Kenneth Chang

Launched 42 years ago, when Jimmy Carter was president, the twin spacecraft have persisted far longer than envisioned, as has their ability to send scientific findings home to Earth.

In a series of papers published Monday in Nature Astronomy, scientists report what Voyager 2 observed at the boundary of the solar wind’s bubble and beyond.

“We’re certainly surprised,” Edward C. Stone, the mission’s project scientist, said of the probe’s longevity during a news conference Thursday. “We’re also wonderfully excited by the fact that they do. When the two Voyagers were launched, the Space Age was only 20 years old. It was hard to know at that time that anything could last over 40 years.”

In many ways, the measurements echoed Voyager 1’s: a jump in the density of particles accompanied by a sharp decrease in their speed, a shift in the magnetic fields.

Voyager 2 also noted some differences, which could give clues about the complicated dynamics in that region of the solar system.

The sun spews in all directions a continuous stream of particles called the solar wind traveling at a speed of 1 million mph. The particles are mostly hydrogen, but, heated to some 3 million degrees Fahrenheit, the atoms are ripped apart into protons and electrons.

At a distance of more than 11 billion miles from the sun, the solar wind, thinning out, is increasingly buffeted by the flow of particles in the interstellar wind and a galactic magnetic field generated by the long ago explosions of distant stars. The interstellar wind is much cooler — just tens of thousands of degrees — and denser.

Voyager 2 is heading in a different direction than Voyager 1, which could explain some of the differences. The sun was also more active in 2012, near the maximum phase of its cycle of activity. The sun is now near its lull, known as the solar minimum.

With Voyager 1, the outward velocity of the solar wind dropped to zero long before the boundary; it was pushed sideways. With Voyager 2, the outward velocities fluctuated, sometimes dipping to zero but then rising again.

Curiously, the distances from the sun for the two crossings out of the solar system were similar. Scientists had expected that the bubble would be pushed outward during the solar maximum and collapse inward during the solar minimum.

“A lot of the models leave a lot to be desired,” said Stamatios Krimigis, a scientist at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, and the principal investigator of one of the Voyager instruments.

Voyager 2 also measured what scientists describe as a magnetic barrier, “like the pileup of slowly moving cars on a major highway, a few miles ahead of the scene of an accident,” Leonard F. Burlaga, a scientist working with the spacecraft’s magnetometer, wrote in an email.

When solar wind slows, the density of particles increases, and the magnetic field strengthens.

“Again, it’s like the cars, which turn away from the lanes of the accident and move slowly along the available lanes,” Burlaga said. “The cars are more densely spaced, the drivers are heated, but they eventually move along.”

The missions were originally designed to last four years to fly by Jupiter and Saturn. Voyager 2 also visited Uranus and Neptune. Voyager 2 still has five functioning instruments for measuring the void; Voyager 1 has four.

Both Voyagers are expected to last another five years or so until their batteries die out. Both are powered by electricity generated by the heat of radioactive plutonium. As the plutonium diminishes, the spacecraft receive less and less energy.

Once the Voyagers shut down, there will be no more data from beyond our solar system for years. Only one other spacecraft, the New Horizons probe that flew by Pluto in 2015 and visited another object in the distant Kuiper belt in January this year, is headed that way. But it is moving more slowly, and its plutonium power will run out before it reaches interstellar space.

“Right now, when the Voyagers go offline, that’s kind of it unless we do something else,” said Ralph McNutt, a physicist at the Johns Hopkins Applied Physics Laboratory.

McNutt is leading a study to look at what it might take to build an ultrafast spacecraft that could leave the solar system in a hurry. The development of NASA’s long-delayed giant rocket, the Space Launch System, makes that mission more plausible.

The mission could also perform what is known as an Oberth maneuver, named after Hermann Oberth, a German physicist who came up with the idea in 1927. A probe would first head to Jupiter, using the giant planet’s gravity to accelerate toward the sun. As it then swings around the sun, the spacecraft would fire a rocket engine, accelerating to a speed where it could cover close to a couple of billion miles a year. That would be more than five times the speed of the Voyagers.

That would be tricky to pull off, however. For such a powered flyby to be effective, the probe would have to travel within 1 million miles or so from the sun.

“Well, it’s not as easy as it sounds,” said Krimigis, who is taking part in the study which should be completed in a couple of years. “At that distance, every metal we know melts.”

