Science

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Rocket delivered to launch site for first human flight to the Moon since 1972

artemis, artemis II, human spaceflight, Kennedy Space Center, NASA, Science, SLS core stage, Space, space launch system / /
Rocket delivered to launch site for first human flight to the Moon since 1972

The central piece of NASA’s second Space Launch System rocket arrived at Kennedy Space Center in Florida this week. Agency officials intend to start stacking the towering launcher in the next couple of months for a mission late next year carrying a team of four astronauts around the Moon.

The Artemis II mission, officially scheduled for September 2025, will be the first voyage by humans to the vicinity of the Moon since the last Apollo lunar landing mission in 1972. NASA astronauts Reid Wiseman, Victor Glover, Christina Koch, and Canadian mission specialist Jeremy Hansen will ride the SLS rocket away from Earth, then fly around the far side of the Moon and return home inside NASA’s Orion spacecraft.

“The core is the backbone of SLS, and it’s the backbone of the Artemis mission,” said Matthew Ramsey, NASA’s mission manager for Artemis II. “We’ve been waiting for the core to get here because all the integrated tests and checkouts that we do have to have the core stage. It has the flight avionics that drive the whole system. The boosters are also important, but the core is really the backbone for Artemis. So it’s a big day.”

The core stage rolled off of NASA’s Pegasus barge at Kennedy early Wednesday, following a weeklong ocean voyage from New Orleans, where Boeing builds the rocket under contract to NASA.

Ramsey told Ars that ground teams hope to begin stacking the rocket’s two powerful solid rocket boosters on NASA’s mobile launcher platform in September. Each booster, supplied by Northrop Grumman, is made of five segments with pre-packed solid propellant and a nose cone. All the pieces for the SLS boosters are at Kennedy and ready for stacking, Ramsey said.

The SLS upper stage, built by United Launch Alliance, is also at the Florida launch site. Now, the core stage is at Kennedy. In August or September, NASA plans to deliver the two remaining elements of the SLS rocket to Florida. These are the adapter structures that will connect the core stage to the upper stage, and the upper stage to the Orion spacecraft.

A heavy-duty crane inside the cavernous Vehicle Assembly Building (VAB) will hoist each segment of the SLS boosters into place on the launch platform. Once the boosters are fully stacked, ground teams will lift the 212-foot (65-meter) core stage vertical in the transfer aisle running through the center of the VAB. A crane will then lower the core stage between the boosters. That could happen as soon as December, according to Ramsey.

Then comes the launch vehicle stage adapter, the upper stage, the Orion stage adapter, and finally, the Orion spacecraft itself.

Moving toward operations

NASA’s inspector general reported in 2022 that NASA’s first four Artemis missions will each cost $4.1 billion. Subsequent documents, including a Government Accountability Office report last year, suggest the expendable SLS core stage is responsible for at least a quarter of the cost for each Artemis flight.

The core stage for Artemis II is powered by four hydrogen-fueled RS-25 engines produced by Aerojet Rocketdyne. Two of the reusable engines for Artemis II have flown on the space shuttle, and the other two RS-25s were built in the shuttle era but never flew. Each SLS launch will put the core stage and its engines in the Atlantic Ocean.

Steve Wofford, who manages the stages office for the SLS program at NASA’s Marshall Space Flight Center, told Ars there are “no major configuration differences” between the core stages for Artemis I and Artemis II. The only minor differences involve instrumentation that NASA wanted on Artemis I to measure pressures, accelerations, vibrations, temperatures, and other parameters on the first flight of the Space Launch System.

“We are still working off some flight observations that we made on Artemis I, but no showstoppers,” Wofford said. “On the first article, the test flight, Artemis I, we really loaded it up. That’s a golden opportunity to learn as much as you can about the vehicle and the flight regime, and anchor all your models… As you progress, you need less and less of that. So Core Stage 2 will have less development flight instrumentation than Core Stage 1, and then Core Stage 3 will have less still.”

Rocket delivered to launch site for first human flight to the Moon since 1972 Read More »

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NASA nears decision on what to do with Boeing’s troubled Starliner spacecraft

Boeing, butch wilmore, commercial crew, Commercial space, human spaceflight, international space station, NASA, Science, Space, spacex, starliner, suni williams / /
Boeing's Strainer spacecraft is seen docked at the International Space Station in this picture taken July 3.

Enlarge / Boeing’s Strainer spacecraft is seen docked at the International Space Station in this picture taken July 3.

The astronauts who rode Boeing’s Starliner spacecraft to the International Space Station last month still don’t know when they will return to Earth.

Astronauts Butch Wilmore and Suni Williams have been in space for 51 days, six weeks longer than originally planned, as engineers on the groundwork through problems with Starliner’s propulsion system.

The problems are twofold. The spacecraft’s reaction control thrusters overheated, and some of them shut off as Starliner approached the space station June 6. A separate, although perhaps related, problem involves helium leaks in the craft’s propulsion system.

On Thursday, NASA and Boeing managers said they still plan to bring Wilmore and Williams home on the Starliner spacecraft. In the last few weeks, ground teams completed testing of a thruster on a test stand at White Sands, New Mexico. This weekend, Boeing and NASA plan to fire the spacecraft’s thrusters in orbit to check their performance while docked at the space station.

“I think we’re starting to close in on those final pieces of flight rationale to make sure that we can come home safely, and that’s our primary focus right now,” Stich said.

The problems have led to speculation that NASA might decide to return Wilmore and Williams to Earth in a SpaceX Crew Dragon spacecraft. There’s one Crew Dragon currently docked at the station, and another one is slated to launch with a fresh crew next month. Steve Stich, manager of NASA’s commercial crew program, said the agency has looked at backup plans to bring the Starliner crew home on a SpaceX capsule, but the main focus is still to have the astronauts fly home aboard Starliner.

“Our prime option is to complete the mission,” Stich said. “There are a lot of good reasons to complete this mission and bring Butch and Suni home on Starliner. Starliner was designed, as a spacecraft, to have the crew in the cockpit.”

