Science

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NASA confirms “independent review” of Orion heat shield issue

artemis, artemis I, artemis II, human spaceflight, NASA, orion, Science, Space, victor glover / /
The Orion spacecraft after splashdown in the Pacific Ocean at the end of the Artemis I mission.

Enlarge / The Orion spacecraft after splashdown in the Pacific Ocean at the end of the Artemis I mission.

NASA has asked a panel of outside experts to review the agency’s investigation into the unexpected loss of material from the heat shield of the Orion spacecraft on a test flight in 2022.

Chunks of charred material cracked and chipped away from Orion’s heat shield during reentry at the end of the 25-day unpiloted Artemis I mission in December 2022. Engineers inspecting the capsule after the flight found more than 100 locations where the stresses of reentry stripped away pieces of the heat shield as temperatures built up to 5,000° Fahrenheit.

This was the most significant discovery on the Artemis I, an unpiloted test flight that took the Orion capsule around the Moon for the first time. The next mission in NASA’s Artemis program, Artemis II, is scheduled for launch late next year on a test flight to send four astronauts around the far side of the Moon.

Another set of eyes

The heat shield, made of a material called Avcoat, is attached to the base of the Orion spacecraft in 186 blocks. Avcoat is designed to ablate, or erode, in a controlled manner during reentry. Instead, fragments fell off the heat shield that left cavities resembling potholes.

Investigators are still looking for the root cause of the heat shield problem. Since the Artemis I mission, engineers conducted sub-scale tests of the Orion heat shield in wind tunnels and high-temperature arcjet facilities. NASA has recreated the phenomenon observed on Artemis I in these ground tests, according to Rachel Kraft, an agency spokesperson.

“The team is currently synthesizing results from a variety of tests and analyses that inform the leading theory for what caused the issues,” said Rachel Kraft, a NASA spokesperson.

Last week, nearly a year and a half after the Artemis I flight, the public got its first look at the condition of the Orion heat shield with post-flight photos released in a report from NASA’s inspector general. Cameras aboard the Orion capsule also recorded pieces of the heat shield breaking off the spacecraft during reentry.

NASA’s inspector general said the char loss issue “creates a risk that the heat shield may not sufficiently protect the capsule’s systems and crew from the extreme heat of reentry on future missions.”

“Those pictures, we’ve seen them since they were taken, but more importantly… we saw it,” said Victor Glover, pilot of the Artemis II mission, in a recent interview with Ars. “More than any picture or report, I’ve seen that heat shield, and that really set the bit for how interested I was in the details.”

NASA confirms “independent review” of Orion heat shield issue Read More »

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DeepMind adds a diffusion engine to latest protein-folding software

AI, biochemistry, Biology, deepmind, Google, protein folding, Science / /

Added complexity —

Major under-the-hood changes let AlphaFold handle protein-DNA complexes and more.

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image of a complicated mix of lines and ribbons arranged in a complicated 3D structure.

Enlarge / Prediction of the structure of a coronavirus Spike protein from a virus that causes the common cold.

Google DeepMind

Most of the activities that go on inside cells—the activities that keep us living, breathing, thinking animals—are handled by proteins. They allow cells to communicate with each other, run a cell’s basic metabolism, and help convert the information stored in DNA into even more proteins. And all of that depends on the ability of the protein’s string of amino acids to fold up into a complicated yet specific three-dimensional shape that enables it to function.

Up until this decade, understanding that 3D shape meant purifying the protein and subjecting it to a time- and labor-intensive process to determine its structure. But that changed with the work of DeepMind, one of Google’s AI divisions, which released Alpha Fold in 2021, and a similar academic effort shortly afterward. The software wasn’t perfect; it struggled with larger proteins and didn’t offer high-confidence solutions for every protein. But many of its predictions turned out to be remarkably accurate.

Even so, these structures only told half of the story. To function, almost every protein has to interact with something else—other proteins, DNA, chemicals, membranes, and more. And, while the initial version of AlphaFold could handle some protein-protein interactions, the rest remained black boxes. Today, DeepMind is announcing the availability of version 3 of AlphaFold, which has seen parts of its underlying engine either heavily modified or replaced entirely. Thanks to these changes, the software now handles various additional protein interactions and modifications.

Changing parts

The original AlphaFold relied on two underlying software functions. One of those took evolutionary limits on a protein into account. By looking at the same protein in multiple species, you can get a sense for which parts are always the same, and therefore likely to be central to its function. That centrality implies that they’re always likely to be in the same location and orientation in the protein’s structure. To do this, the original AlphaFold found as many versions of a protein as it could and lined up their sequences to look for the portions that showed little variation.

Doing so, however, is computationally expensive since the more proteins you line up, the more constraints you have to resolve. In the new version, the AlphaFold team still identified multiple related proteins but switched to largely performing alignments using pairs of protein sequences from within the set of related ones. This probably isn’t as information-rich as a multi-alignment, but it’s far more computationally efficient, and the lost information doesn’t appear to be critical to figuring out protein structures.

Using these alignments, a separate software module figured out the spatial relationships among pairs of amino acids within the target protein. Those relationships were then translated into spatial coordinates for each atom by code that took into account some of the physical properties of amino acids, like which portions of an amino acid could rotate relative to others, etc.

In AlphaFold 3, the prediction of atomic positions is handled by a diffusion module, which is trained by being given both a known structure and versions of that structure where noise (in the form of shifting the positions of some atoms) has been added. This allows the diffusion module to take the inexact locations described by relative positions and convert them into exact predictions of the location of every atom in the protein. It doesn’t need to be told the physical properties of amino acids, because it can figure out what they normally do by looking at enough structures.

(DeepMind had to train on two different levels of noise to get the diffusion module to work: one in which the locations of atoms were shifted while the general structure was left intact and a second where the noise involved shifting the large-scale structure of the protein, thus affecting the location of lots of atoms.)

During training, the team found that it took about 20,000 instances of protein structures for AlphaFold 3 to get about 97 percent of a set of test structures right. By 60,000 instances, it started getting protein-protein interfaces correct at that frequency, too. And, critically, it started getting proteins complexed with other molecules right, as well.