This article originally appeared in

Voyager 2's Discoveries From Interstellar Space

The Voyager 2 spacecraft burst out of the bubble of gases expanding from the sun and into the wild of the Milky Way a year ago. It was the second spacecraft to cross that boundary and directly observe the interstellar medium. Its faster-moving twin, Voyager 1, made the crossing six years earlier, in August 2012.

That is one of the musings of chemists at New York University who came across an insecticide that had been developed by German scientists during World War II in the course of conducting abstract research on another topic.

It became a historical science mystery.

“Two years ago, we never thought we’d be doing this,” said Michael D. Ward, an NYU chemistry professor.

In postwar Allied intelligence reports examined by Ward and his colleagues, German scientists claimed their insecticide, now called DFDT, was more effective than DDT. Allied officials dismissed those assertions as fanciful, especially given the deplorable behavior of Hoechst, the German chemical manufacturer that developed the insecticide, during the war. The company had forced residents of countries occupied by Germany to work in its factories, and it tested drugs on concentration camp prisoners.

The insecticide was forgotten for decades.

Now, work by Ward and his colleagues, reported this month in an article in the Journal of the American Chemical Society, appears to corroborate the German claims. The forgotten compound killed mosquitoes in as little as one-fourth the time as DDT.

DDT, initially regarded as a magical miracle chemical, was sprayed profusely after World War II until environmental concerns arose in the 1960s. Although many nations banned it in the 1970s, some use still continues. In 2006, the World Health Organization endorsed the use of DDT as part of efforts to control malaria, primarily for the spraying of indoor walls. That involves much smaller amounts than what was used by farmers in the past.

Conceivably the more lethal DFDT could be used in even smaller, possibly safer doses. A new option could allow public health officials to rotate insecticides and thwart the resistance to DDT in many mosquitoes today.

“It’s exciting and desperately needed,” said Duane J. Gubler, an emeritus professor in the emerging infectious diseases program at Duke University and the National University of Singapore Graduate Medical School. He was not involved in the study.

But will anyone today risk the time and money needed to determine whether DFDT could be a safe and effective tool against malaria as well as other mosquito-borne diseases like Zika, dengue and yellow fever?

“Donors, governments, they just don’t want the backlash, even if it’s not wholly justified,” said Bart Kahr, Ward’s colleague at NYU and an author of the paper.

The effectiveness of DDT, an abbreviation for dichloro-diphenyl-trichloroethan, as an insecticide was first discovered in 1939 by Paul Hermann Müller, a Swiss chemist. His company, J.R. Geigy, in Basel, patented the compound.

DDT is what is known as a contact insecticide. “The insects have to walk on the crystals in order to die,” Kahr said.

After DDT is absorbed through an insect’s feet, it binds to nerve cells, causing them to become stuck in the “on” position, firing continuously. The compound does not have that effect in mammals.

The United States and other Allies licensed DDT from Geigy and manufactured as much as they could to control malaria and typhus during World War II. After the war, DDT was widely used by farmers, and over the years, 2 million tons of the insecticide were sprayed.

An aggressive effort by World Health Organization to eradicate malaria in 1955 succeeded in some parts of the world, but many mosquitoes subsequently developed resistance — the survivors were more likely to possess a genetic trait that protected them from the poison, which they passed to their many offspring. The disease roared back.

“We knocked them down, and then after a while they fly away,” Gubler said.

A turning point leading to the decline of DDT was the publication in 1962 of “Silent Spring” by Rachel Carson. The book was a harbinger of the environmental movement, documenting the ecological devastation caused by indiscriminate use of insecticides. DDT molecules endure for decades and accumulate in animals higher up the food chain.

The United States banned DDT in 1972, and many other nations followed.

Kahr and Ward think the outcome might have been different if the substance developed by the Nazi-era scientists had been used instead.

The NYU chemists started the research with no interest in insecticides whatsoever.

They were studying materials that crystallize in a twisted helical pattern. One of the ways to identify such molecules is to scan the internet for images of crystals made by hobbyists. DDT, they found, exhibited the characteristic pinwheel gradients of a helical crystal when illuminated with polarized light.

Jingxiang Yang, a postdoctoral researcher at NYU, started growing DDT crystals and found not only the expected crystals but also more jumbled, chaotic patterns.

“There was some organized and some crazy,” Kahr said. “We didn’t expect the other stuff, and that other stuff turned out to be a different arrangement of molecules in the crystal. That form wasn’t known to science.”

