Science – Page 18

Rocket Report: NASA delays Artemis again; SpinLaunch spins a little cash

rocket report, Science, Space / DJ Henderson / December 7, 2024

All the news that’s fit to lift

A report in which we read some tea leaves.

Look a the rocket which has now launched 400 times. Credit: SpaceX

Welcome to Edition 7.22 of the Rocket Report! The big news is the Trump administration’s announcement that commercial astronaut Jared Isaacman would be put forward as the nominee to serve as the next NASA Administrator. Isaacman has flown to space twice, and demonstrated that he takes spaceflight seriously. More background on Isaacman, and possible changes, can be found here.

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.

Orbex pauses launch site work in Sutherland, Scotland. Small-launch vehicle developer Orbex will halt work on its own launch site in northern Scotland and instead use a rival facility in the Shetland Islands, Space News reports. Orbex announced December 4 that it would “pause” construction of Sutherland Spaceport in Scotland and instead use the SaxaVord Spaceport on the island of Unst in the Shetlands for its Prime launch vehicle. Orbex had been linked to Spaceport Sutherland since the UK Space Agency announced in 2018 it selected the site for a vertical launch complex.

Pivoting to medium lift? … The move, Orbex said, will free up resources to allow the company to focus on launch vehicle development, including both Prime and a new medium-class vehicle called Proxima. “This decision will help us to reach first launch in 2025 and provides SaxaVord with another customer to further strengthen its commercial proposition. It’s a win-win for UK and Scottish space,” Phil Chambers, chief executive of Orbex, said. If you’re reading the tea leaves here, one might guess that the smaller Prime rocket will never launch, and the medium-lift design is a hail mary. We’ll see. (submitted by Ken the Bin)

SpinLaunch raises a little cash. Space startup SpinLaunch is fundraising again, though TechCrunch reports that it was exploring raising a significantly more ambitious sum earlier this year. The company has closed an $11.5 million round out of a planned $25 million, according to a filing with the US Securities and Exchange Commission. SpinLaunch confirmed funding to TechCrunch but did not comment on the amount raised. It last raised $71 million in a Series B funding round in 2022. SpinLaunch, as the name implies, plans to build a kinetic launch system as a low-cost, high-cadence alternative to rockets.

Putting the spin into SpinLaunch … A person familiar with the company’s plans told TechCrunch that the startup had talked to investors around nine months ago, hoping they would pile into a $350 million round at a $2 billion valuation. In response to a question about this fundraising target, SpinLaunch CEO David Wrenn said the figures were “highly inaccurate and misleading” and that he was “pleased with our recently closed financing.” Someone is spinning something, clearly. (submitted by Ken the Bin)

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Vega C successfully returns to flight. After originally targeting November 29 for the return-to-flight mission of the Vega C rocket, Arianespace successfully launched the vehicle on Thursday, December 5, Space News reports. The three solid-fuel lower stages of the Vega C performed as expected, followed by three burns by the liquid-propellant AVUM+ upper stage. That upper stage deployed its payload, the Sentinel-1C satellite, about one hour and 45 minutes after liftoff. The launch was the first for the Vega C since a December 2022 launch failure on the rocket’s second flight that destroyed two Pléiades Neo imaging satellites.

Eyes in the sky … The payload, Sentinel-1C, is a radar imaging satellite built by Thales Alenia Space for the Copernicus program of Earth observation missions run by ESA and the European Commission. It replaces the Sentinel-1B spacecraft that malfunctioned in orbit nearly three years ago. It joins the existing, but aging, Sentinel-1A satellite and includes new capabilities to monitor maritime traffic with an Automatic Identification System receiver.

PLD Space secures loan for Miura 5 rocket. The Spanish launch company said this week that it had secured an 11 million euro loan ($11.6 million) from COFIDES, a state-owned development fund, to support the development of the launch site for its Miura 5 rocket in Kourou, French Guiana. The company said the funding bolsters its mission to ensure autonomous and competitive European access to space while strengthening Europe’s space infrastructure.

A public-private partnership … “This initiative exemplifies the critical role of public-private collaboration in supporting strategic and innovative projects, which rely on institutional backing as an anchor investor during the early stages of technological development,” added Spanish Secretary of State for Trade Amparo López Senovilla. The Miura 5 rocket will have an estimated payload capacity of 1 metric ton to low-Earth orbit and may make its debut in 2026. (submitted by Ken the Bin)

SpaceX value may soar higher. SpaceX is in talks to sell insider shares in a transaction valuing the rocket and satellite maker at about $350 billion, according to people familiar with the matter, Bloomberg reports. That would be a significant premium to a previously mulled valuation of $255 billion as reported by Bloomberg News and other media outlets just last month. SpaceX was last valued at about $210 billion in a tender offer earlier this year.

A big post-election bump … The current conversations are ongoing, and the details could change depending on interest from insider sellers and buyers, sources told the publication. The potential transaction would cement SpaceX’s status as the most valuable private startup in the world and rival the market capitalizations of some of the largest public companies. SpaceX has established itself as the industry’s preeminent rocket launch provider, lofting satellites, cargo, and people to space for NASA, the Pentagon, and commercial partners, and is building out a large network of Starlink satellites providing Internet service. (submitted by Ken the Bin)

China debuts a new medium-lift rocket. China’s new Long March 12 rocket made a successful inaugural flight Saturday, placing two experimental satellites into orbit and testing uprated, higher-thrust engines that will allow a larger Chinese launcher in development to send astronauts to the Moon. The Long March 12 is the newest member of China’s Long March rocket family, which has been flying since China launched its first satellite into orbit in 1970, Ars reports.

Rocket likely to be used for megaconstellation deployment … Like all of China’s other existing rockets, the Long March 12 configuration that flew Saturday is fully disposable. At the Zhuhai Airshow earlier this month, China’s largest rocket company displayed another version of the Long March 12 with a reusable first stage but with scant design details. The Long March 12 is powered by four kerosene-fueled YF-100K engines on its first stage, generating more than 1.1 million pounds, or 5,000 kilonewtons, of thrust at full throttle. These engines are upgraded, higher-thrust versions of the YF-100 engines used on several other types of Long March rockets. (submitted by EllPeaTea and Ken the Bin)

Falcon 9 rocket reaches some remarkable milestones. About 10 days ago, SpaceX launched a batch of Starlink v2-mini satellites from Kennedy Space Center in Florida on a Falcon 9 rocket, marking the 400th successful mission by the Falcon 9 rocket. Additionally, it was the Falcon program’s 375th booster recovery, according to SpaceX. Finally, with this mission, the company shattered its record for turnaround time from the landing of a booster to its launch to 13 days and 12 hours, down from 21 days, Ars reports.

A rapidly reusable shuttle … All told, in November, SpaceX launched 16 Falcon 9 rockets. The previous record for monthly launches by the Falcon 9 rocket was 14. SpaceX is on pace to launch 135 or more Falcon 9 and Falcon Heavy missions this year. That is a meaningful number, because over the course of the three decades it flew into orbit, NASA’s space shuttle flew 135 missions. The space shuttle was a significantly more complex vehicle, and unlike the Falcon 9 rocket, humans flew aboard it during every mission. However, there is some historical significance in the fact that the Falcon rocket may fly as many missions in a single year as the space shuttle did during its lifetime.

