓励安全和环境上可持续的重返做法。

In April 2021, the attention of the world was focused on the uncontrolled re-entry of a Chinese Long March 5B rocket body. At over 20 tonnes, the rocket body's exceptional size prompted safety concerns, with the NASA Administrator accusing China of failing to meet responsible standards for space flight. But China denied any wrongdoing. It pointed out that the risk of casualties was low and accused NASA of hypocrisy, as uncontrolled rocket re-entries are common. Indeed, just one month earlier a SpaceX Falcon 9 rocket body had an uncontrolled re-entry over the Pacific Northwest, attracting considerable attention, with pieces found in Washington State.China is right that uncontrolled re-entries are common - and that is the problem. Launch states have long assumed that the surface area of Earth is so large that uncontrolled re-entries pose a vanishingly small risk to people. This assumption, in turn, has led states and companies to focus on reducing the costs of access to space, including through minimal regulations and disposable equipment.No country or company operating in space is truly being safe. While some are better than others in reducing the percentage of re-entries that are uncontrolled or limiting the mass in uncontrolled objects, all take gambles about whether a piece of their spacecraft will cause damage or casualties. Moreover, launch states take or allow these gambles with respect to the safety of the world's entire population - without letting the rest of the world have a say. Worse yet, our preliminary research indicates that the exported risk falls disproportionately on the states of the Global South. This project will investigate historical, present, and projected casualty risks from uncontrolled rocket body re-entries to understand how launch states export risks globally and to identify trends in those exports. This includes producing visualizations for policy makers that convey the global character of casualty risks through global hazard maps and using simulations to illustrate the low probability/high-consequence character of these risks. The project will also identify changes in domestic and international space law and policy that could dis-incentivize the discarding of large objects in orbit, while incentivizing safe and environmentally sustainable re-entry practices.