Science

NASA chief to scientists on budget cuts: “I feel your pain”

bill nelson, NASA, Science, Space / Shannon Garcia / August 13, 2024

Nelson as Senator Administrator —

“I can’t go and print the dollars.”

Eric Berger – Aug 13, 2024 9: 32 pm UTC

Photo of Bill Nelson. — Enlarge / Administrator Bill Nelson delivering remarks and answering questions from the media at the OFT-2 prelaunch press conference.

Trevor Mahlmann

Ars Technica recently had the opportunity to speak with NASA Administrator Bill Nelson, who has now led the US space agency for more than three years. We spoke about budget issues, Artemis Program timelines, and NASA’s role as a soft power in global diplomacy. What follows is a very lightly edited transcript of the conversation between Senior Space Editor Eric Berger and Nelson.

Ars Technica: I wanted to start with NASA’s budget for next year. We’ve now seen the numbers from the House of Senate, and NASA is once again facing some cuts. And I’m just wondering, what are your big concerns as we get into the final budgeting process this fall?

Administrator Bill Nelson: Well, the big concern is that you can’t put 10 pounds of potatoes in a five-pound sack. When you get cut $4.7 billion over two years, and when $2 billion of that over two years is just in science, then you have to start making some hard choices. Now, I understand the reasons for the cuts. Had I still been a member of the Senate I would’ve voted for it simply because they were held hostage by a small group in the House to get what they wanted. Which was reduced appropriations in order to raise the artificial, statutory budget debt ceiling in order for the government not to go into default. That’s part of the legislative process. It’s part of the compromises that go on. It happened over a year ago, and it was called the Fiscal Responsibility Act. The price for doing that wasn’t cuts across the entire budget. Remember, two-thirds of the budget is entitlement programs like Social Security and Medicare, and it certainly wasn’t in defense. So, all the cuts came out of everything left over, including NASA. I’m hoping that we’re going to get a reprieve come fiscal year ’26 when we will not be in the budgetary constraints of the Fiscal Responsibility Act. But who knows? Because lo and behold, they’ve got another artificial debt ceiling they’re going to have to raise next January.

Ars: What would you say to scientists who are concerned about Chandra, the cancellation of Viper, and Mars Sample Return, who see the budget for Artemis Program holding steady or even going up? It seems to me those of us who lived through Constellation saw this unfolding 15 to 20 years ago. Is the same thing happening with Artemis, is science being cannibalized to pay for human exploration?

Nelson: My response to the scientists is, I feel your pain. But, when I am faced with $2 billion of cuts over two years just in Science, I can’t go and print the dollars. And so, we have to make hard choices. Now, let’s go through those ones that you mentioned. Mars Sample Return. This was getting way out of control. It was going up to $11 billion, and we weren’t even going to get a sample return until 2040. And that’s the decade that when we’re going to land astronauts on Mars. So, something had to be done.

I convinced the budget director, Shalanda Young (director of the US Office of Management and Budget), and she was a partner in this, that we need to get those samples back. And so we pulled the plug on it. We said, “We’re going to start over, and we’re going to go out to all the NASA centers and to private industry, and we’re going to solicit and give some incentive money for their studies. And those studies will come back in, and by the end of the year, we will make a decision.” I’m hopeful that we are going to find such creativity and fiscal discipline that we’re going to end up with a much cheaper Mars sample return that will come back in the mid-30s, instead of all the way to 2040. So, if that’s what happens, and every indication I get is we’re getting some really creative proposals, if that’s what happens, then it’s a win-win. It’s a win for the taxpayer clearly. It’s a win for NASA because we didn’t have the money to spend $11 billion on it.

So, that’s one example. Another one that you used is Viper. Viper was running 40 percent over budget. Now, there comes a limit, and when you have to take a $2 billion hit just to science, you have to make tough choices. And so, that decision was made. We’re still getting (to the Moon) with Intuitive Machines at the end of the year. We are getting a lander that is going to drill to see if there is water underneath the surface. Understand that Viper was a much bigger rover, and it was going to rove around, but it was also 40 percent over budget. And so, these are the choices that you have to make.

You mentioned Chandra. By the way, I think we’ve worked Chandra out. Although it’s not going to have the funding way up there at the top funding. What we have worked out is, we are going to from what we requested, which was $41 million, it’s going to be some amount in excess of that. Although there will be some layoffs, not nearly as many, and all of the science will be protected. There will not be any diminution of the science.

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Researchers figure out how to keep clocks on the Earth, Moon in sync

Science / Kelly Newman / August 13, 2024

Does anyone really know what time it is? —

A single standardized Earth/Moon time would aid communications, enable lunar GPS.

John Timmer – Aug 13, 2024 8: 28 pm UTC

Image of a full Moon behind a dark forest of fir trees. — Enlarge / Without adjustments for relativity, clocks here and on the Moon would rapidly diverge.

Timing is everything these days. Our communications and GPS networks all depend on keeping careful track of the precise timing of signals—including accounting for the effects of relativity. The deeper into a gravitational well you go, the slower time moves, and we’ve reached the point where we can detect differences in altitude of a single millimeter. Time literally flows faster at the altitude where GPS satellites are than it does for clocks situated on Earth’s surface. Complicating matters further, those satellites are moving at high velocities, an effect that slows things down.

It’s relatively easy to account for that on the Earth, where we’re dealing with a single set of adjustments that can be programmed into electronics that need to keep track of these things. But plans are in place to send a large array of hardware to the Moon, which has a considerably lower gravitational field (faster clocks!), which means that objects can stay in orbit despite moving more slowly (also faster clocks!).

It would be easy to set up an equivalent system to track time on the Moon, but that would inevitably see the clocks run out of sync with those on Earth—a serious problem for things like scientific observations. So, the International Astronomical Union has a resolution that calls for a “Lunar Celestial Reference System” and “Lunar Coordinate Time” to handle things there. On Monday, two researchers at the National institute of Standards and Technology, Neil Ashby and Bijunath Patla, did the math to show how this might work.

Keeping time

We’re getting ready to explore the Moon. If everything goes to plan, China and a US-led consortium will be sending multiple uncrewed missions, potentially leading to a permanent human presence. We’ll have an increasing set of hardware, and eventually facilities on the lunar surface. Tracking just a handful of items at once was sufficient for the Apollo missions, but future missions may need to land at precise locations, and possibly move among them. That makes the equivalent of a lunar GPS valuable, as NIST notes in its press release announcing the work.

