Making ‘Space Travel’ a Step Closer – A Mythical Form of Space Propulsion – EmDrive – FINALLY – Gets a REAL Test

Scientists have debated for decades whether the propulsion concept known as EmDrive is real or wishful thinking. A sensitive new tool may at last provide an answer.

Since the Birth of the Space Age the dream of catching a ride to another solar system has been hobbled by the “tyranny of the rocket equation,” which sets hard limits on the speed and size of the spacecraft we sling into the cosmos.

Even with today’s most powerful rocket engines, scientists estimate it would take 50,000 years to reach our closest interstellar neighbor, Alpha Centauri. If humans ever hope to see an alien sunrise, transit times will have to drop significantly.

Of the advanced propulsion concepts that could theoretically pull that off, few have generated as much excitement—and controversy—as the EmDrive.

First described nearly two decades ago, the EmDrive works by converting electricity into microwaves and channeling this electromagnetic radiation through a conical chamber. In theory, the microwaves can exert force against the walls of the chamber to produce enough thrust to propel a spacecraft once it’s in space.

At this point, however, the EmDrive exists only as a laboratory prototype, and it’s still unclear whether it’s able to produce thrust at all. If it does, the forces it generates aren’t strong enough to be registered by the naked eye, much less propel a spacecraft.

Over the past few years, however, a handful of research teams, including one from NASA, claim to have successfully produced thrust with an EmDrive. If true, it would amount to one of the biggest breakthroughs in the history of space exploration. The problem is that the thrust observed in these experiments is so small that it’s hard to tell if it’s real.

TECHNISCHE UNIVERSITÄT DRESDEN

The resolution lies in designing a tool that can measure these minuscule amounts of thrust. So a team of physicists at Germany’s Technische Universität Dresden set out to create a device that would fill this need. Led by physicist Martin Tajmar, the SpaceDrive project aims to create an instrument so sensitive and immune to interference that it would put an end to the debate once and for all.

In October, Tajmar and his team presented their second set of experimental EmDrive measurements at the International Astronautical Congress, and their results will be published in Acta Astronautica this August. Based on the results of these experiments, Tajmar says a resolution to the EmDrive saga may only be a few months away.

Many scientists and engineers dismiss the EmDrive because it appears to violate the laws of physics. Microwaves pushing on the walls of an EmDrive chamber seem to generate thrust ex nihilo, which runs afoul of the conservation of momentum—it’s all action and no reaction. Proponents of the EmDrive, in turn, have appealed to fringe interpretations of quantum mechanics to explain how the EmDrive might work without violating Newtonian physics.

“From the theory point of view, no one takes this seriously,” Tajmar says. If the EmDrive is able to produce thrust, as some groups have claimed, he says they have “no clue where this thrust is coming from.” When there’s a theoretical rift of this magnitude in science, Tajmar sees only one way to close it: experimentation.

In late 2016, Tajmar and 25 other physicists gathered in Estes Park, Colorado, for the first conference dedicated to the EmDrive and related exotic propulsion systems. One of the most exciting presentations was given by Paul March, a physicist at NASA’s Eagleworks lab, where he and his colleague Harold White had been testing various EmDrive prototypes. According to March’s presentation and a subsequent paper published in the Journal of Propulsion and Power, he and White observed several dozen micro-newtons of thrust in their EmDrive prototype. (For the sake of comparison, a single SpaceX Merlin engine produces around 845,000 Newtons of thrust at sea level.)

The problem for Harold and White, however, was that their experimental setup allowed for several sources of interference, so they couldn’t say for sure whether what they observed was thrust.

Tajmar and the Dresden group used a close replica of the EmDrive prototype used by Harold and White in their tests at NASA. It consists of a copper frustum—a cone with its top lopped off—that is just under a foot long. This design can be traced back to the engineer Roger Shawyer, who first described the EmDrive in 2001. During tests, the EmDrive cone is placed in a vacuum chamber. Outside the chamber, a device generates a microwave signal that gets relayed, using coaxial cables, to antennas inside the cone.

This isn’t the first time the Dresden team has sought to measure nearly imperceptible amounts of force. They built similar contraptions for their work on ion thrusters, which are used to precisely position satellites in space. These micro-newton thrusters are the kind that were used by the LISA Pathfinder mission, which needs extremely precise positioning ability to detect faint phenomena like gravitational waves. But to study the EmDrive and similar propellantless propulsion systems, Tajmar says, required nano-newton resolution.

Their approach was to use a torsion balance, a pendulum-type balance that measures the amount of torque applied to the axis of the pendulum. A less sensitive version of this balance was also used by the NASA team when they thought their EmDrive produced thrust.