Starliner launched from Cape Canaveral Space Force Station in Florida on June 5. Wilmore and Williams are the first astronauts to fly into space on Boeing’s commercial crew capsule, and this test flight is intended to pave the way for future operational flights to rotate crews of four to and from the International Space Station.

Once NASA fully certifies Starliner for operational missions, the agency will have two human-rated spaceships for flights to the station. SpaceX’s Crew Dragon has been flying astronauts since 2020.

Tests, tests, and more tests

NASA has extended the duration of the Starliner test flight to conduct tests and analyze data in an effort to gain confidence in the spacecraft’s ability to safely bring its crew home and to better understand the root causes of the overheating thrusters and helium leaks. These problems are inside Starliner’s service module, which is jettisoned to burn up in the atmosphere during reentry, while the reusable crew module, with the astronauts inside, parachutes to an airbag-cushioned landing.

The most important of these tests was a series of test-firings of a Starliner thruster on the ground. This thruster was taken from a set of hardware slated to fly on a future Starlink mission, and engineers put it through a stress test, firing it numerous times to replicate the sequence of pulses it would see in flight. The testing simulated two sequences of flying up to the space station, and five sequences the thruster would execute during undocking and a deorbit burn for return to Earth.

“This thruster has seen quite a bit of pulses, maybe even more than what we would anticipate we would see during a flight, and more aggressive in terms of two uphills and five downhills,” Stich said. “What we did see in the thruster is the same kind of thrust degradation that we’re seeing on orbit. In a number of the thrusters (on Starliner), we’re seeing reduced thrust, which is important.”

Starliner’s flight computer shut off five of the spacecraft’s 28 reaction control system thrusters, produced by Aerojet Rocketdyne, during the rendezvous with the space station last month. Four of the five thrusters were recovered after overheating and losing thrust, but officials have declared one of the thrusters unusable.

The thruster tested on the ground showed similar behavior. Inspections of the thruster at White Sands showed bulging in a Teflon seal in an oxidizer valve, which could restrict the flow of nitrogen tetroxide propellant. The thrusters, each generating about 85 pounds of thrust, consume the nitrogen tetroxide, or NTO, oxidizer and mix it with hydrazine fuel for combustion.

A poppet valve, similar to an inflation valve on a tire, is designed to open and close to allow nitrogen tetroxide to flow into the thruster.

“That poppet has a Teflon seal at the end of it,” Nappi said. “Through the heating and natural vacuum that occurs with the thruster firing, that poppet seal was deformed and actually bulged out a little bit.”

Stich said engineers are evaluating the integrity of the Teflon seal to determine if it could remain intact through the undocking and deorbit burn of the Starliner spacecraft. The thrusters aren’t needed while Starliner is attached to the space station.

“Could that particular seal survive the rest of the flight? That’s the important part,” Stich said.

NASA nears decision on what to do with Boeing’s troubled Starliner spacecraft Read More »

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Astronomers find first emission spectra in brightest GRB of all time

astronomy, astrophysics, B.O.A.T., Fermi space telescope, Gamma ray bursts, Physics, Science / /

shine on, you beautiful BOAT —

Chance that first detected emission line is a noise fluctuation is one in half a billion.

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A jet of particles moving at nearly light speed emerges from a massive star in this artist’s concept.

Enlarge / A jet of particles moving at nearly light-speed emerges from a massive star in this artist’s concept of the BOAT.

NASA’s Goddard Space Flight Center Conceptual Image Lab

Scientists have been all aflutter since several space-based detectors picked up a powerful gamma-ray burst (GRB) in October 2022—a burst so energetic that astronomers nicknamed it the BOAT (Brightest Of All Time). Now an international team of astronomers has analyzed an unusual energy peak detected by NASA’s Fermi Gamma-ray Space Telescope and concluded that it was an emission spectra, according to a new paper published in the journal Science. Per the authors, it’s the first high-confidence emission line ever seen in 50 years of studying GRBs.

As reported previously, gamma-ray bursts are extremely high-energy explosions in distant galaxies lasting between mere milliseconds to several hours. There are two classes of gamma-ray bursts. Most (70 percent) are long bursts lasting more than two seconds, often with a bright afterglow. These are usually linked to galaxies with rapid star formation. Astronomers think that long bursts are tied to the deaths of massive stars collapsing to form a neutron star or black hole (or, alternatively, a newly formed magnetar). The baby black hole would produce jets of highly energetic particles moving near the speed of light, powerful enough to pierce through the remains of the progenitor star, emitting X-rays and gamma rays.

Those gamma-ray bursts lasting less than two seconds (about 30 percent) are deemed short bursts, usually emitting from regions with very little star formation. Astronomers think these gamma-ray bursts are the result of mergers between two neutron stars, or a neutron star merging with a black hole, comprising a “kilonova.” That hypothesis was confirmed in 2017 when the LIGO collaboration picked up the gravitational wave signal of two neutron stars merging, accompanied by the powerful gamma-ray bursts associated with a kilonova.

Several papers were published last year reporting on the analytical results of all the observational data. Those findings confirmed that GRB 221009A was indeed the BOAT, appearing especially bright because its narrow jet was pointing directly at Earth. But the various analyses also yielded several surprising results that puzzled astronomers. Most notably, a supernova should have occurred a few weeks after the initial burst, but astronomers didn’t detect one, perhaps because it was very faint, and thick dust clouds in that part of the sky were dimming any incoming light.

Earlier this year, astronomers confirmed that the BOAT came from a supernova, thanks to the telltale signatures of key elements like calcium and oxygen that one would expect to find with a supernova. However, they did not find evidence of the expected heavy elements like platinum and gold, which bears on the longstanding question of the origin of such elements in the universe. The BOAT might just be special in that regard; further data will tell us more.

“It gave me goosebumps”

A few minutes after the BOAT erupted, Fermi’s Gamma-ray Burst Monitor recorded an unusual energy peak. Scientists now say this feature is the first high-confidence emission line ever seen in 50 years of studying GRBs.

The newly detected spectral emission line was likely caused by the collision of matter and anti-matter, according to the authors, producing a pair of gamma rays that are blue-shifted toward higher energies because we are looking into the jet. Having a spectral emission associated with a GRB is important because it can shed light on the specific chemicals involved in the interactions. There have been prior studies reporting possible evidence for absorption or emission lines in other GRBs, but they have usually turned out likely to be statistical noise.