All that could potentially be handled by an independent lunar positioning system, if we’re willing to accept it marching to its own temporal beat. But that will become a problem if we’re ultimately going to do things like perform astronomy from the Moon, as the precise timing of events will be critical. Allowing for two separate systems would also mean switching all the timekeeping systems on board craft as they travel between the two.

The theory behind how to handle creating a single system has all been worked out. But the practicality of doing so has been left as an exercise for future researchers. But, apparently, the future is now.

Ashby and Patla worked on developing a system where anything can be calculated in reference to the center of mass of the Earth/Moon system. Or, as they put it in the paper, their mathematical system “enables us to compare clock rates on the Moon and cislunar Lagrange points with respect to clocks on Earth by using a metric appropriate for a locally freely falling frame such as the center of mass of the Earth–Moon system in the Sun’s gravitational field.”

What does this look like? Well, a lot of deriving equations. The paper’s body has 55 of them, and there are another 67 in the appendices. So, a lot of the paper ends up looking like this.

Enlarge / A typical section of the paper describing how the new system was put together.

Ashby and Patla, 2024

Things get complicated because there are so many factors to consider. There are tidal effects from the Sun and other planets. Anything on the surface of the Earth or Moon is moving due to rotation; other objects are moving while in orbit. The gravitational influence on time will depend on where an object is located. So, there’s a lot to keep track of.

Future proof

Ashby and Patla don’t have to take everything into account in all circumstances. Some of these factors are so small they’ll only be detectable with an extremely high-precision clock. Others tend to cancel each other out. Still, using their system, they’re able to calculate that an object near the surface of the Moon will pick up an extra 56 microseconds every day, which is a problem in situations where we may be relying on measuring time with nanosecond precision.

And the researchers say that their approach, while focused on the Earth/Moon system, is still generalizable. Which means that it should be possible to modify it and create a frame of reference that would work on both Earth and anywhere else in the Solar System. Which, given the pace at which we’ve sent things beyond low-Earth orbit, is probably a healthy amount of future-proofing.

The Astronomical Journal, 2024. DOI: 10.3847/1538-3881/ad643a (About DOIs).

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Why cricket’s latest bowling technique is so effective against batters

aerodynamics, cricket game, fluid dynamics, Magnus effect, Physics, Science, sports science / Mike M. / August 13, 2024

Enlarge / Some cricket bowlers favor keeping the arm horizontal during delivery, the better to trick the batsmen.

Although the sport of cricket has been around for centuries in some form, the game strategy continues to evolve in the 21st century. Among the newer strategies employed by “bowlers”—the equivalent of the pitcher in baseball—is delivering the ball with the arm horizontally positioned close to the shoulder line, which has proven remarkably effective in “tricking” batsmen in their perception of the ball’s trajectory.

Scientists at Amity University Dubai in the United Arab Emirates were curious about the effectiveness of the approach, so they tested the aerodynamics of cricket balls in wind tunnel experiments. The team concluded that this style of bowling creates a high-speed spinning effect that shifts the ball’s trajectory mid-flight—an effect also seen in certain baseball pitches, according to a new paper published in the journal Physics of Fluids.

“The unique and unorthodox bowling styles demonstrated by cricketers have drawn significant attention, particularly emphasizing their proficiency with a new ball in early stages of a match,” said co-author Kizhakkelan Sudhakaran Siddharth, a mechanical engineer at Amity University Dubai. “Their bowling techniques frequently deceive batsmen, rendering these bowlers effective throughout all phases of a match in almost all formats of the game.”

As previously reported, any moving ball leaves a trail of air as it travels; the inevitable drag slows the ball down. The ball’s trajectory is affected by diameter and speed and by tiny irregularities on the surface. Baseballs, for example, are not completely smooth; they have stitching in a figure-eight pattern. Those stitches are bumpy enough to affect the airflow around the baseball as it’s thrown toward home plate. As a baseball moves, it creates a whirlpool of air around it, commonly known as the Magnus effect. The raised seams churn the air around the ball, creating high-pressure zones in various locations (depending on the pitch type) that can cause deviations in its trajectory.

Physicists have been enthusiastically studying baseballs since the 1940s, when Lyman Briggs became intrigued by whether a curveball actually curves. Initially, he enlisted the aid of the Washington Senators pitching staff at Griffith Stadium to measure the spin of a pitched ball; the idea was to determine how much the curve of a baseball depends on its spin and speed.

Briggs followed up with wind tunnel experiments at the National Bureau of Standards (now the National Institute of Standards and Technology) to make even more precise measurements since he could control most variables. He found that spin rather than speed was the key factor in causing a pitched ball to curve and that a curveball could dip up to 17.5 inches as it travels from the pitcher’s mound to home plate.

Enlarge / The first recorded photo of a cricket match taken on July 25, 1857, by Roger Fenton.

Public domain

In 2018, we reported on a Utah State University study to explain the fastball’s unexpected twist in experiments using Little League baseballs. The USU scientists fired the balls one by one through a smoke-filled chamber. Two red sensors detected the balls as they zoomed past, triggering lasers that acted as flashbulbs. They then used particle image velocimetry to calculate airflow at any given spot around the ball. Conclusion: It all comes down to spin speed, spin axis, and the orientation of the ball, and there is no meaningful aerodynamical difference between a two-seam fastball and a four-seam fastball.

In 2022, two physicists developed a laser-guided speed measurement system to measure the change in speed of a baseball mid-flight and then used that measurement to calculate the acceleration, the various forces acting on the ball, and the lift and drag. They suggested their approach could also be used for other ball sports like cricket and soccer.

Enlarge / The Armfield C15-15 Wake Survey Rake measured pressure downstream of the ball.

A.B. Faazil et al., 2024

Similarly, golf ball dimples reduce the drag flow by creating a turbulent boundary layer of air, while the ball’s spin generates lift by creating a higher air pressure area on the bottom of the ball than on the top. The surface patterns on volleyballs can also affect their trajectories. Conventional volleyballs have six panels, but more recent designs have eight panels, a hexagonal honeycomb pattern, or dimples. A 2019 study found that the surface panels on conventional volleyballs can give rise to unpredictable trajectories on float serves (which have no spin), and modifying the surface patterns could make for a more consistent flight.

