Gene editing could drastically increase global food security and reduce reliance on chemical fertilisers and pesticides in the coming decade, a scientific adviser to the UK government's environment department has said. From a report: Speaking before the introduction of a bill on genetic technologies to the House of Lords on Wednesday, Prof Gideon Henderson said the legislation aimed to create a simpler regulatory framework that would speed up the development and commercialisation of gene-edited products by allowing them to be treated differently to genetically modified organisms (GMOs), which are subject to strict regulation. "We anticipate [the bill] will enable precision-bred crops to navigate the regulatory system much more quickly, in something like one year compared with approximately 10 years under the present regime," Henderson said. This could have numerous benefits, from building crops that are more resistant to the climate crisis, pests and diseases, to increasing crop yields, which could help to combat global hunger, Henderson said. It could also be used to create more nutritious crops, such as vitamin D-enriched tomatoes. The bill will also allow for similar changes for livestock to follow, once a regulatory system has been developed to safeguard animal welfare, for example preventing the creation of fast-growing animals that are unable to stand.

CVS Health will stop filling prescriptions for controlled substances ordered by clinicians working for telehealth startups Cerebral and Done Health starting Thursday, a move that will impact thousands of patients. From a report: A CVS spokesman confirmed the change in a statement, citing concerns CVS has with the two companies following a review it conducted. Cerebral had earlier disclosed the change in a statement to The Wall Street Journal. Cerebral called CVS's decision unfortunate, adding that it was "doing everything possible to ensure these patients get access to medications that their healthcare providers have determined they need." Some pharmacies had already blocked or delayed certain prescriptions from Cerebral and Done prescribers over concerns that clinicians were writing too many stimulant prescriptions, The Journal reported in April. Cerebral had said prescription delays occurred because of confusion around telehealth policies. Done declined to comment at the time.

Cerebral and Done between them treat tens of thousands of patients for attention-deficit hyperactivity disorder, prescribing stimulants such as Adderall. Psychiatrists say stimulants can have significant benefits for people properly diagnosed with ADHD. But they are classified as schedule 2 controlled substances by the federal government due to their potential for abuse, the same category as OxyContin and Vicodin. Cerebral and Done grew very quickly from the onset of the Covid-19 pandemic, attracting patients with social-media ads that offered an ADHD diagnosis and prescriptions to treat the condition. Previously, clinicians were prohibited from prescribing stimulants without an in-person visit. The U.S. relaxed those rules in March 2020 for all schedule 2 substances due to the coronavirus public-health emergency.

Researchers at the University of Texas at Austin have now demonstrated a low-cost gel film that can pull many liters of water per day out of even very dry air. New Atlas reports: The gel is made up of two main ingredients that are cheap and common -- cellulose, which comes from the cell walls of plants, and konjac gum, a widely used food additive. Those two components work together to make a gel film that can absorb water from the air and then release it on demand, without requiring much energy. First, the porous structure of the gum attracts water to condense out of the air around it. The cellulose meanwhile is designed to respond to a gentle heat by turning hydrophobic, releasing the captured water.

In tests, the gel film was able to wring an astonishing amount of water out of the air. At a relative humidity of 30 percent, it could produce 13 L (3.4 gal) of water per day per kilogram of gel, and even when the humidity dropped to just 15 percent -- which is low, even for desert air -- it could still produce more than 6 L (1.6 gal) a day per kilogram. [...] And the new gel film's efficiency could be improved even further, the team says, by creating thicker films, absorbent beds, or other array formations of the material. Perhaps most importantly, the material is extremely inexpensive to produce, costing as little as $2 per kilogram. The research was published in the journal Nature Communications.

More than one in 10 cases of coronary heart disease could be prevented if people reduced their TV viewing to less than an hour a day, research suggests. From a report: Coronary heart disease occurs when fatty material builds up inside the coronary arteries causing them to narrow, reducing the heart's blood supply. Researchers say cutting down on time spent in front of the TV could lower the risk of developing the disease. "Reducing time spent watching TV should be recognised as a key behavioural target for prevention of coronary heart disease, irrespective of genetic susceptibility and traditional risk markers," said Dr Youngwon Kim, an assistant professor at the University of Hong Kong and an author of the research.