That led to the next set of experiments. “Since we have two forms,” Kahr said, “it was natural to ask, which of these forms was the historical killer of insects?”

It turned out that the chaotic form of DDT is deadlier.

As they were going through early scientific data on DDT, the NYU chemists found mentions of DFDT.

The compound, difluoro-diphenyl-trichloro-ethane, is the same molecule as DDT, except with fluorine atoms replacing two of the chlorines.

The Germans developed DFDT at least in part to avoid paying the licensing fees for DDT to the Swiss. It is also possible that the chemical ingredients for DFDT, although considerably more expensive at the time than those for DDT, may have been more readily available in wartime Germany.

Allied military officials noted the German use of DFDT but concluded that claims of superiority to DDT “are not clearly supported by their meager and inadequate tests against houseflies.”

As DDT use burgeoned, DFDT was forgotten, even after Paul Hermann Müller, who won the Nobel Prize in medicine in 1948 for his work with DDT, praised DFDT, noting that it killed mosquitoes more quickly.

In the NYU experiments, DFDT killed off half of the mosquitoes subjected to it in about half an hour, compared to a couple of hours for DDT.

Kahr wonders: If DFDT had displaced DDT, would the 1955 push have succeeded in bringing malaria under control before resistance set in? “What if this compound wasn’t forgotten,” he said. “What would the world be like? Science doesn’t go as linearly as the general public thinks it does.”

Contemporary experts in insecticide use are skeptical of DFDT’s prospects as a solution to malaria, pointing to similarities in its chemical structures to DDT’s.

“I suspect that the mode of action of DFDT is probably identical to DDT in this respect,” said Jeffrey R. Bloomquist, a professor of insecticide toxicology and resistance at the University of Florida. “So there would be cross resistance to it in the field, even though it has not been in use.”

Helen Jamet, deputy director of vector control for the malaria team at the Bill and Melinda Gates Foundation, also said that a DDT-like insecticide may not be up to the task. “It would not be helpful to put a molecule out there to which there is already widespread resistance in the field,” she said.

Rather, the bigger hope is to find new chemicals that kill mosquitoes through different biological mechanisms. Jamet said that several are in development and could be ready for use in two to three years.

Ward responded that sometimes, as researchers developing drugs have found, the change of a single atom can dramatically change the chemical behavior of a molecule.

The NYU scientists are planning to collaborate with Ke Dong, an entomologist at Michigan State University, to test DFDT on DDT-resistant mosquitoes. “We will see,” she said.

If DFDT can kill those, it potentially could be an important new tool — insecticide resistance can be minimized by periodically switching to a different insecticide. And the amounts needed for battling malaria are small.

“What the environmentalists don’t say and realize is that if it’s used for public health and not agriculture, there’s very little environmental impact,” Gubler said.

But the study’s authors agree that more research would be required to prove that hypothesis.

“We’re not in a position to say this should be used now,” Kahr said. “We don’t know the real environmental impact and the toxicology and effect on ecosystems, and all of that stuff would have to be studied by other scientists that aren’t really us.”

A Nazi Version of DDT Was Forgotten. Could It Help Fight Malaria?

What if, after the Allies won World War II, world health officials had employed a Nazi version of DDT against mosquitoes that transmit malaria? Could that persistent disease, which still infects more than 200 million people a year and kills 400,000 of them, have been wiped off the planet?

The cause was a heart attack, his stepson Sasha Dobrovolsky said.

Feigenbaum’s intense, eclectic curiosity led him to questions far astray from the ones usually asked by theoretical physicists. How does one make the most accurate maps? What makes the moon look larger when it is closer to the horizon? What design of paper money would thwart photocopying?

His friends recalled meals, full of red wine and red meat (no vegetables), at which the conversation — not just about physics but also about literature and classical music — would stretch late into the night.

Feigenbaum’s lifestyle and his Renaissance intellect were a poor fit to the demands of modern publish-or-perish academia. But by following his own path, he uncovered a pattern of chaos that is universal in math and in nature.

At Los Alamos National Laboratory in New Mexico in the mid-1970s, Feigenbaum, using a programmable calculator, found what seemed at first a mathematical curiosity. A simple equation generated a sequence of numbers, which were initially trivial: the same number over and over. But as a parameter in the equation shifted, the output became more varied. First the numbers bounced back and forth between two values, then they cycled among four values, then eight, and so on, with the rate of the change quickening until the patterns lost all hint of repeating cycles.

