Northrop Grumman has launched a private satellite-servicing mission to attach life-extending "jetpacks" to aging communications satellites in geosynchronous orbit. "It's the second satellite-saving mission to launch this month, all part of a growing, money-saving effort to keep spacecraft running as long as possible," reports Phys.org. From the report: Launched by SpaceX, Northrop Grumman's mission robotic vehicle -- dubbed MRV -- and its jetpacks will spend the next year angling into the proper orbit 22,300 miles (36,000 kilometers) above Earth. Hundreds of satellites orbit at this so-called geosynchronous orbit, where they match the speed of Earth's rotation and keep to the same part of the sky for continuous coverage. Once in place by mid-2027, the minivan-sized spacecraft will use its 10-foot (9-meter) arms to attach a jetpack to an aging communication satellite. Then it will zip off to two more satellites in need. For its debut flight, the spacecraft was accompanied by three electric-propelled jetpacks that peeled away separately following liftoff. Like the MRV, the jetpacks will use their own xenon gas thrusters to get to the desired orbit. Once in place, the jetpacks will wait for the robot to grab them, one at a time, and plug them into their designated satellites. Each jetpack -- the size of a washing machine -- will provide the necessary oomph for an out-of-gas satellite to keep operating for several more years instead of retiring. If it works, it will be a boon for satellite operators SES of Luxembourg and Optus of Australia, saving them millions of dollars in replacement costs.

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A new study proposes using shoebox-sized detector satellites to sniff out nuclear weapons launched by adversary nations. The idea is aimed at addressing fears that a space-based nuclear detonation could destroy satellites across low Earth orbit and make some orbits unusable for years. Space.com shares the findings from a new paper authored by Areg Danagoulian, an associate professor of nuclear science and engineering at the Massachusetts Institute of Technology: No reliable way currently exists to detect and defuse a nuclear bomb in space. Danagoulian proposes a constellation of small "9U" cubesats, each one about the size of a large shoebox and each carrying a special detector capable of sensing radiation emitted by unexploded nuclear bombs. He explores a scenario in which Russia launches a suspected space nuke into an orbit with an altitude of 1,200 miles (2,000 km). That number is not random. In 2022, Russia's Kosmos 2553 satellite, orbiting at that exact altitude, triggered suspicions it might be testing components for a future orbital nuclear weapon. Russia claims the satellite just observes Earth. At that altitude, the satellite passes through the Van Allen belt, a region of intense cosmic radiation trapped by Earth's magnetic field. Most of the belt stretches between altitudes of around 600 miles (1,000 km) to tens of thousands of miles, but in some areas the radiation can reach much closer to Earth's surface. The interaction between the fissile material inside the nuke and the energetic particles from the radiation belt would create distinct signatures, Danagoulian said, which could help confirm whether a suspicious satellite carries a nuke or not. "The thermonuclear weapon would contain a significant amount of uranium," Danagoulian said. "The high-energy protons [in the uranium] would break up when another proton is coming in and shred the nuclei. That would knock out a large number of neutrons. This interaction turns that device into a very intense neutron source that otherwise would not be there." he process is known as proton-induced neutron spallation, which essentially means the ejection of fragments from material triggered by impacts of protons. The detector satellite Danagoulian proposes would have to be able to get quite close to the suspect spacecraft -- a few kilometers. The inspector spacecraft would carry a sensor combining two types of detectors. At the heart of the device is a neutron scintillator, which detects all incoming neutrons and protons. Around it is a "cage of diamond" detector that detects only neutrons -- not protons. Such a set-up helps filter out the particles present in the environment naturally, said Danagoulian. In addition, by using two "planes of neutron detectors," the sensor can determine the direction from which the neutrons arrived. "If the external diamond detector triggers and gives a signal, you can ignore the particle, because it's most likely a proton and not a neutron," said Danagoulian. "Once you identify those neutrons, by having those two detections, you can back project and find out where the neutron came from." Danagoulian says such a nuke sniffer would have to be launched into an orbit aligned with that of the suspicious satellite and creep up as close as 2.5 miles (4 km) from it. It would then take about a week to gather enough measurements to confirm whether the object is hiding a nuke or not. A constellation of 10 such satellites could reduce the process to mere hours, Danagoulian said. If a nuke were detected, the military could then try to jam the satellite's communications link from the ground, making it impossible for the adversary to remotely detonate the bomb. There is currently no technology available to safely defuse a nuclear weapon in space. [...] Danagoulian also suggests that high-grade radiation hardening could improve satellites' chances of surviving a nuclear winter in space. The paper has been published in the journal Nature.