While the team did not look at what was behind the association, Kim said previous studies had found excessive TV viewing time is associated with adverse levels of cholesterol and glucose in the body. "Unfavourable levels of these cardiometabolic risk markers may then lead to increased risk of developing coronary heart disease," he said. Writing in the journal BMC Medicine, Kim and colleagues report how they used data from 373,026 white British people aged 40-69 who were part of an endeavour known as the UK Biobank study.

New research explains how meteorites called aubrites may actually be shattered pieces of the planet closest to the sun from the early days of the solar system. From a report: Mercury does not make sense. It is a bizarre hunk of rock with a composition that is unlike its neighboring rocky planets. "It's way too dense," said David Rothery, a planetary scientist at the Open University in England. Most of the planet, the closest to the sun, is taken up by its core. It lacks a thick mantle like Earth has, and no one is quite sure why. One possibility is that the planet used to be much bigger -- perhaps twice its current bulk or more. Billions of years ago, this fledgling proto-Mercury, or super Mercury, could have been hit by a large object, stripping away its outer layers and leaving the remnant we see behind.

While a nice idea, there has never been direct evidence for it. But some researchers think they have found something. In work presented [PDF] at the Lunar and Planetary Science Conference in Houston in March, Camille Cartier, a planetary scientist at the University of Lorraine in France, and colleagues said pieces of this proto-Mercury may be hiding in museums and other meteorite collections. Studying them could unlock the planet's mysteries. "We don't have any samples of Mercury" at the moment, said Dr. Cartier. Gaining such specimens "would be a small revolution" in understanding the natural history of the solar system's smallest planet. According to the Meteoritical Society, nearly 70,000 meteorites have been gathered around the world from places as remote as the Sahara and Antarctica, finding their way into museums and other collections. Most are from asteroids ejected from the belt between Mars and Jupiter, while more than 500 come from the moon. More than 300 are from Mars.

As states race to keep plants open, California becomes a test case of how much the tide has shifted. From a report: Charles Komanoff was for decades an expert witness for groups working against nuclear plants, delivering blistering critiques so effective that he earned a spot at the podium when tens of thousands of protesters descended on Washington in 1979 over the Three Mile Island meltdown. Komanoff would go on to become an unrelenting adversary of Diablo Canyon, the hulking 37-year-old nuclear facility perched on a pristine stretch of California's Central Coast that had been the focal point of anti-nuclear activism in America. But his last letter to California Gov. Gavin Newsom, in February, was one Komanoff never expected to write. He implored Newsom to scrap state plans to close the coastal plant. "We're going to have to give up some of our long-held beliefs if we are going to deal with climate," Komanoff said in an interview. "I am still a solar and wind optimist. But I am a climate pessimist. The climate is losing."

Komanoff's conversion is emblematic of the rapidly shifting politics of nuclear energy. The long controversial power source is gaining backers amid worries that shutting U.S. plants, which emit almost no emissions, makes little sense as governments race to end their dependence on fossil fuels and the war in Ukraine heightens worries about energy security and costs. The momentum is driven in large part by longtime nuclear skeptics who remain unsettled by the technology but are now pushing to keep existing reactors running as they face increasingly alarming news about the climate.

The latest report from the U.N. Intergovernmental Panel on Climate Change, published in April, warned that the world is so dangerously behind on climate action that within a decade it could blow past the targets crucial to containing warming to a manageable level. Emissions analysts are increasingly critical of retirements of existing nuclear reactors as they take large amounts of low-emissions power off the grid, undermining the gains made as sources such as wind and solar come online. The movement to keep plants open comes despite persistent worries about toxic waste and just a decade after the nuclear disaster at Japan's Fukushima plant. It has been boosted by growing public acceptance of nuclear power and has nurtured an unlikely coalition of industry players, erstwhile anti-nukers, and legions of young grass-roots environmental activists more worried about climate change than nuclear accidents.