That’s not the case with this latest detection, according to co-author Om Sharan Salafia at INAF-Brera Observatory in Milan, Italy, who added that the odds of this turning out to be a statistical fluctuation “are less than one chance in half a billion.” His INAF colleague and co-author, Maria Edvige Ravasio, said that when she first saw the signal, “it gave me goosebumps.”

Why did astronomers take so long to detect it? When the BOAT first erupted in 2022, it saturated most of the space-based gamma-ray detectors, including the Fermi Space Telescope, making them unable to measure the most intense part of that blast. The emission line didn’t appear until a good five minutes after the burst when it had sufficiently dimmed for Fermi to make a measurement. The spectral emission lasted for about 40 seconds and reached a peak energy of about 12 MeV, compared to 2 or 3 MeB for visible light, per the authors.

Science, 2024. DOI: 10.1126/science.adj3638  (About DOIs).

Astronomers find first emission spectra in brightest GRB of all time Read More »

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Astronauts find their tastes dulled, and a VR ISS hints at why

food, Human behavior, international space station, Science, Space exploration, taste / /

Pass the sriracha —

The visual environment of the ISS seems to influence people’s experience of food.

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Image of astronauts aboard the ISS showing off pizzas they've made.

Enlarge / The environment you’re eating in can influence what you taste, and space is no exception.

Astronauts on the ISS tend to favor spicy foods and top other foods with things like tabasco or shrimp cocktail sauce with horseradish. “Based on anecdotal reports, they have expressed that food in space tastes less flavorful. This is the way to compensate for this,” said Grace Loke, a food scientist at the RMIT University in Melbourne, Australia.

Loke’s team did a study to take a closer look at those anecdotal reports and test if our perception of flavor really changes in an ISS-like environment. It likely does, but only some flavors are affected.

Tasting with all senses

“There are many environmental factors that could contribute to how we perceive taste, from the size of the area to the color and intensity of the lighting, the volume and type of sounds present, the way our surroundings smell, down to even the size and shape of our cutlery. Many other studies covered each of these factors in some way or another,” said Loke.

That’s why her team started to unravel the bland ISS food mystery by recreating the ISS environment in VR. “Certain environments are difficult to be duplicated, such as the ISS, which led us to look at digital solutions to mimic how it felt [to be] living and working in these areas,” said Julia Low, a nutrition and food technologist at the RMIT University and co-author of the study.

Once the VR version of the ISS was ready, the team had 54 participants smell flavors of vanilla, almonds, and lemon. The first round of tests was done in a pretty normal room, and the second with the VR goggles on, running the simulated ISS environment complete with sterile, cluttered spaces, sounds present at the real ISS, and objects floating around in microgravity.

The participants said the lemon flavor seemed the same in both rounds. Almonds and vanilla, on the other hand, seemed more intense when participants were in the VR environment. While that’s the opposite of what might be expected from astronauts’ dining habits, it is informative. “The bottom line is we may smell aromas differently in a space-like environment, but it is selective as to what kind of aromas. We’re not entirely sure why this happens, but knowing that a difference exists is the first step to find out more,” Loke said.

Loke and her colleagues then pulled out a mass spectrometer and took a closer look at the composition of the flavors they used in the tests.

Space-ready ingredients

The lemon flavor in Loke’s team tests was lemon essential oil applied to a cotton ball, which was then placed in a closed container that was kept sealed until it was given to the participants to smell. The vapors released from the container contained several volatile chemicals such as limonene, camphene, 3-carene, and monoterpene alcohols like linalool, carveol, and others.

Almond flavors contained similar chemicals, but there was one notable difference: the almond and vanilla flavors contained benzaldehyde, while the lemon did not. “Benzaldehyde naturally gives off a sweet aroma, while the lemon aroma, which did not have it, has a more fruity and citrusy aroma profile. We believe that it may be the sweet characteristics of aromas that leads to a more intense perception in [simulated] space,” said Loke.

Astronauts find their tastes dulled, and a VR ISS hints at why Read More »

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Barbie movie “may have spurred interest in gynecology,” study finds

Barbie, culture, gynecology, health, Popular Culture, Science, women's health / /

Do you need a gynecologist? —

The movie apparently sparked some questions.

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A digital advertisement board displaying a Barbie movie poster is seen in New York on July 24, 2023.

Enlarge / A digital advertisement board displaying a Barbie movie poster is seen in New York on July 24, 2023.

This post contains spoilers—for the movie and women’s health care.

There’s nothing like stirrups and a speculum to welcome one to womanhood, but for some, the recent Barbie movie apparently offered its own kind of eye-opening introduction.

The smash-hit film ends with the titular character making the brave decision to exit Barbieland and enter the real world as a bona fide woman. The film’s final scene follows her as she fully unfurls her new reality, attending her first woman’s health appointment. “I’m here to see my gynecologist,” she enthusiastically states to a medical receptionist. For many, the line prompted a wry chuckle, given her unsuspecting eagerness and enigmatic anatomy. But for others, it apparently raised some fundamental questions.

Online searches in the US for “gynecologist”—or alternate spellings, such as “gynaecologist”—rose an estimated 51 percent over baseline in the week following Barbie‘s July 21, 2023 release, according to a study published Thursday in JAMA Network Open. Moreover, searches related to the definition of gynecology spiked 154 percent. Those search terms included “gynecologist meaning,” “what is a gynecologist,” “what does a gynecologist do,” “why see a gynecologist,” and the weightiest of questions: “do I need a gynecologist.”

The “Barbie effect”

The study’s authors, led by researchers at Harvard Medical School, assessed 34 query terms that fit into six categories of searches, including “gynecologist,” “gynecologist definition,” “gynecologist appointment,” “doctors,” “doctor’s appointment,” and “women’s health.” The last three served as controls for more general interest in medical information. As the authors put it, the three control searches helped establish “whether unobserved contemporaneous factors influencing health-seeking behavior more generally may have contributed to gynecologic-related search volume.”