Long March 3B hits a milestone. China launched a new communication engineering test satellite early Tuesday with its workhorse Long March 3B rocket. This added to a series of satellites potentially for undisclosed military purposes, Space News reports. The launch was, notably, the 100th of the workhorse Long March 3B.

First time to the century marker … The rocket has performed 96 successful launches with two failures and two partial failures. The first launch, in February 1996 carrying Intelsat 708, infamously saw the rocket veer off course shortly after clearing the tower and impacting a nearby village. Developed by the state-run China Academy of Launch Vehicle Technology, the three-stage and four-liquid-booster rocket is the only Chinese launcher to reach 100 launches. (submitted by Ken the Bin)

NASA delays Artemis launches again. In a news conference Thursday, NASA officials discussed changes to the timeline for future Artemis missions due to problems with Orion’s heat shield. The agency announced it is now targeting April 2026 for Artemis II (from September 2025) and mid-2027 for Artemis III (from September 2026). NASA said it now understands the technical cause of the heat shield issues observed during the Artemis I flight in late 2022 and will fly the heat shield as-is on Artemis II, with some changes to the reentry profile.

This may not be the final plan … The timing of this news conference was interesting, as there will be a changing of administrations at NASA in the coming weeks. The Trump administration has put forward commercial astronaut Jared Isaacman to lead NASA, and as Ars reported Thursday, there are likely some significant shakeups coming in the Artemis program. One possibility is that the Space Launch System rocket could be scrapped, with commercial rockets used to fly the Artemis missions.

Next three launches

Dec. 8: Falcon 9 | Starlink 12-5 | Cape Canaveral Space Force Station, Florida | 05: 10 UTC

Dec. 12: Falcon 9 | Starlink 11-2 | Vandenberg Space Force Base, California | 19: 33 UTC

Dec. 12: Falcon 9 | O3b mPOWER 7 & 8 | Kennedy Space Center, Fla. | 20: 58 UTC

Eric Berger is the senior space editor at Ars Technica, covering everything from astronomy to private space to NASA policy, and author of two books: Liftoff, about the rise of SpaceX; and Reentry, on the development of the Falcon 9 rocket and Dragon. A certified meteorologist, Eric lives in Houston.

Rocket Report: NASA delays Artemis again; SpinLaunch spins a little cash Read More »

Two European satellites launch on mission to blot out the Sun—for science

european space agency, india, isro, launch, proba-3, Science, solar eclipse, Space / Shannon Garcia / December 7, 2024

This will all happen nearly 40,000 miles above the Earth, so you won’t need your eclipse glasses.

An infrared view of a test of the Proba-3 mission’s laser ranging system, which will allow two spacecraft to fly in formation with millimeter-scale precision. Credit: ESA – M. Pédoussaut / J. Versluys

Two spacecraft developed by the European Space Agency launched on top of an Indian rocket Thursday, kicking off a mission to test novel formation flying technologies and observe a rarely seen slice of the Sun’s ethereal corona.

ESA’s Proba-3 mission is purely experimental. The satellites are loaded with sophisticated sensors and ranging instruments to allow the two spacecraft to orbit the Earth in lockstep with one another. Proba-3 will attempt to achieve millimeter-scale precision, several orders of magnitude better than the requirements for a spacecraft closing in for docking at the International Space Station.

“In a nutshell, it’s an experiment in space to demonstrate a new concept, a new technology that is technically challenging,” said Damien Galano, Proba-3’s project manager.

The two Proba-3 satellites launched from India at 5: 34 am EST (10: 34 UTC) Thursday, riding a Polar Satellite Launch Vehicle (PSLV). The PSLV released Proba-3 into a stretched-out orbit with a low point of approximately 356 miles (573 kilometers), a high point of 37,632 miles (60,563 kilometers), and an inclination of 59 degrees to the equator.

India’s PSLV accelerates through the speed of sound shortly after liftoff with the Proba-3 mission Thursday. Credit: ISRO

After initial checkouts, the two Proba-3 satellites, each smaller than a compact car, will separate from one another to begin their tech demo experiments early next year. The larger of the two satellites, known as the Coronagraph spacecraft, carries a suite of science instruments to image the Sun’s corona, or outer atmosphere. The smaller spacecraft, named Occulter, hosts navigation sensors and low-impulse thrusters to help it maneuver into position less than 500 feet (150 meters) from its Coronagraph companion.

From the point of view of the Coronagraph spacecraft, this is just the right distance for a 4.6-foot (1.4-meter) disk mounted to Proba-3’s Occulter spacecraft to obscure the surface of the Sun. The occultation will block the Sun’s blinding glare and cast a shadow just 3 inches (8 centimeters) onto the Coronagraph satellite, revealing the wispy, super-heated gases that make up the solar corona.

Why do this?

The corona is normally hidden by the brightness of the Sun and is best observed from Earth during total solar eclipses, but these events only last a few minutes. Scientists devised a way to create artificial eclipses using devices known as coronagraphs, which have flown in space on several previous solar research missions. However, these coronagraphs were placed inside a single instrument on a single spacecraft, limiting their effectiveness due to complications from diffraction or vignetting, where sunlight encroaches around the edge of the occulting disk or misses the imaging detector entirely.

Ideally, scientists would like to place the occulting disk much farther from the camera taking images of the Sun. This would more closely mimic what the human eye sees during a solar eclipse. With Proba-3, ESA will attempt to do just that.

“There was simply no other way of reaching the optical performance Proba-3 requires than by having its occulting disk fly on a separate, carefully controlled spacecraft,” said Joe Zender, ESA’s Proba-3 mission scientist. “Any closer and unwanted stray light would spill over the edges of the disk, limiting our close-up views of the Sun’s surrounding corona.”

But deploying one enormous 150-meter-long spacecraft would be cost-prohibitive. With contributions from 14 member states and Canada, ESA developed the dual-spacecraft Proba-3 mission on a budget of approximately 200 million euros ($210 million) over 10 years. Spain and Belgium, which are not among ESA’s highest-spending member states, funded nearly three-quarters of Proba-3’s cost.

The Proba-3 satellites will use several sensors to keep station roughly 150 meters away from one another, including inter-satellite radio links, satellite navigation receivers, and cameras on the Occulter spacecraft to help determine its relative position by monitoring LEDs on the Coronagraph satellite.

For the most precise navigation, the Occulter satellite will shine a laser toward a reflector on the Coronagraph spacecraft. The laser light bounced back to the Occulter spacecraft will allow it to autonomously and continuously track the range to its companion and send signals to fire cold gas thrusters and make fine adjustments.

The laser will give Proba-3 the ability to control the distance between the two satellites with an error of less than a millimeter—around the thickness of an average fingernail—and hold position for up to six hours, 50 times longer than the maximum duration of a total solar eclipse. Proba-3 will create the eclipses while it is flying farthest from Earth in its nearly 20-hour orbit.