Researchers from the University of Gottingen have published new calculations of the physics of the sun's atmosphere that resolve the apparent contradiction between the modern standard model of solar evolution and the "tried-and-true" method called spectral analysis. "The new calculations of the physics of the sun's atmosphere yield updated results for abundances of different chemical elements, which resolve the conflict," reports Phys.Org. "Notably, the sun contains more oxygen, silicon and neon than previously thought. The methods employed also promise considerably more accurate estimates of the chemical compositions of stars in general." From the report: Highly accurate helioseismic measurements gave results about the sun's interior structure that were at odds with the solar standard models. According to helioseismology, the so-called convective region within our sun where matter rises and sinks down again, like water in a boiling pot, was considerably larger than the standard model predicted. The speed of sound waves near the bottom of that region also deviated from the standard model's predictions, as did the overall amount of helium in the sun. To top it off, certain measurements of solar neutrinos -- fleeting elementary particles, hard to detect, reaching us directly from the sun's core regions -- were slightly off compared to experimental data, as well. Astronomers had what they soon came to call a "solar abundances crisis," and in search of a way out, some proposals ranged from the unusual to the downright exotic. Did the sun maybe accrete some metal-poor gas during its planet-forming phase? Is energy being transported by the notoriously non-interacting dark matter particles?

The newly published study by Ekaterina Magg, Maria Bergemann and colleagues has managed to resolve that crisis, by revisiting the models on which the spectral estimates of the sun's chemical composition are based. [...] In this study they tracked all chemical elements that are relevant to the current models of how stars evolved over time, and applied multiple independent methods to describe the interactions between the sun's atoms and its radiation field in order to make sure their results were consistent. For describing the convective regions of our sun, they used existing simulations that take into account both the motion of the plasma and the physics of radiation ("STAGGER" and "CO5BOLD"). For the comparison with spectral measurements, they chose the data set with the highest available quality: the solar spectrum published by the Institute for Astro- and Geophysics, University of GÃttingen. "We also extensively focused on the analysis of statistical and systematic effects that could limit the accuracy of out results," notes Magg. The new calculations showed that the relationship between the abundances of these crucial chemical elements and the strength of the corresponding spectral lines was significantly different from what previous authors had claimed. Consequently, the chemical abundances that follow from the observed solar spectrum are somewhat different than stated in previous analysis.

"We found, that according to our analysis the sun contains 26% more elements heavier than helium than previous studies had deduced," explains Magg. In astronomy, such elements heavier than helium are called "metals." Only on the order of a thousandth of a percent of all atomic nuclei in the sun are metals; it is this very small number that has now changed by 26% of its previous value. Magg adds: "The value for the oxygen abundance was almost 15% higher than in previous studies." The new values are, however, in good agreement with the chemical composition of primitive meteorites ("CI chondrites") that are thought to represent the chemical make-up of the very early solar system. When those new values are used as the input for current models of solar structure and evolution, the puzzling discrepancy between the results of those models and helioseismic measurements disappears.

An anonymous reader quotes a report from The Guardian: Scientists have created genetically edited tomatoes, each containing as much provitamin D3 -- the precursor to vitamin D -- as two eggs or a tablespoon of tuna. Outdoor field trials of the tomatoes are expected to begin in the UK next month, and if successful, could provide an important new dietary source of vitamin D. The tomato plants were created by making tiny changes to an existing tomato gene using an editing technique called Crispr-Cas9. "It's like a pair of molecular tweezers, which you can use to precisely snip out a very small fragment of the gene to enhance a desirable trait in plants a lot quicker than traditional breeding process, and without introducing any foreign DNA from other species," said Jie Li at the John Innes Centre in Norwich, who led the research.