DeepMind adds a diffusion engine to latest protein-folding software Read More »

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No one has seen the data behind Tyson’s “climate friendly beef” claim

beef, cattle, climate change, greenhouse gas, Science, syndication / /
feedlot

Enlarge / The Environmental Working Group published a new analysis on Wednesday outlining its efforts to push the USDA for more transparency, including asking for specific rationale in allowing brands to label beef as “climate friendly.”

Carolyn Van Houten/Washington Post via Getty

About five miles south of Broken Bow, in the heart of central Nebraska, thousands of cattle stand in feedlots at Adams Land & Cattle Co., a supplier of beef to the meat giant Tyson Foods.

From the air, the feedlots look dusty brown and packed with cows—not a vision of happy animals grazing on open pastureland, enriching the soil with carbon. But when the animals are slaughtered, processed, and sent onward to consumers, labels on the final product can claim that they were raised in a “climate friendly” way.

In late 2022, Tyson—one of the country’s “big four” meat packers—applied to the US Department of Agriculture (USDA), seeking a “climate friendly” label for its Brazen Beef brand. The production of Brazen Beef, the label claims, achieves a “10 percent greenhouse gas reduction.” Soon after, the USDA approved the label.

Immediately, environmental groups questioned the claim and petitioned the agency to stop using it, citing livestock’s significant greenhouse gas emissions and the growing pile of research that documents them. These groups and journalism outlets, including Inside Climate News, have asked the agency for the data it used to support its rubber-stamping of Tyson’s label but have essentially gotten nowhere.

“There are lots of misleading claims on food, but it’s hard to imagine a claim that’s more misleading than ‘climate friendly’ beef,” said Scott Faber, a senior vice president at the Environmental Working Group (EWG). “It’s like putting a cancer-free label on a cigarette. There’s no worse food choice for the climate than beef.”

The USDA has since confirmed it is currently considering and has approved similar labels for more livestock companies, but would not say which ones.

On Wednesday, the EWG, a longtime watchdog of the USDA, published a new analysis, outlining its efforts over the last year to push the agency for more transparency, including asking it to provide the specific rationale for allowing Brazen Beef to carry the “climate friendly” label. Last year, the group filed a Freedom of Information Act request, seeking the data that Tyson supplied to the agency in support of its application, but received only a heavily redacted response. EWG also petitioned the agency to not allow climate friendly or low carbon claims on beef.

To earn the “climate friendly” label, Tyson requires ranchers to meet the criteria of its internal “Climate-Smart Beef” program, but EWG notes that the company fails to provide information about the practices that farmers are required to adopt or about which farmers participate in the program. The only farm it has publicly identified is the Adams company in Nebraska.

A USDA spokesperson told Inside Climate News it can only rely on a third-party verification company to substantiate a label claim and could not provide the data Tyson submitted for its review.

“Because Congress did not provide USDA with on-farm oversight authority that would enable it to verify these types of labeling claims, companies must use third-party certifying organizations to substantiate these claims,” the spokesperson wrote in an email, directing Inside Climate News to the third-party verifier or Tyson for more information.

The third-party verification company, Where Food Comes From, did not respond to emailed questions from Inside Climate News, and Tyson did not respond to emails seeking comment.

The USDA said it is reviewing EWG’s petitions and announced in June 2023 that it’s working on strengthening the “substantiation of animal-raising claims, which includes the type of claim affixed to the Brazen Beef product.”

The agency said other livestock companies were seeking similar labels and that the agency has approved them, but would not identify those companies, saying Inside Climate News would have to seek the information through a Freedom of Information Act request.

“They’re being incredibly obstinate about sharing anything right now,” said Matthew Hayek, a researcher with New York University who studies the environmental and climate impacts of the food system. “Speaking as a scientist, it’s not transparent and it’s a scandal in its own right that the government can’t provide this information.”

This lack of transparency from the agency worries environmental and legal advocacy groups, especially now that billions of dollars in taxpayer funds are available for agricultural practices deemed to have benefits for the climate. The Biden administration’s signature climate legislation, the Inflation Reduction Act, appropriated nearly $20 billion for these practices; another $3.1 billion is available through a Biden-era program called the Partnership for Climate-Smart Commodities.

“This is an important test case for USDA,” Faber said. “If they can’t say no to a clearly misleading climate claim like ‘climate friendly’ beef, why should they be trusted to say no to other misleading climate claims? There’s a lot of money at stake.”

No one has seen the data behind Tyson’s “climate friendly beef” claim Read More »

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Amid two wrongful death lawsuits, Panera to pull the plug on “charged” drinks

caffeine, charged, deaths, fast food, health, lemonade, panera, Science / /

Zapped —

A large previously contained nearly as much caffeine as the FDA’s daily safe limit.

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Dispensers for Charged Lemondade, a caffeinated lemonade drink, at Panera Bread, Walnut Creek, California, March 27, 2023.

Enlarge / Dispensers for Charged Lemondade, a caffeinated lemonade drink, at Panera Bread, Walnut Creek, California, March 27, 2023.

Panera Bread will stop selling its highly caffeinated “Charged” drinks, which have been the subject of at least three lawsuits and linked to at least two deaths.

It is unclear when exactly the company will pull the plug on the potent potables, but in a statement to Ars Tuesday, Panera said it was undergoing a “menu transformation” that includes an “enhanced beverage portfolio.” The company plans to roll out various new drinks, including a lemonade and tea, but a spokesperson confirmed that the new flavors would not contain added caffeine as the “charged” drinks did.

The fast-casual cafe-style chain drew national attention in 2022 for the unexpectedly high caffeine levels in the drinks, which were initially offered as self-serve with free refills.

The versions of the drinks at the time were labeled as containing 389 mg to 390 mg of caffeine in a large, 30-ounce drink, while the other option, a 20-ounce regular, contained 260 mg. According to the Food and Drug Administration, a limit of 400 mg of caffeine per day is generally considered safe for healthy adults, but a smaller amount is advised for adults with certain medical conditions or who are pregnant or breastfeeding. A standard 8-ounce cup of coffee generally contains between 80 to 100 mg of caffeine, while a Red Bull energy drink also contains 80 mg.