To accurately gauge the small amount of force, the Dresden team used a laser interferometer to measure the physical displacement of the balance scales produced by the EmDrive. According to Tajmar, their torsion scale has a nano-newton resolution and supports thrusters weighing several pounds, making it the most sensitive thrust balance in existence.

But a really sensitive thrust balance isn’t much use unless you can also determine whether the detected force is in fact thrust and not an artifact of outside interference. And there are plenty of alternate explanations for Harold and White’s observations.

To determine whether an EmDrive actually produces thrust, researchers must be able to shield the device from interference caused by the Earth’s magnetic poles, seismic vibrations from the environment, and the thermal expansion of the EmDrive due to heating from the microwaves.

Tweaks to the design of the torsion balance—to better control the EmDrive’s power supply and shield it from magnetic fields—took care of some of the interference issues, Tajmar says. A more difficult problem was how to address “thermal drift.” When power flows to the EmDrive, the copper cone heats up and expands, which shifts its center of gravity just enough to cause the torsion balance to register force that can be mistaken as thrust. Tajmar and his team hoped that changing the orientation of the thruster helped address that issue.

Over the course of 55 experiments, Tajmar and his colleagues registered an average of 3.4 micro-newtons of force from the EmDrive, which was very similar to what the NASA team found. Alas, these forces did not appear to pass the thermal drift test. The forces seen in the data were more indicative of thermal expansion than thrust.

All hope is not lost for the EmDrive, however. Tajmar and his colleagues are also developing two additional types of thrust balances, including a superconducting balance that will, among other things, help to eliminate false positives produced by thermal drift.

If they detect force from an EmDrive on these balances, there’s a high probability that it is actually thrust. But if no force is registered on these balances, it likely means that all the previous EmDrive thrust observations were false positives. Tajmar says he hopes to have a final verdict by the end of the year.

But even a negative result from that work might not kill the EmDrive for good. There are many other propellantless propulsion designs to pursue. And if scientists ever do develop new forms of weak propulsion, the hyper-sensitive thrust balances developed by Tajmar and the Dresden team will almost certainly play a role in sorting science fact from science fiction.

New Research in Human Hibernation for Space Travel – Plus Nanotechnology in Space

No interstellar travel movie is complete without hibernators. From Prometheus to Passengers, we’ve watched protagonists awaken in hibernation pods, rebooting their fragile physiology from a prolonged state of suspended animation—a violent process that usually involves ejecting stomach fluids.

This violent re-awakening seems to make sense. Humans, after all, don’t naturally hibernate. But a small, eclectic group of scientists is battling nature to trigger artificial hibernation in humans. If successful, they could delay aging, treat life-threatening illnesses, and get us to Mars and beyond.

Last week, a group of experts gathered in New Orleans to explore the possibility of inducing “synthetic” hibernation in humans. Scientists are learning from nature to understand the factors that lead to hibernation and re-awakening in animals.

The Hibernation Enigma

What better way to pass long stretches of life-threating coldness and food poverty than to enter deep unconsciousness? Much of the animal kingdom hibernates through winters: bears, squirrels, hedgehogs. Even our primate cousin, the fat-tailed lemur, drastically drops its metabolic rate when food supplies dwindle.

What about us? Although we (regrettably) don’t hibernate, a handful of “miracles” suggests that a metabolic deep freeze may help preserve our injured bodies in a beneficial way.

In 1999, radiologist Dr. Anna Bagenholm fell into a frozen stream while skiing in Norway. By the time she was retrieved, she had been under ice for over 80 minutes. By all accounts she was clinically dead—no breathing, no heartbeat. Her body temperature dropped to an unprecedented 56.7 °F (13.7 °C).

Yet when doctors gradually warmed her blood, her body began to slowly heal. By the next day, her heart restarted. By day 12, she opened her eyes.  Eventually she fully recovered.

Bagenholm’s case is just one hint that humans have the ability to recover from a severely depressed metabolic state. For years doctors have employed therapeutic hypothermia—lowering body temperature by a few degrees for several days—to help keep patients with brain injuries or epilepsy in suspended animation.

This rapid cooling helps preserve tissues that have been cut off from blood supply, so they require less oxygen to function. In China, experiments have helped keep people in a deep freeze for up to two weeks.

The promise of therapeutic hypothermia is so great that in 2014, NASA partnered with the Altanta-based SpaceWorks and gave preliminary funding to a space-travel hibernator for a mission to Mars.