In this case, their focus was an enzyme found in tomato plants that normally converts provitamin D3 into cholesterol. By altering this enzyme, the researchers managed to block this pathway, meaning provitamin D3 accumulated in the tomatoes' fruits and leaves. They calculated that the amount of provitamin D3 in one tomato fruit -- if converted to vitamin D3 -- would be equivalent to levels present in two medium-sized eggs or 28 grams of tuna. To convert this into active vitamin D3, the fruit would still need to be exposed to UVB light, or they could potentially be grown outdoors, something the researchers plan to test in upcoming field trials. The research was published in Nature Plants. "Unlike GMOs, the tomato plants do not contain genes from other organisms and could theoretically have been created through selective breeding -- albeit much more slowly," notes the Guardian. Therefore, they could be allowed under a proposed genetic technology (precision breeding) bill aimed to allow gene-edited plants to be treated differently to genetically modified organisms (GMOs).

joshuark writes: NASA programmer/scientist, Ron Garret shares his experience debugging LISP code from 150-million miles away on the robotic Mars rover Sojourner. Garret describes his experience in a recent episode of Adam Gordon Bell's Corecursive podcast. Garret later explains, "And it didn't work..." for the next project NASA's New Millennium project using LISP.

Like a professor said in LISP programming class, LISP -- getting it done is half DEFUN. Garret had written an essay in 2006 , titled, "How knowing LISP destroyed my programming career." Available on the web archive. So much for LISPcraft, or the Little LISPer.

The BBC reports on "the next generation of genetic modification technology" — which goes beyond simply introducing a "lab-tweaked gene" into an organism. Instead it introduces a "gene drive" — a lab-tweaked gene "that targets and removes a specific natural gene." if an animal (parent A) that contains a gene drive mates with one that doesn't (parent B), then in the forming embryo that starts to combine their genetic material, parent A's gene drive immediately gets to work. It recognises the natural gene version of itself in the opposite chromosome from parent B, and destroys it, by cutting it out of the DNA chain. Parent B's chromosome then repairs itself — but does so, by copying parent A's gene drive. So, the embryo, and the resulting offspring, are all but guaranteed to have the gene drive, rather than a 50% chance with standard GM — because an embryo takes half its genes from each parent.

Gene drives are created by adding something called Crispr, a programmable DNA sequence, to a gene. This tells it to target the natural version of itself in the DNA of the other parent in the new embryo. The gene drive also contains an enzyme that does the actual cutting.

It is hoped that gene drives can be used to greatly reduce the numbers of malarial mosquitos, and other pests or invasive species.... One organisation at the forefront of this is Target Malaria, which has developed gene drives that stop mosquitos from producing female offspring. This is important for two reasons — only the females bite, and without females, mosquito numbers will plummet. The core aim is to greatly reduce the number of people who die from malaria — of which there were sadly 627,000 in 2020, according to the World Health Organization. It could also slash the economic impact of the disease. With 241 million cases in 2020, mostly in Africa, malaria is estimated to cost the continent $12bn (£9.7bn) in reduced economic output every year....

One of the world's pioneering developers of gene drives is US biologist Kevin Esvelt, an assistant professor at Massachusetts Institute of Technology. He first came up with the technology back in 2013.... Prof Esvelt adds that this technology is being provided by something called "daisy chain". This is where a gene drive is designed to become inert after a few generations. Or halving its spread every generation until it eventually stops. Using this technology he says it is possible to control and isolate the spread of gene drives. "A town could release GM organisms with its boundaries to alter the local population [of a particular organism] while minimally affecting the town next door," he says.
The technology has not been authorized for use "in the wild," the article points out. But there are currently no bans on laboratories researching it.

"NASA has released a huge new report that astronomers are calling Hubble's magnum opus," reports New Atlas.

"Analyzing 30 years of data from the famous space telescope, the new study makes the most precise measurement yet of how fast the universe is expanding." Astronomers have known for the better part of a century that the universe is expanding, thanks to the observation that galaxies are moving away from us — and the farther away they are, the faster they're traveling. The speed at which they're moving, relative to their distance from Earth, is a figure called the Hubble constant, and measuring this value was one of the primary missions of the space telescope of the same name.

