Keith’s note: I just got an update from KeepTheShuttle. OMB wants NASA and the Smithsonian to figure out how to cut Space Shuttle Discovery apart into pieces to move it. As you will recall that option was ruled out when Space Shuttle Endeavour was moved to Los Angeles on the now-defunct 747 carrier and then moved through the streets where utilities were moved and trees were cut down. Every effort was taken to preserve the integrity of this historic space ship. Now Texas Senators Ted Cruz and John Cornyn are only interested in snagging a tourist attraction – not a precious historic relic that deserves to be preserved – and certainly not chopped up like a leftover exhibit from a state fair and tossed on a flatbed. Full statement below.
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This development is unprecedented and alarming. NASA did not design the shuttle orbiters to be disassembled, and complicating factors include the shuttle’s aluminum frame, ~24,000 delicate ceramic tiles that coat the shuttle’s underside (the black part), and ~2,000 thermal insulation fabric blankets that coat the rest of the shuttle (the white part). Disassembling Discovery would cause significant and irreparable damage to these and other portions of the shuttle.
Discovery also holds particular value, as the shuttle was specially preserved to serve as a future reference for researchers. To quote Dennis Jenkins, who was the director of NASA’s program to retire the shuttle fleet “We spent a lot of time and money to preserve Discovery in as near to flight condition as we could to put it in the national collection, so that any future engineer or historian has a reference vehicle to look at, measure or do whatever they need”. The process that the White House is now asking the Smithsonian and NASA to explore would permanently ruin this work and significantly hamper the ability of future generations to study and learn from Discovery.
The letter also references that NASA and the Smithsonian are in agreement that the cost to move Discovery to Houston would, at minimum, be between $120 million and $150 million, exclusive of the cost of building a new exhibit in Houston. This number significantly exceeds the $85 million authorized for the relocation and a new exhibit by the OBBBA, and indicates that additional taxpayer funding will be necessary. A
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Letter from the Smithsonian to Congressional Authorizing & Appropriating Committees:
“The Smithsonian has been asked by OMB to work with NASA to prepare to move the Discovery space shuttle to Houston, TX, within the 18 months specified in the reconciliation bill signed into law on July 4, 2025. The bill does not specifically mention Discovery as the designated vehicle for relocation, and its terms could include any number of space vehicles, but the administration is interpreting the law as sufficiently specific to move forward with the transfer of Discovery. The Smithsonian and NASA have been asked to begin by verifying the actual costs associated with the move.
While an engineering study will be necessary due to the size and weight of the space vehicle, both NASA and the Smithsonian believe that Discovery will have to undergo significant disassembly to be moved.
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NASA transferred “all rights, title, interest and ownership” of the shuttle to the Smithsonian. We remain concerned about the unprecedented nature of a removal of an object from the national collection, and that we would be causing damage to the most intact orbiter from the space shuttle program
NASA is inviting the public to join the agency’s Artemis II test flight as four astronauts venture around the Moon and back to test systems and hardware needed for deep space exploration. As part of the agency’s “Send Your Name with Artemis II” effort, anyone can claim their spot by signing up before Jan. 21.
Participants will launch their name aboard the Orion spacecraft and SLS (Space Launch System) rocket alongside NASA astronauts Reid Wiseman, Victor Glover, Christina Koch, and CSA (Canadian Space Agency) astronaut Jeremy Hansen.
“Artemis II is a key test flight in our effort to return humans to the Moon’s surface and build toward future missions to Mars, and it’s also an opportunity to inspire people across the globe and to give them an opportunity to follow along as we lead the way in human exploration deeper into space,” said Lori Glaze, acting associate administrator, Exploration Systems Development Mission Directorate at NASA Headquarters in Washington.
The collected names will be put on an SD card loaded aboard Orion before launch. In return, participants can download a boarding pass with their name on it as a collectable.
To add your name and receive an English-language boarding pass, visit:
As part of a Golden Age of innovation and exploration, the approximately 10-day Artemis II test flight, launching no later than April 2026, is the first crewed flight under NASA’s Artemis campaign. It is another step toward new U.S.-crewed missions on the Moon’s surface that will help the agency prepare to send the first astronauts – Americans – to Mars.
The National Oceanic and Atmospheric Administration is narrowing the capabilities and reducing the number of next-generation weather and climate satellites it plans to build and launch in the coming decades, two people familiar with the plans told CNN.
This move — which comes as hurricane season ramps up with Erin lashing the East Coast — fits a pattern in which the Trump administration is seeking to not only slash climate pollution rules, but also reduce the information collected about the pollution in the first place. Critics of the plan also say it’s a short-sighted attempt to save money at the expense of understanding the oceans and atmosphere better.
Two planned instruments, one that would measure air quality, including pollution and wildfire smoke, and another that would observe ocean conditions in unprecedented detail, are no longer part of the project, the sources said.
“This administration has taken a very narrow view of weather,” one NOAA official told CNN, noting the jettisoned satellite instruments could have led to better enforcement and regulations on air pollution by more precisely measuring it.
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Having fewer satellites in the sky means less redundancy and raises the risk of critical data outages, the NOAA official stated. “It’s gambling with the continuity of an operational system that we’ve relied on since the early 70s,” they said.
The satellite series is meant to be the successor to the GOES satellites, which provide a wealth of data for weather forecasting, with the first launch set for 2032 and service lasting through 2055.
Project Hyperion explores the feasibility of crewed interstellar travel via generation ships, using current and near-future technologies. A generation ship is a hypothetical spacecraft designed for long-duration interstellar travel, where the journey may take centuries to complete. The idea behind a generation ship is that the initial crew would live, reproduce, and die on the ship, with their descendants continuing the journey until reaching the destination. These ships are often envisioned as self-sustaining ecosystems, featuring agriculture, habitation, and other necessary life-support systems to ensure survival across multiple generations.
The Initiative for Interstellar Studies (i4is) is delighted to reveal the winners of the Project Hyperion Design Competition, a landmark global challenge that called upon interdisciplinary teams to envision a generation ship—a crewed interstellar spacecraft designed for a 250-year journey to a habitable planet. The teams designed habitats of such a spacecraft that would allow a society to sustain itself and flourish in a highly resource-constrained environment.
The Project Hyperion Design Competition required architectural designers, engineers, and social scientists to collaborate and address critical mission aspects that enable a spacecraft to function as a closed society over centuries. The collaboration between different disciplines is key to finding holistic solutions that do justice to the complexity of the requirements, in order to provide:
Habitability for 1,000 ± 500 people over centuries
Artificial gravity via rotation
A society that ensures good living conditions, including essential provisions such as shelter, clothing, and other basic needs.