Scientists hope to achieve at least 1,000 hours of artificial totality during Proba-3’s two-year prime mission.

Proba-3’s Occulter spacecraft (top) and Coronagraph spacecraft (bottom) will hold position 150 meters away from one another. Credit: ESA-P. Carril

The corona extends millions of miles from the Sun’s convective surface, with temperatures as hot as 3.5 million degrees Fahrenheit. Still, the corona is easily outshined by the glare from the Sun itself. Scientists say it’s important to study this region to understand how the Sun generates the solar wind and drives geomagnetic storms that can affect the Earth.

NASA’s Parker Solar Probe, well-insulated from the scorching heat, became the first spacecraft to fly through the corona in 2021. It is collecting data on the actual conditions within the Sun’s atmosphere, while a network of other spacecraft monitor solar activity from afar to get the big picture.

Proba-3 is tasked with imaging a normally invisible part of the corona as close as 43,500 miles (70,000 kilometers) above the Sun’s surface. Extreme ultraviolet instruments are capable of observing the part of the corona closest to the Sun, while existing coronagraphs on other satellites are good at seeing the outermost portion of the corona.

“That leaves a significant observing gap, from about 3 solar radii down to 1.1 solar radii, that Proba-3 will be able to fill,” said Andrei Zhukov of the Royal Observatory of Belgium, principal investigator for Proba-3’s coronagraph instrument. “This will make it possible, for example, to follow the evolution of the colossal solar explosions called Coronal Mass Ejections as they rise from the solar surface and the outward acceleration of the solar wind.”

Proba-3’s coronagraph instrument will take images as often as once every two seconds, helping scientists search for small-scale fast-moving plasma waves that might be responsible for driving up the corona’s hellish temperatures. The mission will also hunt for the glow of plasma jets scientists believe have a role in accelerating the solar wind, a cloud of particles streaming away from the Sun at speeds of up to 1.2 million mph (2 million km/hr).

These are two of the core science objectives for the Proba-3 mission. But the project has a deeper purpose of proving two satellites can continually fly in tight formation. This level of precision could meet the exacting demands of future space missions, such as Mars Sample Return and the clearing of space junk from low-Earth orbit, according to ESA.

“Proba-3’s coronal observations will take place as part of a larger in-orbit demonstration of precise formation flying,” said Josef Aschbacher, ESA’s director general. “The best way to prove this new European technology works as intended is to produce novel science data that nobody has ever seen before.

“It is not practical today to fly a single 150-meter-long spacecraft in orbit, but if Proba-3 can indeed achieve an equivalent performance using two small spacecraft, the mission will open up new ways of working in space for the future,” Aschbacher said in a statement. “Imagine multiple small platforms working together as one to form far-seeing virtual telescopes or arrays.”

Stephen Clark is a space reporter at Ars Technica, covering private space companies and the world’s space agencies. Stephen writes about the nexus of technology, science, policy, and business on and off the planet.

Two European satellites launch on mission to blot out the Sun—for science Read More »

After critics decry Orion heat shield decision, NASA reviewer says agency is correct

heat shield, orion, Science, Space / Shannon Garcia / December 6, 2024

“If this isn’t raising red flags out there, I don’t know what will.”

NASA’s Orion spacecraft, consisting of a US-built crew module and European service module, is lifted during prelaunch processing at Kennedy Space Center in 2021. Credit: NASA/Amanda Stevenson

Within hours of NASA announcing its decision to fly the Artemis II mission aboard an Orion spacecraft with an unmodified heat shield, critics assailed the space agency, saying it had made the wrong decision.

“Expediency won over safety and good materials science and engineering. Sad day for NASA,” Ed Pope, an expert in advanced materials and heat shields, wrote on LinkedIn.

There is a lot riding on NASA’s decision, as the Artemis II mission involves four astronauts and the space agency’s first crewed mission into deep space in more than 50 years.

A former NASA astronaut, Charles Camarda, also expressed his frustrations on LinkedIn, saying the space agency and its leadership team should be “ashamed.” In an interview on Friday, Camarda, an aerospace engineer who spent two decades working on thermal protection for the space shuttle and hypersonic vehicles, said NASA is relying on flawed probabilistic risk assessments and Monte Carlo simulations to determine the safety of Orion’s existing heat shield.

“I worked at NASA for 45 years,” Camarda said. “I love NASA. I do not love the way NASA has become. I do not like that we have lost our research culture.”

NASA makes a decision

Pope, Camarada, and others—an official expected to help set space policy for the Trump administration told Ars on background, “It’s difficult to trust any of their findings”—note that NASA has spent two years assessing the char damage incurred by the Orion spacecraft during its first lunar flight in late 2022, with almost no transparency. Initially, agency officials downplayed the severity of the issue, and the full scope of the problem was not revealed until a report this May by NASA’s inspector general, which included photos of a heavily pock-marked heat shield.

This year, from April to August, NASA convened an independent review team (IRT) to assess its internal findings about the root cause of the charring on the Orion heat shield and determine whether its plan to proceed without modifications to the heat shield was the correct one. However, though this review team wrapped up its work in August and began briefing NASA officials in September, the space agency kept mostly silent about the problem until a news conference on Thursday.

The inspector general’s report on May 1 included new images of Orion’s heat shield. Credit: NASA Inspector General

“Based on the data, we have decided—NASA unanimously and our decision-makers—to move forward with the current Artemis II Orion capsule and heat shield, with a modified entry trajectory,” Bill Nelson, NASA’s administrator, said Thursday. The heat shield investigation and other issues with the Orion spacecraft will now delay the Artemis II launch until April 2026, a slip of seven months from the previous launch date in September 2025.

Notably the chair of the IRT, a former NASA flight director named Paul Hill, was not present at Thursday’s news conference. Nor did the space agency release the IRT’s report on its recommendations to NASA.

In an interview, Camarda said he knew two people on the IRT who dissented from its conclusions that NASA’s plan to fly the Orion heat shield, without modifications to address the charring problem, was acceptable. He also criticized the agency for not publicly releasing the independent report. “NASA did not post the results of the IRT,” he said. “Why wouldn’t they post the results of what the IRT said? If this isn’t raising red flags out there, I don’t know what will.”

The view from the IRT

Ars took these concerns to NASA on Friday, and the agency responded by offering an interview with Paul Hill, the review team’s chair. He strongly denied there were any dissenting views.

“Every one of our conclusions, every one of our recommendations, was unanimously agreed to by our team,” Hill said. “We went through a lot of effort, arguing sentence by sentence, to make sure the entire team agreed. To get there we definitely had some robust and energetic discussions.”

Hill did acknowledge that, at the outset of the review team’s discussions, two people were opposed to NASA’s plan to fly the heat shield as is. “There was, early on, definitely a difference of opinion with a couple of people who felt strongly that Orion’s heat shield was not good enough to fly as built,” he said.