Although the flight into space would only last a few months, putting astronauts into an inactive state could dramatically cut down on the required amount of food and habitat size. A hibernation state could also help prevent serious side effects from low gravity, such as changes in spinal fluid flow that diminishes eyesight.

Direct muscle stimulation, courtesy of the hibernation pod, could prevent muscle wasting in zero G, and a deep state of unconsciousness could potentially minimize psychological challenges like boredom and loneliness.

The project made it to the second funding round, but many questions remained. One issue with the proposal is that prolonged hypothermia is terrible for health: blood clots, bleeding, infection, and liver failure may occur. On a spaceship without sophisticated medical facilities, these complications could be deadly.

Another problem is that we don’t fully understand what happens in an animal when it goes into hibernation. That’s what the New Orleans conference tried to address.

Biological Inspiration

To Dr. Hannah Carey at the University of Wisconsin, the answer to human hibernation may not lie in medical treatments, but in nature.

Carey studies the hibernation habits of the ground squirrel, a petite omnivorous rodent that roams North American prairies. Between late September and May, the ground squirrel hibernates in underground burrows to survive bitter winters.

“The fact that there is hibernation in the primate lineage makes any discoveries with biomedical potential that much more applicable to human beings,” she said.

One peculiar observation Carey has made is that low metabolic rate doesn’t last all winter. Periodically, hibernating animals will rouse from their torpor state for half a day, raising their body temperatures back to normal. The animals still don’t eat or drink during these periods, however.

Read More: Nanotechnology In Space

“Originally hibernation was considered a continuation of sleep, but physiologically it is very different because your metabolism is totally suspended, although it is still regulated,” saidOxford neuroscientist Dr. Vlad Vyazovskiy, who also presented at the conference. “Torpor, this extreme metabolic challenge, seems to do something to the brain or body which necessitates sleep, which in turn provides some type of restoration.”

Neuroscientists have long appreciated the benefits of sleep. For example, studies show that sleep helps the brain clear toxic waste through its lymphatic system and allows the brain’s synapses to “reset.” If hibernation contributes to a sleep-deprived state, could periodically inducing sleep be the answer to long-term torpor?

We don’t yet know. But to Carey, these findings from animals suggest that on the quest to human hibernation, unraveling the biology of natural hibernators may be preferable to hypothermia-based medical practices.

Artificial Hibernation

While Cary and Vyazovskiy study how hibernating animals remain healthy, Dr. Matteo Cerri at the University of Bologna in Italy has a different focus: how to artificially induce torpor in non-hibernating animals.

The answer may lie in a small group of neurons in a brain region called the raphe pallidus. Because metabolism dramatically slows during hibernation, hormonal and brain mechanisms are likely involved to kick-start the process, he explained.

Back in 2013, his team was one of the first to induce a hibernation-like state in rats, which don’t normally hibernate. They injected a chemical into the raphe pallidus to inhibit neuronal activity. These neurons are usually involved in the “thermoregulatory cold defense,” said Cerri, in that they’ll trigger biological responses to counteract the lowering of body temperature.

The rats were then placed into a dark, chilly room and fed high-fat diets—conditions known to lower metabolic rate.

Shutting down defense neurons for six hours resulted in a drastic temperature drop in the rats’ brains. Their heart rates and blood pressure also decreased. Eventually, their brain wave patterns began to resemble animals in natural hibernation.

The best part? When the team stopped their treatment, the rats recovered—they didn’t show any signs of abnormal behavior the next day.

Previous attempts at inducing torpor in non-hibernating animals have failed, the team said, but in this study they showed that inhibiting raphe pallidus neurons is essential to inducing a torpor-like state.

If the results hold up in larger mammals, it could spell trouble for human hibernation. Cerri and others are working to further dissect the brain’s control over torpor and how to hijack it for the purpose of inducing a hibernation-like state.

What’s Next?

Human hibernation isn’t yet on the horizon. But results from the conference presenters, among others, are gradually nailing down the molecular and neural factors that could potentially allow us to go into deep freeze.

Leopold Summerer, who leads the Advanced Concepts Team at the European Space Agency, is hopeful about future prospects for human hibernation. “We see the science has advanced enough to put some of the science fiction into the realm of science reality,” he said.

Article by Shelly Fan

Connecting the Future of Electric Vehicles with Our Exploration of Space – “Back to the Future”

Special Contribution by Jason Torchinsky 

Yesterday, we reported on an alarming development for the future of electric cars: we may not have enough of the crucial minerals needed for their batteries to meet the expected demand. Supplies of nickel and cobalt are going to be needed in far larger quantities than ever before, and it’s looking like we may not have the necessary resources. 