In September 2022, Sarah Katz, a 21-year-old with a heart condition, died after allegedly drinking one of the highly caffeinated lemonades from a restaurant in Philadelphia. In a wrongful death lawsuit filed against Panera in October 2023, Katz’s parents alleged that she didn’t know the drink contained potentially dangerous amounts of caffeine. Rather, she was “reasonably confident it was a traditional lemonade and/or electrolyte sports drink containing a reasonable amount of caffeine safe for her to drink,” the lawsuit stated.

Also in October, Dennis Brown, a 46-year-old man in Florida, went into cardiac arrest while walking home from a Panera, where he allegedly drank a charged lemonade and then had two refills. His family filed a lawsuit against Panera in December.

According to CNN, a third lawsuit was filed in January by a woman who claims she developed an irregularly fast heartbeat and palpitations after drinking the two-and-a-half caffeinated lemonades in April 2023. “The primary reason she ordered this drink was because it was advertised as ‘plant-based’ and ‘clean,’” the complaint states.

In a statement to Ars in December, Panera said it “stands firmly by the safety of our products.” However, the company increased warnings on the drinks last year and moved containers behind the counter in some stores. Most notably, it also reduced the labeled amount of caffeine in the drinks. The current menu lists the “Charged Sips” drinks as having between 155 mg to 302 mg, depending on the flavor and size.

Amid two wrongful death lawsuits, Panera to pull the plug on “charged” drinks Read More »

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The surprise is not that Boeing lost commercial crew but that it finished at all

Boeing, Features, Science, Space, starliner / /

Boeing really is going —

“The structural inefficiency was a huge deal.”

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Boeing's Starliner spacecraft is lifted to be placed atop an Atlas V rocket for its first crewed launch.

Enlarge / Boeing’s Starliner spacecraft is lifted to be placed atop an Atlas V rocket for its first crewed launch.

United Launch Alliance

NASA’s senior leaders in human spaceflight gathered for a momentous meeting at the agency’s headquarters in Washington, DC, almost exactly ten years ago.

These were the people who, for decades, had developed and flown the Space Shuttle. They oversaw the construction of the International Space Station. Now, with the shuttle’s retirement, these princely figures in the human spaceflight community were tasked with selecting a replacement vehicle to send astronauts to the orbiting laboratory.

Boeing was the easy favorite. The majority of engineers and other participants in the meeting argued that Boeing alone should win a contract worth billions of dollars to develop a crew capsule. Only toward the end did a few voices speak up in favor of a second contender, SpaceX. At the meeting’s conclusion, NASA’s chief of human spaceflight at the time, William Gerstenmaier, decided to hold off on making a final decision.

A few months later, NASA publicly announced its choice. Boeing would receive $4.2 billion to develop a “commercial crew” transportation system, and SpaceX would get $2.6 billion. It was not a total victory for Boeing, which had lobbied hard to win all of the funding. But the company still walked away with nearly two-thirds of the money and the widespread presumption that it would easily beat SpaceX to the space station.

The sense of triumph would prove to be fleeting. Boeing decisively lost the commercial crew space race, and it proved to be a very costly affair.

With Boeing’s Starliner spacecraft finally due to take flight this week with astronauts on board, we know the extent of the loss, both in time and money. Dragon first carried people to the space station nearly four years ago. In that span, the Crew Dragon vehicle has flown thirteen public and private missions to orbit. Because of this success, Dragon will end up flying 14 operational missions to the station for NASA, earning a tidy fee each time, compared to just six for Starliner. Through last year, Boeing has taken $1.5 billion in charges due to delays and overruns with its spacecraft development.

So what happened? How did Boeing, the gold standard in human spaceflight for decades, fall so far behind on crew? This story, based largely on interviews with unnamed current and former employees of Boeing and contractors who worked on Starliner, attempts to provide some answers.

The early days

When the contracts were awarded, SpaceX had the benefit of working with NASA to develop a cargo variant of Dragon, which by 2014 was flying regular missions to the space station. But the company had no experience with human spaceflight. Boeing, by contrast, had decades of spaceflight experience, but it had to start from scratch with Starliner.

Each faced a deeper cultural challenge. A decade ago, SpaceX was deep into several major projects, including developing a new version of the Falcon 9 rocket, flying more frequently, experimenting with landing and reuse, and doing cargo supply missions. This new contract meant more money but a lot more work. A NASA engineer who worked closely with both SpaceX and Boeing in this time frame recalls visiting SpaceX and the atmosphere being something like a frenzied graduate school, where all of the employees were being pulled in different directions. Getting engineers to focus on Crew Dragon was difficult.

But at least SpaceX was in its natural environment. Boeing’s space division had never won a large fixed-price contract. Its leaders were used to operating in a cost-plus environment, in which Boeing could bill the government for all of its expenses and earn a fee. Cost overruns and delays were not the company’s problem—they were NASA’s. Now Boeing had to deliver a flyable spacecraft for a firm, fixed price.

Boeing struggled to adjust to this environment. When it came to complicated space projects, Boeing was used to spending other people’s money. Now, every penny spent on Starliner meant one less penny in profit (or, ultimately, greater losses). This meant that Boeing allocated fewer resources to Starliner than it needed to thrive.

“The difference between the two company’s cultures, design philosophies, and decision-making structures allowed SpaceX to excel in a fixed-price environment, where Boeing stumbled, even after receiving significantly more funding,” said Lori Garver in an interview. She was deputy administrator of NASA from 2009 to 2013 during the formative years of the commercial crew program and is the author of Escaping Gravity.

So Boeing faced financial pressure from the beginning. At the same time, it was confronting major technical challenges. Building a human spacecraft is very difficult. Some of the biggest hurdles would be flight software and propulsion.