The dynamics had, in the terminology of physics, passed into the realm of deterministic chaos. That is, each number of the sequence could be computed precisely, but the resulting pattern appeared to be complex and random.

Feigenbaum looked at another simple equation, and it exhibited the same behavior, known as period doubling. More startling, the number that characterized the rate of doubling was the same: As the periods multiplied, each doubling occurred about 4.669 times as quickly as the previous one.

This number is now known as the Feigenbaum constant. Feigenbaum was able to prove why it is a universal mathematical value, much as pi — the ratio of the circumference of a circle to its diameter — is the same for all circles.

“There aren’t too many fundamental constants,” said Kenneth Brecher, an emeritus professor of astronomy at Boston University, who met Feigenbaum when both were graduate students at the Massachusetts Institute of Technology. “And he was the only living person that had one.”

In 1979, a French scientist, Albert J. Libchaber, observed the same cascade of period doublings in the temperature fluctuations in the center of a convecting fluid. Feigenbaum’s theory of the transition from order to chaos now described phenomena in the real world.

“It’s observed in nature and not simply mathematical equations,” said David Campbell, a physics and engineering professor at Boston University and a longtime friend of Feigenbaum’s.

The same ideas have now also been applied to describe the rise and fall of fish populations, the dripping of a leaky faucet and the swings of financial markets.

“We know systems can do this,” Campbell said. “We understand that, and so we know to look for it. When you find, let’s say, period doubling transitions in dung beetle reproduction, it’s not a huge surprise.”

Mitchell Jay Feigenbaum was born in Philadelphia on Dec. 19, 1944, and grew up in Brooklyn, the son of Abraham and Mildred Feigenbaum. His father was a chemist, his mother a schoolteacher. After graduating with a bachelor’s degree in electrical engineering from the City College of New York, he pursued particle physics at the Massachusetts Institute of Technology, completing his doctorate in 1970.

During a postdoctoral fellowship at Cornell, Feigenbaum was already allowing his focus to wander. “He was not very happy with the physics he was doing at that time,” said Predrag Cvitanovic, a theoretical physicist at the Georgia Institute of Technology, who was a graduate student at Cornell at the time.

“The main thing he did is he solved the New York Times crossword puzzle every morning,” Cvitanovic said. “It was just clear that he was very smart. He didn’t produce anything I was aware of.”

A second unproductive postdoctoral fellowship followed, at Virginia Polytechnic Institute and State University in Blacksburg, Virginia. And then a shake-up at Los Alamos rescued Feigenbaum.

Peter A. Carruthers had been installed as director of the laboratory’s theoretical division and wanted to revitalize it. He dismissed some senior scientists and recruited promising younger scientists — including Feigenbaum, even though he did not possess much of a track record.

Feigenbaum moved to Los Alamos in 1974. A year after his arrival, he made his breakthrough on period doubling. Publishing his findings took a few years more.

“The referees rejected it, because he had submitted it to a normal math journal,” Brecher said. “They didn’t know what he was talking about.”

Feigenbaum’s ideas took hold in the 1980s. He moved to Cornell in 1982 as a physics professor and to Rockefeller University in 1986.

In 1984, he won a MacArthur Fellowship (the so-called genius grant of no-strings-attached money), and in 1986 he and Libchaber shared the Wolf Prize in Physics, which is often a precursor to a Nobel. He was a member of the National Academy of Sciences and the American Academy of Arts and Sciences.

Feigenbaum worked in other areas as well — cartography, for example, with the Hammond World Atlas Corp. Projecting cartographic details from a round world onto a flat piece of paper necessarily requires distortion. Feigenbaum figured out what projection would be most accurate for a given region and converted the time-consuming manual mapmaking process into a quick digital one.

He also figured out an efficient method of placing labels on maps. Instead of relying on the whim of the mapmaker, Feigenbaum used physics. He imagined placing electrical charges on the words. Similar charges repel each other, and thus the words would shift to ideal spacing, subject to other mapmaking requirements; the name of a river, for example, needed to be next to the river without obscuring the river.

While serving on a National Research Council committee on the design of next-generation currency design in 1993, Feigenbaum developed a fractal-based geometric pattern that digital copiers could not reproduce without visible flaws.

