Issue 69 | Breaking Space News: Sept 21 - 27, 2025

Hello there, Explorer.🚀

The geopolitical landscape remains unsettled, yet science and the steady pace of scientific discovery offer a reminder of progress unfolding beyond today’s conflicts. Also, new developments in commercial innovation this week. Don’t forget to click below for the full newsletter experience. ⬇️⬇️

Hope you enjoy this Space!

• PRIMER

  • What Are Gravastars

• IMAGES

  • Partial Eclipse From Space

• SCIENCE

  • NASA Demonstrates Space-Based System for Early Tsunami Detection

  • NASA Tests Deep Space Laser Communications Across 218M Miles and Sets New Deep Space Transmission Record

  • Russia’s Bion-M2 Biosatellite, Carrying Mice, Flies, and Microbes for Biomedical Research, Returns From Orbit

  • Largest-Ever Universe Simulation With 3.4 Billion Galaxies Provides Testbed for Mapping Dark Matter and Dark Energy

  • NASA, NOAA Launch IMAP SWFO-L1, and Carruthers Observatory to Investigate Solar Activity and Interplanetary Space

  • Private Spacecraft to Test First‑of‑Its‑Kind Orbital Boost for NASA's Swift Space Telescope

• MILITARY

  • US Defense Space Strategy Advances as NRO and SDA Expand Proliferated Satellite Constellations With SpaceX, Lockheed Martin Deliveries

  • China’s Growing Space Capabilities Draw Attention From US Defense Leaders

  • L3Harris Expands Defense Programs With AI Counter‑UAS Tests and Air Force Satcom Development

• COMMERCIAL

  • Quantum Space Acquisition, Zeno–Orano Nuclear Power Deal, Geespace Funding, and Axiom–Redwire Partnership Highlight Global Industry Movements

  • Purdue University Crew to Fly on Virgin Galactic Suborbital Mission in 2027

  • UK’s Space Forge and US Firm United Semiconductors Collaborate to Develop Space‑Based Semiconductor Supply Chain

• RESEARCH SPOTLIGHT

  • The Nearest Technologically Advanced Neighbors Could Be 33,000 Light‑Year Away

  • New Study Finds Sub‑Neptune Exoplanets Probably Not Water Worlds

  • Centrifugal Nuclear Rocket Concept Using Liquid Uranium Aims to Cut Travel Time to Mars and Beyond

PRIMER

What Are Gravastars

Gravastars, short for gravitational vacuum stars, are a speculative alternative to black holes, first proposed in 2001 by physicists Pawel Mazur and Emil Mottola. Instead of collapsing into a singularity, a gravastar would feature a core filled with a dark-energy–like vacuum, surrounded by a thin shell of ultra-dense matter. From the outside, it would look almost identical to a black hole, but crucially, it would lack both a singularity and a true event horizon.

The model was designed to address puzzles such as the information paradox and the physical meaning of infinite density. In theory, gravastars could form when collapsing stars stabilize before reaching singularity, though no observational evidence yet supports their existence. Gravitational wave detections so far remain consistent with black holes, making gravastars difficult to confirm or rule out. Still, they remain part of the broader conversation about exotic compact objects and the limits of general relativity.

The black hole information paradox is the conflict between general relativity and quantum mechanics: if a black hole evaporates through Hawking radiation, all information about what fell in seems to be lost, but quantum theory requires that information be preserved. In short, it asks whether black holes destroy information, something physics says should never happen. Fun times.

Kurzgesagt made a neat video about Gravastars. Check it out below:

IMAGES

Partial Eclipse From Space : GOES-19 Satellite, NOAA

SCIENCE

NASA Demonstrates Space-Based System for Early Tsunami Detection

12 September, 2025

NASA’s experimental GUARDIAN system, short for GNSS Upper Atmospheric Real-time Disaster Information and Alert Network, recently passed a critical real-world test during a magnitude 8.8 earthquake off Russia’s Kamchatka Peninsula on July 29-30, 2025. Developed at Jet Propulsion Laboratory in Southern California, and installed just one day prior, the system detected tsunami-induced atmospheric pressure waves within 20 minutes of the quake and issued alerts up to 40 minutes before waves reached Hawaii and other Pacific sites.