The surprise is not that Boeing lost commercial crew but that it finished at all Read More »

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Mayans burned and buried dead political regimes

Archeology, mayans, Politics, ruling dynasties, Science / /

Winning isn’t everything! —

After burning, the remains were dumped in construction fill.

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A long, rectangular stone building.

Enlarge / Mayans built impressive structures and occasionally put interesting items in the construction fill.

As civilizations evolve, so do the political regimes that govern them. But the transition from one era to another is not always quiet. Some ancient Mayan rulers made a very fiery public statement about who was in charge.

When archaeologists dug up the burned fragments of royal bodies and artifacts at the Mayan archaeological site of Ucanal in Guatemala, they realized they were looking at the last remnants of a fallen regime. There was no scorching on the walls of the structure they were found beneath. This could have only meant that the remains (which had already been in their tombs a hundred years) were consumed by flames in one place and buried in another. But why?

The team of archaeologists, led by Christina T. Halperin of the University of Montreal, think this was the doing of a new leader who wanted to annihilate all traces of the old regime. He couldn’t just burn them. He also had to bury them where they would be forgotten.

Into the fire

While there is other evidence of Mayans burning bodies and objects from old regimes, a ritual known as och-i k’ak’ t-u-muk-il (“the fire entered his/her tomb”), this is the first time burnt royal remains have been discovered somewhere other than their original tomb. They were found underneath construction fill at the base of a temple where the upper parts are thought to have been made from materials that had not lasted long.

Radiocarbon dating revealed these remains were burned around the same time as the ascent of the ruler Papmalil, who assumed the title of ochk’in kaloomte’ or “western overlord,” suggesting he may have been foreign. Inscriptions of his name were seen at the same site where the burnt fragments were unearthed. Papmalil’s rise meant the fall of the K’anwitznal dynasty—the one that the bones and ornaments most likely belonged to. It also marked the start of a period of great prosperity.

“Papmalil’s rule was not only seminal because of his possible foreign origins—perhaps breaking the succession of ruling dynasts at the site—but also because his rule shifted political dynamics in the southern Maya Lowlands,” the archeologists said in a study recently published in the journal Antiquity.

The overthrowing of the K’anwitznal dynasty is evidenced on the wall of a temple at Caracol, a site not far from Ucanal. An engraving on a Caracol altar shows a captive K’anwitzanl ruler in bondage. Other engravings made only two decades later depict Papmalil as the ruling figure, and the way he is pictured giving gifts to other kings is a testament to his regime’s increased strength in foreign relations.

Ashes to ashes

The archaeological team sees Papmalil’s accession as a pivotal point after which the city of Ucanal would go on to thrive. As other rulers had done before him, he apparently wanted to dismantle the old regime and make the fall of the K’anwitznal rulers known to everyone. Though the location of the K’anwitznal tombs is unknown, the team used a map of the site they had already made to determine that the temple where the burnt remains were found stood in what was once a public plaza.

Halperin thinks that the bones of these royals and the lavish ornaments the royals were buried with were believed to have had some sort of life force or spirit that needed to be conquered before the new regime would be secure. It was evident, because of shrinkage, warping, and discoloration, that the human bones, which belonged to four individuals (three of which were determined to be male), had been burned, suggesting temperatures of at least 800° C (1,472° F). Fractures and fissures on the jade and greenstone ornaments were also signs of burning at high temperatures.

“Because the fire-burning event itself had the potential to be highly ceremonial, public, and charged with emotion, it could dramatically mark the dismantling of an ancient regime,” the team said in the same study.

To the archaeologists, there is almost no doubt that the burning of the bones and artifacts found at the Ucanal site was an act of desecration, even though the location where they had been thrown into the fire is still a mystery. They’re convinced by the way that the remains were treated no differently than construction debris, deposited at the base of a temple during construction.

Other findings from cremations have shown a level of reverence for the bones of deposed rulers and dynasties. At another site that Halperin also investigated, the cremated bones of a queen were arranged carefully along with her jewelry. That was apparently not enough for Papmalil. Even today, some leaders just feel the need to be heard more loudly than others.

Antiquity, 2024.  DOI: 10.15184/aqy.2024.38

Mayans burned and buried dead political regimes Read More »

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Two seconds of hope for fusion power

fusion, fusion power, nuclear physics, Physics, Science, tokamak / /
image of a person in protective clothing, standing in a circular area with lots of mirrored metal panels.

Enlarge / The interior or the DIII-D tokamak.

Using nuclear fusion, the process that powers the stars, to produce electricity on Earth has famously been 30 years away for more than 70 years. But now, a breakthrough experiment done at the DIII-D National Fusion Facility in San Diego may finally push nuclear fusion power plants to be roughly 29 years away.

Nuclear fusion ceiling

The DIII-D facility is run by General Atomics for the Department of Energy. It includes an experimental tokamak, a donut-shaped nuclear fusion device that works by trapping astonishingly hot plasma in very strong, toroidal magnetic fields. Tokamaks, compared to other fusion reactor designs like stellarators, are the furthest along in their development; ITER, the world’s first power-plant-size fusion device now under construction in France, is scheduled to run its first tests with plasma in December 2025.

But tokamaks have always had some issues. Back in 1988, Martin Greenwald, a Massachusetts Institute of Technology expert on plasma physics, proposed an equation that described an apparent limit on how dense plasma could get in tokamaks. He argued that maximum attainable density is dictated by the minor radius of a tokamak and the current induced in the plasma to maintain magnetic stability. Going beyond that limit was supposed to make the magnets incapable of holding the plasma, heated up to north of 150 million degrees Celsius away from the walls of the machine.

Since the power output of a tokamak was proportional to the square of fuel density, this limit didn’t bode well for fusion power plants. A commercial reactor would either need to be huge or drive absurdly high plasma currents. The former meant it would be catastrophically expensive to build, and the latter that it would be expensive to run.

But there has been hope. Since then, many research teams working at different tokamak facilities—including the Joint European Torus (JET) in Britain or ASDEX Upgrade in Germany—achieved plasma densities exceeding the Greenwald limit. In response, Martin Greenwald himself revised his claim a bit, saying that the limit applied not to the line averaged plasma density in the entire reactor but only to the portion of the plasma occupying less than 10 percent of the radius near the reactor’s wall.