In 1996, he helped found Numerix, a company that produced software to quickly calculate the risk and pricing of financial derivatives.

“He didn’t publish very much, but he did a lot of work,” said Nigel Goldenfeld, a University of Illinois physicist and another founder of Numerix. “He was motivated by a sense of beauty, and he saw the beauty in a lot of different problems.”

In addition to his stepson Sasha, Feigenbaum is survived by another stepson, Kiril Dobrovolsky; a brother, Edward; and a sister, Glenda Jeunelot. His marriages to Cornelia Dobrovolsky and Gunilla Ohman ended in divorce.

In the past decade, Feigenbaum was fascinated by anamorphic art — images that appear three-dimensional when reflected off a cylindrical mirror.

He wrote a 238-page manuscript, “Reflections on a Tube,” about how what one sees is influenced not only by the physics of optics but also by the peculiarities of the human vision system. Even though the book has been almost finished for a decade, Feigenbaum continued to tinker with it. Friends say they will now finally publish it.

This article originally appeared in <a href="https://www.nytimes.com/2019/07/18/science/mitchell-feigenbaum-dead.html" id="666a2852-dd10-343a-acf0-89e5e6d6dcf8">The New York Times</a>.

Mitchell Feigenbaum, Physicist Who Made Sense of Chaos, Dies at 74

Mitchell J. Feigenbaum, a pioneer in the field of mathematical physics known as chaos, died June 30 in New York. He was 74.

Last month, the rocket company, Blue Origin, tweeted without explanation a photograph of the Endurance, the ship that Sir Ernest Shackleton sailed to Antarctica in 1914. Shackleton was aiming to make the first land crossing of the continent.

Jeff Bezos, founder and chief executive of Amazon who also owns Blue Origin, will explain what this means Thursday. At an event in the nation’s capital, the company announced, Bezos will provide, “an update on our progress and share our vision of going to space to benefit Earth.”

Shackleton failed. The Endurance became trapped in the ice for months until floes crushed the hull, and the ship sank. But all 28 men on the Endurance survived their ordeal and were rescued, making the expedition an epic and inspiring failure.

Bezos is likely planning something that he hopes will be more successful.

— What are Blue Origin’s goals?

Bezos founded his rocket company in 2000, which means that it has been around longer than the other, better-known billionaire rocket company, Elon Musk’s SpaceX. Musk started SpaceX in 2002.

But for the first 15 years of its existence, Blue Origin operated quietly, saying almost nothing beyond an occasional blog post by Bezos. When one of its rockets crashed during a test flight in 2011, a week passed before Bezos acknowledged the failure.

In 2016, Bezos finally invited journalists for a visit to Blue Origin’s headquarters in Kent, Washington, south of Seattle. There he described his vision: millions of people living and working in space, as humanity would look elsewhere in the solar system for energy and raw materials. He expected that much of the world’s heavy manufacturing would move off Earth, allowing the planet to return to a more pristine state.

Bezos noted that he had studied and thought about rockets since he was 5 years old. “I never expected to have the resources to start a space company,” he said. “I won a lottery ticket called Amazon.com.”

Two years ago, Bezos said he would be selling $1 billion a year in Amazon stock to finance Blue Origin. Bezos will retain control of Blue Origin after his divorce this year.

— What has Blue Origin done so far?

Blue Origin has become less secretive. It now regularly livestreams test flights of its suborbital New Shepard rocket. That spacecraft is designed to take space tourists on short hops into space, where passengers will experience just a few minutes of weightlessness before New Shepard’s passenger capsule returns to Earth’s surface.

The company said during its latest test — the 11th — that the first flights carrying people will occur later this year.

Outside NASA’s Kennedy Space Center in Florida, Blue Origin has built a new factory for manufacturing a larger rocket, New Glenn, that is scheduled to take satellites, and possibly people, to orbit beginning in 2021. There is mention of an even larger rocket, New Armstrong, but no details have been released.

— How do the plans tie in with Shackleton?

It probably has to do with the South Pole — on the moon.

In the last couple of years, the Trump administration has revived plans to send astronauts back to the moon, and NASA last year announced a road map that included turning to commercial companies for sending experiments and cargo to the lunar surface.

Officials at Blue Origin have described Blue Moon, an uncrewed robotic lander that would do just that. Last year, Blue Origin received $13 million from NASA to work on technologies needed for a moon lander.