To measure the Hubble constant, astronomers study distances to objects whose brightness is known well — that way, the dimmer it appears, the farther away it is. For relatively close objects within our galaxy or in nearby ones, this role is filled by Cepheids, a class of stars that pulse in a predictable pattern. For greater distances, astronomers use what are called Type Ia supernovae — cosmic explosions with a well-defined peak brightness....

For the new study, a team of scientists has now gathered and analyzed the most comprehensive catalog of these objects so far, to make the most precise measurement of the Hubble constant yet. This was done by studying 42 galaxies that contained both Cepheids and Type Ia supernovae, as imaged by the Hubble telescope over the last 30 years.

"This is what the Hubble Space Telescope was built to do, using the best techniques we know to do it," said Adam Riess, lead scientist of the team. "This is likely Hubble's magnum opus, because it would take another 30 years of Hubble's life to even double this sample size."
The article points out that these detailed real-world observations of the Hubble "constant" now show a small discrepancy, which suggests "new physics could be at work."

And it's the new James Webb Space Telescope that will now be studying these same phenomena at an even higher resolution.

"Made In Space, Redwire, and Bigelow, move over," writes long-time Slashdot reader Dr. Crash. "There's yet another 3D printing in space group — and it's not a startup." Mitsubishi Electric just went public with a UV-sensitive resin specially made to print in zero-G and in a hard vacuum — as in outside the airlock.

The polymer is tuned to harden with solar ultraviolet light, so no UV lasers needed (saving power and launch weight).

Their first goal? Printing cubesat parabolic dishes in orbit, so a 300mm cubesat could have what looks like a one-meter dish antenna — or anything else that can be freeform-printed.
This "photopolymerization" technology "specifically addresses the challenge of equipping small, inexpensive spacecraft buses with large structures, such as high-gain antenna reflectors," according to Mitsubishi's announcement — arguing that it also ultimately "enables on-orbit fabrication of structures that greatly exceed the dimensions of launch vehicle fairings."

Boeing's Starliner successfully docked to the International Space Station Friday night for the first time.

And right now, Boeing is beginning the official hatch-opening ceremon, in which the space station astronauts already on the ISS "open the hatch to the vehicle and retrieve some cargo that's packed inside," explains the Verge: NASA tasked Boeing with conducting an uncrewed flight demonstration of Starliner to show that the capsule can hit all of the major milestones it'll need to hit when it is carrying passengers... This mission is called OFT-2 since it's technically a do-over of a mission that Boeing attempted back in 2019, called OFT. During that flight, Starliner launched to space as planned, but a software glitch prevented the capsule from getting in the right orbit it needed to reach to rendezvous with the ISS. Boeing had to bring the vehicle home early, and the company never demonstrated Starliner's ability to dock with the ISS....

Using a series of sensors, the capsule autonomously guided itself onto an open docking port on the space station.... Docking occurred a little over an hour behind schedule, due to some issues with Starliner's graphics and docking ring, which were resolved ahead of the docking....

[Thursday] At 6:54PM ET, Starliner successfully launched to space on top of an Atlas V rocket, built and operated by the United Launch Alliance. Once Starliner separated from the Atlas V, it had to fire its own thrusters to insert itself into the proper orbit for reaching the space station. However, after that maneuver took place, Boeing and NASA revealed that two of the 12 thrusters Starliner uses for the procedure failed and cut off too early. The capsule's flight control system was able to kick in and rerouted to a working thruster, which helped get Starliner into a stable orbit.... Today, Boeing revealed that a drop in chamber pressure had caused the early cutoff of the thruster, but that system behaved normally during follow-up burns of the thrusters. And with redundancies on the spacecraft, the issue "does not pose a risk to the rest of the flight test," according to Boeing.