While the researchers noted clear spikes in “gynecologist” and “gynecologist definition” searches, they saw no changes in search trends for the three control search categories during the week after the movie’s release: “doctors,” “doctor’s appointment,” and “women’s health.” This suggested that the increase in gynecology-related searches may, in fact, be linked to the movie rather than some increased interest in health care generally.

The researchers also did not see a corresponding increase in searches related to gynecology appointments, suggesting that the transient online interest in gynecology didn’t translate to online searches for actual gynecological care, with queries such as “gynecologist near me.” The researchers speculate that two factors might explain this. For one, there’s the possibility that the data couldn’t capture care-seeking decisions. It may be that there’s a longer, variable time gap between newfound awareness of gynecology and the decision to seek care. The second possibility is that the people searching for basic information about gynecology may not need gynecological care themselves.

Overall, the authors conclude that “Barbie’s closing line may have spurred interest in gynecology.” The finding is supported by earlier work that also suggests popular culture can have measurable influences on health literacy and awareness among the general public, the authors conclude. For instance, when journalist Katie Couric live streamed her colonoscopy, there was a transient 21 percent increase in colonoscopies, and when actress Angelina Jolie penned an editorial about her experience with breast cancer, there was a transient 64 percent increase in genetic testing for breast cancer risk (BRCA testing). But while the “Barbie effect” seems to have raised some awareness of gynecology, it remains unclear if it will lead to a measurable improvement in health outcomes.

Barbie movie “may have spurred interest in gynecology,” study finds Read More »

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US solar production soars by 25 percent in just one year

Energy, fossil fuels, nuclear power, renewable energy, Science, Sustainability / /

Solar sailing —

2024 is seeing the inevitable outcome of the building boom in solar farms.

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A single construction person set in the midst of a sea of solar panels.

With the plunging price of photovoltaics, the construction of solar plants has boomed in the US. Last year, for example, the US’s Energy Information Agency expected that over half of the new generating capacity would be solar, with a lot of it coming online at the very end of the year for tax reasons. Yesterday, the EIA released electricity generation numbers for the first five months of 2024, and that construction boom has seemingly made itself felt: generation by solar power has shot up by 25 percent compared to just one year earlier.

The EIA breaks down solar production according to the size of the plant. Large grid-scale facilities have their production tracked, giving the EIA hard numbers. For smaller installations, like rooftop solar on residential and commercial buildings, the agency has to estimate the amount produced, since the hardware often resides behind the metering equipment, so only shows up via lower-than-expected consumption.

In terms of utility-scale production, the first five months of 2024 saw it rise by 29 percent compared to the same period in the year prior. Small-scale solar was “only” up by 18 percent, with the combined number rising by 25.3 percent.

Most other generating sources were largely flat, year over year. This includes coal, nuclear, and hydroelectric, all of which changed by 2 percent or less. Wind was up by 4 percent, while natural gas rose by 5 percent. Because natural gas is the largest single source of energy on the grid, however, its 5 percent rise represents a lot of electrons—slightly more than the total increase in wind and solar.

US electricity sources for January through May of 2024. Note that the numbers do not add up to 100 percent due to the omission of minor contributors like geothermal and biomass.

Enlarge / US electricity sources for January through May of 2024. Note that the numbers do not add up to 100 percent due to the omission of minor contributors like geothermal and biomass.

John Timmer

Overall, energy use was up by about 4 percent compared to the same period in 2023. This could simply be a matter of changing weather conditions that require more heating or cooling. But there have been several trends that should increase electricity usage: the rise of bitcoin mining, the growth of data centers, and the electrification of appliances and transport. So far, that hasn’t shown up in the actual electricity usage in the US, which has stayed largely flat for decades. It could be possible that 2024 is the year when usage starts going up again.

More to come

It’s worth noting that this data all comes from before some of the most productive months of the year for solar power; overall, the EIA is predicting that solar production could rise by as much as 42 percent in 2024.

So, where does this leave the US’s efforts to decarbonize? If we combine nuclear, hydro, wind, and solar under the umbrella of carbon-free power sources, then these account for about 45 percent of US electricity production so far this year. Within that category, wind and solar now produce more than three times hydroelectric, and roughly the same amount as nuclear.

Wind and solar have also produced 1.3 times as much electricity as coal so far in 2024, with solar alone now producing about half as much as coal. That said, natural gas still produces twice as much electricity as wind and solar combined, indicating we still have a long way to go to decarbonize our grid.

When you look at the generating facilities that will be built over the next 12 months, it's difficult not to see a pattern.

Enlarge / When you look at the generating facilities that will be built over the next 12 months, it’s difficult not to see a pattern.

Still, we can expect solar’s productivity to climb even before the year is out. That’s in part because we don’t yet have numbers for June, the month that contains the longest day of the year. But it’s also because the construction boom shows no sign of stopping. As noted here, solar and wind deployments are expected to dwarf everything else over the coming year. The items in gray on the map primarily represent battery storage, which will allow us to make better use of those renewables, as well.

By contrast, facilities that are scheduled for retirement over the next year largely consist of coal and natural gas plants.

US solar production soars by 25 percent in just one year Read More »

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Scientists unlock more secrets of Rembrandt’s pigments in The Night Watch

art conservation, chemistry, Physics, pigments, rembrandt, Science, The Night Watch / /

More from operation night watch —

Use of arsenic sulfides for yellow, orange/red hues adds to artist’s known pigment palette.

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The Nightwatch, or Militia Company of District II under the Command of Captain Frans Banninck Cocq (1642)

Enlarge / Rembrandt’s The Night Watch underwent many chemical and mechanical alterations over the last 400 years.

Public domain

Since 2019, researchers have been analyzing the chemical composition of the materials used to create Rembrandt’s masterpiece, The Night Watch, as part of the Rijksmuseum’s ongoing Operation Night Watch, devoted to its long-term preservation. Chemists at the Rijksmuseum and the University of Amsterdam have now detected unusual arsenic-based yellow and orange/red pigments used to paint the duff coat of one of the central figures in the painting, according to a recent paper in the journal Heritage Science. It’s a new addition to Rembrandt’s known pigment palette that further adds to our growing body of knowledge about the materials he used.