However, Hill said the IRT was won over by the depth of NASA’s testing and the openness of agency engineers who worked with them. He singled out Luis Saucedo, a NASA engineer at NASA’s Johnson Space Center who led the agency’s internal char loss investigation.

“The work that was done by NASA, it was nothing short of eye-watering, it was incredible,” Hill said.

At the base of Orion, which has a titanium shell, there are 186 blocks of a material called Avcoat individually attached to provide a protective layer that allows the spacecraft to survive the heating of atmospheric reentry. Returning from the Moon, Orion encounters temperatures of up to 5,000° Fahrenheit (2,760° Celsius). A char layer that builds up on the outer skin of the Avcoat material is supposed to ablate, or erode, in a predictable manner during reentry. Instead, during Artemis I, fragments fell off the heat shield and left cavities in the Avcoat material.

Work by Saucedo and others, including substantial testing in ground facilities, wind tunnels, and high-temperature arc jet chambers, allowed engineers to find the root cause of gases getting trapped in the heat shield and leading to cracking. Hill said his team was convinced that NASA successfully recreated the conditions observed during reentry and were able to replicate during testing the Avcoat cracking that occurred during Artemis I.

When he worked at the agency, Hill played a leading role during the investigation into the cause of the loss of space shuttle Columbia, in 2003. He said he could understand if NASA officials “circled the wagons” in response to the IRT’s work, but he said the agency could not have been more forthcoming. Every time the review team wanted more data or information, it was made available. Eventually, this made the entire IRT comfortable with NASA’s findings.

Publicly, NASA could have been more transparent

The stickiest point during the review team’s discussions involved the permeability of the heat shield. Counter-intuitively, the heat shield was not permeable enough during Artemis I. This led to gas buildup, higher pressures, and the cracking ultimately observed. The IRT was concerned because, as designed, the heat shield for Artemis II is actually more impermeable than the Artemis I vehicle.

Why is this? It has to do with the ultrasound testing that verifies the strength of the bond between the Avcoat blocks and the titanium skin of Orion. With a more permeable heat shield, it was difficult to complete this testing with the Artemis I vehicle. So the shield for Artemis II was made more impermeable to accommodate ultrasound testing. “That was a technical mistake, and when they made that decision they did not understand the ramifications,” Hill said.

However, Hill said NASA’s data convinced the IRT that modifying the entry profile for Artemis II, to minimize the duration of passage through the atmosphere, would offset the impermeability of the heat shield.

Hill said he did not have the authority to release the IRT report, but he did agree that the space agency has not been forthcoming with public information about their analyses before this week.

“This is a complex story to tell, and if you want everybody to come along with you, you’ve got to keep them informed,” he said of NASA. “I think they unintentionally did themselves a disservice by holding their cards too close.”

After critics decry Orion heat shield decision, NASA reviewer says agency is correct Read More »

US to start nationwide testing for H5N1 flu virus in milk supply

Biology, bird flu, Flu virus, H5N1, health, Infectious disease, medicine, Science / DJ Henderson / December 6, 2024

So, the ultimate goal of the USDA is to eliminate cattle as a reservoir. When the Agency announced it was planning for this program, it noted that there were two candidate vaccines in trials. Until those are validated, it plans to use the standard playbook for handling emerging infections: contact tracing and isolation. And it has the ability to compel cattle and their owners to be more cooperative than the human population turned out to be.

The five-step plan

The USDA refers to isolation and contact tracing as Stage 3 of a five-stage plan for controlling H5N1 in cattle, with the two earlier stages being the mandatory sampling and testing, meant to be handled on a state-by-state basis. Following the successful containment of the virus in a state, the USDA will move on to batch sampling to ensure each state remains virus-free. This is essential, given that we don’t have a clear picture of how many times the virus has jumped from its normal reservoir in birds into the cattle population.

That makes it possible that reaching Stage 5, which the USDA terms “Demonstrating Freedom from H5 in US Dairy Cattle,” will turn out to be impossible. Dairy cattle are likely to have daily contact with birds, and it may be that the virus will be regularly re-introduced into the population, leaving containment as the only option until the vaccines are ready.

Testing will initially focus primarily on states where cattle-to-human transmission is known to have occurred or the virus is known to be present: California, Colorado, Michigan, Mississippi, Oregon, and Pennsylvania. If you wish to track the progress of the USDA’s efforts, it will be posting weekly updates.

US to start nationwide testing for H5N1 flu virus in milk supply Read More »

Lizards and snakes are 35 million years older than we thought

Biology, fossils, lizards, paleontology, reptiles, Science / 9u50fv / December 6, 2024

Lizards are ancient creatures. They were around before the dinosaurs and persisted long after dinosaurs went extinct. We’ve now found they are 35 million years older than we thought they were.

Cryptovaranoides microlanius was a tiny lizard that skittered around what is now southern England during the late Triassic, around 205 million years ago. It likely snapped up insects in its razor teeth (its name means “hidden lizard, small butcher”). But it wasn’t always considered a lizard. Previously, a group of researchers who studied the first fossil of the creature, or holotype, concluded that it was an archosaur, part of a group that includes the extinct dinosaurs and pterosaurs along with extant crocodilians and birds.

Now, another research team from the University of Bristol has analyzed that fossil and determined that Cryptovaranoides is not an archosaur but a lepidosaur, part of a larger order of reptiles that includes squamates, the reptile group that encompasses modern snakes and lizards. It is now also the oldest known squamate.

The misunderstandings about this species all come down to features in its bones that are squamate apomorphies. These are traits unique to squamates that were not present in their ancestral form, but evolved later. Certain forelimb bones, skull bones, jawbones, and even teeth of Cryptovaranoides share characteristics with those from both modern and extinct lizards.

Wait, what is that thing?

So what does the new team argue that the previous team that studied Cryptovaranoides gets wrong? The new paper argues that the interpretation of a few bones in particular stand out, especially the humerus and radius.

In the humerus of this lizard, structures called the ectepicondylar and entepicondylar foramina, along with the radial condyle, were either not considered or may have been misinterpreted. The entepicondylar foramen is an opening in the far end of the humerus, which is an upper arm bone in humans and upper forelimb bone in lizards. The ectepicondylar foramen is a structure on the outer side of the humerus where the extensor muscles attach, helping a lizard bend and straighten its legs. Both features are “often regarded as key lepidosaur and squamate characteristics,” the Bristol research team said in a study recently published in Royal Society Open Science.

Lizards and snakes are 35 million years older than we thought Read More »

New drone has legs for landing gear, enabling efficient launches

Drones, robotics, Science / Mike M. / December 5, 2024

The RAVEN walks, it flies, it hops over obstacles, and it’s efficient.

The RAVEN in action. Credit: EPFL/Alain Herzog

Most drones on the market are rotary-wing quadcopters, which can conveniently land and take off almost anywhere. The problem is they are less energy-efficient than fixed-wing aircraft, which can fly greater distances and stay airborne for longer but need a runway, a dedicated launcher, or at least a good-fashioned throw to get to the skies.