From a physics standpoint, the float serve is similar to throwing a knuckleball in baseball, which is largely unaffected by the Magnus force because it has no spin. Its trajectory is determined entirely by how the seams affect the turbulent airflow around the baseball. The seams of a baseball can change the speed (velocity) of the air near the ball’s surface, speeding the ball up or slowing it down, depending on whether said seams are on the top or the bottom. The panels on conventional volleyballs have a similar effect.

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I trust NASA’s safety culture this time around, and so should you

Science, Space / DJ Henderson / August 12, 2024

Through a cloud-washed blue sky above Launch Pad 39A, Space Shuttle <em>Columbia</em> hurtles toward space on mission STS-107. ” src=”https://cdn.arstechnica.net/wp-content/uploads/2016/01/16271647815_f0b8187e11_o-640×474.jpg”></img><figcaption>
<p>Through a cloud-washed blue sky above Launch Pad 39A, Space Shuttle <em>Columbia</em> hurtles toward space on mission STS-107. </p>
<p>NASA</p>
</figcaption></figure>
<p>My first real taste of space journalism came on the morning of February 1, 2003. An editor at the Houston Chronicle telephoned me at home on a Saturday morning and asked me to hurry to Johnson Space Center to help cover the loss of Space Shuttle <em>Columbia</em>.</p>
<p>At the time, I did not realize this tragedy would set the course for the rest of my professional life, that of thinking and writing about spaceflight. This would become the consuming passion of my career.</p>
<p>I’ve naturally been thinking a lot about <em>Columbia</em> in recent weeks. While the parallels between that Space Shuttle mission and the first crewed flight of Boeing’s Starliner spacecraft are not exact, there are similarities. Most significantly, after the Space Shuttle launched, there were questions about the safety of the vehicle’s return home due to foam striking the leading edge of the spacecraft’s wing.</p>
<p>Two decades later, there are many more questions, both in public and private, about the viability of Starliner’s propulsion system after irregularities during the vehicle’s flight to the space station in June. NASA officials made the wrong decision during the <em>Columbia</em> accident. So, facing another <a href=

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NASA is about to make its most important safety decision in nearly a generation

Boeing, commercial crew, Features, human spaceflight, NASA, Science, Space, starliner / Shannon Garcia / August 12, 2024

Boeing's Starliner spacecraft, seen docked at the International Space Station through the window of a SpaceX Dragon spacecraft. — Enlarge / Boeing’s Starliner spacecraft, seen docked at the International Space Station through the window of a SpaceX Dragon spacecraft.

As soon as this week, NASA officials will make perhaps the agency’s most consequential safety decision in human spaceflight in 21 years.

NASA astronauts Butch Wilmore and Suni Williams are nearly 10 weeks into a test flight that was originally set to last a little more than one week. The two retired US Navy test pilots were the first people to fly into orbit on Boeing’s Starliner spacecraft when it launched on June 5. Now, NASA officials aren’t sure Starliner is safe enough to bring the astronauts home.

Three of the managers at the center of the pending decision, Ken Bowersox and Steve Stich from NASA and Boeing’s LeRoy Cain, either had key roles in the ill-fated final flight of Space Shuttle Columbia in 2003 or felt the consequences of the accident.

At that time, officials misjudged the risk. Seven astronauts died, and the Space Shuttle Columbia was destroyed as it reentered the atmosphere over Texas. Bowersox, Stich, and Cain weren’t the people making the call on the health of Columbia‘s heat shield in 2003, but they had front-row seats to the consequences.

Bowersox was an astronaut on the International Space Station when NASA lost Columbia. He and his crewmates were waiting to hitch a ride home on the next Space Shuttle mission, which was delayed two-and-a-half years in the wake of the Columbia accident. Instead, Bowersox’s crew came back to Earth later that year on a Russian Soyuz capsule. After retiring from the astronaut corps, Bowersox worked at SpaceX and is now the head of NASA’s spaceflight operations directorate.

Stich and Cain were NASA flight directors in 2003, and they remain well-respected in human spaceflight circles. Stich is now the manager of NASA’s commercial crew program, and Cain is now a Boeing employee and chair of the company’s Starliner mission director. For the ongoing Starliner mission, Bowersox, Stich, and Cain are in the decision-making chain.

All three joined NASA in the late 1980s, soon after the Challenger accident. They have seen NASA attempt to reshape its safety culture after both of NASA’s fatal Space Shuttle tragedies. After Challenger, NASA’s astronaut office had a more central role in safety decisions, and the agency made efforts to listen to dissent from engineers. Still, human flaws are inescapable, and NASA’s culture was unable to alleviate them during Columbia‘s last flight in 2003.

NASA knew launching a Space Shuttle in cold weather reduced the safety margin on its solid rocket boosters, which led to the Challenger accident. And shuttle managers knew foam routinely fell off the external fuel tank. In a near-miss, one of these foam fragments hit a shuttle booster but didn’t damage it, just two flights prior to Columbia‘s STS-107 mission.

“I have wondered if some in management roles today that were here when we lost Challenger and Columbia remember that in both of those tragedies, there were those that were not comfortable proceeding,” Milt Heflin, a retired NASA flight director who spent 47 years at the agency, wrote in an email to Ars. “Today, those memories are still around.”

“I suspect Stich and Cain are paying attention to the right stuff,” Heflin wrote.

The question facing NASA’s leadership today? Should the two astronauts return to Earth from the International Space Station in Boeing’s Starliner spacecraft, with its history of thruster failures and helium leaks, or should they come home on a SpaceX Dragon capsule?

Under normal conditions, the first option is the choice everyone at NASA would like to make. It would be least disruptive to operations at the space station and would potentially maintain a clearer future for Boeing’s Starliner program, which NASA would like to become operational for regular crew rotation flights to the station.

But some people at NASA aren’t convinced this is the right call. Engineers still don’t fully understand why five of the Starliner spacecraft’s thrusters overheated and lost power as the capsule approached the space station for docking in June. Four of these five control jets are now back in action with near-normal performance, but managers would like to be sure the same thrusters—and maybe more—won’t fail again as Starliner departs the station and heads for reentry.