As previously reported, past analyses of Rembrandt’s paintings identified many pigments the Dutch master used in his work, including lead white, multiple ochres, bone black, vermilion, madder lake, azurite, ultramarine, yellow lake, and lead-tin yellow, among others. The artist rarely used pure blue or green pigments, with Belshazzar’s Feast being a notable exception. (The Rembrandt Database is the best resource for a comprehensive chronicling of the many different investigative reports.)

Early last year, the researchers at Operation Night Watch found rare traces of a compound called lead formate in the painting—surprising in itself, but the team also identified those formates in areas where there was no lead pigment, white or yellow. It’s possible that lead formates disappear fairly quickly, which could explain why they have not been detected in paintings by the Dutch Masters until now. But if that is the case, why didn’t the lead formate disappear in The Night Watch? And where did it come from in the first place?

Hoping to answer these questions, the team whipped up a model of “cooked oils” from a 17th-century recipe and analyzed those model oils with synchrotron radiation. The results supported their hypothesis that the oil used for light parts of the painting was treated with an alkaline lead drier. The fact that The Night Watch was revarnished with an oil-based varnish in the 18th century complicates matters, as this may have provided a fresh source of formic acid, such that different regions of the painting rich in lead formates may have formed at different times in the painting’s history.

Last December, the team turned its attention to the preparatory layers applied to the canvas. It’s known that Rembrandt used a quartz-clay ground for The Night Watch—the first time he had done so, perhaps because the colossal size of the painting “motivated him to look for a cheaper, less heavy and more flexible alternative for the ground layer” than the red earth, lead white, and cerussite he was known to use on earlier paintings.

The Night Watch. (b) Detail of figure’s embroidered gold buff coat. (c) X-ray diffraction image of coat detail showing arsenic. (d) Stereomicroscope image showing arsenic hot spot.” height=”531″ src=”https://cdn.arstechnica.net/wp-content/uploads/2024/07/rembrandt1-640×531.jpg” width=”640″>

Enlarge / (a) Rembrandt’s The Night Watch. (b) Detail of figure’s embroidered gold buff coat. (c) X-ray diffraction image of coat detail showing arsenic. (d) Stereomicroscope image showing arsenic hot spot.

N. De Keyser et al., 2024

They used 3D X-ray methods to capture more detail, revealing the presence of an unknown (and unexpected) lead-containing layer located just underneath the ground layer. This could be due to using a lead compound added to the oil used to prepare the canvas as a drying additive—perhaps to protect the painting from the damaging effects of humidity. (Usually a glue sizing was used before applying the ground layer.) The lead layer discovered last year could be the reason for the unusual lead protrusions in areas of The Night Watch, since there are no other lead-containing compounds in the paint. It’s possible that lead migrated into the painting’s ground layer from the lead-oil preparatory layer below.

An intentional combination

The presence of arsenic sulfides in The Night Watch appears to be an intentional pigment combination by Rembrandt, according to the authors of this latest paper. Artists throughout history have used naturally occurring orpiment and realgar, as well as artificial arsenic sulfide pigments, to get yellow, orange, and red hues in their paints. Orpiment was also used for medicinal purposes, in hair removal creams and oils, in wax seals, yellow ink, bookbinder green (mixed with indigo), and for the treatment or coating of metals like silver.

However, the use of artificial arsenic sulfides has rarely been reported in artworks, although they are mentioned in multiple artists’ treatises dating back to the 15th century. Earlier work using advanced analytical techniques such as Raman spectroscopy and X-ray powder diffraction revealed that Rembrandt used arsenic sulfide pigments (artificial orpiment) in two late paintings: The Jewish Bride (c 1665) and The Man in a Red Cap (c 1665).

For this latest work, Nouchka De Keyser of the Rijksmuseum and co-authors used macroscopic X-ray fluorescence imaging to map The Night Watch, which revealed the presence of arsenic and sulfur in the doublet sleeves and embroidered buff coat worn by Lt. Willem Van Ruytenburch, i.e., the central figure to the right of Captain Frans Bannick Cocq in the painting. The researchers initially assumed that this was due to Rembrandt’s use of orpiment for yellow hues and realgar for red hues.

Ars Vitraria Experimentalis, 1679. (c) Page from the Weimar taxa of 1674 including prices for white, yellow, and red arsenic.” height=”300″ src=”https://cdn.arstechnica.net/wp-content/uploads/2024/07/rembrandt2-640×300.jpg” width=”640″>

Enlarge / (a, b) Pages from Johann Kunckel’s Ars Vitraria Experimentalis, 1679. (c) Page from the Weimar taxa of 1674 including prices for white, yellow, and red arsenic.

N. De Keyser et al., 2024

To learn more, they took tiny samples and analyzed them with light microscopy, micro-Raman spectroscopy, electron microscopy, and X-ray powder diffraction. They found the yellow particles were actually pararealgar while the orange to red particles were semi-amorphous pararealgar. These are more unusual arsenic sulfide components, typically associated with degradation products from either the natural minerals or their artificial equivalents as they age.

But De Keyser et al. concluded that the presence of these components was actually an intentional mixture, based on their perusal of multiple historical sources and catalogs of collection cabinets with long lists of various arsenic sulfides. There was clearly contemporary knowledge of manipulating both natural and artificial arsenic sulfides to get different shades of yellow, orange, and red.

They also found vermilion and lead-tin yellow in the paint mixture; Rembrandt was known to use these to add brightness and intensity to his paintings. In the case of The Night Watch, “Rembrandt clearly aimed for a bright orange tone with a high color strength that allowed him to create an illusion of the gold thread embroidery in Van Ruytenburch’s costume,” the authors wrote. “The artificial orange to red arsenic sulfide might have offered different optical and rheological paint properties as compared to the mineral form of orpiment and realgar.”

In addition, the team examined paint samples from different artists known to use arsenic sulfides—whose works are also part of the Rijksmuseum collection—and found a similar mixture of pigments in a painting by Rembrandt’s contemporary, Willem Kalf. “It is evidence that a variety of natural and artificial arsenic sulfides were manufactured and traded during Rembrandt’s time and were available in Amsterdam,” the authors wrote—most likely imported, since the Dutch Republic did not have considerable mining resources.