To get past this limit, a team of Swiss researchers at the École Polytechnique Fédérale de Lausanne built a fixed-wing flying robot called RAVEN (Robotic Avian-inspired Vehicle for multiple ENvironments) with a peculiar bio-inspired landing gear: a pair of robotic bird-like legs. “The RAVEN robot can walk, hop over obstacles, and do a jumping takeoff like real birds,” says Won Dong Shin, an engineer leading the project.

Smart investments

The key challenge in attaching legs to drones was that they significantly increased mass and complexity. State-of-the-art robotic legs were designed for robots walking on the ground and were too bulky and heavy to even think about using on a flying machine. So, Shin’s team started their work by taking a closer look at what the leg mass budget looked like in various species of birds.

It turned out that the ratio of leg mass to the total body weight generally increased with size in birds. A carrion crow had legs weighing around 100 grams, which the team took as their point of reference.

The robotic legs built by Shin and his colleagues resembled a real bird’s legs quite closely. Simplifications introduced to save weight included skipping the knee joint and actuated toe joints, resulting in a two-segmented limb with 64 percent of the weight placed around the hip joint. The mechanism was powered by a standard drone propeller, with the ankle joint actuated through a system of pulleys and a timing belt. The robotic leg ended with a foot with three forward-facing toes and a single backward-facing hallux.

There were some more sophisticated bird-inspired design features, too. “I embedded a torsional spring in the ankle joint. When the robot’s leg is crouching, it stores the energy in that spring, and then when the leg stretches out, the spring works together with the motor to generate higher jumping speed,” says Shin. A real bird can store elastic energy in its muscle-tendon system during flexion and release it very rapidly during extension for a jumping takeoff. The spring’s job was to emulate this mechanism, and it worked pretty well—“It actually increased the jumping speed by 25 percent,” Shin says.

In the end, the robotic legs weighed around 230 grams, way more than the real ones in a carrion crow, but it turned out that was good enough for the RAVEN robot to walk, jump, take off, and fly.

Crow’s efficiency

The team calculated the necessary takeoff speed for two birds with body masses of 490 grams and a hair over 780 grams; these were 1.85 and 3.21 meters per second, respectively. Based on that, Shin figured the RAVEN robot would need to reach 2.5 meters per second to get airborne. Using the bird-like jumping takeoff strategy, it could reach that speed in just 0.17 seconds.

How did nature’s go-to takeoff procedure stack up against other ways to get to the skies? Other options included a falling takeoff, where you just push your aircraft off a cliff and let gravity do its thing, or standing takeoff, where you position the craft vertically and rely on the propeller to lift it upward. “When I was designing the experiments, I thought the jumping takeoff would be the least energy-efficient because it used extra juice from the battery to activate the legs,” Shin says. But he was in for a surprise.

“What we meant by energy efficiency was calculating the energy input and energy output. The energy output was the kinetic energy and the potential energy at the moment of takeoff, defined as the moment when the feet of the robot stop touching the ground,” Shin explains. The energy input was calculated by measuring the power used during takeoff.

The RAVEN takes flight.

“It turned out that the jumping takeoff was actually the most energy-efficient strategy. I didn’t expect that result. It was quite surprising”, Shin says.

The energy cost of the jumping takeoff was slightly higher than that of the other two strategies, but not by much. It required 7.9 percent more juice than the standing takeoff and 6.9 percent more than the falling takeoff. At the same time, it generated much higher acceleration, so you got way better bang for the buck (at least as far as energy was concerned). Overall, jumping with bird-like legs was 9.7 times more efficient than standing takeoff and 4.9 times more efficient than falling takeoff.

One caveat with the team’s calculations was that a fixed-wing drone with a more conventional design, one using wheels or a launcher, would be much more efficient in traditional takeoff strategies than a legged RAVEN robot. “But when you think about it, birds, too, would fly much better without legs. And yet they need them to move on the ground or hunt their prey. You trade some of the in-flight efficiency for more functions,” Shin claims. And the legs offered plenty of functions.

Obstacles ahead

To demonstrate the versatility of their legged flying robot, Shin’s team put it through a series of tasks that would be impossible to complete with a standard drone. Their benchmark mission scenario involved traversing a path with a low ceiling, jumping over a gap, and hopping onto an obstacle. “Assuming an erect position with the tail touching the ground, the robot could walk and remain stable even without advanced controllers,” Shin claims. Walking solved the problem of moving under low ceilings. Jumping over gaps and onto obstacles was done by using the mechanism used for takeoff: torsion springs and actuators. RAVEN could jump over an 11-centimeter-wide gap and onto an obstacle 26-centimeter-high.

But Shin says RAVEN will need way more work before it truly shines. “At this stage, the robot cannot clear all those obstacles in one go. We had to reprogram it for each of the obstacles separately,” Shin says. The problem is the control system in RAVEN is not adaptive; the actuators in the legs perform predefined sets of motions to send the robot on a trajectory the team figured out through computer simulations. If there was something blocking the way, RAVEN would have crashed into it.

Another, perhaps more striking limitation is that RAVEN can’t use its legs to land. But this is something Shin and his colleagues want to work on in the future.

“We want to implement some sensors, perhaps vision or haptic sensors. This way, we’re going to know where the landing site is, how many meters away from it we are, and so on,” Shin says. Another modification that’s on the way for RAVEN is foldable wings that the robot will use to squeeze through tight spaces. “Flapping wings would also be a very interesting topic. They are very important for landing, too, because birds decelerate first with their wings, not with their legs. With flapping wings, this is going to be a really bird-like robot,” Shin claims.

All this is intended to prepare RAVEN for search and rescue missions. The idea is legged flying robots would reach disaster-struck areas quickly, land, traverse difficult terrain on foot if necessary, and then take off like birds. “Another application is delivering parcels. Here in Switzerland, I often see helicopters delivering them to people living high up in the mountains, which I think is quite costly. A bird-like drone could do that more efficiently,” Shin suggested.

Nature, 2024. DOI: 10.1038/s41586-024-08228-9

John is Ars Technica’s science editor. He has a Bachelor of Arts in Biochemistry from Columbia University, and a Ph.D. in Molecular and Cell Biology from the University of California, Berkeley. When physically separated from his keyboard, he tends to seek out a bicycle, or a scenic location for communing with his hiking boots.

New drone has legs for landing gear, enabling efficient launches Read More »

Study: Warming has accelerated due to the Earth absorbing more sunlight

albedo, atmospheric science, climate change, Earth science, global warming, Science / DJ Henderson / December 5, 2024

The concept of an atmospheric energy imbalance is pretty straightforward: We can measure both the amount of energy the Earth receives from the Sun and how much energy it radiates back into space. Any difference between the two results in a net energy imbalance that’s either absorbed by or extracted from the ocean/atmosphere system. And we’ve been tracking it via satellite for a while now as rising greenhouse gas levels have gradually increased the imbalance.

But greenhouse gases aren’t the only thing having an effect. For example, the imbalance has also increased in the Arctic due to the loss of snow cover and retreat of sea ice. The dark ground and ocean absorb more solar energy compared to the white material that had previously been exposed to the sunlight. Not all of this is felt directly, however, as a lot of the areas where it’s happening are frequently covered by clouds.