Though, it’s worth mentioning that this is only a problem if you have what the intergalactic call a “planetary mindset.” There’s plenty of what we need just outside our door, in asteroids.

Asteroid mining has been discussed and planned and speculated about for decades, but so far there’s never really been a compelling economic reason to take the risks inherent in starting an entirely new, space-based industry.

Electric car demand may be that crucial factor that changes everything, though. Nickel and cobalt of sufficient quality and quantity may be becoming scarce on Earth, but there’s literally tons and tons and tons of the stuff pirouetting around in the inky black of space.

There’s incredibly, astoundingly valuable asteroids out there, and many we’ve already identified, like 241 Germania, which has as much mineral value in it as the entire Earth’s yearly GDP. Nickel and cobalt are abundant elements in these asteroids, and researchers have even already picked a dozen small asteroids close enough to Earth that they could be mined with just the technology that we have right now.

Those 12 asteroids are close enough to the L1 or L2 Lagrangian Points–stable areas where the gravity between two bodies, like the Earth and moon, cancel one another out–that getting them to these stable, accessible orbits is easy enough that researchers call them EROs, for Easily Retrievable Objects.

Companies like Planetary Resources have been working on asteroid mining for years, but have mostly been focused on the in-space uses of those resources, as opposed to bringing those resources back to Earth. This animation gives a sense of the way they’ve been thinking so far:

While in-space use of asteroid mineral resources is absolutely important, the recently seen expected demand for electric cars–most obviously seen in the amount of interest and pre-orders Tesla got for its upcoming Model 3–changes things dramatically. Electric car demand could easily be the backbone of the justification for asteroid mining that returns resources to Earth.

Where it was once thought that it didn’t make economic sense to mine asteroids for terrestrial use, that thinking is changing. In fact, a recent study by Noah Poponak of Goldman Sachs says the opposite:

“While the psychological barrier to mining asteroids is high, the actual financial and technological barriers are far lower. Prospecting probes can likely be built for tens of millions of dollars each and Caltech has suggested an asteroid-grabbing spacecraft could cost $2.6 billion.”

For comparison, $2.6 billion is how much money Lyft has raised. Lyft! What have they produced? Fuzzy pink car-moustaches and an app, neither of which can grab asteroid one.

Legally, things are looking good, too. An Obama-era law, the U.S. Commercial Space Launch Competitiveness Act, was passed that acknowledges that while legally no one can own the moon or an asteroid, private companies can own any materials taken from those celestial objects, which means asteroid mining for profit is legal.

If electric cars provide the economic push needed to get us to send grizzled robot space prospectors out to get that sweet, sweet space-cobalt, it’s hard not to see a possible significant competitive advantage for one of the key players, Tesla.

That’s because as we all know, Elon Musk is behind not just Tesla but SpaceX, likely the most successful private space-launch company around. SpaceX has capable launch vehicles and likely the expertise to design and build robotic mining spacecraft, which could give Tesla total control of their entire vertical from mining the resources in space, transporting them back to Earth (humans have been sending material from space to Earth since the start of the space program, remember), manufacturing those resources into batteries, and from there into electric cars.

Has this been Elon’s plan all along? Has all the Mars colonization hype just been a red-planet herring to distract us from his real preparations for large-scale asteroid mining?

Probably not, but it’s fun to think about. There’s also an environmental argument in favor of asteroid mining for electric car batteries. Where electric cars are far cleaner at the car level, they still take an environmental toll to build, since mining isn’t exactly the most eco-friendly endeavor. Moving that part of the equation off-planet would made the overall life cycle of an electric car vastly better for the Earth, for the simple reason it’s just not happening there.

Rice U: Long Nanotube fibers for use in Large-Scale Aerospace, Consumer Electronics and Textile Applications

Rice University researchers advance characterization, purification of Nanotube wires and films

RICE UNIVERSITY

To make continuous, strong and conductive carbon nanotube fibers, it’s best to start with long nanotubes, according to scientists at Rice University.

The Rice lab of chemist and chemical engineer Matteo Pasquali, which demonstrated its pioneering method to spin carbon nanotube into fibers in 2013, has advanced the art of making nanotube-based materials with two new papers in the American Chemical Society’s ACS Applied Materials and Interfaces.

The first paper characterized 19 batches of nanotubes produced by as many manufacturers to determine which nanotube characteristics yield the most conductive and strongest fibers for use in large-scale aerospace, consumer electronics and textile applications.