Unlike traditional deep-ocean sensors, GUARDIAN monitors distortions in Global Navigation Satellite System (GNSS) signals caused by tsunami-generated waves in the ionosphere. These disturbances, often dismissed as signal errors, are repurposed as diagnostic clues. Within 10 minutes, the system can generate Total Electron Content (TEC) time series snapshots, offering near-real-time insights.

While expert interpretation is still required, GUARDIAN’s performance suggests a promising supplement to conventional tsunami warning systems. Its ability to detect far-field events from space could enhance early warning capabilities for vulnerable coastal regions.

NASA Tests Deep Space Laser Communications Across 218M Miles and Sets New Deep Space Transmission Record

18 September, 2025

NASA’s Deep Space Optical Communications (DSOC) experiment aboard the Psyche spacecraft has exceeded all technical goals, completing its 65th and final test in August 2025. The system successfully exchanged laser signals across 218 million miles or 351 million km. Separately, on December 3, 2024, the project set a new benchmark for deep space optical communications by downlinking data from Psyche at a distance of 307 million miles (~494 million km).

DSOC streamed an ultra-high-definition video from 19 million miles (30 million km) away at 267 megabits per second in December 2023, demonstrating data rates comparable to household broadband. For reference, Their average distance between Earth and Mars is around 140 million miles or 225 million km.

The Psyche spacecraft, launched by NASA on Oct. 13, 2023, is on a mission to a unique metal-rich asteroid with the same name. The asteroid is located in the main asteroid belt between Mars and Jupiter and its gravity will capture the spacecraft in late July 2029.

Over two years, DSOC downlinked 13.6 terabits of engineering and test data, validating the use of near-infrared lasers for high-bandwidth communications beyond Mars distances. The system’s photon-based encoding and precision tracking mark a shift from traditional radio systems, offering scalable solutions for future missions. Managed by JPL, DSOC’s success lays groundwork for real-time data return from deep space, including human exploration scenarios.

Russia’s Bion-M2 Biosatellite, Carrying Mice, Flies, and Microbes for Biomedical Research, Returns From Orbit

21 September, 2025

Russia’s Bion-M2 biosatellite returned to Earth on September 19, 2025, after a 30-day orbital mission carrying 75 mice, over 1,500 fruit flies, cell cultures, plant seeds, and microorganisms. Launched from Baikonur Cosmodrome aboard a Soyuz-2.1b rocket, the spacecraft entered a polar orbit at roughly 370–380 km altitude and 97° inclination. The mission, jointly run by Roscosmos, the Russian Academy of Sciences, and the Institute of Biomedical Problems, aimed to study the effects of microgravity and cosmic radiation on biological systems.

The scientific program included ten research sections, ranging from gravitational physiology and radiobiology to biotechnology and lunar simulant exposure. Upon landing in Russia’s Orenburg region, recovery crews quickly extracted specimens for on-site analysis, including motor function tests on flies to assess nervous system impacts. Basalt samples embedded with microbial strains were placed inside the Bion capsule’s hull to test whether bacteria could endure the intense thermal conditions experienced during atmospheric reentry. This inclusion aboard Bion-M2 also served as a test of panspermia-related hypotheses, probing whether life could survive atmospheric reentry, an essential condition for theories suggesting interplanetary transfer of organisms via meteorites.

The mission might contribute to broader efforts to understand spaceflight’s biological risks and inform life support strategies for future crewed exploration.

Largest-Ever Universe Simulation With 3.4 Billion Galaxies Provides Testbed for Mapping Dark Matter and Dark Energy

22 September,2025

The Euclid Consortium released the largest synthetic universe to date, mapping 3.4 billion galaxies with 400 modeled properties and tracking gravitational interactions of over four trillion particles.

The European Space Agency’s Euclid telescope, launched in 2023, is designed to map the “dark universe,” the unseen dark matter and dark energy that shape cosmic structure. To prepare for the torrent of data Euclid will collect, scientists have built Flagship 2 galaxy mock, the largest computer simulation of the universe ever created.

It was developed using an algorithm by UZH astrophysicist Joachim Stadel and executed in 2019 on the Piz Daint supercomputer, back then the world’s third most powerful, using more than 80% of its capacity. This synthetic universe acts as a testing ground for Euclid’s analysis pipelines, ensuring the mission can handle real observations. Euclid will survey one-third of the sky for dark matter and dark energy signals, mapping galaxies up to 10 billion years old. By comparing simulated and observed data, scientists hope to refine the standard cosmological model and probe whether dark energy, the mysterious force driving cosmic acceleration, has remained constant over time.