Robust life support systems for food, water, waste, and the atmosphere
Knowledge transfer mechanisms to retain culture and technologies
Astronomers have discovered a huge filament of hot gas bridging four galaxy clusters. At 10 times as massive as our galaxy, the thread could contain some of the Universe’s ‘missing’ matter, addressing a decades-long mystery.
The astronomers used the European Space Agency’s XMM-Newton and JAXA’s Suzaku X-ray space telescopes to make the discovery.
Over one-third of the ‘normal’ matter in the local Universe – the visible stuff making up stars, planets, galaxies, life – is missing. It hasn’t yet been seen, but it’s needed to make our models of the cosmos work properly.
Said models suggest that this elusive matter might exist in long strings of gas, or filaments, bridging the densest pockets of space. While we’ve spotted filaments before, it’s tricky to make out their properties; they’re typically faint, making it difficult to isolate their light from that of any galaxies, black holes, and other objects lying nearby.
New research is now one of the first to do just this, finding and accurately characterising a single filament of hot gas stretching between four clusters of galaxies in the nearby Universe.
“For the first time, our results closely match what we see in our leading model of the cosmos – something that’s not happened before,” says lead researcher Konstantinos Migkas of Leiden Observatory in the Netherlands. “It seems that the simulations were right all along.”
XMM-Newton on the case
Clocking in at over 10 million degrees, the filament contains around 10 times the mass of the Milky Way and connects four galaxy clusters: two on one end, two on the other. All are part of the Shapley Supercluster, a collection of more than 8000 galaxies that forms one of the most massive structures in the nearby Universe.
The filament stretches diagonally away from us through the supercluster for 23 million light-years, the equivalent of traversing the Milky Way end to end around 230 times.
Konstantinos and colleagues characterised the filament by combining X-ray observations from XMM-Newton and Suzaku, and digging into optical data from several others.
The two X-ray telescopes were ideal partners. Suzaku mapped the filament’s faint X-ray light over a wide region of space, while XMM-Newton pinpointed very precisely contaminating sources of X-rays – namely, supermassive black holes – lying within the filament.
“Thanks to XMM-Newton we could identify and remove these cosmic contaminants, so we knew we were looking at the gas in the filament and nothing else,” adds co-author Florian Pacaud of the University of Bonn, Germany. “Our approach was really successful, and reveals that the filament is exactly as we’d expect from our best large-scale simulations of the Universe.”
Not truly missing
As well as revealing a huge and previously unseen thread of matter running through the nearby cosmos, the finding shows how some of the densest and most extreme structures in the Universe – galaxy clusters – are connected over colossal distances.
It also sheds light on the very nature of the ‘cosmic web’, the vast, invisible cobweb of filaments that underpins the structure of everything we see around us.
“This research is a great example of collaboration between telescopes, and creates a new benchmark for how to spot the light coming from the faint filaments of the cosmic web,” adds Norbert Schartel, ESA XMM-Newton Project Scientist.
“More fundamentally, it reinforces our standard model of the cosmos and validates decades of simulations: it seems that the ‘missing’ matter may truly be lurking in hard-to-see threads woven across the Universe.”
Piecing together an accurate picture of the cosmic web is the domain of ESA’s Euclid mission. Launched in 2023, Euclid is exploring this web’s structure and history. The mission is also digging deep into the nature of dark matter and energy – neither of which have ever been observed, despite accounting for a whopping 95% of the Universe – and working with other dark Universe detectives to solve some of the biggest and longest-standing cosmic mysteries.
In what seemed to be a development that came from nowhere, there’s a new entrant into the reusable launch systems competition – Honda. The giant Japanese industrial conglomerate recently launched a prototype reusable rocket up to 300m and landed it safely back on Earth.
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Honda’s first test launch took place on June 17th. During the test, a prototype rocket that was 6.3m tall and 85 cm in diameter, with a wet weight of 1312 kg, launched 271.4 m into the air and landed 37 cm from its nominal landing spot after a 56.6 second flight. Data was collected throughout the test to inform the next round of testing.
This step is the equivalent to the famous “Grasshopper” experiments that SpaceX completed back in 2013, where the rocket would launch, hover and return to the ground. It was a necessary step on the path to reusable rocketry, and Honda is now only the fourth company to ever complete this feat.
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SpaceX is famous for it’s work culture that is at least partly driven by fear of failure [and, a huge string of failures!], which probably won’t be the case for the Honda engineers who could simply shuffle off to other parts of the organization if their rocketry experiments fail. But, given Japan’s increasing presence in the growing space industry, it was only a matter of time before a Japanese champion would join the fray of the new RLV industry.
Headquartered in Japan, the commercial space company ispace is dedicated to creating robotic spacecraft and other technology to support the discovery, mapping, and harvesting of natural resources on the Moon. One of the main tools in their arsenal is the RESILIENCE lander, a small, lightweight uncrewed spacecraft designed for low-cost, high-frequency transportation of instruments and other supplies to the lunar surface. Earlier today, the company announced that their second mission with the RESILIENCE lander (SMBC x HAKUTO-R Venture Moon) entered lunar orbit.
According to a company statement, the orbital injection maneuver was completed by 5:41 a.m. JST (1:41 p.m. PST; 4:41 p.m. EST) on May 7th, 2025. This marks the successful completion of the mission’s seventh Mission Milestone, which included completing the first lunar orbit insertion maneuver and reaffirming “the ability of space to deliver spacecraft and payloads into stable lunar orbits.” The orbital maneuver consisted of the longest thruster burn during Mission 2, lasting approximately 9 minutes. The team at the Mission Control Center in Nihonbashi, Tokyo, confirmed that RESILIENCE is now maintaining a stable attitude above the lunar surface.
On April 24th, 2025, RESILIENCE completed the maneuvers to transition the lander from deep space and closer to the Moon to complete the orbital injection. Before that, RESILIENCE completed a lunar flyby that verified the spacecraft’s propulsion, guidance, control, and navigation systems. Following the flyby, the lander spent about two months in a low-energy transfer orbit. Mission specialists are now preparing for the final orbit maneuvers in preparation for a lunar landing, which is scheduled to take place no earlier than June 5th, 2025.
RESILIENCE was launched on January 15th, 2025, at 12:44 p.m. PST (03:44 p.m. EST)
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For this mission, the RESILIENCE is transporting several payloads for commercial customers.
These include the TENACIOUS micro rover by ispace-EUROPE, which will be deployed on the surface to explore the landing site, collect lunar regolith, and relay data back to the lander. Other payloads include a water electrolyzer, a food production experiment, a deep space radiation probe, a commemorative alloy plate, and a “Moonhouse,” a model house created by Swedish artists to be placed on the surface. The mission also carries a UNESCO memory disk, a cultural artifact containing data on humanity’s linguistic and cultural diversity.