NASA is aiming to explore craters near the moon’s South Pole, where water ice is believed to exist. The water molecules can be broken apart into hydrogen and oxygen, which could be used for rocket fuel. The resources would also be handy for astronauts — water for drinking, oxygen for breathing.

Those intriguing craters by the pole include one that is 14 miles wide, 2.5 miles deep and is named Shackleton.

— Do other space companies have moon plans?

NASA’s plans to hire companies to take small payloads to the moon within the next year or so. Many of these companies believe there is a viable business carrying payloads to the moon, although none have been to the moon yet.

A low-cost approach to landing on the moon is risky; SpaceIL, an Israeli nonprofit, attempted to land on the moon in April, but crashed.

Other companies will be competing to build pieces of Gateway, an outpost that NASA plans to put into orbit around the moon as a way station for astronauts headed to the moon’s surface. NASA is also asking for ideas from companies for astronaut-carrying landers.

Last year, SpaceX announced that a Japanese billionaire, Yusaku Maezawa, had signed up for a trip that would go past the moon without landing on it, and swing back to Earth.

— Can anyone make money on the moon?

Under the Outer Space Treaty, no one can own a piece of the moon (or any other piece of the solar system except Earth). But, at least under the reading of some lawyers, companies can sell what they take from the moon.

With NASA, the European Space Agency and others aiming to go to the moon, government business could provide a boon to companies hoping to set up shop there, but how well they will do is still speculative.

This article originally appeared in <a href="https://www.nytimes.com/2019/05/09/science/jeff-bezos-moon.html" id="4f329a02-a174-388b-aae8-ad295ec28977">The New York Times</a>.

WASHINGTON, D.C. — What does a 21st-century rocket company have to do with an ill-fated expedition to Antarctica more than a century ago?

Jeff Bezos' Shot at the Moon? Blue Origin to Announce Vision for Space

Like Frankenstein, Marc Miskin’s robots initially lie motionless. Then their limbs jerk to life.

But these robots are the size of a speck of dust. Thousands fit side by side on a single silicon wafer similar to those used for computer chips, and, like Frankenstein coming to life, they pull themselves free and start crawling.

“We can take your favorite piece of silicon electronics, put legs on it and then build a million of them,” said Miskin, a professor of electrical and systems engineering at the University of Pennsylvania. “That's the vision.”

He imagines a wealth of uses for these microbots, which are about the size of a cell. They could crawl into cellphone batteries and clean and rejuvenate them. They might be a boon to neural scientists, burrowing into the brain to measure nerve signals. Millions of them in a petri dish could be used to test ideas in networking and communications.

The research, presented at a meeting of the American Physical Society in Boston in March, is the latest step in the vision that physicist Richard Feynman laid out in 1959 in a lecture, “There’s Plenty of Room at the Bottom,” about how information could be packed into atomic-scale structures and molecular machines could transform technology.

Over the past 50 years, Feynman’s predictions about information storage have largely come to fruition. “But the second goal — the miniaturization of machines — we’re really just getting started,” Miskin said.

The new robots take advantage of the same basic technology as computer chips. “What we’re doing is stealing from 60 years of silicon,” said Paul McEuen, a physicist at Cornell University. “It’s no big deal to make a silicon chip 100 microns on a side. What didn’t exist is basically the exoskeleton for the robot arms, the actuators.”

While working in McEuen’s laboratory, Miskin developed a technique to put layers of platinum and titanium on a silicon wafer. When an electrical voltage is applied, the platinum contracts while the titanium remains rigid, and the flat surface bends. The bending became the motor that moves the limbs of the robots, each about 100 atoms thick.

The idea is not new. Researchers like Kris Pister of the University of California, Berkeley, have for decades talked of “smart dust,” minuscule sensors that could report on conditions in the environment. But in developing practical versions, the smart dust became larger, more like smart gravel, in order to fit in batteries.

Miskin worked around the power conundrum by leaving out the batteries. Instead, he powers the robots by shining lasers on tiny solar panels on their backs.

“I think it’s really cool,” Pister said of the work by Miskin, McEuen and their collaborators. “They made a super-small robot you can control by shining light on it, and that could have all sorts of interesting applications.”

Because the robots are made using conventional silicon technology, incorporating sensors to measure temperature or electrical pulses should be straightforward.