Nevertheless, the loss of snow and ice has caused the Earth’s reflectivity, termed its albedo, to decline since the 1970s, enhancing the warming a bit.

Vanishing clouds

The new paper finds that the energy imbalance set a new high in 2023, with a record amount of energy being absorbed by the ocean/atmosphere system. This wasn’t accompanied by a drop in infrared emissions from the Earth, suggesting it wasn’t due to greenhouse gases, which trap heat by absorbing this radiation. Instead, it seems to be due to decreased reflection of incoming sunlight by the Earth.

While there was a general trend in that direction, the planet set a new record low for albedo in 2023. Using two different data sets, the teams identify the areas most effected by this, and they’re not at the poles, indicating loss of snow and ice are unlikely to be the cause. Instead, the key contributor appears to be the loss of low-level clouds. “The cloud-related albedo reduction is apparently largely due to a pronounced decline of low-level clouds over the northern mid-latitude and tropical oceans, in particular the Atlantic,” the researchers say.

Study: Warming has accelerated due to the Earth absorbing more sunlight Read More »

How did the CEO of an online payments firm become the nominee to lead NASA?

Features, jared isaacman, NASA, Science, Space / Kelly Newman / December 5, 2024

Expect significant changes for America’s space agency.

Jared Isaacman at SpaceX Headquarters in Hawthorne, California. Credit: SpaceX

President-elect Donald Trump announced Wednesday his intent to nominate entrepreneur and commercial astronaut Jared Isaacman as the next administrator of NASA.

For those unfamiliar with Isaacman, who at just 16 years old founded a payment processing company in his parents’ basement that ultimately became a major player in online payments, it may seem an odd choice. However, those inside the space community welcomed the news, with figures across the political spectrum hailing Isaacman’s nomination variously as “terrific,” “ideal,” and “inspiring.”

This statement from Isaac Arthur, president of the National Space Society, is characteristic of the response: “Jared is a remarkable individual and a perfect pick for NASA Administrator. He brings a wealth of experience in entrepreneurial enterprise as well as unique knowledge in working with both NASA and SpaceX, a perfect combination as we enter a new era of increased cooperation between NASA and commercial spaceflight.”

So who is Jared Isaacman? Why is his nomination being welcomed in most quarters of the spaceflight community? And how might he shake up NASA? Read on.

Meet Jared

Isaacman is now 41 years old, about half the age of current NASA Administrator Bill Nelson. He has founded a couple of companies, including the publicly traded Shift4 (look at the number 4 on a keyboard to understand the meaning of the name), as well as Draken International, a company that trained pilots of the US Air Force.

Throughout his career, Isaacman has shown a passion for flying and adventure. About five years ago, he decided he wanted to fly into space and bought the first commercial mission on a SpaceX Dragon spacecraft. But this was no joy ride. Some of his friends assumed Isaacman would invite them along. Instead, he brought a cancer survivor, a science educator, and a raffle winner. As part of the flight, this Inspiration4 mission raised hundreds of millions of dollars for research into childhood cancer.

After this mission, Isaacman set about a more ambitious project he named Polaris. The nominal plan was to fly two additional missions on Dragon and then become the first person to fly on SpaceX’s Starship. He flew the first of these missions, Polaris Dawn, in September. He brought along a pilot, Scott “Kidd” Poteet, and two SpaceX engineers, Anna Menon and Sarah Gillis. They were the first SpaceX employees to ever fly into orbit.

The mission was characteristic of Isaacman’s goal to expand the horizon of what is possible for humans in space. Polaris Dawn flew to an altitude of 1,408.1 km on the first day, the highest Earth-orbit mission ever flown and the farthest humans have traveled from our planet since Apollo. On the third day of the flight, the four crew members donned spacesuits designed and developed by SpaceX within the last two years. After venting the cabin’s atmosphere into space, first Isaacman and then Gillis spent several minutes extending their bodies out of the Dragon spacecraft.

This was the first private spacewalk in history and underscored Isaacman’s commitment to accelerating the transition of spaceflight as rare and government-driven to more publicly accessible.

Why does the space community welcome him?

In the last five years, Isaacman has impressed most of those within the spaceflight community he has interacted with. He has taken his responsibilities seriously, training hard for his Dragon missions and using NASA facilities such as a pressure chamber at NASA’s Johnson Space Center when appropriate.

Through these interactions—based upon my interviews with many people—Isaacman has demonstrated that he is not a billionaire seeking a joyride but someone who wants to change spaceflight for the better. In his spaceflights, he has also demonstrated himself to be a thoughtful and careful leader.

Two examples illustrate this. The ride to space aboard a Crew Dragon vehicle is dynamic, with the passengers pulling in excess of 3 Gs during the initial ascent, the abrupt cutoff of the main Falcon 9 rocket’s engines, stage separation, and then the grinding thrust of the upper stage engines just behind the capsule. In interviews, each of the Polaris Dawn crew members remarked about how Isaacman calmly called out these milestones in advance, with a few words about what to expect. It had a calming, reassuring effect and demonstrated that his crew’s health and safety were foremost among his concerns.

Another way in which Isaacman shows care for his crew and families is through an annual event called “Fighter Jet Training.” Cognizant of the time crew members spend away from their families training, he invites them and SpaceX employees who have supported his flights to an airstrip in Montana. Over the course of two days, family members get to ride in jets, go on a zero-gravity flight, and participate in other fun activities to get a taste of what flying on the edge is like. Isaacman underwrites all of this as a way of thanking all who are helping him.

The bottom line is that Isaacman, through his actions and words, appears to be a caring person who wants the US spaceflight enterprise to advance to greater heights.

Why would Isaacman want the job?

So why would a billionaire who has been to space twice (and plans to go at least two more times) want to run a federal agency? I have not asked Isaacman this question directly, but in interviews over the years, he has made it clear that he is passionate about spaceflight and views his role as a facilitator desiring to move things forward.

Most likely, he has accepted the job because he wants to modernize NASA and put the space agency in the best position to succeed in the future. NASA is no longer the youthful agency that took the United States to the Moon during the Apollo program. That was more than half a century ago, and while NASA is still capable of great things, it is living with one foot in the past and beholden to large, traditional contractors.

The space agency has a budget of about $25 billion, and no one could credibly argue that all of those dollars are spent efficiently. Several major programs at NASA were created by Congress with the intent of ensuring maximum dollars flowed to certain states and districts. It seems likely that Isaacman and the Trump administration will take a whack at some of these sacred cows.

High on the list is the Space Launch System rocket, which Congress created more than a dozen years ago. The rocket, and its ground systems, have been a testament to the waste inherent in large government programs funded by cost-plus contracts. NASA’s current administrator, Nelson, had a hand in creating this SLS rocket. Even he has decried the effect of this type of contracting as a “plague” on the space agency.

Currently, NASA plans to use the SLS rocket as the means of launching four astronauts inside the Orion spacecraft to lunar orbit. There, they will rendezvous with SpaceX’s Starship vehicle, go down to the Moon for a few days, and then come back to Orion. The spacecraft will then return to Earth.