Heritage Science, 2024. DOI: 10.1186/s40494-024-01350-x  (About DOIs).

Scientists unlock more secrets of Rembrandt’s pigments in The Night Watch Read More »

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No, NASA hasn’t found life on Mars yet, but the latest discovery is intriguing

Life on Mars, Mars, perseverance, Science, Space / /

Look at the big brain on percy —

“These spots are a big surprise.”

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NASA’s Perseverance rover discovered “leopard spots” on a reddish rock nicknamed “Cheyava Falls” in Mars’ Jezero Crater in July 2024.

Enlarge / NASA’s Perseverance rover discovered “leopard spots” on a reddish rock nicknamed “Cheyava Falls” in Mars’ Jezero Crater in July 2024.

NASA/JPL-Caltech/MSSS

NASA’s Perseverance rover has found a very intriguing rock on the surface of Mars.

An arrowhead-shaped rock observed by the rover has chemical signatures and structures that could have been formed by ancient microbial life. To be absolutely clear, this is not irrefutable evidence of past life on Mars, when the red planet was more amenable to water-based life billions of years ago. But discovering these colored spots on this rock is darn intriguing and has Mars scientists bubbling with excitement.

“These spots are a big surprise,” said David Flannery, an astrobiologist and member of the Perseverance science team from the Queensland University of Technology in Australia, in a NASA news release. “On Earth, these types of features in rocks are often associated with the fossilized record of microbes living in the subsurface.”

What the rover found

This is a very recent discovery, and the science has not yet been peer-reviewed. The sample was collected on July 21—a mere four days ago—as the rover explored the Neretva Vallis riverbed. This valley was formed long ago when water rushed into Jezero Crater.

The science team operating Perseverance has nicknamed the rock Chevaya Falls and subjected it to multiple scans by the rover’s SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) instrument. The distinctive colorful spots, containing both iron and phosphate, are a smoking gun for certain chemical reactions—rather than microbial life itself.

On Earth, microbial life can derive energy from these kinds of chemical reactions. So, what we have here is a plausible source of energy for microbes on Mars. In addition, there are organic chemicals present on the same rock, which is consistent with something living there. From this, it is tempting to jump to the idea of microbes living on a rock, eons ago, in a Martian river. But this is not direct evidence of life.

NASA has a seven-step process for determining whether something can be confirmed as extraterrestrial life. This is known as the CoLD scale, for Confidence of Life Detection. In this case, the detection of these spots on a Martian rock represents just the first of seven steps—for example, scientists must still rule out non-biological possibility and identify other signals to have confidence in off-world life.

Bring them home

According to NASA, Perseverance has used all of its available instrumentation to study Chevaya Falls. “We have zapped that rock with lasers and X-rays and imaged it literally day and night from just about every angle imaginable,” said Ken Farley, Perseverance project scientist. “Scientifically, Perseverance has nothing more to give.”

The discovery provides some wind in the sails for NASA’s flagging efforts to devise and fly a Mars Sample Return mission. The agency’s most recent plan, costing $11 billion, was determined to be too expensive. Now, the space agency is asking the industry for help. In June it commissioned 10 studies on alternative means of returning rocks from Mars sooner, and presumably for a lower cost.

Now, scientists can point to rocks like Chevaya Falls and say this is precisely why they must be studied in ultra-capable labs back on Earth.

No, NASA hasn’t found life on Mars yet, but the latest discovery is intriguing Read More »

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Webb directly images giant exoplanet that isn’t where it should be

astronomy, exoplanets, planetary science, Science, Webb telescope / /

How do you misplace that? —

Six times bigger than Jupiter, the planet is the oldest and coldest yet imaged.

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A dark background with read and blue images embedded in it, both showing a single object near an area marked with an asterisk.

Enlarge / Image of Epsilon Indi A at two wavelengths, with the position of its host star indicated by an asterisk.

T. Müller (MPIA/HdA), E. Matthews (MPIA)

We have a couple of techniques that allow us to infer the presence of an exoplanet based on its effects on the light coming from its host star. But there’s an alternative approach that sometimes works: image them directly. It’s much more limited, since the planet has to be pretty big and orbiting far away enough from its star to avoid having light coming from the planet swamped by the far more intense starlight.

Still, it has been done. Massive exoplanets have been captured relatively shortly after their formation, when the heat generated by the collapse of material into the planet causes them to glow in the infrared. But the Webb telescope is far more sensitive than any infrared observatory we’ve ever built, and it has managed to image a relatively nearby exoplanet that’s roughly as old as the ones in our Solar System.

Looking directly at a planet

What do you need to directly image a planet that’s orbiting a star light-years away? The first thing is a bit of hardware called a coronagraph attached to your telescope. This is responsible for blocking the light from the star the planet is orbiting; without it, that light will swamp any other sources in the exosolar system. Even with a good coronagraph, you need the planets to be orbiting at a significant distance from the star so that they’re cleanly separated from the signal being blocked by the coronagraph.

Then, you need the planet to emit a fair bit of light. While the right surface composition might allow the planet to be highly reflective, that’s not going to be a great option considering the distances we’d need the planet to be orbiting to be visible at all. Instead, the planets we’ve spotted so far have been young and still heated by the processes that brought material together to form a planet in the first place. Being really big doesn’t hurt matters either.

Put that all together, and what you expect to be able to spot is a very young, very distant planet that’s massive enough to fall into the super-Jupiter category.

But the launch of the Webb Space Telescope has given us new capabilities in the infrared range, and a large international team of researchers pointed it at a star called Epsilon Indi A. It’s a bit less than a dozen light years away (which is extremely close in astronomical terms), and the star is both similar in size and age to the Sun, making it an interesting target for observations. Perhaps most significantly previous data had suggested a large exoplanet would be found, based on indications that the star was apparently shifting as the exoplanet tugged on it during its orbit.

And there was in fact an indication of a planet there. It just didn’t look much like the expected planet. “It’s about twice as massive, a little farther from its star, and has a different orbit than we expected,” said Elisabeth Matthews, one of the researchers involved.