While the actual density numbers were pushed a little, the working principle behind the Greenwald limit still held—when the plasma density went up above the Greenwald line, the quality of confinement went down. “The major phenomenon people discovered in the high-density experiments was reduced energy confinement when plasma density was increased,” said Siye Ding, a researcher at General Atomics working at the DIII-D National Fusion Facility.

To use fusion for energy production, we need both high density and high confinement. “For the first time, we have experimentally demonstrated how to resolve this problem,” said Ding.

Self-organizing puzzle

“When you make a plasma in your reactor, there is a whole combination of parameters,” explained Andrea Garofalo, a sciences manager at General Atomics who worked on the experiment at DIII-D. “What is the plasma current, what is the toroidal field, what is the external heating versus time. Combinations of such parameters can vary in tokamaks—you can have plasma current higher or lower, you can start the heating early, you can start it later. All this comprises what we call a scenario.”

“We’re talking about optimizing the waveforms of power, fueling, etc. to achieve the right configuration,” he added.

The configuration he and his colleagues achieved (called the high-poloidal-beta scenario) worked like a charm.

People working on nuclear fusion use various metrics that integrate multiple parameters into simple numbers to make it easier to compare the performance of different fusion experiments. The H98Y metric tracks the quality of confinement. The high confinement mode that will be used at ITER has H98Y equal to 1. Plasma density is often denoted as FGR—the Greenwald fraction—which describes how far below or above the Greenwald limit plasma density can get. FGR equal to 1 means density exactly at the Greenwald limit.

Two seconds of hope for fusion power Read More »

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Glow of an exoplanet may be from starlight reflecting off liquid iron

astronomy, atmospheres, exoplanets, Science / /

For all the glory —

A phenomenon called a “glory” may be happening on a hellishly hot giant planet.

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Image of a planet on a dark background, with an iridescent circle on the right side of the planet.

Enlarge / Artist impression of a glory on exoplanet WASP-76b.

Do rainbows exist on distant worlds? Many phenomena that happen on Earth—such as rain, hurricanes, and auroras—also occur on other planets in our Solar System if the conditions are right. Now we have evidence from outside our Solar System that one particularly strange exoplanet might even be displaying something close to a rainbow.

Appearing in the sky as a halo of colors, a phenomenon called a “glory” occurs when light hits clouds made up of a homogeneous substance in the form of spherical droplets. It might be the explanation for a mystery regarding observations of exoplanet WASP-76B. This planet, a scorching gas giant that experiences molten iron rain, has also been observed to have more light on its eastern terminator (a line used to separate the day side from the night side) than its western terminator. Why was there more light on one side of the planet?

After observing it with the CHEOPS space telescope, then combining that with previous observations from Hubble, Spitzer, and TESS, a team of researchers from ESA and the University of Bern in Switzerland now think that the most likely reason for the extra light is a glory.

Seeing the light

Over three years, CHEOPS made 23 observations of WASP-76B in both visible and infrared light. These included phase curves, transits, and secondary eclipses. Phase curves are continuous observations that track a planet’s complete revolution and show changes in its phase or the part of its illuminated side that is facing the telescope. The telescope may see more or less of that side as the planet orbits its star. Phase curves can determine the change in the total brightness of the planet and star as the planet orbits.

Secondary eclipses happen when a planet passes behind its host star and is eclipsed by it. The light seen during such an eclipse can later be compared with the total light both before and after the occultation to give us a sense of the light that’s reflected off the planet. Hot Jupiters like WASP-76B are commonly observed through secondary eclipses.

Phase-curve observations can continue while the planet is eclipsing its star. While it was observing the phase curve of WASP-76B, CHEOPS saw a pre-eclipse excess of light on its night side. This had also been seen in TESS phase-curve and secondary-eclipse observations that had been made earlier.

End of the rainbow?

An advantage of WASP-76b is that it is an ultra-hot Jupiter, so at least its day side does not have the clouds and hazes that often obscure the atmospheres of cooler hot Jupiters. This makes atmospheric emissions much easier to detect. That we had already observed an asymmetry in iron content between the day-side and night-side terminators, discovered in a previous study, made the planet especially intriguing. There was not much gaseous iron in the upper atmosphere of the day-side limb compared to that of the night-side limb. This is probably because it rains iron on the day side of WASP-76b, which then condenses into clouds of iron on the night side.

Observations from Hubble suggested that thermal inversion—when the air near the surface of a planet begins cooling—was occurring on the night side. Cooling on that side would cause iron that had previously condensed into clouds, rained down onto the day side, and then evaporated from the intense heat to condense again. Drops of liquid iron can then form clouds.

These clouds are critical since light from the host star, reflecting off these drops in those clouds, can create the effect of a glory.

“Explaining the observation with the glory effect would require spherical droplets of highly reflective, spherically shaped aerosols and clouds on the planet’s eastern hemisphere,” the researchers said in a paper recently published in Astronomy & Astrophysics.

Glories have been seen off Earth before. They are also known to form in the clouds of Venus. Just like WASP-76b, more pre-eclipse light was observed on Venus, so while a glory is all but definite for the exoplanet, future observations with a more powerful telescope could help determine how similar the phenomenon on WASP-76 is to that on Venus. If they match, this will be the first glory ever observed on an exoplanet.

If future research figures out a definite way to tell whether this is really a glory, these phenomena could tell us more about the atmospheric makeup of exoplanets, depending on the kinds of elements or molecules light is reflecting off of. They might even give away the presence of water, which could mean habitability. While the hypothesized glory on WASP-76b has not been definitively demonstrated, it is anything but a rainbow in the dark.