Boeing also noted today that the Starliner team is investigating some weird behavior of a "thermal cooling loop" but said that temperatures are stable on the spacecraft.
From the space station, NASA astronaut Bob Hines said the achievement "marks a great milestone towards providing additional commercial access to low Earth orbit, sustaining the ISS and enabling NASA's goal of returning humans to the Moon and eventually to Mars.

"Great accomplishments in human spaceflight are long remembered by history. Today will be no different."

A long-time Slashdot reader shares this schedule (EST): 5/20, 3:30 pm — Starliner docking with ISS.
5/21, 11:30 am — Safety checks completed. Hatches opened.
5/24, 12:00 pm — Starliner loading completed. Hatched closed.
5/25, 2:00 pm — Starliner undocking from ISS.
5/25, 5:45 pm — Coverage of Starliner landing begins.

Again, the streams will be broadcast at NASA Television. I don't know about any of you, but I know what I'm doing this weekend.

sciencehabit shares a report from Science Magazine: Some 5400 years ago, about the time humans were inventing writing, an alerce tree (Fitzroya cupressoides) may have started to grow in the coastal mountains of present-day Chile. Sheltered in a cool, damp ravine, it avoided fires and logging that claimed many others of its kind, and it grew into a grizzled giant more than 4 meters across. Much of the trunk died, part of the crown fell away, and the tree became festooned with mosses, lichens, and even other trees that took root in its crevices. Now, the tree -- known as the Alerce Milenario or Gran Abuelo (great-grandfather) tree -- might claim a new and extraordinary title: the oldest living individual on Earth.

Using a combination of computer models and traditional methods for calculating tree age, Jonathan Barichivich, a Chilean environmental scientist who works at the Climate and Environmental Sciences Laboratory in Paris, has estimated that the Alerce Milenario is probably more than 5000 years old. That would make it at least 1 century senior to the current record holder: Methuselah, a bristlecone pine in eastern California with 4853 years' worth of annual growth rings under its gnarled bark. (Some clonal trees that originate from a common root systems, such as that of the Utah-based aspen colony known as "Pando," are thought to be older, but dendrochronologists tend to focus on individual trunks with countable rings.) Many dendrochronologists are likely to be skeptical of Barichivich's claim, which has not yet been published, because it does not involve a full count of tree growth rings. But at least some experts are open to the possibility. "I fully trust the analysis that Jonathan has made," says Harald Bugmann, a dendrochronologist at ETH Zurich. "It sounds like a very smart approach."

Chinese engineers will take the ideas of a research paper and turn it into the world's largest 3D-printed project. Popular Mechanics: Within two years, officials behind this project want to fully automate the unmanned construction of a 590-foot-tall dam on the Tibetan Plateau to build the Yangqu hydropower plant -- completely with robots. The paper, published last month in the Journal of Tsinghua University (Science and Technology), laid out the plans for the dam, as first reported in the South China Morning Post. Researchers from the State Key Laboratory of Hydroscience and Engineering at Tsinghua University in Beijing explain the backbone of automation for the planned Yellow River dam that will eventually offer nearly five billion kilowatt-hours of electricity annually. (It's worth noting that China's Three Gorges Dam -- a hydroelectric gravity dam spanning the Yangtze River -- is the world's largest power station in terms of energy output.) But it's hard to tell what's more ambitious: the fact that the researchers plan to turn a dam site into effectively a massive 3D-printing project, or that through every step of the process the project eliminates human workers as they go fully robotic.

In the dam-"printing" process, machinery will deliver construction materials to the worksite -- the exact location needed, eliminating human error, they say -- and then unmanned bulldozers, pavers, and rollers will form the dam layer by layer. Sensors on the rollers will keep the artificial intelligence (AI) system informed about the firmness and stability of each of the 3D-printed layers until it reaches 590 feet in height, about the same height as the Shasta Dam in California and shorter than the Hoover Dam's 726 feet. With the largest existing 3D-printed structures rising about 20 feet tall -- from houses in China to an office building in Dubai -- the exploration of 3D-printed projects continues to expand. Already we've seen a 1,640-foot-long retention wall in China, housing and office buildings across the globe, and now the U.S. Army has plans for barracks at Fort Bliss in Texas.