At the moment, there’s no explanation for the discrepancy. The odds of it being an unrelated background object are extremely small. And a reanalysis of data on the motion of Epsilon Indi A suggests that this is likely to be the only large planet in the system—there could be additional planets, but they’d be much smaller. So, the researchers named the planet Epsilon Indi Ab, even though that was the same name given to the planet that doesn’t seem to match this one’s properties.

Big, cold, and a bit enigmatic

The revised Epsilon Indi Ab is a large planet, estimated at roughly six times the mass of Jupiter. It’s also orbiting at roughly the same distance as Neptune. It’s generally bright across the mid-infrared, consistent with a planet that’s roughly 275 Kelvin—not too far off from room temperature. That’s also close to what we would estimate for its temperature simply based on the age of the planet. That makes it the coolest exoplanet ever directly imaged.

While the signal from the planet was quite bright at a number of wavelengths, the planet couldn’t even be detected in one area of the spectrum (3.5 to 5 micrometers, for the curious). That’s considered an indication that the planet has high levels of elements heavier than helium, and a high ratio of carbon to oxygen. The gap in the spectrum may influence estimates of the planet’s age, so further observations will probably need to be conducted to clarify why there are no emissions at these wavelengths.

The researchers also suggest that imaging more of these cool exoplanets should be a priority, given that we should be cautious about extrapolating anything from a single example. So, in that sense, this first exoplanet imaging provides an important confirmation that, with Webb and its coronagraph, we’ve now got the tools we need to do so, and they work very well.

Nature, 2024. DOI: 10.1038/s41586-024-07837-8  (About DOIs).

Webb directly images giant exoplanet that isn’t where it should be Read More »

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Woman who went on the lam with untreated TB is now cured

antibiotics, infectious diseases, Science, Tacoma-Pierce County Health Department, tb, Tuberculosis, Washington / /

happy ending —

The woman realized how serious her infection was once she was in custody.

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Scanning electron micrograph of <em>Mycobacterium tuberculosis</em> bacteria, which cause TB.” src=”https://cdn.arstechnica.net/wp-content/uploads/2015/03/5149398678_97948614ea_o-514×640.jpg”></img><figcaption> <p>Scanning electron micrograph of <em>Mycobacterium tuberculosis</em> bacteria, which cause TB.</p> </figcaption></figure> <p>“She’s cured!”</p> <p>Health officials in Washington state are celebrating the clean bill of health for one particularly notable resident: the woman <a href=who refused to isolate and get treatment for her active case of infectious tuberculosis for over a year. She even spent around three months on the lam, dodging police as they tried to execute a civil arrest warrant. During her time as a fugitive, police memorably reported that she took a city bus to go to a casino.

The woman, identified only as V.N. in court documents, had court orders to get treatment for her tuberculosis infection beginning in January of 2022. She refused to comply as the court renewed the orders on a monthly basis and held at least 17 hearings on the matter. The judge in her case issued an arrest warrant in March of 2023, but V.N. evaded law enforcement. She was finally arrested in June of last year and spent 23 days getting court-ordered treatment behind bars before being released with conditions.

This week, James Miller, a health officer for Washington’s Tacoma-Pierce County, where V.N. resides, announced the happy ending.

“The woman cooperated with Pierce County Superior Court’s orders and our disease investigators. She’s tested negative for tuberculosis (also called TB) multiple times. She gained back weight she’d lost and is healthy again,” Miller reported. He noted that V.N. and her family gave the county permission to share the news and said they are now happy she received the treatment she needed.

Amid the legal attempts to get V.N. treated, the health department noted in court documents that V.N. had been in a car accident in January 2023, after which she had gone to an emergency department complaining of chest pain. Doctors there—who did not know she had an active case of tuberculosis—took X-rays of her lungs. The images revealed that her lungs were in such bad shape that the doctors thought she had cancer. In fact, the images revealed that her tuberculosis case was worsening.

Risky infection

Tuberculosis is a potentially life-threatening bacterial infection caused by Mycobacterium tuberculosis, which mostly infects the lungs but can invade other areas of the body as well. The bacteria spread through the air when an infected person coughs, sneezes, spits, or otherwise launches bacterial cells into the air around them. Although transmission mostly occurs from close, prolonged contact, inhaling only a few of the microscopic germs is enough to spark an infection. According to the World Health Organization, tuberculosis killed 1.3 million people in 2022 and infected an estimated 10.6 million. Worldwide, it was the second leading infectious killer after COVID-19 that year.

Treatment for tuberculosis requires lengthy antibiotic regimens, which are typically taken for four to nine months. Drug-resistant infections require second-line, more toxic drugs. In the past, treatment for multi-drug resistant tuberculosis could last up to 20 months, but newer clinical guidances prioritize shorter regimens.

Given the risks to herself and those around her, county health officials did all they could to get V.N. treated. “Seeking a court order is our last resort after we exhaust all other options,” Miller said. “It’s a difficult process that takes a lot of time and coordination with other agencies.”

But according to Miller, V.N. softened to the idea of being treated once she was in custody and county disease investigators worked to gain her trust. “At that point, she realized how serious her situation was and decided to treat her illness,” he said. With treatment, she “regained her health over time.”

“She is now cured, which means that tuberculosis no longer poses a risk to her health,” he concluded. “This also means she is no longer at risk of infecting others.”

Woman who went on the lam with untreated TB is now cured Read More »

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Appeals Court denies stay to states trying to block EPA’s carbon limits

carbon capture, carbon emissions, clean air act, EPA, lawsuit, Policy, Science / /

You can’t stay here —

The EPA’s plan to cut carbon emissions from power plants can go ahead.

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Cooling towers emitting steam, viewed from above.

On Friday, the US Court of Appeals for the DC Circuit denied a request to put a hold on recently formulated rules that would limit carbon emissions made by fossil fuel power plants. The request, made as part of a case that sees 25 states squaring off against the EPA, would have put the federal government’s plan on hold while the case continued. Instead, the EPA will be allowed to continue the process of putting its rules into effect, and the larger case will be heard under an accelerated schedule.