Although, researchers expect broad agreement with the standard cosmological model, they note potential “cracks,” especially around dark energy’s assumed constancy. Euclid released first observational data in March 2025, with additional datasets planned for spring 2026.

NASA, NOAA Launch IMAP, SWFO-L1, and Carruthers Observatory to Investigate Solar Activity and Interplanetary Space

24 September, 2025

NASA and NOAA have launched three spacecraft aboard a SpaceX Falcon 9 on September 24, 2025, to study how solar activity shapes the space environment across the solar system. The primary payload, NASA’s Interstellar Mapping and Acceleration Probe (IMAP), will orbit the Sun-Earth Lagrange Point 1 (L1) to investigate how solar wind interacts with the boundary of the heliosphere and accelerates particles. Accompanying IMAP are NOAA’s Space Weather Follow On-Lagrange 1 (SWFO-L1), designed to monitor solar wind and coronal mass ejections for real-time space weather forecasting, and NASA’s Carruthers Geocorona Observatory, which will image Earth’s hydrogen-rich exosphere to study atmospheric escape.

IMAP aims to build on data from Voyager and IBEX (Interstellar Boundary Explorer), offering higher-resolution maps of energetic particles and interstellar interactions. It will map the outer boundary of the heliosphere, a solar wind-driven bubble that protects the solar system from galactic cosmic rays and contributes to Earth’s habitability. It will also measure solar wind particles flowing outward from the Sun and energetic particles entering from interstellar space, helping scientists understand how these interactions shape the space environment.

NOAA’s SWFO-L1 is built as a continuous, dedicated space weather observatory, positioned to monitor solar activity and near-Earth space conditions around the clock. Its uninterrupted observations are expected to enhance the speed and accuracy of space weather forecasting, supporting timely alerts for geomagnetic storms and solar events.

The Carruthers Geocorona Observatory is the first mission focused on monitoring variations in Earth’s exosphere—the outermost atmospheric layer that influences how the planet reacts to space weather. By observing the geocorona, a faint ultraviolet glow produced when sunlight interacts with hydrogen in the exosphere, the mission will examine how this region responds to solar storms and seasonal shifts.

This mission is a direct outcome of a growing urgency to understand solar dynamics amid rising solar activity and its implications for satellites, astronauts, and infrastructure.

Private Spacecraft to Test First‑of‑Its‑Kind Orbital Boost for NASA's Swift Space Telescope

24 September, 2025

NASA has awarded Arizona-based Katalyst Space Technologies a $30 million contract to attempt an orbital boost of the Neil Gehrels Swift Observatory, a space telescope launched in 2004 to study gamma-ray bursts. Swift’s low-Earth orbit has been steadily decaying faster than expected, with a significant chance of uncontrolled reentry by late 2026 if no action is taken. The decay is also accelerated by heightened solar activity that expands Earth’s atmosphere and increases drag. Rather than allow the spacecraft to reenter, NASA is pursuing a first-of-its-kind demonstration: a commercial robotic spacecraft will rendezvous with Swift in 2026 and raise its altitude.

Katalyst has only about eight months from contract award to launch, an unusually rapid turnaround for a space servicing mission. If successful, this will mark the first time a private vehicle captures and services a U.S. government satellite not designed for in-orbit maintenance. Because the telescope was never designed for servicing, the mission will require a custom robotic capture system to attach safely without damaging its instruments. The effort is in line with NASA’s strategy of leveraging commercial innovation to extend mission lifetimes at lower cost than replacement. Swift has long been at the center of NASA’s efforts to study the high‑energy universe. When sudden cosmic events occur, the telescope acts like a dispatcher, quickly detecting them and sending vital data so other missions can respond and investigate in detail.

For over twenty years, Swift has delivered discoveries that expand our understanding of phenomena ranging from exploding stars, stellar flares, and outbursts in active galaxies to comets, asteroids, and even energetic lightning in Earth’s atmosphere. This rescue dovetails with Katalyst’s planned NEXUS servicing spacecraft, scheduled for 2027, which aims to provide multi‑mission robotic servicing for both government and commercial satellites. NASA’s partnership with Katalyst may not only about preserving Swift’s science but also about demonstrating rapid, autonomous satellite servicing as a strategic capability, an area where other nations, including China (e.g., the Shijian-21 satellite tug in 2022), have already tested similar technologies.