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520-million-year-old larva fossil reveals the origins of arthropods

Archeology, arthropods, Biology, evolution, Science / DJ Henderson / August 11, 2024

Loads of lobopods —

Early arthropod development illuminated by a microscopic fossil.

Elizabeth Rayne – Aug 11, 2024 11: 30 am UTC

Image of a small grey object, curved around its abdomen, with a series of small appendages on the bottom. — Enlarge / The fossil in question, oriented with its head to the left.

Yang Jie / Zhang Xiguang

Around half a billion years ago, in what is now the Yunnan Province of China, a tiny larva was trapped in mud. Hundreds of millions of years later, after the mud had long since become the black shales of the Yuan’shan formation, the larva surfaced again, a meticulously preserved time capsule that would unearth more about the evolution of arthropods.

Youti yuanshi is barely visible to the naked eye. Roughly the size of a poppy seed, it is preserved so well that its exoskeleton is almost completely intact, and even the outlines of what were once its internal organs can be seen through the lens of a microscope. Durham University researchers who examined it were able to see features of both ancient and modern arthropods. Some of these features told them how the simpler, more wormlike ancestors of living arthropods evolved into more complex organisms.

The research team also found that Y. yuanshi, which existed during the Cambrian Explosion (when most of the main animal groups started to appear on the fossil record), has certain features in common with extant arthropods, such as crabs, velvet worms, and tardigrades. “The deep evolutionary position of Youti yuanshi… illuminat[es] the internal anatomical changes that propelled the rise and diversification of [arthropods],” they said in a study recently published in Nature.

Inside out and outside in

While many fossils preserved in muddy environments like the Yuan’shan formation are flattened by compression, Y. yuanshi remained three-dimensional, making it easier to examine. So what exactly did this larva look like on the outside and inside?

The research team could immediately tell that Y. yuanshi was a lobopodian. Lobopodians are a group of extinct arthropods with long bodies and stubby legs, or lobopods. There is a pair of lobopods in the middle of each of its twenty segments, and these segments also get progressively shorter from the front to back of the body. Though soft tissue was not preserved, spherical outlines suggest an eye on each side of the head, though whether these were compound eyes is unknown. This creature had a stomodeum—the precursor to a mouth—but no anus. It would have had to both take in food and dispose of waste through its mouth.

Youti yuanshi has a cavity, known as the perivisceral cavity, that surrounds the outline of a tube that is thought to have once been the gut. The creature’s gut ends without an opening, which explains its lack of an anus. Inside each segment, there is a pair of voids toward the middle. The researchers think these are evidence of digestive glands, especially after comparing them to digestive glands in the fossils of other arthropods from the same era.

A ring around the mouth of the larva was once a circumoral nerve ring, which connected with nerves that extend to eyes and appendages in the first segment. Inside its head is a void that contained the brain. The shape of this empty chamber gives some insight into how the brain was structured. From what the researchers could see, the brain of Y. yuanshi had wedge-shaped frontal portion, and the rest of the brain was divided into two sections, as evidenced by the outline of a membrane in between them.

Way, way, way back then and now

Given its physical characteristics, the researchers think that Y. yuanshi displays features of both extinct and extant arthropods. Some are ancestral characteristics present in all arthropods, living and extinct. Others are ancestral characteristics that may have been present in extinct arthropods but are only present in some living arthropods.

Among the features present in all arthropods today is the protocerebrum; its evolutionary precursor was the circumoral nerve ring present in Y. yuanshi. The protocerebrum is the first segment of the arthropod brain, which controls the eyes and appendages, such as antennae in velvet worms and the mouthparts in tardigrades. Another feature of Y. yuanshi present in extant and extinct arthropods is its circulatory system, which is similar to that of modern arthropods, especially crustaceans.

Lobopods are a morphological feature of Y. yuanshi that are now found only in some arthropods—tardigrades and velvet worms. Many more species of lobopodians existed during the Cambrian. The lobopodians also had a distinctively structured circulatory system in their legs and other appendages, which is closest to that of velvet worms.

“The architecture of the nervous system informs the early configuration of the [arthropod] brain and its associated appendages and sensory organs, clarifying homologies across [arthropods],” the researchers said in the same study.

Yuti yuanshi is still holding on to some mysteries. They mostly have to do with the fact that it is a larva—what it looked like as an adult can only be guessed at, and it’s possible that this species developed compound eyes or flaps for swimming by the time it reached adulthood. Whether it is the larva of an already-known species of extinct lobopod is an open question. Maybe the answers are buried somewhere in the Yuan’shan shale.

Nature, 2024. DOI: 10.1038/s41586-024-07756-8

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China’s Long March 6A rocket is making a mess in low-Earth orbit

broadband, china, long march 6a, military space, Science, Space, space command, telecom / Mike M. / August 10, 2024

Another one —

After nearly every flight, the upper stage of this rocket breaks apart in orbit.

Stephen Clark – Aug 9, 2024 12: 41 pm UTC

Debris from the upper stage of China's Long March 6A rocket captured from the ground by Slingshot Aerospace. — Enlarge / Debris from the upper stage of China’s Long March 6A rocket captured from the ground by Slingshot Aerospace.

The upper stage from a Chinese rocket that launched a batch of Internet satellites Tuesday has broken apart in space, creating a debris field of at least 700 objects in one of the most heavily-trafficked zones in low-Earth orbit.

US Space Command, which tracks objects in orbit with a network of radars and optical sensors, confirmed the rocket breakup Thursday. Space Command initially said the event created more than 300 pieces of trackable debris. The military’s ground-based radars are capable of tracking objects larger than 10 centimeters (4 inches).

Later Thursday, LeoLabs, a commercial space situational awareness company, said its radars detected at least 700 objects attributed to the Chinese rocket. The number of debris fragments could rise to more than 900, LeoLabs said.

The culprit is the second stage of China’s Long March 6A rocket, which lifted off Tuesday with the first batch of 18 satellites for a planned Chinese megaconstellation that could eventually number thousands of spacecraft. The Long March 6A’s second stage apparently disintegrated after placing its payload of 18 satellites into a polar orbit.