Astronomy & Astrophysics, 2024. DOI: 10.1051/0004-6361/202348270

Glow of an exoplanet may be from starlight reflecting off liquid iron Read More »

we-still-don’t-understand-how-one-human-apparently-got-bird-flu-from-a-cow

We still don’t understand how one human apparently got bird flu from a cow

bird flu, cattle, CDC, cows, genetic surveillance, H5N1, human case, Infectious disease, mutations, outbreak, pandemic, Science, USDA, viral sequences, viruses / /
Holstein dairy cows in a freestall barn.

Enlarge / Holstein dairy cows in a freestall barn.

The US Department of Agriculture this week posted an unpublished version of its genetic analysis into the spillover and spread of bird flu into US dairy cattle, offering the most complete look yet at the data state and federal investigators have amassed in the unexpected and worrisome outbreak—and what it might mean.

The preprint analysis provides several significant insights into the outbreak—from when it may have actually started, just how much transmission we’re missing, stunning unknowns about the only human infection linked to the outbreak, and how much the virus continues to evolve in cows. The information is critical as flu experts fear the outbreak is heightening the ever-present risk that this wily flu virus will evolve to spread among humans and spark a pandemic.

But, the information hasn’t been easy to come by. Since March 25—when the USDA confirmed for the first time that a herd of US dairy cows had contracted the highly pathogenic avian influenza H5N1 virus—the agency has garnered international criticism for not sharing data quickly or completely. On April 21, the agency dumped over 200 genetic sequences into public databases amid pressure from outside experts. However, many of those sequences lack descriptive metadata, which normally contains basic and key bits of information, like when and where the viral sample was taken. Outside experts don’t have that crucial information, making independent analyses frustratingly limited. Thus, the new USDA analysis—which presumably includes that data—offers the best yet glimpse of the complete information on the outbreak.

Undetected spread

One of the big takeaways is that USDA researchers think the spillover of bird flu from wild birds to cattle began late last year, likely in December. Thus, the virus likely circulated undetected in dairy cows for around four months before the USDA’s March 25 confirmation of an infection in a Texas herd.

This timeline conclusion largely aligns with what outside experts previously gleaned from the limited publicly available data. So, it may not surprise those following the outbreak, but it is worrisome. Months of undetected spread raise significant concerns about the country’s ability to identify and swiftly respond to emerging infectious disease outbreaks—and whether public health responses have moved past the missteps seen in the early stages of the COVID-19 pandemic.

But another big finding from the preprint is how many gaps still exist in our current understanding of the outbreak. To date, the USDA has identified 36 herds in nine states that have been infected with H5N1. The good news from the genetic analysis is that the USDA can draw lines connecting most of them. USDA researchers reported that “direct movement of cattle based upon production practices” seems to explain how H5N1 hopped from the Texas panhandle region—where the initial spillover is thought to have occurred—to nine other states, some as far-flung as North Carolina, Michigan, and Idaho.

Bayes factors for inferred movement between different discrete traits of H5N1 clade 2.3.4.4b viruses demonstrating the frequency of movement.

Enlarge / Bayes factors for inferred movement between different discrete traits of H5N1 clade 2.3.4.4b viruses demonstrating the frequency of movement.

Putative transmission pathways of HPAI H5N1 clade 2.3.4.4b genotype B3.13 supported by epidemiological links, animal movements, and genomic analysis.

Enlarge / Putative transmission pathways of HPAI H5N1 clade 2.3.4.4b genotype B3.13 supported by epidemiological links, animal movements, and genomic analysis.

Putative transmission pathways of HPAI H5N1 clade 2.3.4.4b genotype B3.13 supported by epidemiological links, animal movements, and genomic analysis. [/ars_img]The bad news is that those lines connecting the herds aren’t solid. There are gaps in which the genetic data suggests unidentified transmission occurred, maybe in unsampled cows, maybe in other animals entirely. The genetic data is clear that once this strain of bird flu—H5N1 clade 2.3.4.4 genotype B3.13 —hopped into cattle, it could readily spread to other mammals. The genetic data links viruses from cattle moving many times into other animals: There were five cattle-to-poultry jumps, one cattle-to-raccoon transmission, two events where the virus moved from cattle to domestic cats, and three times when the virus from cattle spilled back into wild birds.

“We cannot exclude the possibility that this genotype is circulating in unsampled locations and hosts as the existing analysis suggests that data are missing and undersurveillance may obscure transmission inferred using phylogenetic methods,” the USDA researchers wrote in their preprint.

We still don’t understand how one human apparently got bird flu from a cow Read More »

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NASA hasn’t landed on the Moon in decades—China just sent its third in six years

Chang'e 6, china vs united state, Science, Space / /

Marching on —

China is going. NASA is talking about going. What gives?

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A Long March 5 rocket carrying the Chang'e-6 lunar probe blasts off from the Wenchang Space Launch Center on May 3, 2024 in Wenchang, China.

Enlarge / A Long March 5 rocket carrying the Chang’e-6 lunar probe blasts off from the Wenchang Space Launch Center on May 3, 2024 in Wenchang, China.

Li Zhenzhou/VCG via Getty Images

China is going back to the Moon for more samples.

On Friday the country launched its largest rocket, the Long March 5, carrying an orbiter, lander, ascent vehicle, and a return spacecraft. The combined mass of the Chang’e-6 spacecraft is about 8 metric tons, and it will attempt to return rocks and soil from the far side of the Moon—something scientists have never been able to study before in-depth.

The mission’s goal is to bring about 2 kg (4.4 pounds) of rocks back to Earth a little more than a month from now.

Chang’e-6 builds upon the Chinese space program’s successful lunar program. In 2019, the Chang’e-4 mission made a soft landing on the far side of the Moon, the first time this had ever been done by a spacecraft. The far side is more challenging than the near side, because line-of-sight communications are not possible with Earth.

Then, in late 2020, the Chang’e-5 mission landed on the near side of the Moon and successfully collected 1.7 kg of rocks. These were subsequently blasted off the surface of the Moon and returned to China where they have been studied since. It marked the first time in half a century, since efforts by the United States and Soviet Union, that samples were returned from the Moon.

Ambitious plans

The latest Chinese flight to the Moon launched Friday will synthesize the country’s learnings from its last two missions, by collecting and returning samples from the far side of the Moon.