MILITARY

US Defense Space Strategy Advances as NRO and SDA Expand Proliferated Satellite Constellations With SpaceX, Lockheed Martin Deliveries

22 September, 2025

The United States is accelerating its adoption of proliferated satellite constellations, with both the National Reconnaissance Office (NRO) and the Space Development Agency (SDA) advancing parallel networks designed to increase resilience and responsiveness in orbit.

On September 22, SpaceX launched the NROL‑48 mission from Vandenberg Space Force Base, marking the 11th deployment of satellites for the NRO’s proliferated architecture. While payload details remain classified, the spacecraft are widely believed to be based on modified Starlink buses carrying reconnaissance and communications sensors. The NRO describes the effort as a shift away from reliance on a small number of exquisite, high‑value satellites toward a distributed system of smaller, lower‑cost spacecraft. Officials argue that such a network will provide faster revisit rates, broader coverage, and greater survivability in a contested space environment. Since May 2024, the NRO has launched 11 missions under this model, all on Falcon 9 rockets.

Meanwhile, the Space Development Agency (SDA) is building its Proliferated Warfighter Space Architecture (PWSA), with Lockheed Martin playing a central role. In September, Lockheed completed delivery of 21 satellites for the next launch of the Transport Layer Tranche 1 constellation. These spacecraft, based on Terran Orbital buses and equipped with Link‑16 tactical radios and optical crosslinks, are designed to extend secure, jam‑resistant communications globally. Lockheed emphasizes that the satellites incorporate digital engineering, automation, and modular production techniques to accelerate delivery and reduce costs. Once on orbit, they will provide real‑time data relay and sensor‑to‑shooter connectivity, forming part of a six‑plane constellation.

Together, the NRO’s reconnaissance satellites and the SDA’s communications layer illustrate a structural shift in U.S. defense space strategy. Both agencies are pursuing resilience through numbers, modularity, and rapid launch cadence, signaling a long‑term commitment to distributed architectures as the foundation of national security in orbit.

China’s Growing Space Capabilities Draw Attention From US Defense Leaders

22 September, 2025

At the Air, Space and Cyber Conference in Maryland, senior U.S. defense leaders voiced mounting concerns over China’s rapid advances in air and space capabilities, warning that the pace of Beijing’s innovation could erode longstanding American advantages. Air Force Secretary Troy Meink described the situation as a potential “Sputnik moment,” citing both the Air Force’s readiness shortfalls and China’s ability to field new systems at a fraction of U.S. development timelines. He argued that sustaining superiority will require faster innovation, greater efficiency in sustainment, and a willingness to retire platforms unable to survive in contested environments.

Space Force Chief Gen. Chance Saltzman echoed the urgency, calling for acquisition reform that prioritizes speed over perfection. He urged the service to accept “good enough” systems that can be fielded quickly, rather than waiting for flawless designs, and emphasized closer collaboration with industry to leverage commercial innovation.

Intelligence officials highlighted reusable launch as a key differentiator. SpaceX’s dominance in booster recovery has enabled the U.S. to sustain a high launch cadence, while China remains reliant on expendable rockets. However, Beijing’s push into reusability is viewed as a strategic concern, with officials warning that once achieved, it could allow China to deploy large constellations at scale. Complementing this, China has demonstrated on‑orbit refueling and maneuvering satellites, raising questions about potential counterspace applications.

The competition is not limited to hardware. Recent reports confirm that after one of U.S. defense contractor Maxar Technologies’ WorldView Legion satellites imaged China’s new Earth observation satellite, Shijian-26 in June 2025, Chinese Jilin-1 sats returned the favor by photographing Maxar’s satellite in September. Analysts see this as part of a broader intelligence contest in orbit, where transparency and deterrence are increasingly intertwined.

The security environment is shifting: the U.S. seeks to accelerate procurement and readiness, while China expands capabilities across launch, orbital operations, and surveillance, reshaping the balance of power in space.