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A security researcher says evidence suggests the U.S. military has been using an obscure GPS message field for nearly 20 years to broadcast encrypted key-distribution data, effectively turning GPS satellites into a global "numbers station." The hidden-looking 176-bit messages appear tied to the Pentagon's Over-the-Air Distribution system for remotely updating cryptographic keys, meaning ordinary GPS receivers may have been receiving the traffic all along without anyone outside the military noticing. The findings have been detailed by Steven Murdoch, an information security expert, in a new article in Inside GNSS. 404 Media reports: [...] From the beginning, he suspected that the subframe field contained encrypted transmissions because the data was so random. "Random data is actually very unusual to get in nature," Murdoch said. "If you see it, either it's been carefully designed to be random -- but then, why is someone sending out random data? -- or it's encrypted data. I thought encrypted data is by far the most likely explanation." He returned to the subframe on and off over the years, and solicited guesses about its content on Stack Exchange in 2023. Ahmed Kamruddin, a master's student at UCL, developed the project further in 2025. Then, this year, Murdoch put the last pieces of the puzzle together over several weeks by analyzing open archive Global Navigation Satellite System (GNSS) recordings collected since 2007 and kept by GFZ Helmholtz Centre for Geosciences. This dataset included more than 12 million observations of Subframe 4, Page 17, yielding 3,994 unique 176-bit messages. Within this corpus, Murdoch pinpointed key-repeating "sentinels" including a pattern that appeared in February 2010 and was broadcast on and off across dozens of satellites for more than a decade. Murdoch discovered that this particular sentinel was transmitted by all 31 operational satellites within a window of a few hours on May 26, 2011, potentially heralding the activation of a new operational system. He confirmed that this timeline coincided with the rollout of the military's Over-the-Air Distribution (OTAD) and the Over-the-Air Rekeying (OTAR) by cross-referencing declassified documents, including a 2015 presentation about the dates of the operation. "There was a perfect match between the timeline and that presentation and the change points that were automatically identified from the data," Murdoch said. "That was the smoking gun that made me think: This is what it's for." These automated systems replaced the cumbersome manual distribution of cryptographic keying material, allowing military GPS receivers around the world to be rekeyed remotely through satellite broadcasts rather than through onsite procedures. For the next 11 years, this expansive rekeying operation was overlooked in public GPS data. In 2022, the system entered a new phase, according to Murdoch's analysis. The shift was characterized by a slowing in the message rotation rate. Later, in December 2023, broadcasts carrying a distinctive "TEXT" prefix emerged then gradually spread across the constellation. Murdoch isn't sure what explains the recent transition, though it could be a possible modernization of the infrastructure or the introduction of a new protocol. But to him, the bigger takeaway is that the signals were always available for anyone willing to take a closer look, a discovery that suggests that there could be more revelations hidden for the cryptographically curious among us. "Every receiver in the world decodes Subframe 4, Page 17," Murdoch said in his new article. "Almost none of them have ever looked at it. The lesson generalizes: There is more to learn from the bytes already arriving at our antennas than from the bytes we wish were specified differently. The data are publicly available. The signal is overhead, twice a day, every day."

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An anonymous reader quotes a report from Reuters: Elon Musk's Starlink and Amazon's low-earth-orbit satellite business may be able to acquire some European mobile satellite spectrum next year, two people with direct knowledge of the matter said on Tuesday. But they said two-thirds of the satellite spectrum that allows mobile devices and vehicles to communicate seamlessly even in remote locations, would be reserved for European companies. U.S. companies Viasat and EchoStar hold licenses that are due to expire in May 2027 and the European Commission has been considering how to allocate future spectrum at the same time as the bloc pushes to reduce reliance on U.S. tech. The European Union's IRIS2 multi-orbit array of 290 satellites, a response to Starlink, will be among the European companies to receive some spectrum, the sources said. British and Norwegian companies can also bid for a license, the people said. Details of the proposal, set to be announced on Wednesday, could still change at a meeting of commissioners on the day, one of the sources. Commission spokesman Thomas Regnier said EU-wide satellite connectivity was "synonymous with resilience, security, and capability" given the current geopolitical context. "Satellite connectivity is a key piece of our technological sovereignty, our security, and our defense, as also highlighted by IRIS2," he added.

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