{"id":112686,"date":"2025-09-04T00:00:07","date_gmt":"2025-09-04T00:00:07","guid":{"rendered":"https:\/\/www.newsbeep.com\/uk\/112686\/"},"modified":"2025-09-04T00:00:07","modified_gmt":"2025-09-04T00:00:07","slug":"bigger-is-better-for-interstellar-spacecraft-by-avi-loeb-sep-2025","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/uk\/112686\/","title":{"rendered":"Bigger is Better for Interstellar Spacecraft | by Avi Loeb | Sep, 2025"},"content":{"rendered":"

\"Avi<\/a>Press enter or click to view image in full size\"\"(Credit: Adrian Mann<\/a>)<\/p>\n

All spacecraft ever built by humans are smaller than 100 meters, the scale of a football field. They were all designed to explore the solar system and maintain their technological functions for less than a century.<\/p>\n

However, exploration of interstellar space requires long journeys, lasting millions to billions of years. Since the heat loss and the damage from impact by interstellar radiation, micrometeorites, dust or gas particles, scale with surface area (size squared) while precious commodities and power supply scale with volume (size cubed), it is advantageous to make interstellar spacecraft bigger. Another reason to go big is that one can create artificial gravity by the centrifugal acceleration of a rotating spacecraft. For a given rotation period, the centrifugal acceleration scales with size squared. The larger is the size, the smaller is the variation of the artificial gravity across a human body \u2014 equivalent to a tidal force that can rip it apart.<\/p>\n

The reflection of sunlight from the interstellar object 3I\/ATLAS<\/a>, suggests a diameter of 20\u201346 kilometers for the reflecting object or dust cloud around it. This range of scales is similar to the dimensions of the interstellar spacecraft Rama in the science fiction novel \u201cRendezvous with Rama<\/a>\u201d by Arthur C. Clarke. The possibility that 3I\/ATLAS is a giant spacecraft \u2014 as suggested by its fine-tuned alignment with the planets around the Sun, was discussed in an email that I received today from co-founder of the Galileo Project<\/a> and CEO of the Bruker Corporation, Dr. Frank Laukien, who wrote:<\/p>\n

\u201cHi Avi,<\/p>\n

As I have been following your essays on 3I\/ATLAS, I realized that for future biological space exploration by humans (not just AI machines) and the settlement of habitable-life zone exoplanets or exomoons, or perhaps human life on space stations, will require megastructures.<\/p>\n

3I\/ATLAS with 20\u201346 km potential core diameter (unless there is a dense dust cloud) might be the right order of magnitude, \u2026 much, much larger than spaceships that we may have conceived of so far at NASA, SpaceX or in SciFi movies. These megastructures would have to be assembled in orbit, and large Starship SpaceX rockets can help with lift-off from Earth to assemble them.<\/p>\n

Why so big?<\/p>\n

A first analogy was the thick fur and body size of large mammals during the last glacial period, aka the \u2018Ice Age\u2019, which had to contend with bitter cold, and a lower surface-to-volume ratio was beneficial to preserve warmth. During space travel, we have to contend with high-energy radiation \u2026 so we need a thick outer layer for shielding, and that can be destroyed by cosmic dust and radiation over time, while preserving the interior. For this, small surface-to-volume ratio and a thick \u2018skin\u2019 are favorable, which makes very large structures or megastructures the preferred architecture over small spaceships or International-Space-Station type small structures.<\/p>\n

In addition, we will need small modular reactor fission or large (3 gigawatts) fusion power plants with full tritium breeding blanket and tritium full cycle. Such a nearly inexhaustible fusion energy reactor and power plant tend to be big and heavy (of the order of 100 meters in diameter, and a mass of ~50 kilotons), and again only compatible with megastructures.<\/p>\n

Such megastructures with a vast amount of energy could generate the lighting conditions and atmospheres we humans need from our evolutionary history on Earth, and could support synthetic agriculture, water and oxygen renewal, cryogenics to freeze space travelers, or enough space for perhaps 10\u2013100 thousand humans on such a space megastructure with a habitable-zone conditions inside its protective skin, and with enough space that passengers don\u2019t all go totally claustrophobic and insane.<\/p>\n

In that sense, just the speculations about 3I\/ATLAS perhaps being technological has already been eye-opening for me, in that megastructures make so much sense for human space exploration or as star-orbiting living platforms\u2026<\/p>\n