As UNESCO describes it, the disk “serves as a repository of cultural heritage,” which will be preserved for millions of years in case human civilization collapses someday:
A longstanding prediction in interstellar theory posits that significant quantities of molecular gas, crucial for star formation, may be undetected due to being ’dark’ in commonly used molecular gas tracers, such as carbon monoxide. We report the discovery of Eos, a dark molecular cloud located just 94 pc from the Sun.This cloud is identified using H2 far-ultraviolet fluorescent line emission, which traces molecular gas at the boundary layers of star-forming and supernova remnant regions. The cloud edge is outlined along the high-latitude side of the North Polar Spur
AtmoSense, which began in late 2020, set out to understand the fundamentals of energy propagation from the Earth’s surface to the ionosphere to determine whether the atmosphere can be used as a sensor. A fundamental science effort, AtmoSense aimed to measure acoustic and electromagnetic waves propagating through the atmosphere to see if they could provide clues about the nature, location, and size of a disturbance event that occurred on Earth. Precisely locating illicit underground explosions by a rogue nation or identifying other national security-relevant events could be done in the future just by using signals detected and modeled from the atmosphere. The open-source tools developed under AtmoSense may be the first step toward “reading” — from extended distances — information contained in atmospheric waves propagating from an event happening anywhere in the world.
Benefits for a range of computationally complex problems
“High-resolution surface-to-space simulation of acoustic waves was considered impossible before the program began, but we accomplished it,” said Michael “Orbit” Nayak, DARPA AtmoSense program manager. “We used to call the ionosphere the ‘ignorosphere,’ but AtmoSense made some key interdisciplinary breakthroughs to address what used to be a massively intractable problem. We can now model across six orders of magnitude, in 3D, what happens to the energy emanating from a small, meters-scale disturbance as it expands up into the atmosphere to propagate over thousands of kilometers, and potentially around the world.”
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An unplanned discovery: SpaceX Falcon 9 re-entries detected
Following one of the New Mexico test-range detonations in 2024, a performer team noticed something unusual in their analysis of sensor data.
“As the team was looking at the data, they saw a huge drop in what’s called total electron content that puzzled them,” Nayak said. “Imagine that you have water going through a hose. That’s a flow of electrons, and if you put your fist in front of the hose, you’ll notice a significant drop in water volume coming out of the hose.”
In preparing to analyze their field test data, the team noticed a similar sizable dip in the electron content compared to the background electron readings at a specific location in the atmosphere. As they did more forensics, they correlated the disturbance to a SpaceX Falcon 9 re-entry that happened the same day of the detonation test. Their sensor data had unexpectedly captured the SpaceX reentry into the atmosphere, resulting in the specific drop in electron content.
“Then they decided to pull other SpaceX reentry data, across dozens of launches, to see if they could spot a similar electron drop,” Nayak said. “The phenomenon is highly repeatable. We discovered an unplanned new technique for identifying objects entering the earth’s atmosphere.” The Embry-Riddle University team, led by Jonathan Snively and Matt Zettergren, in collaboration with Pavel Inchin of Computational Physics, Inc., have submitted their novel results for peer-reviewed publication.
Earth’s atmosphere is shrinking due to climate change and one of the possible negative impacts is that space junk will stay in orbit for longer, bonk into other bits of space junk, and make so much mess that low Earth orbits become less useful.
That miserable set of predictions appeared on Monday in a Nature Sustainabilitypaper titled “Greenhouse gases reduce the satellite carrying capacity of low Earth orbit.”
Penned by two boffins from MIT, and another from University of Birmingham, the paper opens with the observation that “Anthropogenic contributions of greenhouse gases in Earth’s atmosphere have been observed to cause cooling and contraction in the thermosphere.”
The Thermosphere extends from about 90 km to 500 km above Earth’s surface. While conditions in the thermosphere are hellish, it’s not a hard vacuum. NASA describes it as home to “very low density of molecules” compared to the Exosphere’s “extremely low density.”
Among the molecules found in the Thermosphere is Carbon Dioxide (CO2) which conducts heat that from lower down in the atmosphere then radiates it outwards.
“Thus, increasing concentrations of CO2 inevitably leads to cooling in the upper atmosphere. A consequence of cooling is a contraction of the global thermosphere, leading to reductions in mass density at constant altitude over time.”
That’s unwelcome because the very low density of matter in the Thermosphere is still enough to create drag on craft in low Earth orbit – enough drag that the International Space Station requires regular boosts to stay in orbit.
It’s also enough draft to slow space junk closer so it falls into denser parts of the atmosphere that vaporizes it. A less dense Thermosphere, the authors warn, means more space junk orbiting for longer and the possibility of Kessler syndrome instability – space junk bumping into space junk and breaking it up into smaller pieces until there’s so much space junk some orbits become too dangerous to host satellites.
Which is bad because we’re using low Earth orbit a lot these days for things like broadband satellites.
NASA and the Italian Space Agency made history on March 3, when the Lunar GNSS Receiver Experiment (LuGRE) became the first technology demonstration to acquire and track Earth-based navigation signals on the Moon’s surface.
The LuGRE payload’s success in lunar orbit and on the surface indicates that signals from the GNSS (Global Navigation Satellite System) can be received and tracked at the Moon. These results mean NASA’s Artemis missions, or other exploration missions, could benefit from these signals to accurately and autonomously determine their position, velocity, and time. This represents a steppingstone to advanced navigation systems and services for the Moon and Mars.
An artist’s concept of the LuGRE payload on Blue Ghost and its three main records in transit to the Moon, in lunar orbit and on the Moon’s surface.
NASA/Dave Ryan
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The road to the historic milestone began on March 2 when the Firefly Aerospace’s Blue Ghost lunar lander touched down on the Moon and delivered LuGRE, one of 10 NASA payloads intended to advance lunar science. Soon after landing, LuGRE payload operators at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, began conducting their first science operation on the lunar surface.
Members from NASA and Italian Space Agency watching the Blue Ghost lunar lander touch down on the Moon.
NASA
With the receiver data flowing in, anticipation mounted. Could a Moon-based mission acquire and track signals from two GNSS constellations, GPS and Galileo, and use those signals for navigation on the lunar surface?
Then, at 2 a.m. EST on March 3, it was official: LuGRE acquired and tracked signals on the lunar surface for the first time ever and achieved a navigation fix — approximately 225,000 miles away from Earth.
Now that Blue Ghost is on the Moon, the mission will operate for 14 days providing NASA and the Italian Space Agency the opportunity to collect data in a near-continuous mode, leading to additional GNSS milestones. In addition to this record-setting achievement, LuGRE is the first Italian Space Agency developed hardware on the Moon, a milestone for the organization.