The researchers determined the nanotubes’ aspect ratio — length versus width — is a critical factor, as is the overall purity of the batch. They found the tubes’ diameters, number of walls and crystalline quality are not as important to the product properties.

Pasquali said that while the aspect ratio of nanotubes was known to have an influence on fiber properties, this is the first systematic work to establish the relationship across a broad range of nanotube samples. Researchers found that longer nanotubes could be processed as well as shorter ones, and that mechanical strength and electrical conductivity increased in lockstep.

The best fibers had an average tensile strength of 2.4 gigapascals (GPa) and electrical conductivity of 8.5 megasiemens per meter, about 15 percent of the conductivity of copper. Increasing nanotube length during synthesis will provide a path toward further property improvements, Pasquali said.

The second paper focused on purifying fibers produced by the floating catalyst method for use in films and aerogels. This process is fast, efficient and cost-effective on a medium scale and can yield the direct spinning of high-quality nanotube fibers; however, it leaves behind impurities, including metallic catalyst particles and bits of leftover carbon, allows less control of fiber structure and limits opportunities to scale up, Pasquali said.

“That’s where these two papers converge,” he said. “There are basically two ways to make nanotube fibers. In one, you make the nanotubes and then you spin them into fibers, which is what we’ve developed at Rice. In the other, developed at the University of Cambridge, you make nanotubes in a reactor and tune the reactor such that, at the end, you can pull the nanotubes out directly as fibers.

“It’s clear those direct-spun fibers include longer nanotubes, so there’s an interest in getting the tubes included in those fibers as a source of material for our spinning method,” Pasquali said. “This work is a first step toward that goal.”

The reactor process developed a decade ago by materials scientist Alan Windle at the University of Cambridge produces the requisite long nanotubes and fibers in one step, but the fibers must be purified, Pasquali said. Researchers at Rice and the National University of Singapore (NUS) have developed a simple oxidative method to clean the fibers and make them usable for a broader range of applications.

The labs purified fiber samples in an oven, first burning out carbon impurities in air at 500 degrees Celsius (932 degrees Fahrenheit) and then immersing them in hydrochloric acid to dissolve iron catalyst impurities.

Impurities in the resulting fibers were reduced to 5 percent of the material, which made them soluble in acids. The researchers then used the nanotube solution to make conductive, transparent thin films.

“There is great potential for these disparate techniques to be combined to produce superior fibers and the technology scaled up for industrial use,” said co-author Hai Minh Duong, an NUS assistant professor of mechanical engineering. “The floating catalyst method can produce various types of nanotubes with good morphology control fairly quickly. The nanotube filaments can be collected directly from their aerogel formed in the reactor. These nanotube filaments can then be purified and twisted into fibers using the wetting technique developed by the Pasquali group.”

Pasquali noted the collaboration between Rice and Singapore represents convergence of another kind. “This may well be the first time someone from the Cambridge fiber spinning line (Duong was a postdoctoral researcher in Windle’s lab) and the Rice fiber spinning line have converged,” he said. “We’re working together to try out materials made in the Cambridge process and adapting them to the Rice process.”

###

Alumnus Dmitri Tsentalovich, currently an academic visitor at Rice, is lead author of the characterization paper. Co-authors are graduate students Robert Headrick and Colin Young, research scientist Francesca Mirri and alumni Junli Hao and Natnael Behabtu, all of Rice.

Thang Tran of Rice and NUS and Headrick are co-lead authors of the catalyst paper. Co-authors are graduate student Amram Bengio and research specialist Vida Jamali, both of Rice, and research scientist Sandar Myo and graduate student Hamed Khoshnevis, both of NUS.

The Air Force Office of Scientific Research, the Welch Foundation and NASA supported both projects. The characterization project received additional support from the Department of Energy. The catalyst project received additional support from the Temasek Laboratory in Singapore.

Influence of Carbon Nanotube Characteristics on Macroscopic Fiber Properties: http://pubs.acs.org/doi/abs/10.1021/acsami.7b10968

Purification and Dissolution of Carbon Nanotube Fibers Spun from Floating Catalyst Method: http://pubs.acs.org/doi/abs/10.1021/acsami.7b09287

This news release can be found online at http://news.rice.edu/2017/10/15/long-nanotubes-make-strong-fibers/

What Are Carbon Nanotubes and What are some of their Applications

Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure.

 

 

 

These cylindrical carbonmolecules have unusual properties, which are valuable for nanotechnology, electronics, optics and other fields of materials science and technology. Owing to the material’s exceptional strength and stiffness, nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1,^[1] significantly larger than for any other material.