“If the Chang’e-6 mission can achieve its goal, it will provide scientists with the first direct evidence to understand the environment and material composition of the far side of the moon, which is of great significance,” said Wu Weiren, an academician of the Chinese Academy of Engineering and chief designer of China’s lunar exploration program.

This mission follows the launch and deployment of the Queqiao-2 relay satellite in March, which will serve as a bridge between communications from the far side of the Moon to operators back on Earth. China has also announced two future lunar missions, Chang’e-7 and Chang’e-8, later this decade. These robotic missions will land near the lunar South Pole, test lunar resources, and prepare the way for future crewed missions.

Nominally, China’s current plan calls for the first landing of two taikonauts on the surface of the Moon in 2029 or 2030. Eventually it wants to establish a lunar outpost.

China’s lunar missions are not operating in a vacuum—OK, technically, they are—but the point here is that China’s exploration efforts are proceeding alongside a parallel effort by the United States, NASA, and about three dozen partners under the auspices of the Artemis program.

Can NASA compete?

After decades of focusing its exploration efforts elsewhere, NASA finally turned back to the Moon about seven years ago. Since that time it has worked alongside the commercial space industry to develop a plan for a sustainable return to the lunar surface.

From the outside, China’s lunar program appears to be in the lead. It is difficult to argue about the string of successes with the Chang’e lunar program and the unprecedented landing on the far side of the Moon. If Chang’e-6 proves successful, that will be another strike in favor of China’s lunar program.

But to its credit, NASA is not simply seeking to replicate the glories of its Apollo lunar program in the 1960s and early 1970s. China’s first lunar mission with astronauts, for example, is intended to land two taikonauts on the Moon for just a few hours. The vehicles will be fully expendable, as were the Apollo rockets and spacecraft more than half a century ago.

NASA is taking a different approach, working with industry to develop a fleet of commercial cargo landers—such as Intuitive Machines’ largely successful Odysseus mission earlier this year—as well as larger human landers built by SpaceX and Blue Origin. This overall “architecture” is far more complex, requiring myriad launches to refuel spacecraft in orbit. It will likely take several years longer to get to the first lunar landing missions, either later this decade or earlier in the 2030s. But should NASA persist and succeed in this approach, it will open up a highway to the Moon the likes of which could only be dreamed of during the Apollo era. Imagine a flotilla of spacecraft going to and from the Moon. That’s the vision.

So it’s a competition between China’s embrace of a traditional approach versus NASA’s efforts to open the way into some kind of new future. Watching how this lunar competition unfolds over the next decade will be one of the most fascinating stories to follow.

NASA hasn’t landed on the Moon in decades—China just sent its third in six years Read More »

rocket-report:-astroscale-chases-down-dead-rocket;-ariane-6-on-the-pad

Rocket Report: Astroscale chases down dead rocket; Ariane 6 on the pad

ariane 6, china, launch, long march-5, NASA, orion, rocket report, Science, Space, spacex, starship / /

RIP B1060 —

Rocket Factory Augsburg, a German launch startup, nears a test-firing of its booster.

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This image captured by Astroscale's ADRAS-J satellite shows the discarded upper stage from a Japanese H-IIA rocket.

Enlarge / This image captured by Astroscale’s ADRAS-J satellite shows the discarded upper stage from a Japanese H-IIA rocket.

Welcome to Edition 6.42 of the Rocket Report! Several major missions are set for launch in the next few months. These include the first crew flight on Boeing’s Starliner spacecraft, set for liftoff on May 6, and the next test flight of SpaceX’s Starship rocket, which could happen before the end of May. Perhaps as soon as early summer, SpaceX could launch the Polaris Dawn mission with four private astronauts, who will perform the first fully commercial spacewalk in orbit. In June or July, Europe’s new Ariane 6 rocket is slated to launch for the first time. Rest assured, Ars will have it all covered.

As always, we welcome reader submissions, and if you don’t want to miss an issue, please subscribe using the box below (the form will not appear on AMP-enabled versions of the site). Each report will include information on small-, medium-, and heavy-lift rockets as well as a quick look ahead at the next three launches on the calendar.

German rocket arrives at Scottish spaceport. Rocket Factory Augsburg has delivered a booster for its privately developed RFA One rocket to SaxaVord Spaceport in Scotland, the company announced on X. The first stage for the RFA One rocket was installed on its launch pad at SaxaVord to undergo preparations for a static fire test. The booster arrived at the Scottish launch site with five of its kerosene-fueled Helix engines. The remaining four Helix engines, for a total of nine, will be fitted to the RFA One booster at SaxaVord, the company said.

Aiming to fly this year… RFA hopes to launch its first orbital-class rocket by the end of 2024. The UK’s Civil Aviation Authority last month granted a range license to SaxaVord Spaceport to allow the spaceport operator to control the sea and airspace during a launch. RFA is primarily privately funded but has won financial support from the European Space Agency, the UK Space Agency, and the German space agency, known as DLR. The RFA One rocket will have three stages, stand nearly 100 feet (30 meters) tall, and can carry nearly 2,900 pounds (1,300 kilograms) of payload into a polar Sun-synchronous orbit.

Arianespace wins ESA launch contract. The European Space Agency has awarded Arianespace a contract to launch a joint European-Chinese space science satellite in late 2025, European Spaceflight reports. The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) is a 4,850-pound (2,200-kilogram) spacecraft that will study Earth’s magnetic environment on a global scale. The aim of the mission is to build a more complete understanding of the Sun-Earth connection. On Tuesday, ESA officially signed a contract for Arianespace to launch SMILE aboard a Vega C rocket, which is built by the Italian rocket-maker Avio.