Best wishes,<\/p>\n

Frank\u201d<\/p>\n

In order to acquire more inspiration from 3I\/ATLAS, we need to image it. On October 3, 2025, 3I\/ATLAS will pass at a distance of 29 million kilometers from Mars. At that time, several Mars orbiters will have the opportunity to image it. First, NASA\u2019s HiRISE camera<\/a> onboard the Mars Reconnaissance Orbiter will be able to image 3I\/ATLAS with a resolution of 30 kilometers per pixel. China also has its Tianwen-1 orbiter, which carries a comparable high-resolution camera. The European Space Agency (ESA) is planning to use spectrometers as well as the High-Resolution Stereo Camera onboard the Mars Express<\/a> and the Color and Stereo Surface Imaging System onboard the ExoMars Trace Gas Orbiter<\/a>.<\/p>\n

But with a traditional mindset of comet experts, the anomalies in the data might not be recognized as such. The manager of the Galileo Project<\/a>, Dr. Zhenia Shmeleva, emailed me today a related insight:<\/p>\n

\u201cDear Avi,<\/p>\n

Your latest essay made me think about how we approach the unknown, and it brought to mind one of my favorite books, Solaris by Stanislaw Lem, where he questions whether we seek other worlds or only ourselves.<\/p>\n

In the common-room scene in the spaceship over Solaris, Snaut says: \u201cWe have no need of other worlds. We need mirrors. We don\u2019t know what to do with other worlds\u2026 We don\u2019t want to conquer the cosmos; we simply want to extend the boundaries of Earth to the frontiers of the cosmos\u2026 We are only seeking Man. We have no need of other worlds. A single world, our own, suffices us; but we can\u2019t accept it for what it is.\u201d<\/p>\n

Snaut\u2019s critique is harsh. When we set out into the cosmos, we claim to seek other civilizations, knowledge, and the alien. In truth, we tend to extend humanity outward and encounter ourselves again in different forms. We colonize conceptually and practically, imposing our own categories rather than engaging with what is genuinely other. When we meet something truly alien, like the Solaris-ocean, we recoil because it fails to mirror us and does not fit our frameworks.<\/p>\n

This is a real failure mode: treating the unknown as confirmation of ourselves. How should science fight this, how can we prevent anthropocentric biases from steering hypotheses and interpretations? A tricky question for me.<\/p>\n

Best wishes,<\/p>\n

Zhenya\u201d<\/p>\n

Speaking about anthropocentric biases, the visionary congresswoman Anna Paulina Luna who chairs the Task Force on the \u201cDeclassification of Federal Secrets\u201d, announced today (here<\/a>) a congressional hearing on September 9, 2025 to discuss the transparency of the U.S. government regarding Unidentified Anomalous Phenomena (UAP) \u2014 which motivate data collection by three Galileo Project<\/a> observatories. Congressional Task Force members will hear from witnesses on concerns regarding the disclosure of UAP and information held by federal agencies.<\/p>\n

When reading the morning news, I often feel like being in a party where the attendees are misbehaving. All I can hope for is that new guests in the form of 3I\/ATLAS or UAP will improve the situation.<\/p>\n

ABOUT THE AUTHOR<\/p>\n

Press enter or click to view image in full size\"\"(Image Credit: Chris Michel, National Academy of Sciences, 2023)<\/p>\n

Avi Loeb is the head of the Galileo Project, founding director of Harvard University\u2019s \u2014 Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011\u20132020). He is a former member of the President\u2019s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of \u201cExtraterrestrial:<\/a> The First Sign of Intelligent Life Beyond Earth<\/a>\u201d and a co-author of the textbook \u201cLife in the Cosmos<\/a>\u201d, both published in 2021. The paperback edition of his new book, titled \u201cInterstellar<\/a>\u201d, was published in August 2024.<\/p>\n","protected":false},"excerpt":{"rendered":"Press enter or click to view image in full size(Credit: Adrian Mann) All spacecraft ever built by humans…\n","protected":false},"author":2,"featured_media":112687,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[90,416,56,54,55],"class_list":{"0":"post-112686","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-science","9":"tag-space","10":"tag-uk","11":"tag-united-kingdom","12":"tag-unitedkingdom"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/112686","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/comments?post=112686"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/112686\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/112687"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=112686"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=112686"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=112686"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}