An ancient forest has been found at the bottom of a giant sinkhole in China, with trees up to 40 metres (130ft) tall. From a report: Scientists believe it could contain undiscovered plant and animal species. Cave explorers in the Guangxi region of southern China alerted scientists when they found the sinkhole, which had a primitive forest inside. Among 30 sinkholes in Leye County this is the largest, at 306 metres long, 150 metres wide and 192 metres deep. Zhang Yuanhai, a senior engineer at the Institute of Karst Geology of the China Geological Survey, told the state news agency Xinhua that the site had three caves in its walls and a well-preserved primitive forest at the bottom. Scientists trekked for hours to reach the base of the sinkhole to see what it contained. Chen Lixin, who led the expedition team, said that as well as the trees there was dense undergrowth on the floor that came up to his shoulders.

Two satellites recently exchanged more than 200 gigabits of data over a distance of about 60 miles (100 kilometers) using laser communication in space. Gizmodo reports: Satellites generally don't communicate directly with each other. Instead, they use radio signals to transfer data down to a ground station on Earth, which then relays this data to another satellite. Optical terminals between satellites are considered to be faster and more secure. CACI International -- the company that developed the optical terminals for the space lasers -- announced the achievement on Tuesday in a press release. The two satellites, named Able and Baker, were launched last summer by the U.S. Defense Advanced Research Projects Agency as part of its Blackjack project. DARPA is seeking to build a constellation of small satellites in low Earth orbit for the purpose of supporting military operations.

The two satellites successfully pulled off the 40-minute laser communications experiment on April 14, during which time Able and Baker used CACI's CrossBeam free-space optical terminals. Infrared lasers transmit data by encoding the message into an optical signal, which is then carried to a receiver. The experiment, known as Mandrake 2, was funded by the Space Development Agency (SDA) and the Air Force Research Laboratory. Mandrake 2 launched on June 30, 2021 as an early risk-reduction flight for DARPA's Blackjack constellation project. The Blackjack constellation aims to deploy an initial batch of 20 small satellites in low Earth orbit, which will connect with each other to form a mesh network in space.

The idea is not to rival commercial satellite constellations such as SpaceX's Starlink, but rather to have a government-owned constellation that the military can use to connect to its bases, sensors, and weapons across the world. The SDA is planning to launch the 20 satellites this fall and then launch an additional 126 satellites by 2024, according to SpaceNews. The agency is seeking to create a full constellation that would include somewhere between 300 and 500 satellites in low Earth orbit. The satellites are being developed by Lockheed Martin, Northrop Grumman, and York Space.

An anonymous reader quotes a report from Interesting Engineering: In 1958, a combine carrying a full load of freshly harvested crops might weigh 8,800 pounds (4000 kg). Today, a fully loaded combine can clock in at 80,000 pounds (36,000 kg). The story of increasingly large farm vehicles isn't necessarily bad. The invention of these huge machines -- along with advances like new fertilizers and genetically modified crops -- mean that today's farmers can grow far more food than ever before. But there's reason to worry that equipment manufacturers have begun pushing the envelope too far. In a paper published Monday in the peer-reviewed journal PNAS, researchers show that farm equipment has grown so large that its heft can damage the soil that lies more than 20 inches (0.5 m) below the surface.

It's been obvious for a long time that the weight of farm vehicles driving over fields causes the upper layers of soil to compact. Engineers have mitigated this by putting progressively bigger tires on heavier farm vehicles. They've also used more flexible materials that make it possible to inflate the tires to lower pressure. Those changes increase the amount of surface area contact between the vehicle and the ground. These measures have enabled engineers to build larger and larger vehicles without increasing the amount of contact stress on the upper layers of soil.

