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

2021年4月，中国长征五号乙火箭机体失控重返大气层，举世瞩目。超过20吨的火箭身体的异常大小引发了安全问题，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，伤亡风险很低，并指责NASA虚伪，因为不受控制的火箭重新进入大气层是很常见的。事实上，就在一个月前，SpaceX猎鹰9号火箭的主体在太平洋西北部失控重返大气层，引起了相当大的关注，在华盛顿州发现了碎片。中国说得对，失控重返大气层很常见--这就是问题所在。发射国家长期以来一直认为，地球表面面积如此之大，以至于不受控制的重返大气层对人类构成的风险微乎其微。反过来，这一假设导致各州和公司专注于降低进入太空的成本，包括通过最低限度的监管和一次性设备。在太空运营的任何国家或公司都不是真正安全的。虽然一些公司在降低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公司做得更好，但它们都在押注自己的航天器的一块碎片是否会造成破坏或人员伤亡。此外，发射国在不让世界其他国家拥有话语权的情况下，采取或允许这些涉及世界全体人口安全的赌博。更糟糕的是，我们的初步研究表明，出口风险不成比例地落在了全球南部的各州身上。该项目将调查失控火箭再入造成的历史、现在和预计的伤亡风险，以了解发射国如何向全球输出风险，并确定这些出口的趋势。这包括为政策制定者制作可视化图，通过全球危险地图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方面的变化，这些变化可能不鼓励在轨道上丢弃大型物体，同时鼓励安全和在环境上可持续的再入做法。

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.