In addition, owing to their extraordinary thermal conductivity, mechanical, and electrical properties, carbon nanotubes find applications as additives to various structural materials. For instance, nanotubes form a tiny portion of the material(s) in some (primarily carbon fiber) baseball bats, golf clubs, car parts or damascus steel.

 

NASA and Rice U Collaborate on’Fuzzy Fibers’ (carbide nanotubes) that can take the Heat from NextGen Rockets

Researchers create tough material for next generation of powerful engines

To stand up to the heat and pressure of next-generation rocket engines, the composite fibers used to make them should be fuzzy.

The Rice University laboratory of materials scientist Pulickel Ajayan, in collaboration with NASA, has developed “fuzzy fibers” of silicon carbide that act like Velcro and stand up to the punishment that materials experience in aerospace applications.

Silicon carbide nanotubes attached to separate silicon carbide fibers, used by NASA, entangle each other in this electron microscope image. The material created at Rice University is intended for a ceramic composite that would make rocket engines stronger, lighter and better able to withstand extreme heat.

Credit: Ajayan Research Group/Rice University

 

 

The fibers strengthen composites used in advanced rocket engines that have to withstand temperatures up to 1,600 degrees Celsius (2,912 degrees Fahrenheit). Ceramic composites in rockets now being developed use silicon carbide fibers to strengthen the material, but they can crack or become brittle when exposed to oxygen.

The Rice lab embedded silicon carbide nanotubes and nanowires into the surface of NASA’s fibers. The exposed parts of the fibers are curly and act like the hooks and loops that make Velcro so valuable — but on the nanoscale.

The result, according to lead researchers Amelia Hart, a Rice graduate student, and Chandra Sekhar Tiwary, a Rice postdoctoral associate, creates very strong interlocking connections where the fibers tangle; this not only makes the composite less prone to cracking but also seals it to prevent oxygen from changing the fiber’s chemical composition.

The work is detailed in the American Chemical Society journal Applied Materials and Interfaces.

The work began when Hart, who had been studying the growth of carbon nanotubes on ceramic wool, met Michael Meador, then a scientist at NASA’s Glenn Research Center, Cleveland, at the kickoff reception for Rice’s Materials Science and NanoEngineering Department. (Meador is now nanotechnology project manager at NASA’s Game Changing Technologies program.)

That led to a fellowship in Cleveland and the chance to combine her ideas with those of NASA research engineer and paper co-author Janet Hurst. “She was partially converting silicon carbide from carbon nanotubes,” Hart said. “We used her formulation and my ability to grow nanotubes and figured out how to make the new composite.”

Back at Rice, Hart and her colleagues grew their hooks and loops by first bathing silicon carbide fiber in an iron catalyst and then using water-assisted chemical vapor deposition, a process developed in part at Rice, to embed a carpet of carbon nanotubes directly into the surface. These become the template for the final product. The fibers were then heated in silicon nanopowder at high temperature, which converts the carbon nanotubes to silicon carbide “fuzz.”

The researchers hope their fuzzy fibers will upgrade the strong, light and heat-resistant silicon carbide fibers that, when put in ceramic composites, are being tested for robust nozzles and other parts in rocket engines. “The silicon carbide fiber they already use is stable to 1,600 C,” Tiwary said. “So we’re confident that attaching silicon carbide nanotubes and wires to add strength will make it even more cutting-edge.”

The new materials should also make entire turbo engines significantly lighter, Hart said. “Before they used silicon carbide composites, many engine parts were made of nickel superalloys that had to incorporate a cooling system, which added weight to the whole thing,” she said. “By switching to ceramic matrix composites, they could take out the cooling system and go to higher temperatures. Our material will allow the creation of larger, longer-lasting turbo jet engines that go to higher temperatures than ever before.”

Friction and compression testing showed the lateral force needed to move silicon carbide nanotubes and wires over each other was much greater than that needed to slide past either plain nanotubes or unenhanced fibers, the researchers reported. They were also able to easily bounce back from high compression applied with a nano-indenter, which showed their ability to resist breaking down for longer amounts of time.

Tests to see how well the fibers handled heat showed plain carbon nanotubes burning away from the fibers, but the silicon carbide nanotubes easily resisted temperatures of up to 1,000 C.

Hart said the next step will be to apply her conversion techniques to other carbon nanomaterials to create unique three-dimensional materials for additional applications.

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Story Source:

Materials provided by Rice University. Note: Content may be edited for style and length.