The LuGRE payload also broke GNSS records on its journey to the Moon. On Jan. 21, LuGRE surpassed the highest altitude GNSS signal acquisition ever recorded at 209,900 miles from Earth, a record formerly held by NASA’s Magnetospheric Multiscale Mission. Its altitude record continued to climb as LuGRE reached lunar orbit on Feb. 20 — 243,000 miles from Earth. This means that missions in cislunar space, the area of space between Earth and the Moon, could also rely on GNSS signals for navigation fixes.
Blue Ghost, a NASA-funded lunar lander built and operated by the private U.S. company Firefly Aerospace, has successfully touched down on the moon.
After 45 days in space—and a pulse-pounding semi-autonomous hour-long descent to its landing site—at 3:35 A.M. EST three of the boxy, car-sized spacecraft’s four footpad-tipped legs crunched into the surface of Mare Crisium, a vast and ancient impact basin filled with frozen lava on the moon’s northeastern near side. This marks the second time the U.S. has soft-landed on the moon since the crewed Apollo 17 mission of 1972; the first occurred just over a year ago when another robotic commercial mission, the Odysseus lander from the company Intuitive Machines, made moonfall lopsided but intact in a crater near the lunar south pole.
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Now that it’s on the moon, Blue Ghost is set to spend about two weeks performing a series of scientific and technological studies using a suite of ten experiments provided by NASA as part of the space agency’s Commercial Lunar Payload Services (CLPS) public-private partnership initiative. CLPS is NASA’s effort to save costs by enlisting more than a dozen U.S. firms to ferry cargo and science experiments to the moon, and is tied to the space agency’s ambitious Artemis program meant to return astronauts there later this decade.
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The initiative has funded all three U.S. commercial lunar landing attempts to date, having earmarked up to $2.8 billion for missions through 2028. And its next installment—Intuitive Machines’s Athena lander—is already enroute. Scheduled for a March 6 landing, Athena will target the flat-topped lunar mountain of Mons Mouton just 160 kilometers from the lunar south pole, where it’s planned to function for about ten days.
If all goes well, on March 14 both Blue Ghost and Athena will witness a lunar eclipse as Earth’s shadow briefly passes across the moon. Two days after that, the lunar night will fall, plunging the surface into two weeks of darkness and cold to which both landers will likely succumb.
In the meantime, yet another commercial lunar lander—Resilience, built by the Japanese company ispace—will be preparing for its own appointment with destiny, a landing projected for May at a site called Mare Frigoris in the moon’s far north. This would be ispace’s second lunar landing attempt, after its first mission crashed in 2023.
Resilience, also called HAKUTO-R Mission 2, launched to the moon alongside Blue Ghost on a SpaceX Falcon 9 rocket in late February. But unlike other landers the Japanese mission is taking a more leisurely, fuel-saving trajectory to reach its lunar destination. Tallying in Blue Ghost as well, the trio of spacecraft marked the first time in history that three landers were simultaneously bound for the moon.
Deep, Dusty Science—Plus a Lunar Sunset
Blue Ghost’s ten NASA payloads include an experiment to gather and analyze samples of lunar soil, investigations of how hazardous moon dust sticks to—and can be cleared from—various materials, a camera to study space weather and another to monitor the dust kicked-up by the spacecraft’s landing, and more. A retroreflector carried onboard will serve as a target for lasers beamed from Earth, allowing determination of the Earth-moon distance to sub-millimeter precision. And another instrument will seek to detect and use GPS signals from Earth-orbiting satellites as a proof-of-principle for future lunar navigation.
The lander’s farthest-reaching experiments, however, may be those that study the moon’s innards to illuminate new chapters of its 4.5-billion-year-history. According to NASA scientists, Mare Crisium is a region that may be more representative of the moon’s average composition than any site studied by the Apollo astronauts.
One of these inward-looking instruments, dubbed LISTER (short for Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity), is a drill capable of reaching a record-setting 3 meters beneath the lunar surface to measure heat flowing up from within—deep enough to give scientists a better idea of how exactly the moon cooled from a ball of molten rock to the cold, inert world we know today. Another, called the Lunar Magnetotelluric Sounder (LMS), will place electrodes across a roughly 700-square-meter swath of terrain. Its measurements of subtle electric and magnetic currents coursing through the moon can probe more than a thousand kilometers into the interior—two-thirds of the way to the lunar center. Scientists hope that the fresh view of our satellite’s inner composition and structure may also shed light on the deep evolution of other rocky worlds such as Venus, Mars and even Earth.
Blue Ghost can endure the frigid lunar night for several hours, but its most poignant final feat on the moon is planned to occur before night falls, during the lunar sunset. Twilight unfolds slowly on the moon, and as the sun slips behind the lunar limb, its light scatters off dust lofted by electrostatic charges and micrometeoroid impacts in the near-vacuum conditions. This creates something called lunar horizon glow, a phenomenon most notably observed by NASA astronaut Eugene Cernan during Apollo 17, the final mission of the Apollo program. Before it passes into darkness, Blue Ghost will beam its high-definition view of the glow back to Earth, offering a fleeting glimpse of this beautiful and rarely seen lunar wonder.
In a statement adopted in October 2024, the American Astronomical Society declared that humankind’s scientific understanding of the universe is under threat from space activities, including the proliferation of satellite constellations, space debris, and radio- and electromagnetic interference. Of note is the potential for a space-based eyesore: giant billboards hanging out in low Earth orbit.
“It is the position of the American Astronomical Society that obtrusive space advertising should be prohibited by appropriate international convention, treaty, or law,” the statement read.
Congress already prohibits domestic launches of any “payload containing any material to be used for the purposes of obtrusive space advertising,” in which obtrusive space advertising is defined as “advertising in outer space that is capable of being recognized by a human being on the surface of the Earth without the aid of a telescope or other technological device.”
“The US federal ban on obtrusive space advertising is a critical bulwark against an insidious fouling of the natural sky by private interests,” said James Lowenthal, an astronomer at Smith College and member of the AAS’ Committee for the Protection of Astronomy and the Space Environment (COMPASSE), in an email to Gizmodo. “That ban recognizes that the sky belongs to everyone, and must be protected for all humans now and in the future.”
“But the ban applies only to US launches; other countries could approve launches of ‘space billboards’ from their soil that would be visible from around the world,” Lowenthal added. “That’s why an international ban is critical.”
LignoSat was sent to the ISS in November 2024 on a mission to demonstrate that wood could be a viable material from which to build spacecraft. The goal of the satellite includes studying how the selected wood reacts when exposed to the environment of space and its resistance to cosmic radiation.
Researchers will also monitor geomagnetic levels to determine whether the geomagnetic field can penetrate the satellite and interfere with the electronics.