Space Command said in a statement it has “observed no immediate threats” and “continues to conduct routine conjunction assessments to support the safety and sustainability of the space domain.” According to LeoLabs, radar data indicated the rocket broke apart at an altitude of 503 miles (810 kilometers) at approximately 4: 10 pm EDT (20: 10 UTC) on Tuesday, around 13-and-a-half hours after it lifted off from northern China.

At this altitude, it will take decades or centuries for the wispy effect of aerodynamic drag to pull the debris back into the atmosphere. As the objects drift lower, their orbits will cross paths with SpaceX’s Starlink Internet satellites, the International Space Station and other crew spacecraft, and thousands more pieces of orbital debris, putting commercial and government satellites at risk of collision.

A new debris field of nearly 1,000 objects would be a significant addition to the approximately 46,000 objects Space Command tracks in Earth orbit. According to statistics compiled by Jonathan McDowell, an astrophysicist who monitors global launch and spaceflight activity, this would rank in the top five of all debris-generation events since the dawn of the Space Age.

This rocket has a track record

The medium-class Long March 6A rocket has launched seven times since debuting in March 2022, and military and commercial satellite tracking organizations have reported several breakups of the rocket’s upper stage. In November 2022, a Long March 6A upper stage disintegrated in orbit, creating a debris field of more than 500 trackable objects, according to NASA’s Orbital Debris Program Office.

Commercial satellite tracking companies observed smaller debris fields following several other Long March 6A flights this year.

In its space environment statistics report, the European Space Agency says there have been more than 640 “breakups, explosions, collisions, or anomalous events resulting in fragmentation” in orbit. So these things happen frequently. But it’s not clear what makes the Long March 6A, which has a relatively short flight history, particularly vulnerable to creating debris.

A Long March 6A rocket launches the first 18 Internet satellites for China's Qianfan, or Thousand Sails, broadband network. — Enlarge / A Long March 6A rocket launches the first 18 Internet satellites for China’s Qianfan, or Thousand Sails, broadband network.

Most rockets operating today either reignite their engines to reenter the atmosphere after deploying their payloads, or if that’s not feasible, they “passivate” themselves to empty their propellant tanks and drain their batteries to reduce the risk of an explosion.

In a report last year, NASA’s Orbital Debris Program Office said the Long March 6A upper stage has a mass of about 5,800 kilograms (12,800 pounds) without kerosene and liquid oxygen propellants. It is powered by a single YF-115 engine.

The launch Tuesday began the deployment of China’s “Thousand Sails” Internet network, which will initially consist of 1,296 satellites, with the possibility to expand to more than 14,000 spacecraft. This will require numerous launches, some of which will presumably use the Long March 6A.

“If even a fraction of the launches needed to field this Chinese megaconstellation generate as much debris as this first launch, the result would be a notable addition to the space debris population in LEO (low-Earth orbit),” said Audrey Schaffer, vice president of strategy and policy at Slingshot Aerospace, a commercial satellite tracking and analytics firm.

China has been responsible for several space debris incidents beyond the latest problems with the Long March 6A rocket. In 2007, China destroyed one of its own spacecraft in an anti-satellite missile test. This was the worst-ever instance of creating space debris, resulting in more than 3,000 trackable objects, and an estimate 150,000 or more smaller fragments.

On four occasions from 2020 through 2022, the massive core stage of China’s heavy-lift Long March 5B rocket has reentered the atmosphere in an uncontrolled manner, raising concerns that falling debris could put people and property at risk on Earth.

China plans more flights with its Long March 5B and Long March 6A rockets. China continued flying the Long March 5B rocket despite the risk it posed to people on the ground. Debris fields in orbit, however, don’t directly threaten any people on Earth, but they do raise the risk to satellites of all nations, including China’s own spacecraft.

“Events like this highlight the importance of adherence to existing space debris mitigation guidelines to reduce the creation of new space debris and underscore the need for robust space domain awareness capabilities to rapidly detect, track, and catalog newly-launched space objects so they can be screened for potential conjunctions,” Schaffer said in a statement.

This story was updated with the detection of additional debris fragments by LeoLabs.

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Rocket Report: Archimedes engine sees first light, New Glenn making moves

rocket report, Science, Space / Mike M. / August 10, 2024

All the news that’s fit to lift —

“Coming soon: a full recovery rehearsal with our landing vessel.”

Eric Berger – Aug 9, 2024 11: 00 am UTC

Enlarge / Rocket Lab says it fired up the Archimedes engine at full thrust this week.

Rocket Lab

Welcome to Edition 7.06 of the Rocket Report! There has been a lot of drama over the last week involving NASA, the crew of Starliner on board the International Space Station, and the launch of the Crew-9 mission on a Falcon 9 rocket. NASA is now down to a binary choice: Fly Butch Wilmore and Suni Williams home on Starliner, or send two astronauts to orbit on Crew-9, and return Wilmore and Williams next February on that spacecraft. We should know NASA’s final decision next week.

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.

Firefly inks another big Alpha contract. Firefly Aerospace said Wednesday that it has signed a multi-launch agreement with L3Harris Technologies for up to 20 launches on Firefly’s Alpha rocket, including two to four missions per year from 2027 to 2031, depending on customer needs. The new agreement is in addition to Firefly’s existing multi-launch agreement with L3Harris for three Alpha missions in 2026. What is not clear is exactly what satellites L3Harris wants to launch.

Putting skins on the wall … “Firefly continues to see growing demand for Alpha’s responsive small-lift services, and we’re committed to providing a dedicated launch option that takes our customers directly to their preferred orbits,” said Peter Schumacher, Interim CEO at Firefly Aerospace. This represents another significant win for the Alpha rocket, which can lift about 1 metric ton to low-Earth orbit. Under terms of a separate agreement announced in June, Lockheed purchased 15 launches from Firefly, with an option for 10 more, through the year 2029. (submitted by Ken the Bin and EllPeaTea)

Electron pushing launch cadence. Rocket Lab announced Wednesday that it has scheduled the launch for its 52nd Electron mission, which will deploy a single satellite for American space tech company Capella Space. The mission is scheduled to launch during a 14-day window that opens on August 11 from Rocket Lab Launch Complex 1 on New Zealand’s Mahia Peninsula.

