NASA’s new dark-energy space telescope can also detect killer asteroids
NASA’s new dark-energy space telescope can also detect killer asteroids
NASA 新型暗能量太空望远镜也能探测“杀手级”小行星
EXECUTIVE SUMMARY At the end of August, NASA is set to launch the Nancy Grace Roman Space Telescope from Kennedy Space Center in Florida. Its goal is to help us better understand how the universe works, from the glue-like dark matter that keeps galaxies together to the elusive dark energy that drives the expansion of the cosmos. But Roman could also serve another purpose: defending Earth from killer asteroids. 执行摘要 8 月底，NASA 计划从佛罗里达州的肯尼迪航天中心发射“南希·格雷斯·罗曼太空望远镜”（Nancy Grace Roman Space Telescope）。其目标是帮助我们更好地理解宇宙的运作方式，从维持星系结构的“胶水”——暗物质，到驱动宇宙膨胀的神秘暗能量。但“罗曼”号还可以发挥另一个作用：保护地球免受“杀手级”小行星的威胁。
In September, a multi-institutional team of planetary scientists and astronomers will outline how the space telescope is uniquely placed to scan asteroids and provide information about their trajectories, sizes, and compositions. Roman, named after NASA’s first chief astronomer, is equipped with a super-wide-angle, 300-megapixel infrared camera, allowing it to see a large patch of space at any one time—roughly 100 times larger than is possible with the Hubble Space Telescope. That will allow it to discover thousands of new planets and tens of thousands of exploding stars, and survey over a billion galaxies in remarkable detail. While doing so, it’ll be looking “through” our solar system, and this is what makes it uniquely well placed to spot asteroids. 9 月，一个由多家机构组成的行星科学家和天文学家团队将概述该太空望远镜如何凭借其独特优势扫描小行星，并提供有关其轨道、大小和成分的信息。“罗曼”号以 NASA 首位首席天文学家的名字命名，配备了一台超广角、3 亿像素的红外相机，使其能够一次性观测大片太空区域——视野范围大约是哈勃太空望远镜的 100 倍。这将使它能够发现数千颗新行星和数万颗爆炸恒星，并以惊人的细节勘测超过十亿个星系。在执行这些任务时，它将“穿透”我们的太阳系进行观测，这正是它能够精准定位小行星的独特之处。
A planetary defense pivot 行星防御的转向
Roman was not built for this purpose, but last summer, it was (once again) threatened with significant funding cuts by the Trump administration. “My colleague Rick Cosentino [a planetary scientist at NASA] said to me in July 2025 that we need to show what Roman can do for planetary defense as a way to further increase the visibility of the mission with lawmakers and taxpayers,” says Bryan Holler, a researcher at the Space Telescope Science Institute in Baltimore. “罗曼”号并非为此目的而建造，但去年夏天，它（再次）面临特朗普政府大幅削减预算的威胁。巴尔的摩太空望远镜科学研究所的研究员布莱恩·霍勒（Bryan Holler）表示：“我的同事、NASA 行星科学家里克·科森蒂诺（Rick Cosentino）在 2025 年 7 月对我说，我们需要展示‘罗曼’号在行星防御方面的潜力，以此进一步提高立法者和纳税人对该任务的关注度。”
Holler and his colleagues’ proposal, which will be presented at the Europlanet Science Congress at The Hague, reveals that Roman’s epic field of view and infrared vision allow it to spot small asteroids up to 60 feet long. This is comparable to the asteroid that exploded above the Russian city of Chelyabinsk in 2013, unleashing the force of 500,000 tons of TNT and sending 1,500 people to the hospital. 霍勒及其同事将在海牙举行的欧洲行星科学大会上提交一份提案，揭示“罗曼”号宏大的视野和红外视觉使其能够发现长达 60 英尺（约 18 米）的小型小行星。这与 2013 年在俄罗斯车里雅宾斯克市上空爆炸的小行星相当，那次爆炸释放了相当于 50 万吨 TNT 的能量，导致 1500 人受伤入院。
Roman’s software will need some tweaking to spy space rocks. The telescope, as designed, will see through—and beyond—the solar system in order to gather the clearest possible pictures of the rest of the universe. “Streaks, whether caused by cosmic rays or glitches or asteroids, are caught by the software and discarded,” says Andy Rivkin, a planetary scientist and planetary defense researcher at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. But astronomers could go in, study those streaks, and pick out those they identify as asteroids. “罗曼”号的软件需要进行一些调整才能探测到太空岩石。按照设计，该望远镜将穿透并超越太阳系，以收集宇宙其余部分最清晰的图像。马里兰州劳雷尔约翰霍普金斯应用物理实验室的行星科学家兼行星防御研究员安迪·里夫金（Andy Rivkin）说：“无论是宇宙射线、故障还是小行星造成的条纹，都会被软件捕捉并丢弃。”但天文学家可以介入，研究这些条纹，并挑选出他们认定为小行星的目标。
Even with those potential adjustments, Roman won’t be an asteroid-finding wunderkind on its own. Its strength lies in its ability to complement the James Webb Space Telescope (JWST), another observatory that’s built to peer at galaxies and stars in the far reaches of the universe. It can also intensely focus on a single asteroid when needed—as it did last year, playing a key role in tracking 2024 YR4, which was briefly the most dangerous asteroid ever discovered. “But Roman’s field of view is much bigger,” says Rivkin. That means it could look at multiple questionable asteroids very quickly. 即使进行了这些潜在调整，“罗曼”号本身也不会成为发现小行星的“神童”。它的优势在于能够与詹姆斯·韦伯太空望远镜（JWST）形成互补，后者是为观测宇宙深处的星系和恒星而建造的。在需要时，它还可以集中精力观测单颗小行星——正如去年它在追踪 2024 YR4 时所做的那样，该小行星曾一度被认为是史上最危险的小行星。“但‘罗曼’号的视野要大得多，”里夫金说。这意味着它可以非常迅速地观察多颗可疑小行星。