But it may not keep it … In late 2023, ESA member states agreed to allow Avio to market and manage the launch of Vega C flights independent of Arianespace. When the deal was initially struck, 17 flights were contracted through Arianespace to be launched aboard Vega vehicles. While these missions are still managed by Arianespace, Avio is working with the launch provider to strike a deal that would allow the Italian rocket builder to assume the management of all Vega flights. The Vega C rocket has been grounded since a launch failure in 2022 forced Avio to redesign the nozzle of the rocket’s solid-fueled second-stage motor. Vega C is scheduled to return to flight before the end of 2024. (submitted by Ken the Bin)

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Update on ABL’s second launch. ABL Space Systems expected to launch its second light-class RS1 rocket earlier this year, but the company encountered an anomaly during ground testing at the launch site in Alaska, according to Aria Alamalhodaei of TechCrunch. Kevin Sagis, ABL’s chief engineer, said there is “no significant delay” in the launch of the second RS1 rocket, but the company has not announced a firm schedule. “During ground testing designed to screen the vehicle for flight, an issue presented that caused us to roll back to the hangar,” Sagis said, according to Alamalhodaei. “We have since resolved and dispositioned the issue. There was no loss of hardware and we have validated vehicle health back out on the pad. We are continuing with preparations for static fire and launch.”

Nearly 16 months without a launch … ABL’s first RS1 test flight in January 2023 ended seconds after liftoff with the premature shutdown of its liquid-fueled engines. The rocket crashed back onto its launch pad in Alaska. An investigation revealed a fire in the aft end of the RS1 booster burned through wiring harnesses, causing the rocket to lose power and shut off its engines. Engineers believe the rocket’s mobile launch mount was too small, placing the rocket too close to the ground when it ignited its engines. This caused the hot engine exhaust to recirculate under the rocket and led to a fire in the engine compartment as it took off.

Rocket Report: Astroscale chases down dead rocket; Ariane 6 on the pad Read More »

alarming-superbug-from-deadly-eyedrop-outbreak-has-spread-to-dogs

Alarming superbug from deadly eyedrop outbreak has spread to dogs

antibiotics, CDC, drug resistance, eyedrop, EzriCare, fda, infectious diseases, outbreak, Pseudomonas aeruginosa, Science / /

gone to the dogs —

It’s unclear how the dogs became infected with the same strain in the eyedrops.

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A dog gets examined by veterinary technicians in Texas.

Enlarge / A dog gets examined by veterinary technicians in Texas.

Two separately owned dogs in New Jersey tested positive last year for a dreaded, extensively drug resistant bacterial strain spread in the US by contaminated artificial eye drops manufactured in India. Those drops caused a deadly multi-state outbreak in humans over many months last year, with at least 81 people ultimately infected across 18 states. Fourteen people lost their vision, an additional four had eyeballs surgically removed, and four people died.

The preliminary data on the dogs—presented recently at a conference of disease detectives hosted by the Centers for Disease Control and Prevention—highlights that now that the deadly outbreak strain has been introduced around the US, it has the potential to lurk in unexpected places, spread its drug resistance to fellow bacteria, and cause new infections in people and animals who may have never used the drops.

The two dogs in New Jersey were not known to have received the drops linked to the outbreak: EzriCare Artificial Tears and two additional products made by the same manufacturer, which were recalled in February 2023. Such over-the-counter products are sometimes used in animals as well as people. But the dogs’ separate owners said they didn’t recall using the drops either. They also didn’t report any exposures in health care settings or recent international travel that could explain the infections. One of the dogs did, at one point, receive eye drops, but they were not an outbreak-associated brand. The only connection between the two dogs was that they were both treated at the same veterinary hospital, which didn’t stock the outbreak-associated eyedrops.

The dogs’ infections were caught between March and June 2023 when clinicians at the veterinary hospital were working to address a chronic cough in one of the dogs and a stubborn ear infection in the other, according to CBS News, which was present for the CDC’s conference of its Epidemic Intelligence Service in Atlanta. The ear and lung swabs were sent to an academic veterinary laboratory in Pennsylvania, where a microbiologist noticed that bacteria from both swabs had uncommon drug-resistance features. The microbiologist then uploaded genetic sequences of the bacterial strains to a national database, where they caught the attention of the CDC and state health authorities.

The genetic sequences uploaded were of the carbapenemase-producing carbapenem-resistant Pseudomonas aeruginosa (CP-CRPA) strain—and they were highly similar to the bacterial strain identified in the deadly eyedrop outbreak. These bacteria are extensively resistant to antibiotics, resisting even last-line drugs, and can silently colonize animals and humans for months or years. An investigation ensued.

Infection gaps

Emma Price, the CDC epidemic intelligence service officer who presented the investigation’s findings at the conference, suggested it was fortunate they were able to make the connection. “Because [the academic veterinary laboratory] had a grant and a veterinary microbiologist works there, he did his great due diligence and uploaded the results. That’s how we got the notification, because the strain matched the outbreak strain,” Price told CBS News.

However, the disease detectives were ultimately unable to identify exactly how the two dogs became infected. “Shared exposures included treatment in the veterinary hospital’s surgical preparation and recovery areas for both canines and ophthalmology department visits by either the affected canine or another animal in the same household,” Price and colleagues wrote in their findings. But all of the sampling done of the veterinary hospital where the dogs were treated turned up negative for the eyedrop outbreak strain.

In the process of the investigation, the epidemiologists also conducted an infection control assessment of the veterinary hospital, finding a variety of “gaps.” These included problems with hand hygiene practices, personal protective equipment use—including use of gloves—and equipment and environmental cleaning and disinfection at the hospital. Price noted that these problems are not uncommon and that there is a general lack of emphasis on infection control in veterinary settings.

Though Price and her colleagues were unable to identify the direct route of infection, they suspect the dogs were likely infected either by exposure to a contaminated product or secondary transmission at the veterinary hospital.

Both dogs have since made full recoveries, but because CRPA strains can silently colonize many body sites on both humans and animals, it’s possible that the bacteria still linger on the dogs or on the other pets and people in their households. Price warned the owners of possible future transmission and recommended they flag this risk to their health care providers. She also noted the potential for the bacteria to spread from dog to dog. It would be ideal to “keep the dogs away from other dogs in the future, which we understand is a difficult thing to do,” she said.

Alarming superbug from deadly eyedrop outbreak has spread to dogs Read More »