Getting to ten much faster … Should this launch take place at the opening of this window, this Electron flight would occur just eight days after the most recent Electron mission on August 3. This upcoming mission for Capella will be Rocket Lab’s tenth mission for 2024, equaling the company’s annual launch record set in 2023. (submitted by Ken the Bin)

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PLD Space to start work on launch site. PLD Space plans to start building launch facilities for its Miura 5 rocket in October from the Diamant site at Guiana Space Centre, cofounder and Chief Business Development Officer Raúl Verdú said this week, Space News reports. Diamant has been dormant for decades after once being used for the French rocket of the same name, and “in the area where we are there is nothing,” Verdú said, “we have to do everything from scratch.”

Lots of things to build … PLD Space, Germany’s Isar Aerospace and a handful of other small European launchers are working with France’s CNES space agency to convert the site into a multi-use facility. In June, the Spanish company announced a 10 million euro ($11 million) investment plan for 15,765 square meters of space at Diamant, divided between a launch zone and a preparation area comprising an integration hangar, clean room, control center, commercial and work offices. CNES is providing common infrastructure such as roads and electricity networks. (submitted by Ken the Bin)

Japanese firm raises $21 million. Interstellar Technologies announced a new fundraising round that brings its total capital and government funding to $117 million, Payload reports. After building and launching a suborbital rocket called Momo, the company is building its first orbital rocket, dubbed ZERO, with a goal of flying in 2025. This rocket is intended to carry 800 kg of payload to low-Earth orbit, and be cheaper than Rocket Lab’s Electron, COO Keiji Atsuta said.

Big help from Japan … Interstellar’s latest round was led by Japanese VC fund SBI and NTT Docomo, the country’s leading mobile firm. Previously, it received a large amount of funding, $96 million, from the Japanese government. “The Japanese government has explicitly expressed its support for private rockets due to the growing importance of the space industry, and being selected for this support program has significantly accelerated our business,” Interstellar CEO Takahiro Inagawa said. (submitted by Ken the Bin)

Cross-border deal benefits Nova Scotia spaceport. The Canadian government says it has completed negotiations with the United States on an agreement that would allow the use of US space launch technology, expertise, and data for space launches in Canada, the AP reports. Maritime Launch Services, the company developing Canada’s first commercial spaceport in northeastern Nova Scotia, called the agreement a major step forward for the industry.

US rockets could launch from Canada … Ottawa has said it hopes to position Canada as future leader in commercial space launches. The country has geographical advantages, including a vast, sparsely populated territory and high-inclination orbits. The agreement, which is yet to be signed, will establish the legal and technical safeguards needed while ensuring the proper handling of sensitive technology, the government said in a news release. (submitted by JoeyS-IVB)

Rocket Report: Archimedes engine sees first light, New Glenn making moves Read More »

Pass the mayo: Condiment could help improve fusion energy yields

condiments, fluid dynamics, hydrodynamics, nuclear fusion, nuclear physics, phase transitions, Physics, Rayleigh-Taylor instability, Science / Mike M. / August 9, 2024

Don’t hold the mayo —

Controlling a problematic instability could lead to cheaper internal fusion.

Jennifer Ouellette – Aug 9, 2024 8: 48 pm UTC

Inertial confinement fusion is one method for generating energy through nuclear fusion, albeit one plagued by all manner of scientific challenges (although progress is being made). Researchers at LeHigh University are attempting to overcome one specific bugbear with this approach by conducting experiments with mayonnaise placed in a rotating figure-eight contraption. They described their most recent findings in a new paper published in the journal Physical Review E with an eye toward increasing energy yields from fusion.

The work builds on prior research in the LeHigh laboratory of mechanical engineer Arindam Banerjee, who focuses on investigating the dynamics of fluids and other materials in response to extremely high acceleration and centrifugal force. In this case, his team was exploring what’s known as the “instability threshold” of elastic/plastic materials. Scientists have debated whether this comes about because of initial conditions, or whether it’s the result of “more local catastrophic processes,” according to Banerjee. The question is relevant to a variety of fields, including geophysics, astrophysics, explosive welding, and yes, inertial confinement fusion.

How exactly does inertial confinement fusion work? As Chris Lee explained for Ars back in 2016:

The idea behind inertial confinement fusion is simple. To get two atoms to fuse together, you need to bring their nuclei into contact with each other. Both nuclei are positively charged, so they repel each other, which means that force is needed to convince two hydrogen nuclei to touch. In a hydrogen bomb, force is generated when a small fission bomb explodes, compressing a core of hydrogen. This fuses to create heavier elements, releasing a huge amount of energy.

Being killjoys, scientists prefer not to detonate nuclear weapons every time they want to study fusion or use it to generate electricity. Which brings us to inertial confinement fusion. In inertial confinement fusion, the hydrogen core consists of a spherical pellet of hydrogen ice inside a heavy metal casing. The casing is illuminated by powerful lasers, which burn off a large portion of the material. The reaction force from the vaporized material exploding outward causes the remaining shell to implode. The resulting shockwave compresses the center of the core of the hydrogen pellet so that it begins to fuse.

If confinement fusion ended there, the amount of energy released would be tiny. But the energy released due to the initial fusion burn in the center generates enough heat for the hydrogen on the outside of the pellet to reach the required temperature and pressure. So, in the end (at least in computer models), all of the hydrogen is consumed in a fiery death, and massive quantities of energy are released.

That’s the idea anyway. The problem is that hydrodynamic instabilities tend to form in the plasma state—Banerjee likens it to “two materials [that] penetrate one another like fingers” in the presence of gravity or any accelerating field—which in turn reduces energy yields. The technical term is a Rayleigh-Taylor instability, which occurs between two materials of different densities, where the density and pressure gradients move in opposite directions. Mayonnaise turns out to be an excellent analog for investigating this instability in accelerated solids, with no need for a lab setup with high temperature and pressure conditions, because it’s a non-Newtonian fluid.

“We use mayonnaise because it behaves like a solid, but when subjected to a pressure gradient, it starts to flow,” said Banerjee. “As with a traditional molten metal, if you put a stress on mayonnaise, it will start to deform, but if you remove the stress, it goes back to its original shape. So there’s an elastic phase followed by a stable plastic phase. The next phase is when it starts flowing, and that’s where the instability kicks in.”