According to NASA, three wood species had previously been exposed to space before honoki magnolia was selected to construct the cubesat. The 10cm long wood panels used in the constructions were assembled using a Japanese wood joinery method called “Blind Miter Dovetail Joint.” This method means that glue and nails are not required.
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LignoSat was part of the Japanese Experiment Module (JEM) Small Satellite Orbital Deployer-30 (J-SSOD-30) CubeSat deployment mission, handled by the JEM Remote Manipulator System (JEMRMS). It is expected to spend a few months in low Earth orbit before eventually reentering the Earth’s atmosphere and burning up.
Considering the rate at which satellites are being launched into orbit – SpaceX sent a batch of 24 Starlink satellites into space earlier this week – the prospect of building the spacecraft out of materials with less of an environmental impact is appealing, although LignoSat does incorporate components made from more conventional materials.
According to a J-Stories report, researchers hope that more of the aluminum parts used to attach electronic components to the wooden box could be replaced by wood in the future.
In the report, Koji Murata of the Graduate School of Agriculture, Kyoto University, said, “If the launch of the wooden satellite proves that timber can be used in space, it should change how we look at timber on Earth and lead to new uses and a reevaluation of the material.”
The ionosphere is a layer of weakly ionized plasma bathed in Earth’s geomagnetic field extending about 50–1,500 kilometres above Earth1. The ionospheric total electron content varies in response to Earth’s space environment, interfering with Global Satellite Navigation System (GNSS) signals, resulting in one of the largest sources of error for position, navigation and timing services2. Networks of high-quality ground-based GNSS stations provide maps of ionospheric total electron content to correct these errors, but large spatiotemporal gaps in data from these stations mean that these maps may contain errors3. Here we demonstrate that a distributed network of noisy sensors—in the form of millions of Android phones—can fill in many of these gaps and double the measurement coverage, providing an accurate picture of the ionosphere in areas of the world underserved by conventional infrastructure. Using smartphone measurements, we resolve features such as plasma bubbles over India and South America, solar-storm-enhanced density over North America and a mid-latitude ionospheric trough over Europe. We also show that the resulting ionosphere maps can improve location accuracy, which is our primary aim. This work demonstrates the potential of using a large distributed network of smartphones as a powerful scientific instrument for monitoring Earth.
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Although measurements from individual mobile phones are noisier than those from conventional monitoring stations, we have shown that millions of phones in concert yield valuable measurements of ionospheric TEC. Other recent work has shown that phone accelerometers can detect earthquakes to provide early warning33 and that phone barometers can improve weather forecasting34. Building on these examples, our work continues to illuminate the potential for mobile phone sensors as a powerful tool to improve the scientific understanding of our planet.
The world’s first wood-panelled satellite has been launched into space to test the suitability of timber as a renewable building material in future exploration of destinations like the Moon and Mars.
Made by researchers in Japan, the tiny satellite weighing just 900g is heading for the International Space Station […]. It will then be released into orbit above the Earth.
Named LignoSat, after the Latin word for wood, its panels have been built from a type of magnolia tree, using a traditional technique without screws or glue.
Researchers at Kyoto University who developed it hope it may be possible in the future to replace some metals used in space exploration with wood.
“Wood is more durable in space than on Earth because there’s no water or oxygen that would rot or inflame it,” Kyoto University forest science professor Koji Murata told Reuters news agency.
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Dr Barber said it wasn’t the first time that wood had been used on spacecraft.
“We use wood – cork – on the re-entry, outer shell of vessels of spacecraft to help them survive re-entry into Earth’s atmosphere.”
Russian and Soviet lunar landers used cork to help the rover have grip as it was descending to the surface, he added.
“There’s nothing wrong with using wood in space – it’s using the right material for the right task.”
He pointed out that wood has properties that are hard to control.
“So from an engineering point of view it’s quite a difficult material to work with… I think wood’s always going to have a problem to make critical structures like parts of spacecraft where you need to predict how strong it’s going to be.”
The researchers at Kyoto University hope using wood in making spacecraft could also be much less polluting than metal ones when they burn-up on re-entry at the end of their life.
The dawn of annoyingly massive satellites is upon us, shielding our views of the shimmering cosmos. Five of the largest communication satellites just unfolded in Earth orbit, and this is only the beginning of a Texas startup’s constellation of cellphone towers in space.
AST SpaceMobile announced today that its first five satellites, BlueBirds 1 to 5, unfolded to their full size in space. Each satellite unfurled the largest ever commercial communications array to be deployed in low Earth orbit, stretching across 693 square feet (64 square meters) when unfolded. That’s bad news for astronomers as the massive arrays outshine most objects in the night sky, obstructing observations of the universe around us.
Things are just getting started for AST SpaceMobile, however, as the company seeks to create the first space-based cellular broadband network directly accessible by cell phones. “The deployment of our first five BlueBird commercial satellites marks just the beginning of our journey,” Abel Avellan, founder and CEO of AST SpaceMobile, said in a statement. “Our team is already hard at work building the next generation of satellites, which will offer ten times the capacity of our current BlueBirds, further transforming mobile connectivity and delivering even greater benefits to our customers and partners worldwide.”
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Unfortunately, now there’s five more of them. AST SpaceMobile launched its five BlueBird satellites on September 12, seeking to build a constellation of more than 100 satellites in low Earth orbit to provide nationwide coverage across the U.S.
The latest constellation is an indication of an increasingly worrying problem that’s suffocating Earth orbit, with the number of large satellites increasing five times over the past 12 years, according to a letter sent by a group of space experts to the Federal Communications Commission (FCC).
“Experts from top universities are warning we’re in a short window of time when we can prevent making a mess of space and our atmosphere rather than spend decades cleaning it up,” Lucas Gutterman, director of the U.S. PIRG Education Fund’s Designed to Last Campaign, said in the letter. “The new space race doesn’t need to create massive space waste.”
The letter calls on the FCC to follow the recommendations of the U.S. Government Accountability Office and stop excluding satellites from environmental reviews. AST SpaceMobile isn’t the only company trying to build cellular towers in space. SpaceX is building its own constellation of satellites, with more than 6,000 Starlink satellites currently in low Earth orbit. Amazon, OneWeb, and Lynk Global are other companies trying to get in on the action.
Those satellites, however, have a major impact that can’t be ignored. “Artificial satellites, even those invisible to the naked eye, can obstruct astronomical observations that help detect asteroids and understand our place in the universe,” Robert McMillan, an astronomy professor and founder of the Spacewatch Project at the University of Arizona, said in the letter.
Orbital mechanics is a fun subject, as it involves a lot of seemingly empty space that’s nevertheless full of very real forces, all of which must be taken into account lest one’s spacecraft ends up performing a sudden lithobraking maneuver into a planet or other significant collection of matter in said mostly empty space. The primary concern here is that of gravitational pull, and the way it affects one’s trajectory and velocity. With a single planet providing said gravitational pull this is quite straightforward to determine, but add in another body (like the Moon) and things get trickier. Add another big planetary body (or a star like our Sun), and you suddenly got yourself the restricted three-body problem, which has vexed mathematicians and others for centuries.