L3Harris Expands Defense Programs With AI Counter‑UAS Tests and Air Force Satcom Development

22 September, 2025

L3Harris Technologies is advancing multiple U.S. defense programs that highlight the convergence of artificial intelligence and satellite communications in contested environments. At a recent U.S. military technology exercise, the company and Shield AI demonstrated an AI‑enabled counter‑drone system. The trial integrated L3Harris’s WESCAM MX electro‑optical/infrared sensors with Shield AI’s Tracker software, detecting unmanned aerial systems (UAS) at longer ranges and in cluttered conditions. Officials noted the capability could be incorporated into the U.S. government’s VAMPIRE counter‑UAS platform, with further work focused on refining behavior models across air, land, and maritime domains.

In parallel, L3Harris is preparing to scale production of its Rapidly Adaptable Standards‑compliant Open Radio (RASOR) terminals after successful U.S. Air Force flight tests. Developed under the Air Force Research Laboratory’s Defense Experimentation Using Commercial Space Internet (DEUCSI) program, the modular radios allow military aircraft to connect simultaneously to commercial broadband constellations such as Starlink and Amazon’s Kuiper while maintaining encrypted, government‑grade communications.

The company also recently completed a Critical Design Review for RASOR under the Air Force’s Global Lightning initiative, validating its modular open systems approach. The review confirmed that the radios can support both commercial and military waveforms, with scalability from three to 12 modem slots. Upcoming hardware tests are expected to support additional Air Force flight trials in late 2025.

Taken together, these efforts illustrate how L3Harris is positioning itself at the intersection of autonomy and hybrid communications, reflecting a broader Pentagon strategy to integrate commercial space infrastructure with government systems while countering emerging threats such as low‑cost drones.

COMMERCIAL

Quantum Space Acquisition, Zeno–Orano Nuclear Power Deal, Geespace Funding, and Axiom–Redwire Partnership Highlight Global Industry Movements

Announcements this week, across the global space sector, highlight how propulsion, power, and infrastructure advances are converging to shape the next phase of orbital and deep‑space activity.

22 September, 2025

In the United States, Quantum Space has acquired electric propulsion provider Phase Four’s multi‑mode propulsion assets, including a Los Angeles integration facility. The technology allows spacecraft to switch between chemical and electric propulsion modes, combining high thrust with long‑duration efficiency. Integrated into Quantum’s Ranger platform, the system is intended to support U.S. national security, civil science, and commercial missions from low Earth orbit to cislunar space. The acquisition is in line with the growing demand for maneuverability and persistence in contested orbits, where rapid repositioning and efficient station‑keeping are increasingly critical.

24 September, 2025

Meanwhile, nuclear power for space is moving from concept toward supply chain development. Zeno Power, the Seattle-based nuclear battery manufacturer and French nuclear recycler, Orano have finalized an agreement granting Zeno priority access to americium‑241 recovered from used nuclear fuel at Orano’s La Hague facility in France. Americium‑241, with a half‑life exceeding 400 years, offers a long‑lived alternative to scarce plutonium‑238 for radioisotope power systems (RPS, nuclear batteries). Zeno is developing americium‑fueled batteries for NASA lunar rovers and infrastructure, aiming to provide reliable power through the two‑week lunar night and in permanently shadowed regions. On a positive note this marks a push to extract value from recycled nuclear material, reframing waste as a resource for frontier energy needs.

24 September, 2025

In China, Geespace, the satellite arm of automaker Geely, secured 2 billion yuan/$281 million in provincial and municipal funding to accelerate its Geesatcom Internet of Things constellation and build a global headquarters. With 64 satellites already in orbit, owing to the launch on September 24, and a first‑phase target of 72, the company has signed partnerships with operators across the Middle East, Africa, Asia, and Latin America.

The constellation aims to support 20 million users worldwide, processing up to 340 million daily messages. It can serve 5 million high‑frequency and 15 million lower‑frequency users, transmitting 1,900‑byte packets for text, voice, and images. The investment signals strong state‑backed support for commercial constellations, positioning Geespace to compete internationally in IoT and, eventually, broadband and navigation services.

