¶China’s reusable rockets are in the wings. SpaceX remains the undisputed leader in reusable-rocket development—the company probably will carry ~90% of global payload mass to orbit in 2025, mostly on ‘flight-proven’ boosters. In the US, the competitors closest to reuse are Rocket Lab and Blue Origin. Blue Origin’s New Glenn had its maiden flight in January from LC-36, demonstrating the 7-meter-diameter first stage intended for reusability (but missed its first droneship landing)—next launch is set for November 9 with another try at booster recovery. Rocket Lab’s Neutron (cf. Issue № 339) is currently under pad integration at Wallops Island, and its Archimedes flight engines are in the midst of final qualification. China’s commercial sector (here’s a round-up of rockets in development) is perhaps in a close third place and is gaining ground quickly. LandSpace’s Zhuque-3 (ZQ-3) is on deck for a potential fourth-quarter 2025 debut after a nine-engine cluster static fire at Jiuquan earlier this year—first reusability attempts are scheduled for sometime next year. ZQ-3 is 76.6 meters tall, with a 660-ton liftoff mass, and is capable of 21.3 tons to LEO when expended, and up to 18.3 and 12.5 tons respectively for down-range and RTLS flight plans. Also privately funded, Space Pioneer is readying its Tianlong-3, having completed a static fire on September 15th (not to mention an unintentional first flight). The 31-meter, 200-ton RP-1 fueled rocket is powered by nine TH-12 engines, enabling vertical landing and designed for up to ten reuses—ahead of an inaugural launch to sun-synchronous orbit, probably in the first half of next year. China Aerospace Science and Technology Corporation (CASC) is conducting 10 km vertical takeoff, vertical landing (VTVL) hops of a Long March reusable-technology demonstrator, and China’s next-generation crewed Long March 10 series includes a smaller, reusable variant now in design and testing. Additionally, Orienspace’s integrated hot-fire tests and JianYuan’s YuanXingZhe-1 sea-splashdown recovery trials (video) have validated propulsion and control subsystems for future reuse on those vehicles as well. Europe is noticeably trailing all these efforts: ESA’s Themis reusable-rocket demonstrator, employing the Prometheus cryogenic engine and a VTVL design, was hoisted onto its pad at Esrange Space Center in Sweden on September 19th, marking the first full-scale European test article ready for low-altitude hops, although somehow still not before 2026. |
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 | A Zhuque-3 test booster during a 2024 VTVL hop test. |
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¶Weird Papers- Could gravity be the byproduct of the simulation we all live in, trying to minimize information entropy (paper)? “It appears that the gravitational attraction is just another optimization mechanism in a computational process that plays a role in reducing the computational power and compressing information.” If you were simulating a Universe, though, would you really choose an optimization mechanism that fundamentally shaped the behavior of the system being optimized? Our Universe looks totally different without gravity—that seems like more than an ‘optimization side effect’. Meanwhile, “the abundance of symmetries observed at all scales in the universe is another example of a computational optimization process, or data compression, because symmetry scales inversely proportional to the information content or computational power.” Eh, maybe? 🤷
- We don’t know the nature of dark matter, the missing 85% of matter in the Universe. If dark matter is a massive particle that doesn’t annihilate when interacting with more of its kind, these particles could slowly accumulate inside exoplanets, eventually forming black holes (paper). So, if we see planet-massed blackholes, that would be telling. On the other hand, the fact that “many exoplanets (and Jupiter in our solar system) [have not] collapsed into black holes” limits superheavy non-annihilating dark matter models, which seems good.
- Another proposed form for dark matter, this time by skipping a step, is just small black holes themselves. Was the highest energy neutrino ever seen (>100 peta-electron-volts, spotted by KM3NeT, c.f. Issue № 329) the result of a microscopic primordial black hole (PBH) exploding within 2,000 AU of Earth (paper)? If real, PBHs would have formed moments after the Big Bang and would slowly evaporate through Hawking radiation. "The more a black hole radiates, the hotter it gets and the more high-energy particles it releases. This is a runaway process that should produce an incredibly violent explosion of the most energetic particles just before a black hole evaporates away. [...] In its final nanosecond, [the researchers] estimate that once a black hole is smaller than an atom, it should emit a final burst of particles, including about 10^20 neutrinos ... with energies of about 100 peta-electron-volts", just about the energy that KM3NeT saw while observing at the bottom of the Mediterranean Sea. (Another recent paper predicted that we'll observe an exploding PBH within the decade.) 💥❓
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 | | Unless it is? “To detect dark matter, we just need to build a bird feeder that spins two squirrels around the rim in opposite directions at relativistic speeds and collides them together.” XKCD #2186 |
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| ¶News in brief. Acting NASA Administrator Sean Duffy says SpaceX is behind schedule on lunar Starship and announced that NASA plans to open Artemis lunar landing contracts to other companies (and Elon complains about Blue’s Mark 1 lander concept) ● Orion arrived at Kennedy’s Vehicle Assembly Building, where cranes will raise the 35-ton spacecraft onto the top of the SLS ● Impulse unveiled plans to develop a lunar lander that will be transported to the Moon via their Helios kick stage ● German launch startup HyImpulse raised $52.5M to continue developing SL-1, their three-stage small launcher designed to carry 600 kg to LEO ● A Falcon booster landed for the 500th time ● Pakistan launched its first hyperspectral satellite aboard a Chinese commercial rocket ● Flow Engineering raised a $23M Series A to develop a requirements management platform for agile hardware teams ● The Air Force approved SpaceX’s plan to double its annual launch capacity at Vandenberg from 50 to 100 missions—up to 95 on Falcon 9 and as many as five on Falcon Heavy, though current commercial demand for the latter remains limited ● Like Vast, Muon Space will integrate with Starlink via satellite laser link ● Space debris may have struck a United Airlines flight over Salt Lake City, although we more strongly suspect a weather balloon ● Two cosmonauts conducted a spacewalk outside the ISS to install a semiconductor experiment and jettison an old camera. |
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 | Russian cosmonaut Aleksei Zubritsky discards a defunct camera from the ISS during his 6+ hour spacewalk. |
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¶Jobs.- AllSpice is hiring a Director of AI and Data Architecture who will be responsible for leading the development of AI-driven tools to enhance both collaboration and automation in hardware design processes.
- AllSpice is also hiring a Senior / Principal Fullstack Engineer who will lead the architecture development of AllSpice’s full-stack web application, focusing on enhancing CAD design capabilities
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| A re-processed image of Buzz Aldrin (right), in his first space selfie during Gemini 12, next to the unprocessed version (left). Those eyes (…have seen aliens?). Andy Saunders has restored many Mercury and Gemini images in his new book, Gemini & Mercury Remastered. Ars has an interview and more images. Credit: NASA / ASU / Andy Saunders |  |
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