More mayo, please

2019 video showcasing the rotating wheel Rayleigh Taylor instability experiment at Lehigh University.

His team’s 2019 experiments involved pouring Hellman’s Real Mayonnaise—no Miracle Whip for this crew—into a Plexiglass container and then creating wavelike perturbations in the mayo. One experiment involved placing the container on a rotating wheel in the shape of a figure eight and tracking the material with a high-speed camera, using an image processing algorithm to analyze the footage. Their results supported the claim that the instability threshold is dependent on initial conditions, namely amplitude and wavelength.

This latest paper sheds more light on the structural integrity of fusion capsules used in inertial confinement fusion, taking a closer look at the material properties, the amplitude and wavelength conditions, and the acceleration rate of such materials as they hit the Rayleigh-Taylor instability threshold. The more scientists know about the phase transition from the elastic to the stable phase, the better they can control the conditions and maintain either an elastic or plastic phase, avoiding the instability. Banerjee et al. were able to identify the conditions to maintain the elastic phase, which could inform the design of future pellets for inertial confinement fusion.

That said, the mayonnaise experiments are an analog, orders of magnitude away from the real-world conditions of nuclear fusion, which Banerjee readily acknowledges. He is nonetheless hopeful that future research will improve the predictability of just what happens within the pellets in their high-temperature, high-pressure environments. “We’re another cog in this giant wheel of researchers,” he said. “And we’re all working towards making inertial fusion cheaper and therefore, attainable.”

DOI: Physical Review E, 2024. 10.1103/PhysRevE.109.055103 (About DOIs).

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People game AIs via game theory

AI, AI training, Behavioral science, Computer science, Human behavior, Science / Kelly Newman / August 9, 2024

Games inside games —

They reject more of the AI’s offers, probably to get it to be more generous.

John Timmer – Aug 9, 2024 8: 13 pm UTC

A judge's gavel near a pile of small change. — Enlarge / In the experiments, people had to judge what constituted a fair monetary offer.

In many cases, AIs are trained on material that’s either made or curated by humans. As a result, it can become a significant challenge to keep the AI from replicating the biases of those humans and the society they belong to. And the stakes are high, given we’re using AIs to make medical and financial decisions.

But some researchers at Washington University in St. Louis have found an additional wrinkle in these challenges: The people doing the training may potentially change their behavior when they know it can influence the future choices made by an AI. And, in at least some cases, they carry the changed behaviors into situations that don’t involve AI training.

Would you like to play a game?

The work involved getting volunteers to participate in a simple form of game theory. Testers gave two participants a pot of money—$10, in this case. One of the two was then asked to offer some fraction of that money to the other, who could choose to accept or reject the offer. If the offer was rejected, nobody got any money.

From a purely rational economic perspective, people should accept anything they’re offered, since they’ll end up with more money than they would have otherwise. But in reality, people tend to reject offers that deviate too much from a 50/50 split, as they have a sense that a highly imbalanced split is unfair. Their rejection allows them to punish the person who made the unfair offer. While there are some cultural differences in terms of where the split becomes unfair, this effect has been replicated many times, including in the current work.

The twist with the new work, performed by Lauren Treimana, Chien-Ju Hoa, and Wouter Kool, is that they told some of the participants that their partner was an AI, and the results of their interactions with it would be fed back into the system to train its future performance.

This takes something that’s implicit in a purely game-theory-focused setup—that rejecting offers can help partners figure out what sorts of offers are fair—and makes it highly explicit. Participants, or at least the subset involved in the experimental group that are being told they’re training an AI, could readily infer that their actions would influence the AI’s future offers.

The question the researchers were curious about was whether this would influence the behavior of the human participants. They compared this to the behavior of a control group who just participated in the standard game theory test.

Training fairness

Treimana, Hoa, and Kool had pre-registered a number of multivariate analyses that they planned to perform with the data. But these didn’t always produce consistent results between experiments, possibly because there weren’t enough participants to tease out relatively subtle effects with any statistical confidence and possibly because the relatively large number of tests would mean that a few positive results would turn up by chance.

So, we’ll focus on the simplest question that was addressed: Did being told that you were training an AI alter someone’s behavior? This question was asked through a number of experiments that were very similar. (One of the key differences between them was whether the information regarding AI training was displayed with a camera icon, since people will sometimes change their behavior if they’re aware they’re being observed.)

The answer to the question is a clear yes: people will in fact change their behavior when they think they’re training an AI. Through a number of experiments, participants were more likely to reject unfair offers if they were told that their sessions would be used to train an AI. In a few of the experiments, they were also more likely to reject what were considered fair offers (in US populations, the rejection rate goes up dramatically once someone proposes a 70/30 split, meaning $7 goes to the person making the proposal in these experiments). The researchers suspect this is due to people being more likely to reject borderline “fair” offers such as a 60/40 split.

This happened even though rejecting any offer exacts an economic cost on the participants. And people persisted in this behavior even when they were told that they wouldn’t ever interact with the AI after training was complete, meaning they wouldn’t personally benefit from any changes in the AI’s behavior. So here, it appeared that people would make a financial sacrifice to train the AI in a way that would benefit others.

Strikingly, in two of the three experiments that did follow up testing, participants continued to reject offers at a higher rate two days after their participation in the AI training, even when they were told that their actions were no longer being used to train the AI. So, to some extent, participating in AI training seems to have caused them to train themselves to behave differently.

Obviously, this won’t affect every sort of AI training, and a lot of the work that goes into producing material that’s used in training something like a Large Language Model won’t have been done with any awareness that it might be used to train an AI. Still, there’s plenty of cases where humans do get more directly involved in training, so it’s worthwhile being aware that this is another route that can allow biases to creep in.

PNAS, 2024. DOI: 10.1073/pnas.2408731121 (About DOIs).

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“Archeology” on the ISS helps identify what astronauts really need

Archeology, Science, Space, space archeology, Space exploration, space station / Mike M. / August 9, 2024

Archeology without the dig —

Regular photography shows a tool shed and more isolated toilet would be appreciated.