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Journal Reference:

1. Amelia H.C. Hart, Ryota Koizumi, John T Hamel, Peter Samora Owuor, Yusuke Ito, Sehmus Ozden, Sanjit Bhowmick, Syed Asif Syed Amanulla, Thierry Tsafack, Kunttal Keyshar, Rahul Mital, Janet Hurst, Robert Vajtai, Chandra Sekhar Tiwary, Pulickel M Ajayan. Velcro®-Inspired SiC Fuzzy Fibers for Aerospace Applications. ACS Applied Materials & Interfaces, 2017; DOI: 10.1021/acsami.7b01378

 

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NASA Data Suggests the World is Running Out … of WATER

The world’s largest underground aquifers – a source of fresh water for hundreds of millions of people — are being depleted at alarming rates, according to new NASA satellite data that provides the most detailed picture yet of vital water reserves hidden under the Earth’s surface.

Twenty-one of the world’s 37 largest aquifers — in locations from India and China to the United States and France — have passed their sustainability tipping points, meaning more water was removed than replaced during the decade-long study period, researchers announced Tuesday. Thirteen aquifers declined at rates that put them into the most troubled category. The researchers said this indicated a long-term problem that’s likely to worsen as reliance on aquifers grows.

Scientists had long suspected that humans were taxing the world’s underground water supply, but the NASA data was the first detailed assessment to demonstrate that major aquifers were indeed struggling to keep pace with demands from agriculture, growing populations, and industries such as mining.

Satellite system flags stressed aquifers

More than half of Earth’s 37 largest aquifers are being depleted, according to gravitational data from the GRACE satellite system.

“The situation is quite critical,” said Jay Famiglietti, senior water scientist at NASA’s Jet Propulsion Laboratory in California and principal investigator of the University of California Irvine-led studies.

Underground aquifers supply 35 percent of the water used by humans worldwide. Demand is even greater in times of drought. Rain-starved California is currently tapping aquifers for 60 percent of its water use as its rivers and above-ground reservoirs dry up, a steep increase from the usual 40 percent. Some expect water from aquifers will account for virtually every drop of the state’s fresh water supply by year end.

Read more: The countries facing the worst water shortages
Lake Mead’s water level has never been lower

The aquifers under the most stress are in poor, densely populated regions, such as northwest India, Pakistan and North Africa, where alternatives are limited and water shortages could quickly lead to instability.

The researchers used NASA’s GRACE satellites to take precise measurements of the world’s groundwater aquifers. The satellites detected subtle changes in the Earth’s gravitational pull, noting where the heavier weight of water exerted a greater pull on the orbiting spacecraft. Slight changes in aquifer water levels were charted over a decade, from 2003 to 2013.

“This has really been our first chance to see how these large reservoirs change over time,” said Gordon Grant, a research hydrologist at Oregon State University, who was not involved in the studies.

But the NASA satellites could not measure the total capacity of the aquifers. The size of these tucked-away water supplies remains something of a mystery. Still, the satellite data indicated that some aquifers may be much smaller than previously believed, and most estimates of aquifer reserves have “uncertainty ranges across orders of magnitude,” according to the research.

Aquifers can take thousands of years to fill up and only slowly recharge with water from snowmelt and rains. Now, as drilling for water has taken off across the globe, the hidden water reservoirs are being stressed.

“The water table is dropping all over the world,” Famiglietti said. “There’s not an infinite supply of water.”

The health of the world’s aquifers varied widely, mostly dependent on how they were used. In Australia, for example, the Canning Basin in the country’s western end had the third-highest rate of depletion in the world. But the Great Artesian Basin to the east was among the healthiest.

Before and after pictures show the extent of California’s drought (Getty)
The difference, the studies found, is likely attributable to heavy gold and iron ore mining and oil and gas exploration near the Canning Basin. Those are water-intensive activities.

The world’s most stressed aquifer — defined as suffering rapid depletion with little or no sign of recharging — was the Arabian Aquifer, a water source used by more than 60 million people. That was followed by the Indus Basin in India and Pakistan, then the Murzuk-Djado Basin in Libya and Niger.

California’s Central Valley Aquifer was the most troubled in the United States. It is being drained to irrigate farm fields, where drought has led to an explosion in the number of water wells being drilled. California only last year passed its first extensive groundwater regulations. But the new law could take two decades to take full effect.

©The Washington Post

Using Nanotechnology to Build a Space Elevator: (With Video) Not So Crazy of an Idea:

A space elevator may sound like an idea that could only exist in science fiction but we may be closer to seeing one in the near future than you might have previously thought. By William Wassmer

2050: A Space Odyssey

A Japanese company, called Obayashi Corporation, recently announced that it intends to build a fully working space elevator by the year 2050. This space elevator would drastically reduce the risks and costs associated with space travel in the future. A space elevator would act as a direct transport route to the frontier of space.