So long, SLS?

Multiple sources have told Ars that the SLS rocket—which has long had staunch backing from Congress—is now on the chopping block. No final decisions have been made, but a tentative deal is in place with lawmakers to end the rocket in exchange for moving US Space Command to Huntsville, Alabama.

So how would NASA astronauts get to the Moon without the SLS rocket? Nothing is final, and the trade space is open. One possible scenario being discussed for future Artemis missions is to launch the Orion spacecraft on a New Glenn rocket into low-Earth orbit. There, it could dock with a Centaur upper stage that would launch on a Vulcan rocket. This Centaur stage would then boost Orion toward lunar orbit.

NASA’s Space Launch System rocket is seen on the launch pad at Kennedy Space Center in April 2022. Credit: Trevor Mahlmann

Such a scenario is elegant because it uses rockets that would cost a fraction of the SLS and also includes all key contractors currently involved in the Artemis program, with the exception of Boeing, which would lose out financially. (Northrop Grumman will still make solids for Vulcan, and Aerojet Rocketdyne will make the RL-10 upper stage engines for that rocket.)

As part of the Artemis program, NASA is competing with China to not only launch astronauts to the south pole of the Moon but also to develop a sustainable base of operations there. While there is considerable interest in Mars, sources told Ars that the focus of the space agency is likely to remain on a program that goes to the Moon first and then develops plans for Mars.

This competition is not one between Elon Musk, who founded SpaceX, and Jeff Bezos, who founded Blue Origin. Rather, they are both seen as players on the US team. The Trump administration seems to view entrepreneurial spirit as the key advantage the United States has over China in its competition with China. This op-ed in Space News offers a good overview of this sentiment.

So whither NASA? Under the Trump administration, NASA’s role is likely to focus on stimulating the efforts by commercial space entrepreneurs. Isaacman’s marching orders for NASA will almost certainly be two words: results and speed. NASA, they believe, should transition to become more like its roots in the National Advisory Committee for Aeronautics, which undertook, promoted, and institutionalized aeronautical research—but now for space.

It is not easy to turn a big bureaucracy, and there will undoubtedly be friction and pain points. But the opportunity here is enticing: NASA should not be competing with things that private industry is already doing better, such as launching big rockets. Rather, it should find difficult research and development projects at the edge of the possible. This will certainly be Isaacman’s most challenging mission yet.

How did the CEO of an online payments firm become the nominee to lead NASA? Read More »

These spiders listen for prey before hurling webs like slingshots

Science / Shannon Garcia / December 4, 2024

Along came a spider

A) Untensed web shown from front view. (B) Tensed web shown from side view. Credit: S.I. Han and T.A. Blackledge, 2024

The 19 spiders built 26 webs over the testing period. For the experiments, Han and Blackledge used a weighted tuning fork with frequencies in the mid-range for whirring wings for many mosquito species in North America as a control stimulus. They also attached actual mosquitos to thin strips of black construction paper by dabbing a bit of superglue on their abdomens or hind legs. This ensured the mosquitos could still beat their wings when approaching the webs. The experiments were recorded on high-speed video for analysis.

As expected, spiders released their webs when flapping mosquitoes drew near, but the video footage showed that the releases occurred before the mosquitoes ever touched the web. The spiders released their webs just as frequently when the tuning fork was brandished nearby. It wasn’t likely that they were relying on visual cues because the spiders were centered at the vertex of the web and anchor line, facing away from the cone. Ray spiders also don’t have well-developed eyes. And one spider did not respond to a motionless mosquito held within the capture cone but released its web only when the insect started flapping its wings.

“The decision to release a web is therefore likely based upon vibrational information,” the authors concluded, noting that ray spiders have sound-sensitive hairs on their back legs that could be detecting air currents or sound waves since those legs are typically closest to the cone. Static webs are known to vibrate in response to airborne sounds, so it seems likely that ray spiders can figure out an insect’s approach, its size, or maybe even its behavior before the prey ever makes contact with the web.

As for the web kinematics, Han and Blackledge determined that they can accelerate up to 504 m/s², reaching speeds as high as 1 m/s, and hence can catch mosquitos in 38 milliseconds or less. Even the speediest mosquitoes might struggle to outrun that.

Journal of Experimental Biology, 2024. DOI: 10.1242/jeb.249237 (About DOIs).

These spiders listen for prey before hurling webs like slingshots Read More »

Dog domestication happened many times, but most didn’t pan out

Archaeology, dog domestication, Dogs, indigenous North America, isotope analysis, nitrogen isotopes, Science / Mike M. / December 4, 2024

The story that data reveals is complicated—but somehow very human.

Until about 13,600 years ago, any wolf living in what is now Alaska would have lived on the usual wolf diet: rabbits, moose, and a whole range of other land animals. But starting around 13,600 years ago, the nitrogen isotopes locked in ancient wolves’ bones suggest that something changed. Some wolves still made their living solely by hunting wild game, but others started living almost entirely on fish. Since it’s unlikely that Alaskan wolves had suddenly taken up fly fishing, the sudden change probably suggests that some wolves had started getting food from people.

They’re good dogs, Brent

The fact that we kept trying to befriend wolves is starkly clear at a site called Hollembaek Hill, where archaeologists unearthed the 8,100-year-old remains of four canines. Their diets (according to the nitrogen isotopes locked in their bones) consisted mostly of salmon, so it’s tempting to assume these were domesticated dogs. But their DNA reveals that all four—including a newborn puppy—are most closely related to modern wolves.

On the other hand, the Hollembaek Hill canines didn’t all look like wild wolves. At least one of them had the large stature of a modern wolf, but others were smaller, like early dogs. And some of their DNA suggests that they may be at least part dog but not actually related to modern dogs. Lanoë and his colleagues suggest that people at Hollembaek Hill 8,000 years ago were living alongside a mix of pet wolves (do not try this at home) and wolf-dog hybrids.

All modern dogs trace their roots to a single group of wolves (now extinct) that lived in Siberia around 23,000 years ago. But sometime between 11,300 and 12,800 years ago, the canines from Hollembaek Hill and another Alaskan site called Swan Point had dog DNA that doesn’t seem related to modern dogs at all. That may suggest that dog domestication was a process that happened several times in different places, creating several branches of a dog family tree, but only one stuck around in the long run.

In other words, long after humans “invented” dogs, it seems that people just kept repeating the process, doing the things that created dogs in the first place: allowing the friendliest, least aggressive wild canids to live near their villages and maybe adopting and feeding them.

Dog domestication happened many times, but most didn’t pan out Read More »

Trump nominates Jared Isaacman to become the next NASA administrator

artemis, Donald Trump, human spaceflight, jared isaacman, NASA, Science, Space, space policy, spacex / Beth Washington / December 4, 2024

President-elect Donald Trump announced Wednesday he has selected Jared Isaacman, a billionaire businessman and space enthusiast who twice flew to orbit with SpaceX, to become the next NASA administrator.