“Roman can provide infrared observations of more asteroids than JWST could hope to observe in a reasonable amount of observing time,” says Holler. If those asteroids are found to be benign travelers, we can relax. But if they might collide with Earth, other telescopes—including JWST—can follow up from Roman’s observations. Those observations could give experts the information they need to assess the likely damage of an upcoming asteroid strike—or to launch a mission to attempt to swat an asteroid away. “在合理的观测时间内，‘罗曼’号能提供的红外观测小行星数量远超 JWST 的预期，”霍勒说。如果发现这些小行星是无害的“过客”，我们就可以放心了。但如果它们可能与地球相撞，包括 JWST 在内的其他望远镜可以根据“罗曼”号的观测结果进行后续跟踪。这些观测数据能为专家提供评估小行星撞击潜在破坏力所需的信息，或者用于启动任务尝试将小行星偏转。
“Roman will sample such a large volume of the cosmos that we’ve long known it will offer vast opportunities for a range of additional science,” says Alise Fisher, the astrophysics communications lead at NASA headquarters in Washington, DC. “‘罗曼’号将对如此庞大的宇宙空间进行采样，我们早就知道它将为一系列额外的科学研究提供巨大的机会，”NASA 华盛顿总部天体物理学传播主管爱丽丝·费舍尔（Alise Fisher）表示。
NASA’s Planetary Defense Coordination Office, and its partners across the world, are chiefly worried about asteroids 460 feet long and larger. Around 25,000 of those are estimated to have near-Earth orbits, and just over half have yet to be found. Should one hit a city, much of it would be destroyed or irreversibly damaged in a heartbeat. Astronomers estimate that there are also 230,000 or so 165-foot-long asteroids orbiting close to Earth, and fewer than 10% have been located. A strike on a city from one of those might not annihilate it, but it would unleash a force comparable to that of a large atomic bomb, albeit without the radiation. NASA 行星防御协调办公室及其全球合作伙伴主要担心的是 460 英尺（约 140 米）及以上大小的小行星。据估计，约有 2.5 万颗此类小行星拥有近地轨道，其中超过一半尚未被发现。如果其中一颗撞击城市，大部分区域会在瞬间被摧毁或遭受不可逆转的破坏。天文学家估计，还有约 23 万颗 165 英尺（约 50 米）长的小行星在近地轨道运行，且被定位的不到 10%。如果其中一颗撞击城市，可能不会将其彻底抹平，但会释放出相当于大型原子弹的能量，尽管没有辐射。
Such an asteroid could theoretically be deflected (by ramming a spacecraft into it) or vaporized (perhaps using a nuclear weapon). But planetary defenders need to know where they are first, which is why NASA funds a network of ground-based telescopes designed to seek them out. They work well, but there’s only so much of the night sky they can see, and Earth’s atmosphere peskily gets in their way. That’s why NASA is launching the Near-Earth Object (NEO) Surveyor space telescope in 2027. By positioning itself between Earth and the sun, it’ll find many elusive asteroids that ground-based telescopes cannot see. And unlike many of its asteroid-seeking cousins, it’ll see in infrared, not visible light. Not only do asteroids show up more clearly in infrared, but seeing them through this lens gives scientists a considerably better measure of their size. In a matter of years, it could find 90% of the city-killer-size asteroids in near-Earth orbits. 理论上，这样的小行星可以通过撞击（用航天器撞击它）或汽化（或许使用核武器）来偏转。但行星防御者首先需要知道它们在哪里，这就是为什么 NASA 资助了一个旨在搜寻它们的地面望远镜网络。它们工作得很好，但能观测到的夜空范围有限，且地球大气层会造成干扰。这就是为什么 NASA 将在 2027 年发射“近地天体（NEO）测量仪”太空望远镜。通过将其定位在地球和太阳之间，它将发现许多地面望远镜无法看到的难以捉摸的小行星。与许多同类小行星搜寻器不同，它将使用红外线而非可见光进行观测。小行星不仅在红外线下显示得更清晰，通过这种镜头观察还能让科学家更准确地测量它们的大小。在几年内，它有望发现近地轨道上 90% 的“城市杀手级”小行星。
Telescope teamwork 望远镜团队协作
NEO Surveyor is explicitly a planetary defense observatory. But it’ll work with other telescopes with more science-minded missions, including Roman and JWST (both of which conveniently have infrared scopes too) as well as the Vera Rubin Observatory, which just began its 10-year survey of the entire night sky from atop a mountain in Chile. As part of its inventory of the cosmos, it’s expected to… 望远镜团队协作 “近地天体测量仪”明确是一座行星防御天文台。但它将与其他以科学任务为主的望远镜协同工作，包括“罗曼”号和 JWST（两者也都配备了红外望远镜），以及刚刚在智利山顶开始其 10 年全夜空巡天任务的薇拉·鲁宾天文台（Vera Rubin Observatory）。作为其宇宙编目工作的一部分，预计它将……