The three-body problem concerns the initial positions and velocities of three point masses. As they orbit each other and one tries to calculate their trajectories using Newton’s laws of motion and law of universal gravitation (or their later equivalents), the finding is that of a chaotic system, without a closed-form solution. In the context of orbital mechanics involving the Earth, Moon and Sun this is rather annoying, but in 1772 Joseph-Louis Lagrange found a family of solutions in which the three masses form an equilateral triangle at each instant. Together with earlier work by Leonhard Euler led to the discovery of what today are known as Lagrangian (or Lagrange) points.
Having a few spots in an N-body configuration where you can be reasonably certain that your spacecraft won’t suddenly bugger off into weird directions that necessitate position corrections using wasteful thruster activations is definitely a plus. This is why especially space-based observatories such as the James Webb Space Telescope love to hang around in these spots.
Stable and Unstable Stable
Although the definition of Lagrange points often makes it sound like you can put a spacecraft in that location and it’ll remain there forever, it’s essential to remember that ‘stationary’ only makes sense in particular observer’s reference frame. The Moon orbits the Earth, which orbits the Sun, which ultimately orbits the center of the Milky Way, which moves relative to other galaxies. Or it’s just the expansion of space-time which make it appear that the Milky Way moves, but that gets one quickly into the fun corners of theoretical physics.
A contour plot of the effective potential defined by gravitational and centripetal forces. (Credit: NASA)
Within the Earth-Sun system, there are five Lagrange points (L1 – L5), of which L2 is currently the home of the James Webb Space Telescope (JWST) and was the home to previous observatories (like the NASA WMAP spacecraft) that benefit from always being in the shadow of the Earth. Similarly, L1 is ideal for any Sun observatory, as like L2 it is located within easy communication distance
Perhaps shockingly, the L3 point is not very useful to put any observatories or other spacecraft, as the Sun would always block communication with Earth. What L3 has in common with L1 and L2 is that all of these are unstable Lagrange points, requiring course and attitude adjustments approximately every 23 days. This contrasts with L4 and L5, which are the two ‘stable’ points. This can be observed in the above contour plot, where L4 and L5 are on top of ‘hills’ and L1 through L3 are on ‘saddles’ where the potential curves up in one direction and down another.
One way to look at it is that satellites placed in the unstable points have a tendency to ‘wander off’, as they don’t have such a wide region of relatively little variance (contour lines placed far from each other) as L4 and L5 do. While this makes these stable points look amazing, they are not as close to Earth as L1 and L2, and they have a minor complication in the fact that they are already occupied, much like the Earth-Moon L4 and L5 points.
Because of how stable the L4 and L5 points are, the Earth-Moon system ones have found themselves home to the Kordylewski clouds. These are effectively concentrations of dust which were first photographed by Polish astronomer Kazimierz Kordylewski in 1961 and confirmed multiple times since. Although a very faint phenomenon, there are numerous examples of objects caught at these points in e.g. the Sun-Neptune system (Neptune trojans) and the Sun-Mars system (Mars trojans). Even our Earth has picked up a couple over the years, many of them asteroids. Of note that is the Earth’s Moon is not in either of these Lagrange points, having become gravitationally bound as a satellite.
All of which is a long way to say that it’s okay to put spacecraft in L4 and L5 points as long as you don’t mind fragile technology sharing the same region of space as some very large rocks, with an occasional new rocky friend getting drawn into the Lagrange point.
Stuff in Lagrange Points
A quick look at the Wikipedia list of objects at Lagrange points provides a long list past and current natural and artificial objects at these locations, across a variety of system. Sticking to just the things that we humans have built and sent into the Final Frontier, we can see that only the Sun-Earth and Earth-Moon systems have so far seen their Lagrange points collect more than space rocks and dust.
These will be joined if things go well by IMAP in 2025 along with SWFO-L1, NEO Surveyor in 2027. These spacecraft mostly image the Sun, monitor solar wind, image the Earth and its weather patterns, for which this L1 point is rather excellent. Of note here is that strictly taken most of these do not simply linger at the L1 point, but rather follow a Lissajous orbit around said Lagrange point. This particular orbital trajectory was designed to compensate for the instability of the L1-3 points and minimize the need for course corrections.
Moving on, the Sun-Earth L2 point is also rather busy:
Many of the planned spacecraft that should be joining the L2 point are also observatories for a wide range of missions, ranging from general observations in a wide range of spectra to exoplanet and comet hunting.
Despite the distance and hazards of the Sun-Earth L4 and L5 points, these host the Solar TErrestrial RElations Observatory (STEREO) A and B solar observation spacecraft. The OSIRIS-REx and Hayabusa 2 spacecraft have passed through or near one of these points during their missions. The only spacecraft planned to be positioned at one of these points is ESA’s Vigil, which is scheduled to launch by 2031 and will be at L5.
Contour plot of the Earth-Moon Lagrange points. (Credit: NASA)
Only the Moon’s L2 point currently has a number of spacecraft crowding about, with NASA’s THEMIS satellites going through their extended mission observations, alongside the Chinese relay satellite Queqiao-2 which supported the Chang’e 6 sample retrieval mission.
In terms of upcoming spacecraft to join the sparse Moon Lagrange crowd, the Exploration Gateway Platform was a Boeing-proposed lunar space station, but it was discarded in favor of the Lunar Gateway which will be placed in a polar near-rectilinear halo orbit (NRHO) with an orbital period of about 7 days. This means that this space station will cover more of the Moon’s orbit rather than remain stationary. It is intended to be launched in 2027, as part of the NASA Artemis program.
Orbital Mechanics Fun
The best part of orbits is that you have so many to pick from, allowing you to not only pick the ideal spot to idle at if that’s the mission profile, but also to transition between them such as when traveling from the Earth to the Moon with e.g. a trans-lunar injection (TLI) maneuver. This involves a low Earth orbit (LEO) which transitions into a powered, high eccentric orbit which approaches the Moon’s gravitational sphere of influence.
Within this and low-energy transfer alternatives the restricted three-body problem continuously applies, meaning that the calculations for such a transfer have to account for as many variables as possible, while in the knowledge that there is no perfect solution. With our current knowledge level we can only bask in the predictable peace and quiet that are the Lagrange points, if moving away from all those nasty gravity wells like the Voyager spacecraft did is not an option.