Miskin said his electrical engineering colleagues are often incredulous when they find out that the robots run on a fraction of a volt and consume only 10 billionths of a watt: “‘You mean you can take my thing and put legs on it?’ ‘Yeah, absolutely.' ‘And then you can have it piloted and compute and do all this other stuff?’ People get really excited.”

Challenges remain. For robots injected into the brain, lasers would not work as the power source. (Miskin said magnetic fields might be an alternative.) He wants to make other robots swim rather than crawl. (For tiny machines, swimming can be arduous as water becomes viscous, like honey.).

Still, Miskin expects that he can demonstrate practical microbots within a few years.

“It really boils down to how much innovation do you have to do?” he said. “And what I love about this project is for a lot of the functional things, the answer is none. You take the parts that exist, and you put them together.”

This article originally appeared in <a href="https://www.nytimes.com/2019/04/30/science/microbots-robots-silicon-wafer.html" id="1acac3d3-3864-3886-aeb6-085d08b9ade9">The New York Times</a>.

(Trilobites)

The Microbots Are on Their Way

It was the second launch for what is the most powerful rocket in operation today, a reminder of its majestic test launch fourteen months ago from the same launchpad, 39A, at NASA’s Kennedy Space Center in Florida.

At moments, the 2018 launch seemed like a lengthy advertisement for the ambitions of Elon Musk, SpaceX’s founder and CEO. It carried a spacesuit-wearing mannequin, nicknamed Starman, seated in the driver’s seat of a red Roadster built by Musk’s other company, Tesla. The sports car and its driver streamed video back to Earth of their journey into the solar system.

This time, the Falcon Heavy’s cargo was more mundane, but also more useful: Arabsat-6A, a Saudi Arabian communications satellite that will relay television, internet and mobile phone signals to the Middle East, Africa and Europe.

Shortly after the launch, the rocket’s three boosters returned to Earth. Two touched down seconds apart at landing pads at Cape Canaveral, not far from the launchpad. The center booster, which went higher and farther, set down on a floating platform in the Atlantic Ocean.

Sticking that third landing was an advancement for SpaceX, after a similar maneuver failed in 2018 on the first try. The booster then missed the platform, hitting the water at more than 300 mph.

— Why is Falcon Heavy different from other SpaceX rockets?

The company’s workhorse is the Falcon 9 rocket, which first launched in 2010. The first stage of the Heavy essentially consists of three Falcon 9 first stages bound together. The second stages of the two rockets are identical.

The additional thrust allows the Heavy to propel 140,000 pounds to low-Earth orbit, nearly three times what the Falcon 9 can lift.

— How does this Falcon Heavy differ from the first one?

On the test flight, the two side boosters were older versions reused from earlier flights. (SpaceX’s best innovation to date is landing the booster stage of its rockets and launching it again; traditionally, rockets have been one-use throwaways, with the booster stages dropped into the ocean.)

For this one, the side boosters had never before been used. They were the latest version of the rocket, called Block Five. (“Block” is what rocket companies call a major upgrade.) That boosts the thrust and how much the Falcon Heavy can carry.

— Why did the second Falcon Heavy flight take so long?

Even though the first Falcon Heavy flight appeared to be nearly flawless, SpaceX probably made adjustments. That, after all, is the reason a rocket company performs a test flight for a new rocket design.

SpaceX also has had a backlog of Falcon 9 missions to fly. It launched 20 Falcon 9 missions in 2018, more than in any previous year, in addition to the one Falcon Heavy launch. The company was also busy at work developing its Crew Dragon capsule for taking NASA astronauts to and from the International Space Station.

The market for the Falcon Heavy is also much smaller than once envisioned. When Musk first announced the rocket in 2011, he said he expected that there would be a 50/50 mix between the Falcon 9 and the Falcon Heavy. In the years since, improvements have made the Falcon 9 more powerful, and miniaturization of electronics has shrunk the size of many satellites.

The Falcon Heavy is now needed for only the largest satellites, such as the 13,000-pound Arabsat-6A satellite, which is headed to geosynchronous orbit more than 22,000 miles above Earth.

The satellite could have been launched on a Falcon 9, but with the added thrust of a Heavy, the satellite could use less of its own fuel to reach its final orbit, extending its lifetime.

— Are there more Falcon Heavy flights planned?

One more Falcon Heavy flight is scheduled for this year — a mission for the U.S. Air Force carrying 25 small satellites.