It's not just the upper layers of soil that farmers need to worry about. In their analysis, the researchers found that "subsoil stresses under farm vehicles have affected progressively deeper soil layers over the past six decades." In the 1940s, '50s, and '60s, farm vehicles weren't heavy enough to compress soil below the level that's tilled each year. But that's no longer the case. Pressure from tractors, combines, and other pieces of equipment "has now penetrated deeper into the subsoil, thus potentially affecting untilled crop root zones," the authors write. Those layers of subsoil may be hidden from view, but they play an important role in what happens at the surface. The researchers say the consequences can combine to result in "a persistent decline in crop yields." This isn't a niche problem either. According to the researchers, "The fraction of arable land that is presently at high risk of subsoil compaction is about 20% of global cropland area, concentrated in mechanized regions in Europe, North America, South America, and Australia."

They say the issue could be addressed if "future agricultural vehicles [are] designed with intrinsic soil mechanical limits in mind to avoid chronic soil compaction."

The engineering team with NASA's Voyager 1 spacecraft is trying to solve a mystery: The interstellar explorer is operating normally, receiving and executing commands from Earth, along with gathering and returning science data. But readouts from the probe's attitude articulation and control system (AACS) don't reflect what's actually happening onboard. NASA's Jet Propulsion Laboratory reports: The AACS controls the 45-year-old spacecraft's orientation. Among other tasks, it keeps Voyager 1's high-gain antenna pointed precisely at Earth, enabling it to send data home. All signs suggest the AACS is still working, but the telemetry data it's returning is invalid. For instance, the data may appear to be randomly generated, or does not reflect any possible state the AACS could be in. The issue hasn't triggered any onboard fault protection systems, which are designed to put the spacecraft into "safe mode" -- a state where only essential operations are carried out, giving engineers time to diagnose an issue. Voyager 1's signal hasn't weakened, either, which suggests the high-gain antenna remains in its prescribed orientation with Earth.

The team will continue to monitor the signal closely as they continue to determine whether the invalid data is coming directly from the AACS or another system involved in producing and sending telemetry data. Until the nature of the issue is better understood, the team cannot anticipate whether this might affect how long the spacecraft can collect and transmit science data. Voyager 1 is currently 14.5 billion miles (23.3 billion kilometers) from Earth, and it takes light 20 hours and 33 minutes to travel that difference. That means it takes roughly two days to send a message to Voyager 1 and get a response -- a delay the mission team is well accustomed to.

The American Institute of Physics reports via Phys.Org: In Physics of Fluids, researchers from the University of Nicosia in Cyprus assessed the potential impact of a rocket launch on atmospheric pollution by investigating the heat and mass transfer and rapid mixing of the combustion byproducts for altitudes up to 67 kilometers into the atmosphere. The team modeled the exhaust gases and developing plume at several altitudes along a typical trajectory of a standard present-day rocket. They did this as a prototypical example of a two-stage rocket to transport people and payloads into Earth's orbit and beyond.

The researchers found the production of thermal nitrogen oxides (NOx), components of the combustion exhaust, can remain high up to altitudes with an ambient atmospheric pressure above or even slightly below the nozzles' exit pressure, i.e., below an altitude of approximately 10 km. At the same time, the emitted mass of carbon dioxide as the rocket climbs 1 kilometer in altitude in the mesosphere is equivalent to that contained in 26 cubic kilometers of atmospheric air at the same altitude. They found the impact on the atmosphere locally and momentarily in the mesosphere can be significant. While air currents will gradually transport and mix the exhaust CO2 throughout the atmosphere, eventually bringing the CO2 back down to its naturally occurring levels, the time scale over which this happens is not clear.

The scientists believe a certain number of rocket launches might still exist above which mesospheric carbon dioxide could accumulate over time, thus increasing the naturally occurring levels and affecting our climate. Their results suggest that in the worst-case scenario, sufficient NOx could be produced over the time it takes the rocket to reach an altitude of 10 kilometers to pollute over 2 cubic kilometers of atmospheric air with a NOx concentration that, according to the World Health Organization, would be at a level hazardous to human health.