A Texas telecommunications startup launched its first five massive “BlueBird” communications satellites into orbit on September 12. Each device is nearly 700-feet-wide when fully deployed, and like BlueWalker 3—AST SpaceMobile’s 2022 prototype, also in orbit—every BlueBird will soon shine brighter than most stars and planets in the night sky. But despite the concerns of critics and experts alike, the company’s CEO vows they are “just getting started.”
Founded in 2017, AST SpaceMobile is currently working with AT&T to construct the world’s first space-based cellular broadband network. In a statement on Thursday, AT&T Chief Operating Officer Jeff McElfresh said it’s all part of a plan to offer “a future where our customers will only be hard to reach if they choose to be.” AST SpaceMobile successfully delivered its BlueWalker 3 prototype into low-Earth orbit (LEO) in September 2022, and demonstrated it by allowing a smartphone to make a voice call the following September. Less than a month after the milestone, an international study published in Nature confirmed BlueWalker 3’s peak brightness matched that of Procyon and Achernar, two of the ten brightest stars in the night sky. Subsequent observations recorded even higher magnitudes similar to the stars that make up the constellation of Orion.
Each of the five BlueBirds now in orbit are roughly the same size as BlueWalker 3, meaning they will soon offer similar experiences for sky observers—sometimes visible even to the naked eye. But to achieve a reliable, high speed, and commercially viable satellite broadband network, AST SpaceMobile says it will need to deploy a constellation of nearly 90 satellites.
During a livestream of Thursday’s launch, company founder, chairman, and CEO Abel Avellan said many future satellite iterations will be “three-and-a-half-times larger” than the current BlueBirds. Such a scaling up would make each new, fully deployed device around 2425-square-feet in diameter, or about half the size of a regulation NBA basketball court. As Gizmodo noted on September 13, there are currently no legal restrictions for satellite brightness.
Gigantic satellite constellation arrays are growing at a rate that eclipses both regulatory oversight and experts’ concerns. Shortly after BlueWalker 3’s launch in 2022, the committee speaking on behalf of the International Astronomical Union uniformly denounced its delivery, describing it as “a big shift in the constellation satellite issue [that] should give us all reason to pause.”
AST SpaceMobile is far from the only company pursuing similar projects. SpaceX’s ongoing Starlink internet endeavor intends to eventually include as many as 7,000 satellites in orbit, in spite of its own share of public criticism. Meanwhile, advocates continue to stress the dangers of orbital pollution from decommissioned satellites and debris, often referred to as “space junk.” Without proper oversight and cleanup efforts, experts have repeatedly warned of the possibility of initiating a “Kessler cascade.” In these scenarios, the untenable amount of human-made objects leads to ever-increasing collisions, causing debris to deorbit and pose a danger to anything in its path.
In a statement provided to Popular Science, a spokesperson said that “AST SpaceMobile is committed to the responsible use of space as we advance our goal of using space-based, satellite technology to connect directly with everyday smartphones and help bring broadband to billions of people worldwide who do not have access today.”
The U.S. Space Force is testing a new ground-based satellite jamming weapon to help keep U.S. military personnel safe from potential “space-enabled” attacks.
The tests were conducted by Space Training and Readiness Command, or STARCOM, which is responsible for educating and training U.S. Space Force personnel. The satellite jammer is known as the Remote Modular Terminal (RMT) and, like other jammers, is designed to deny, degrade, or disrupt communications with satellites overhead, typically through overloading specific portions of the electromagnetic spectrum with interference.
The RMT is “small form-factor system designed to be fielded in large numbers at low-cost and operated remotely” according to Space Force statement. Specifically, the RMT will “unlock the scale to provide counterspace electronic warfare capability to all of the new Space Force components globally,” Lt. Col. Gerrit Dalman said in the statement, meaning it can be used from virtually anywhere to deny adversaries the use of satellites orbiting overhead.
Details about the test are scarce, but Space Force’s statement explains that two RMT units were installed at separate locations and controlled by a third. The jammer was evaluated according to metrics such as “system latency” and “target engagement accuracy,” as well as for how secure its communications were.
Guardians and an Airman during a test of the Space Force’s Remote Modular Terminal (RMT) in Colorado Springs, Colo., April 4, 2024. (Image credit: U.S. Air Force photo by Capt. Charles Rivezzo)
The need for new space-based and counterspace technologies has been stressed by Space Force leadership in recent months.
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According to a slide deck the Space Rapid Capabilities Office presented to industry in October 2023, these jammers are “small transportable systems that can be emplaced in both garrison and austere environments,” meaning they can be used whether infrastructure is present or not.
The mysterious brightening of a galaxy far, far away has been traced to the heart of the star system and the sudden awakening of a giant black hole 1m times more massive than the sun.
Decades of observations found nothing remarkable about the distant galaxy in the constellation of Virgo, but that changed at the end of 2019 when astronomers noticed a dramatic surge in its luminosity that persists to this day.
Researchers now believe they are witnessing changes that have never been seen before, with the black hole at the galaxy’s core putting on an extreme cosmic light show as vast amounts of material fall into it.
“We discovered this source at the moment it started to show these variations in luminosity,” said Dr Paula Sánchez-Sáez, a staff astronomer at the European Southern Observatory headquarters in Garching, Germany. “It’s the first time we’ve see this in real time.”
The galaxy, which goes by the snappy codename SDSS1335+0728 and lies 300m light years away, was flagged to astronomers in December 2019 when an observatory in California called the Zwicky Transient Facility recorded a sudden rise in its brightness.
The alert prompted a flurry of new observations and checks of archived measurements from ground- and space-based telescopes to understand more about the galaxy and its past behaviour.
The scientists discovered the galaxy had recently doubled in brightness in mid-infrared wavelengths, become four times brighter in the ultraviolet, and at least 10 times brighter in the X-ray range.
What triggered the sudden brightening is unclear, but writing in Astronomy and Astrophysics, the researchers say the most likely explanation is the creation of an “active galactic nucleus” where a vast black hole at the centre of a galaxy starts actively consuming the material around it.
Active galactic nuclei emit a broad spectrum of light as gas around the black hole heats up and glows, and surrounding dust particles absorb some wavelengths and re-radiate others.
But it is not the only possibility. The team has not ruled out an exotic form of “tidal disruption event”, a highly restrained phrase to describe a star that is ripped apart after straying too close to a black hole.
Tidal disruption events tend to be brief affairs, brightening a galaxy for no more than a few hundred days, but more measurements are needed to rule out the process. “With the data we have at the moment, it’s impossible to disentangle which of these scenarios is real,” said Sánchez-Sáez. “We need to keep monitoring the source.”
[…] The Chinese Academy of Sciences (CAS) has released the highest-resolution geological maps of the Moon yet. The Geologic Atlas of the Lunar Globe, which took more than 100 researchers over a decade to compile, reveals a total of 12,341 craters, 81 basins and 17 rock types, along with other basic geological information about the lunar surface. The maps were made at the unprecedented scale of 1:2,500,000.