Jacek Krywko – Aug 9, 2024 5: 10 pm UTC

I woman holds a handheld device in front of a rack of equipment. — Enlarge / Jessica Watkins gets to work on the ISS

“Archeology really is a perspective on material culture we use as evidence to understand how humans adapt to their environment, to the situations they are in, and to each other. There is no place, no time that is out of bounds,” says Justin Walsh, an archeologist at Chapman University who led the first off-world archeological study on board the ISS.

Walsh’s and his team wanted to understand, document, and preserve the heritage of the astronaut culture at one of the first permanent space habitats. “There is this notion about astronauts that they are high achievers, highly intelligent, and highly trained, that they are not like you and me. What we learned is that they are just people, and they want the comforts of home,” Walsh says.

Disposable cameras and garbage

“In 2008, my student in an archeology class raised her hand and said, ‘What about stuff in space, is that heritage?’ I said, ‘Oh my God, I’ve never thought of this before, but yes,’” Walsh says. “Think of Tranquility base—it’s an archeological site. You could go back there, and you could reconstruct not only the specific activities of Neil Armstrong and Buzz Aldrin, but you could understand the engineering culture, the political culture, etc. of the society that created that equipment, sent it to the Moon, and left it there.”

So he conceived the idea of an archeological study on the ISS, wrote a proposal, sent it to NASA, and got rejected. NASA said human sciences were not their priority and not part of their mission. But in 2021, NASA changed its mind.

“They said they had an experiment that could not be done at the scheduled time, so they had to delay it. Also, they changed the crew size from six to seven people,” says Walsh. These opened up some idle time in the astronauts’ schedules, allowing NASA to find space in the schedule for less urgent projects on the station. The agency gave Walsh’s team the go-ahead under the condition that their study could be done with the equipment already present on the ISS.

The outline of Walsh’s research was inspired by and loosely based on the Tucson Garbage Project and the Undocumented Migration Project, two contemporary archeology studies. The first drew conclusions about people’s lives by studying the garbage they threw away. The second documented the experiences of migrants on their way to the US from Mexico.

“Jason De León, who is the principal investigator of this project, gave people in Mexico disposable cameras, and he retrieved those cameras from them when they got to the US. He could observe things they experienced without being there himself. For me, that was a lightbulb moment,” says Walsh.

There were cameras on board the ISS and there was a crew to take pictures with them. To pull off an equivalent of digging a test pit in space, Walsh’s team chose six locations on the station, asked the crew to mark them with squares one meter across, and asked the astronauts to take a picture of each of those squares once a day for 60 days, from January to March 2022.

Building a space shed

In the first paper discussing the study’s results, Walsh’s team covered two out of six chosen locations, dubbed squares 03 and 05. The 03 square was in a maintenance area near the four crew berths where the US crew sleeps. It’s near docking ports for spacecraft coming to the ISS. The square was drawn around a blue board with Velcro patches meant to hold tools and equipment in place.

“All historic photographs of this location published by NASA show somebody working in there—fixing a piece of equipment, doing a science experiment,” says Walsh. But when his team analyzed day-by-day photos of the same spot, the items velcroed to the wall hardly changed in those 60 days. “It was the same set of items over and over again. If there was an activity, it was a scientific experiment. It was supposed to be the maintenance area. So where was the maintenance? And even if it was a science area, where’s the science? It was only happening on 10 percent of days,” Walsh says.

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String of record hot months came to an end in July

climate change, Earth science, Science, temperature records / DJ Henderson / August 8, 2024

Hot, but not that hot —

July had the two hottest days recorded but fell 0.04° Celsius short of last year.

John Timmer – Aug 8, 2024 6: 17 pm UTC

Image of a chart with many dull grey squiggly lines running left to right, with an orange and red line significantly above the rest. — Enlarge / Absolute temperatures show how similar July 2023 and 2024 were.

The past several years have been absolute scorchers, with 2023 being the warmest year ever recorded. And things did not slow down in 2024. As a result, we entered a stretch where every month set a new record as the warmest iteration of that month that we’ve ever recorded. Last month, that pattern stretched out for a full 12 months, as June of 2024 once again became the warmest June ever recorded. But, despite some exceptional temperatures in July, it fell just short of last July’s monthly temperature record, bringing the streak to a close.

Europe’s Copernicus system was first to announce that July of 2024 was ever so slightly cooler than July of 2023, missing out on setting a new record by just 0.04° C. So far, none of the other major climate trackers, such as Berkeley Earth or NASA GISS, have come out with data for July. These each have slightly different approaches to tracking temperatures, and, with a margin that small, it’s possible we’ll see one of them register last month as warmer or statistically indistinguishable.

How exceptional are the temperatures of the last few years? The EU averaged every July from 1991 to 2020—a period well after climate change had warmed the planet significantly—and July of 2024 was still 0.68° C above that average.

While it didn’t set a record, both the EU’s Copernicus climate service and NASA’s GISS found that it contained the warmest day ever recorded. In the EU’s case, they were the two hottest days recorded, as the temperatures on the 21st and 22nd were statistically indistinguishable, with only 0.01° C separating them. Late July and early August tend to be the warmest times of the year for surface air temperatures, so we’re likely past the point where any daily records will be set in 2024.

That’s all in terms of absolute temperatures. If you compare each day of the year only to instances of that day in the past, there have been far more anomalous days in the temperature record.

Enlarge / In terms of anomalies over years past, both 2023 (orange) and 2024 (red) have been exceptionally warm.

That image also shows how exceptional the past year’s temperatures have been and makes it clear that 2024 is only falling out of record territory because the second half of 2023 was so exceptionally warm. It’s unlikely that 2024 will be quite as extreme, as the El Niño event that helped drive warming appears to have faded after peaking in December of 2023. NOAA’s latest forecast expects that the Pacific will remain in neutral for another month or two before starting to shift into cooler La Niña conditions before the year is out. (This is based on the August 8 ENSO forecast obtained here.)

In terms of anomalies, July also represents the first time in a year that a month had been less than 1.5° C above preindustrial temperatures (with preindustrial defined as the average over 1850–1900). Capping our modern temperatures at 1.5° C above preindustrial levels is recognized as a target that, while difficult to achieve, would help avoid some of the worst impacts we’ll see at 2° C of warming, and a number of countries have committed to that goal.

Listing image by Dmitriy83

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