Here we go again

The EPA’s efforts to regulate carbon emissions from power plants go back all the way to the second Bush administration, when a group of states successfully sued the EPA to force it to regulate greenhouse gas emissions. This led to a formal endangerment finding regarding greenhouse gases during the Obama administration, something that remained unchallenged even during Donald Trump’s term in office.

Obama tried to regulate emissions through the Clean Power Plan, but his second term came to an end before this plan had cleared court hurdles, allowing the Trump administration to formulate a replacement that did far less than the Clean Power Plan. This took place against a backdrop of accelerated displacement of coal by natural gas and renewables that had already surpassed the changes envisioned under the Clean Power Plan.

In any case, the Trump plan was thrown out by the courts on the day before Biden’s administration, allowing his EPA to start with a clean slate. Biden’s original plan, which would have had states regulate emissions from their electric grids by regulating them as a single system, was thrown out by the Supreme Court, which ruled that emissions would need to be regulated on a per-plant basis in a decision termed West Virginia v. EPA.

So, that’s what the agency is now trying to do. Its plan, issued last year, would allow fossil-fuel-burning plants that are being shut down in the early 2030s to continue operating without restrictions. Others will need to either install carbon capture equipment, or natural gas plants could swap in green hydrogen as their primary fuel.

And again

In response, 25 states have sued to block the rule (you can check out this filing to see if yours is among them). The states also sought a stay that would prevent the rule from being implemented while the case went forward. In it, they argue that carbon capture technology isn’t mature enough to form the basis of these regulations (something we predicted was likely to be a point of contention). The suit also suggests that the rules would effectively put coal out of business, something that’s beyond the EPA’s remit.

The DC Court of Appeals, however, was not impressed, ruling that the states’ arguments regarding carbon capture are insufficient: “Petitioners have not shown they are likely to succeed on those claims given the record in this case.” And that’s the key hurdle for determining whether a stay is justified. And the regulations don’t pose a likelihood of irreparable harm, as the court notes that states aren’t even expected to submit a plan for at least two years, and the regulations won’t kick in until 2030 at the earliest.

Meanwhile, the states cited the Supreme Court’s West Virginia v. EPA decision to argue against these rules, suggesting they represent a “major question” that requires input from Congress. The Court was also not impressed, writing that “EPA has claimed only the power to ‘set emissions limits under Section 111 based on the application of measures that would reduce pollution by causing the regulated source to operate more cleanly,’ a type of conduct that falls well within EPA’s bailiwick.”

To respond to the states’ concerns about the potential for irreparable harm, the court plans to consider them during the 2024 term and has given the parties just two weeks to submit proposed schedules for briefings on the case.

Appeals Court denies stay to states trying to block EPA’s carbon limits Read More »

spacex-just-stomped-the-competition-for-a-new-contract—that’s-not-great

SpaceX just stomped the competition for a new contract—that’s not great

Features, fixed price, NASA, northrop, Science, Space, spacex / /
A rocket sits on a launch pad during a purple- and gold-streaked dawn.

Enlarge / With Dragon and Falcon, SpaceX has become an essential contractor for NASA.

SpaceX

There is an emerging truth about NASA’s push toward commercial contracts that is increasingly difficult to escape: Companies not named SpaceX are struggling with NASA’s approach of awarding firm, fixed-price contracts for space services.

This belief is underscored by the recent award of an $843 million contract to SpaceX for a heavily modified Dragon spacecraft that will be used to deorbit the International Space Station by 2030.

The recently released source selection statement for the “US Deorbit Vehicle” contract, a process led by NASA head of space operations Ken Bowersox, reveals that the competition was a total stomp. SpaceX faced just a single serious competitor in this process, Northrop Grumman. And in all three categories—price, mission suitability, and past performance—SpaceX significantly outclassed Northrop.

Although it’s wonderful that NASA has an excellent contractor in SpaceX, it’s not healthy in the long term that there are so few credible competitors. Moreover, a careful reading of the source selection statement reveals that NASA had to really work to get a competition at all.

“I was really happy that we got proposals from the companies that we did,” Bowersox said during a media teleconference last week. “The companies that sent us proposals are both great companies, and it was awesome to see that interest. I would have expected a few more [proposals], honestly, but I was very happy to get the ones that we got.”

Commercial initiatives struggling

NASA’s push into “commercial” space began nearly two decades ago with a program to deliver cargo to the International Space Station. The space agency initially selected SpaceX and Rocketplane Kistler to develop rockets and spacecraft to accomplish this, but after Kistler missed milestones, the company was subsequently replaced by Orbital Sciences Corporation. The cargo delivery program was largely successful, resulting in the Cargo Dragon (SpaceX) and Cygnus (Orbital Sciences) spacecraft. It continues to this day.

A commercial approach generally means that NASA pays a “fixed” price for a service rather than paying a contractor’s costs plus a fee. It also means that NASA hopes to become one of many customers. The idea is that, as the first mover, NASA is helping to stimulate a market by which its fixed-priced contractors can also sell their services to other entities—both private companies and other space agencies.

NASA has since extended this commercial approach to crew, with SpaceX and Boeing winning large contracts in 2014. However, only SpaceX has flown operational astronaut missions, while Boeing remains in the development and test phase, with its ongoing Crew Flight Test. Whereas SpaceX has sold half a dozen private crewed missions on Dragon, Boeing has yet to announce any.

Such a commercial approach has also been tried with lunar cargo delivery through the “Commercial Lunar Payload Services” program, as well as larger lunar landers (Human Landing System), next-generation spacesuits, and commercial space stations. Each of these programs has a mixed record at best. For example, NASA’s inspector general was highly critical of the lunar cargo program in a recent report, and one of the two spacesuit contractors, Collins Aerospace, recently dropped out because it could not execute on its fixed-price contract.

Some of NASA’s most important traditional space contractors, including Lockheed Martin, Boeing, and Northrop Grumman, have all said they are reconsidering whether to participate in fixed-price contract competitions in the future. For example, Northrop CEO Kathy Warden said last August, “We are being even more disciplined moving forward in ensuring that we work with the government to have the appropriate use of fixed-price contracts.”

So the large traditional space contractors don’t like fixed-price contracts, and many new space companies are struggling to survive in this environment.

SpaceX just stomped the competition for a new contract—that’s not great Read More »