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The CAS also released a book called Map Quadrangles of the Geologic Atlas of the Moon, comprising 30 sector diagrams which together form a visualization of the whole Moon.
Jianzhong Liu, a geochemist at the CAS Institute of Geochemistry in Guiyang and co-leader of the project, says that existing Moon maps date from the 1960s and 1970s. “The US Geological Survey used data from the Apollo missions to create a number of geological maps of the Moon, including a global map at the scale of 1:5,000,000 and some regional, higher-accuracy ones near the landing sites,” he says. “Since then, our knowledge of the Moon has advanced greatly, and those maps could no longer meet the needs for future lunar research and exploration.”
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Liu says that his team has already started work to improve the resolution of the maps, and will produce regional maps of higher accuracy on the basis of scientific and engineering needs. In the meantime, the completed atlas has been integrated into a cloud platform called the Digital Moon, and will eventually become available to the international research community.
A spacecraft containing pharmaceutical drugs that were grown on orbit has finally returned to Earth today after more than eight months in space.
Varda Space Industries’ in-space manufacturing capsule, called Winnebago-1, landed in the Utah desert at around 4:40 p.m. EST. Inside the capsule are crystals of the drug ritonavir, which is used to treat HIV/AIDS. It marks a successful conclusion of Varda’s first experimental mission to grow pharmaceuticals on orbit, as well as the first time a commercial company has landed a spacecraft on U.S. soil, ever.
The capsule will now be sent back to Varda’s facilities in Los Angeles for analysis, and the vials of ritonavir will be shipped to a research company called Improved Pharma for post-flight characterization, Varda said in a statement. The company will also be sharing all the data collected through the mission with the Air Force and NASA, per existing agreements with those agencies.
The first-of-its-kind reentry and landing is also a major win for Rocket Lab, which partnered with Varda on the mission. Rocket Lab hosted Varda’s manufacturing capsule inside its Photon satellite bus; through the course of the mission, Photon provided power, communications, attitude control and other essential operations. At the mission’s conclusion, the bus executed a series of maneuvers and de-orbit burns that put the miniature drug lab on the proper reentry trajectory. The final engine burn was executed shortly after 4 p.m. EST.
[…] how can we determine the mass of something larger, such as the Milky Way? One method is to estimate the number of stars in the galaxy and their masses, then estimate the mass of all the interstellar gas and dust, and then rough out the amount of dark matter… It all gets very complicated.
A better way is to look at how the orbital speed of stars varies with distance from the galactic center. This is known as the rotation curve and gives an upper mass limit on the Milky Way, which seems to be around 600 billion to a trillion solar masses. The wide uncertainty gives you an idea of just how difficult it is to measure our galaxy’s mass. But a new study introduces a new method, and it could help astronomers pin things down.
Estimated escape velocities at different galactic radii. Credit: Roche, et al
The method looks at the escape velocity of stars in our galaxy. If a star is moving fast enough, it can overcome the gravitational pull of the Milky Way and escape into interstellar space. The minimum speed necessary to escape depends upon our galaxy’s mass, so measuring one gives you the other. Unfortunately, only a handful of stars are known to be escaping, which is not enough to get a good handle on galactic mass. So the team looked at the statistical distribution of stellar speeds as measured by the Gaia spacecraft.
The method is similar to weighing the Moon with a handful of dust. If you were standing on the Moon and tossed dust upward, the slower-moving dust particles would reach a lower height than faster particles. If you measured the speeds and positions of the dust particles, the statistical relation between speed and height would tell you how strongly the Moon pulls on the motes, and thus the mass of the Moon. It would be easier just to bring our kilogram and scale to measure lunar mass, but the dust method could work.
In the Milky Way, the stars are like dustmotes, swirling around in the gravitational field of the galaxy. The team used the speeds and positions of a billion stars to estimate the escape velocity at different distances from the galactic center. From that, they could determine the overall mass of the Milky Way. They calculated a mass of 640 billion Suns.
This is on the lower end of earlier estimates, and if accurate it means that the Milky Way has a bit less dark matter than we thought.
Our planet sits in the Habitable Zone of our Sun, the special place where water can be liquid on the surface of a world. But that’s not the only thing special about us: we also sit in the Galactic Habitable Zone, the region within the Milky Way where the rate of star formation is just right.
The Earth was born with all the ingredients necessary for life – something that most other planets lack. Water as a solvent. Carbon, with its ability to form long chains and bind to many other atoms, a scaffold. Oxygen, easily radicalized and transformable from element to element, to provide the chain reactions necessary to store and harvest energy. And more: hydrogen, phosphorous, nitrogen. Some elements fused in the hearts of stars, other only created in more violent processes like the deaths of the most massive stars or the collisions of exotic white dwarfs.
And with that, a steady, long-lived Sun, free of the overwhelming solar flares that could drown the system in deadly radiation, providing over 10 billion years of life-giving warmth. Larger stars burn too bright and too fast, their enormous gravitational weight accelerating the fusion reactions in their cores to a frenetic pace, forcing the stars to burn themselves out in only a few million years. And on the other end of the spectrum sit the smaller red dwarf stars, some capable of living for 10 trillion years or more. But that longevity does not come without a cost. With their smaller sizes, their fusion cores are not very far from their surfaces, and any changes or fluctuations in energy result in massive flares that consume half their faces – and irradiate their systems.
And on top of it all, our neighborhood in the galaxy, on a small branch of a great spiral arm situated about 25,000 light-years from the center, seems tuned for life: a Galactic Habitable Zone.
Too close to the center and any emerging life must contend with an onslaught of deadly radiation from countless stellar deaths and explosions, a byproduct of the cramped conditions of the core. Yes, stars come and go, quickly building up a lot of the heavy elements needed for life, but stars can be hundreds of times closer together in the core. The Earth has already suffered some extinction events likely triggered by nearby supernovae, and in that environment we simply wouldn’t stand a chance. Explosions would rip away our protective ozone layer, exposing surface life to deadly solar UV radiation, or just rip away our atmosphere altogether.
And beyond our position, at greater galactic radii, we find a deserted wasteland. Yes, stars appear and live their lives in those outskirts, but they are too far and too lonely to effectively spread their elemental ash to create a life-supporting mixture. There simply isn’t enough density of stars to support sufficient levels of mixing and recycling of elements, meaning that it’s difficult to even build a planet out there in the first place.
And so it seems that life would almost inevitably arise here, on this world, around this Sun, in this region of the Milky Way galaxy. There’s little else that we could conceivably call home.
RESILIENCE was launched on January 15th, 2025, at 12:44 p.m. PST (03:44 p.m. EST)