“I am delighted to nominate Jared Isaacman, an accomplished business leader, philanthropist, pilot, and astronaut, as Administrator of the National Aeronautics and Space Administration (NASA),” Trump posted on his social media platform, Truth Social. “Jared will drive NASA’s mission of discovery and inspiration, paving the way for groundbreaking achievements in space science, technology, and exploration.”

In a post on X, Isaacman said he was “honored” to receive Trump’s nomination.

“Having been fortunate to see our amazing planet from space, I am passionate about America leading the most incredible adventure in human history,” Isaacman wrote. “On my last mission to space, my crew and I traveled farther from Earth than anyone in over half a century. I can confidently say this second space age has only just begun.”

Top officials who served at NASA under President Trump and President Obama endorsed Isaacman as the next NASA boss.

“Jared Isaacman will be an outstanding NASA Administrator and leader of the NASA family,” said Jim Bridenstine, who led NASA as administrator during Trump’s first term in the White House. “Jared’s vision for pushing boundaries, paired with his proven track record of success in private industry, positions him as an ideal candidate to lead NASA into a bold new era of exploration and discovery. I urge the Senate to swiftly confirm him.”

Lori Garver, NASA’s deputy administrator during the Obama administration, wrote on X that Isaacman’s nomination was “terrific news,” adding that “he has the opportunity to build on NASA’s amazing accomplishments to pave our way to an even brighter future.”

Isaacman, 41, is the founder and CEO of Shift4, a mobile payment processing platform, and co-founded Draken International, which owns a fleet of retired fighter jets to pose as adversaries for military air combat training. If the Senate confirms his nomination, Isaacman would become the 15th NASA administrator, and the fourth who has flown in space.

Trump nominates Jared Isaacman to become the next NASA administrator Read More »

Google’s DeepMind tackles weather forecasting, with great performance

AI, atmospheric science, Computer science, Earth science, meteorology, Science, weather forecasting / DJ Henderson / December 4, 2024

By some measures, AI systems are now competitive with traditional computing methods for generating weather forecasts. Because their training penalizes errors, however, the forecasts tend to get “blurry”—as you move further ahead in time, the models make fewer specific predictions since those are more likely to be wrong. As a result, you start to see things like storm tracks broadening and the storms themselves losing clearly defined edges.

But using AI is still extremely tempting because the alternative is a computational atmospheric circulation model, which is extremely compute-intensive. Still, it’s highly successful, with the ensemble model from the European Centre for Medium-Range Weather Forecasts considered the best in class.

In a paper being released today, Google’s DeepMind claims its new AI system manages to outperform the European model on forecasts out to at least a week and often beyond. DeepMind’s system, called GenCast, merges some computational approaches used by atmospheric scientists with a diffusion model, commonly used in generative AI. The result is a system that maintains high resolution while cutting the computational cost significantly.

Ensemble forecasting

Traditional computational methods have two main advantages over AI systems. The first is that they’re directly based on atmospheric physics, incorporating the rules we know govern the behavior of our actual weather, and they calculate some of the details in a way that’s directly informed by empirical data. They’re also run as ensembles, meaning that multiple instances of the model are run. Due to the chaotic nature of the weather, these different runs will gradually diverge, providing a measure of the uncertainty of the forecast.

At least one attempt has been made to merge some of the aspects of traditional weather models with AI systems. An internal Google project used a traditional atmospheric circulation model that divided the Earth’s surface into a grid of cells but used an AI to predict the behavior of each cell. This provided much better computational performance, but at the expense of relatively large grid cells, which resulted in relatively low resolution.

For its take on AI weather predictions, DeepMind decided to skip the physics and instead adopt the ability to run an ensemble.

Gen Cast is based on diffusion models, which have a key feature that’s useful here. In essence, these models are trained by starting them with a mixture of an original—image, text, weather pattern—and then a variation where noise is injected. The system is supposed to create a variation of the noisy version that is closer to the original. Once trained, it can be fed pure noise and evolve the noise to be closer to whatever it’s targeting.

In this case, the target is realistic weather data, and the system takes an input of pure noise and evolves it based on the atmosphere’s current state and its recent history. For longer-range forecasts, the “history” includes both the actual data and the predicted data from earlier forecasts. The system moves forward in 12-hour steps, so the forecast for day three will incorporate the starting conditions, the earlier history, and the two forecasts from days one and two.

This is useful for creating an ensemble forecast because you can feed it different patterns of noise as input, and each will produce a slightly different output of weather data. This serves the same purpose it does in a traditional weather model: providing a measure of the uncertainty for the forecast.

For each grid square, GenCast works with six weather measures at the surface, along with six that track the state of the atmosphere and 13 different altitudes at which it estimates the air pressure. Each of these grid squares is 0.2 degrees on a side, a higher resolution than the European model uses for its forecasts. Despite that resolution, DeepMind estimates that a single instance (meaning not a full ensemble) can be run out to 15 days on one of Google’s tensor processing systems in just eight minutes.

It’s possible to make an ensemble forecast by running multiple versions of this in parallel and then integrating the results. Given the amount of hardware Google has at its disposal, the whole process from start to finish is likely to take less than 20 minutes. The source and training data will be placed on the GitHub page for DeepMind’s GraphCast project. Given the relatively low computational requirements, we can probably expect individual academic research teams to start experimenting with it.

Measures of success

DeepMind reports that GenCast dramatically outperforms the best traditional forecasting model. Using a standard benchmark in the field, DeepMind found that GenCast was more accurate than the European model on 97 percent of the tests it used, which checked different output values at different times in the future. In addition, the confidence values, based on the uncertainty obtained from the ensemble, were generally reasonable.

Past AI weather forecasters, having been trained on real-world data, are generally not great at handling extreme weather since it shows up so rarely in the training set. But GenCast did quite well, often outperforming the European model in things like abnormally high and low temperatures and air pressure (one percent frequency or less, including at the 0.01 percentile).

DeepMind also went beyond standard tests to determine whether GenCast might be useful. This research included projecting the tracks of tropical cyclones, an important job for forecasting models. For the first four days, GenCast was significantly more accurate than the European model, and it maintained its lead out to about a week.

One of DeepMind’s most interesting tests was checking the global forecast of wind power output based on information from the Global Powerplant Database. This involved using it to forecast wind speeds at 10 meters above the surface (which is actually lower than where most turbines reside but is the best approximation possible) and then using that number to figure out how much power would be generated. The system beat the traditional weather model by 20 percent for the first two days and stayed in front with a declining lead out to a week.

The researchers don’t spend much time examining why performance seems to decline gradually for about a week. Ideally, more details about GenCast’s limitations would help inform further improvements, so the researchers are likely thinking about it. In any case, today’s paper marks the second case where taking something akin to a hybrid approach—mixing aspects of traditional forecast systems with AI—has been reported to improve forecasts. And both those cases took very different approaches, raising the prospect that it will be possible to combine some of their features.

Nature, 2024. DOI: 10.1038/s41586-024-08252-9 (About DOIs).

Google’s DeepMind tackles weather forecasting, with great performance Read More »