25 September, 2025

On the infrastructure front in the U.S., Axiom Space awarded space infrastructure provider, Redwire a contract to supply roll‑out solar arrays for Axiom Space’s first commercial station module, the Payload Power Thermal Module (AxPPTM), scheduled to launch in 2027. The arrays build on Redwire’s ROSA technology, already deployed on the ISS and other missions. Axiom’s phased assembly strategy envisions attaching modules to the ISS before separating into an independent commercial station by 2030, ensuring continuity of U.S. human presence in low Earth orbit after ISS retirement. Progress on the module’s primary structure, built by Thales Alenia Space, is already underway.

26 September, 2025

In Europe, Swiss aerospace company, Beyond Gravity will provide robotic arm thrusters for SWISSto12’s small geostationary satellites, part of a trend toward modular, lighter GEO platforms. Lately, propulsion and robotics suppliers are adapting to new satellite manufacturing models that emphasize cost efficiency and rapid deployment. Another example is Maxar Space Systems, that has been retooling its propulsion and robotics offerings to align with new satellite manufacturing models that prioritize modularity and faster production cycles.

Meanwhile, earlier in the month, SWISSto12 and Astrum Mobile had completed the Preliminary Design Review for NEASTAR‑1, a geostationary satellite built on SWISSto12’s compact HummingSat platform. Designed to deliver satellite‑to‑device services across the Asia‑Pacific, it will broadcast directly to standard smartphones and handhelds, supporting media, IoT connectivity, and emergency alerts. Its high‑power L‑band payload is engineered to maintain service during severe weather and natural disasters, while the smaller, cost‑efficient design aims to accelerate production and launch opportunities.

These developments illustrate how propulsion breakthroughs, nuclear power systems, constellation financing, and commercial station infrastructure are advancing in parallel. Each addresses a different bottleneck: mobility, energy, connectivity, or habitation, but collectively they point to a near‑term space economy defined by greater resilience, diversification, and international competition

Purdue University Crew to Fly on Virgin Galactic Suborbital Mission in 2027

23 September, 2025

Purdue University, long known as the “Cradle of Astronauts,” will extend its legacy with a dedicated suborbital mission aboard Virgin Galactic’s next‑generation Delta spacecraft in 2027. The flight, called Purdue 1, will feature an all‑Boilermaker (a nickname for the university’s students, alumni, and athletic teams) crew of five: aerospace engineering professor Steven Collicott, graduate student Abigail Mizzi, alumnus Jason Williamson, and two additional alumni yet to be named. One passenger seat will be removed to accommodate a payload rack, allowing Collicott and Mizzi to conduct fluid dynamics experiments in real time, research relevant to spacecraft fuel management and long‑duration mission design.

NASA is funding Collicott’s seat through its Flight Opportunities program, while Mizzi’s participation is supported by donations and alumni will self‑fund. Virgin Galactic, which has paused flights to prepare its Delta fleet, frames Purdue 1 as a demonstration of how universities can directly integrate teaching and research into spaceflight.

UK’s Space Forge and US Firm United Semiconductors Collaborate to Develop Space‑Based Semiconductor Supply Chain

26 September, 2025

U.K.‑based Space Forge and U.S. firm United Semiconductors have formalized a partnership to advance semiconductor manufacturing in space. The agreement combines Space Forge’s ForgeStar platform and deposition processes with United Semiconductors’ expertise in crystal growth and wafer processing. Both companies argue that space conditions such as microgravity, vacuum, and thermal stability, could yield higher‑quality semiconductor substrates than those produced on Earth, where contamination and defects remain costly challenges.

Producing silicon wafers is among the most complex and expensive industrial processes on Earth: as transistors shrink, fabrication demands ultra‑clean environments, extreme precision, and acceptance that many wafers will fail. Space conditions may ease some of these constraints.

United Semiconductors has already flown early experiments to the International Space Station, first in late 2024 and again aboard a recent Cygnus XL cargo mission, to test crystal growth and wafer deposition in orbit. Meanwhile, Space Forge is developing returnable satellites designed to bring back manufactured materials. Together, they aim to demonstrate commercial viability by producing wafers for applications in quantum computing, telecommunications, and advanced electronics. The collaboration also highlights a strategic dimension: establishing resilient supply chains for critical technologies. If successful, the effort could position space‑based manufacturing as a complement to terrestrial fabs, rather than a distant science‑fiction concept.