In addition, SpaceX has announced contracts for two Falcon Heavy launches of commercial satellites, and the company has won two competitions to use the rocket for national security missions.

— Will Falcon Heavy go to the moon?

At present, no, but that answer could change.

In 2017, SpaceX announced that two space tourists would go on an around-the-moon trip in one of the company’s Crew Dragon capsules launched by a Falcon Heavy. But when the first Heavy reached the launchpad in 2018, SpaceX said it had decided not to go to the expense and effort of making the rocket safe enough for launching people.

The possibility of using the Falcon Heavy for lunar missions was revived in March by NASA Administrator Jim Bridenstine when he told a Senate committee that the big rocket that his agency is developing, the Space Launch System, would not be ready for its first test flight in 2020. NASA was looking into using commercial rockets as an alternative, he said.

One of the alternatives was putting the second stage of the Space Launch System on top of a Falcon Heavy first stage. Bridenstine later said that option was feasible but could not be done by 2020, because major changes would be needed to the boosters and SpaceX’s launchpad to accommodate the Frankenstein rocket combination.

Bridenstine, however, left the door open, saying that NASA would explore all options to meet the Trump administrations goal of sending astronauts back to the moon by the end of 2024.

— What other rockets is SpaceX planning to build?

SpaceX’s next-generation rocket was once known as BFR where “B” stood for “big” and “R” stood for “rocket.” It now has the less colorful name Starship.

SpaceX has begun small hop tests of a preliminary design, nicknamed Starhopper. The full-fledged design is to reach orbit and eventually make distant journeys to the moon and Mars, but that is still years away.

One of Starship’s first passengers is to be Yusaku Maezawa, founder of the online Japanese clothing company ZOZO. Maezawa had been one of the lunar tourists who had signed up for the Falcon Heavy trip around the moon but now will wait longer for the even larger rocket.

This article originally appeared in <a href="https://www.nytimes.com/2019/04/11/science/falcon-heavy-launch-spacex.html" id="47c6ade0-3b85-3576-a1fc-9e438c2bd2f0">The New York Times</a>.

The Falcon Heavy roared into space Thursday night, arcing atop three columns of flame toward orbit with a large satellite on board.

Falcon Heavy, SpaceX's Giant Rocket, Launches Into Orbit, and Sticks Its Landings

The planned launch of the giant rocket — the most powerful now in operation on Earth — was postponed Wednesday night because of windy conditions high above the launchpad. SpaceX will try again Thursday evening.

The rocket could blast off as early as 6:35 p.m. Eastern time; the launch window lasts until about 8:31 p.m. SpaceX will stream the launch on its YouTube channel.

The majestic test launch of the Falcon Heavy in February 2018 carried the ambitions of SpaceX and Elon Musk, the company’s founder and CEO, to new heights. It also sent Musk’s red Tesla Roadster into a long orbit around the sun, sending views homes to Earth of a spacesuit-wearing mannequin called Starman.

The spacecraft’s payload this time is mundane and useful: Arabsat-6A, a Saudi Arabian communications satellite that will relay television, internet and mobile phone signals to the Middle East, Africa and Europe.

For this one, the side boosters have never before been used. They are the latest version of the rocket, called Block Five. (“Block” is what rocket companies call a major upgrade.) That boosts the thrust and how much the Falcon Heavy can carry.

— Will SpaceX land the three boosters?

Yes. The two side boosters are to return to landing pads at Cape Canaveral, not far from the launchpad, just as in the maiden flight.

The center booster, which will go higher and farther, is to set down on a floating platform in the Atlantic Ocean. That did not quite work as designed on the first try. The booster missed the platform, hitting the water at more than 300 mph.

Musk said the booster did not have enough ignition fuel to light the engines for the final burn.

— Why hasn’t Falcon Heavy flown in more than a year?

It’s the second try for SpaceX’s second Falcon Heavy.

SpaceX's Falcon Heavy to Try Again for Launch of Satellite

This is a feat that has only been accomplished by three nations — the United States, the former Soviet Union and China. The SpaceIL lander is named Beresheet, which means “Genesis” or “in the beginning” in Hebrew.

The mission costs about $100 million, far less than government-sponsored spacecraft that have been to the moon, although it is designed to survive just a few days, and it is not carrying sophisticated payloads.

On Thursday, a small Israeli nonprofit, SpaceIL, will attempt to make history and become the first private organization to land a spacecraft on the moon.

Kenneth Chang

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