RESEARCH SPOTLIGHT

The Nearest Technologically Advanced Neighbors Could Be 33,000 Light‑Year Away

New research presented at the Europlanet Science Congress–DPS 2025 in Helsinki argues that technologically advanced civilizations may be rare because long-lived biospheres likely require plate tectonics and a nitrogen–oxygen atmosphere with carefully balanced carbon dioxide.

Manuel Scherf and Helmut Lammer of the Austrian Academy of Sciences, model how CO2 regulates photosynthesis and atmospheric escape via the carbon–silicate cycle. To sustain a long-lived biosphere, a planet needs enough carbon dioxide to support photosynthesis and prevent the atmosphere from escaping, but not so much that it becomes toxic or overheats. Plate tectonics help maintain this balance by cycling carbon through the carbon–silicate process. However, this regulation isn’t permanent: over time, CO₂ can be drawn down to levels that halt photosynthesis.

On Earth, photosynthesis could cease in 200 million to roughly one billion years; planets with ~10% CO2 might sustain biospheres ~4.2 billion years, while ~1% CO2 yields up to ~3.1 billion years. They also note oxygen must be ≥18% to permit open-air combustion essential for metallurgy. Comparing biosphere durations with the ~4.5‑billion‑year timescale for technological intelligence on Earth, they infer the nearest technological neighbors may lie ~33,000 light‑years away, and temporal overlap with us would require civilizational lifetimes of at least ~280,000 years (and ~10 million years for ten contemporaries). Despite uncertainties, they recommend continued search for extraterrestrial intelligence to test these assumptions.

New Study Finds Sub‑Neptune Exoplanets Probably Not Water Worlds

New simulations led by ETH Zurich challenge the idea that many sub‑Neptune exoplanets are water worlds, finding that surface water is limited to a few percent at most. The team modelled chemical equilibrium between long‑lived magma oceans and hydrogen‑rich atmospheres, showing hydrogen and oxygen bind to metal and silicate compounds and sequester water into planetary interiors, reducing observable H2O despite initial ice accretion beyond the snow line.

Sub‑Neptune planets, larger than Earth but smaller than Neptune, have long been touted as potential “water worlds” after forming beyond their stars’ snow lines and migrating inward, where retained ice might melt beneath hydrogen‑rich skies. Such hypothetical worlds were dubbed "Hycean planets," a blend of "hydrogen" and "ocean." In planet-formation terms, the snow line is the distance in a protoplanetary disk beyond which temperatures are low enough for water and other volatiles to freeze into ice.

The work implies Hycean planets with global oceans making up tens of percent of mass are unlikely and that planets often considered exceptionally wet may instead resemble Earth’s modest water fraction. That shifts the search for habitable surface water toward smaller, terrestrial planets requiring more sensitive telescopes than JWST. Authors warn uncertainties in chemical models and formation histories remain, but argue that accounting for atmosphere‑interior coupling is essential for interpreting exoplanet spectra and refining targets in the search for life in future surveys. The research was published in The Astrophysical Journal Letters.

Centrifugal Nuclear Rocket Concept Using Liquid Uranium Aims to Cut Travel Time to Mars and Beyond

Researchers have designed a centrifugal nuclear thermal rocket (CNTR) that uses liquid uranium to heat propellant directly. The new design could roughly double the nuclear thermal propulsion efficiency and raise specific impulse (how efficient a rocket is at generating thrust) above legacy NERVA‑era values, which could shorten deep‑space transit times and expand mission mass margins. NERVA was a U.S. nuclear‑thermal rocket program (1961–1973) that developed and ground‑tested reactor‑heated hydrogen engines that roughly doubled chemical rockets’ specific impulse but was canceled before any in‑space tests.

The team from Ohio State University positions CNTR as an alternative to solid fuel reactor cores, arguing liquid uranium and centrifugal containment reduce engine risk while enabling higher performance and flexible propellant choices. Engineers report prototype development, computational models, and test‑stand work but note substantial engineering hurdles remain, including startup and shutdown stability, uranium loss mitigation, and failure modes.

If matured, CNTR could change mission architectures for crewed Mars trips, cis‑lunar logistics, and rapid robotic missions to outer planets by reducing travel time and propellant needs, yet demonstrators and safety reviews are essential before operational adoption. The project is NASA‑funded and aims for design readiness within five years pending. A paper describing the CNTR design was published in the journal Acta Astronautica.

Despatch Out. 👽🛸