Diamond Nanothreads

The space elevator still has a lot of theoretical challenges to overcome before it can be realised. Currently the largest challenge facing the space elevator project is the creation of a cable that would be strong enough to support the immense forces that it would be subjected to.

Advances in research into nanotechnology and carbon nanotube materials are now presenting us with the opportunity to create a cable that could actually handle the forces that would be exerted on it.

Researchers are currently exploring the idea of using ‘diamond nano-threads’ as the material of choice for a space elevator cable. These nanothreads, which are currently being developed by John V. Badding and his research team at Penn State University, have a unique structure compared to other carbon nanotubes.

John Badding, Professor of Chemistry at Penn State, Talks About his Research

The unique structure which diamond nanothreads have is achieved by compressing benzene, a ring of six carbon atoms, causing the benzene to stack. Eventually the pressure becomes too much and the benzene breaks apart, only to reform again in the shape of a tetrahedron as the pressure is slowly released by the scientists.

One of our wildest dreams for the nanomaterials we are developing is that they could be used to make the super-strong, lightweight cables that would make possible the construction of a space elevator which so far has existed only as a science-fiction idea.

John V. Badding, Professor of Chemistry at Penn State University

Badding’s team are the first to develop a structure in which tetrahedrons, pyramids with a triangular base, are connected end by end in order to form an incredibly strong structure.

Creating Incredibly Light and Incredibly Strong Cables

The strength of a diamond nanothread means that this nanomaterial could be used to create the cables of a space elevator. The cables need to be both incredibly light and incredibly strong in order to provide the stability required for a space elevator to operate.

Diamond nanothreads would be ideal for this use due to their stiffness and strength, as well as the fact that they are light in weight. However, currently used processes and techniques to create carbon nanotubes have limitations and are not yet able to produce the quantity or quality of nanomaterials which a space elevator cable would require.

However, the Obayashi Corporation believes that large scale production technology will have been established by 2030, leading them to predict that they could complete their space elevator project by 2050. The construction of a cable is the first step in creating a space elevator because it requires the most research in order to be fully realised.

Diamond Nanothreads – Image Credit: John Badding Lab | Penn State University

The Main Components of a Space Elevator

The other four main components required to build a space elevator are:

• an anchoring station placed on the surface of the earth
• a counterweight in space which will help stabilise the orbit of the cable
• a mechanical lifter to pull the elevator up the cable
• a power source located on the earth to deliver power to the elevator

The Anchoring Station

The anchoring station will serve as a starting base for space elevator missions and will most likely originate from a location in the Pacific Ocean. Using a location on the surface of the Pacific Ocean would allow the anchoring station to move along the ocean surface to help the cable avoid any threatening objects. A location along the equator in the Pacific Ocean would also help to minimise the threat that extreme weather could pose to the space elevator and its operation.

The Counterweight

The counterweight helps to stabilise the space elevator by keeping the cable at its maximum length and tension as it orbits around the earth. Researchers believe that the ideal counterweight could be the same spacecraft which will be used to launch the cable into space. This dual purpose spacecraft/counterweight would help to minimise the economic costs of the counterweight and the spacecraft delivering the cable.

An Elevator to Space: Markus Landgraf at TEDxRheinMain

The Mechanical Lifter

The mechanical lifter will work in conjunction with the cable to provide the elevator with its vertical motion. One of the potential designs for the lifter is a series of rollers with traction tread that would look something similar to the rollers on a tank. These rollers would pull the cable through the space elevator and thus pull the elevator upwards into space.

The Power Source

The power source will wirelessly deliver power from the anchoring station to the space elevator as it makes its journey upwards towards space. This can be done by firing a laser at photovoltaic cells, which will convert the energy from the laser into electricity that the mechanical lifter can use.

Whilst the concept of wirelessly transferred power sounds like something straight from the pages of a science fiction novel, we have been using microwaves to fly model aircraft for over 20 years.

Some Challenges to Overcome

Even if all of these components work in unison there are still a number of challenges that need to be overcome in order to create a working space elevator. For example, low earth orbit objects could potentially damage or cut the cable that the space elevator is using. If the cable was to be cut it could fall back to the earth and cause enormous damage to the anchor station and the surrounding area.

Another major concern which has to be considered is the political impact of creating a space elevator. If the space elevator’s anchor station is situated in international waters, then who would own the space elevator and how would you equally share the usage of the space elevator? These are just a few of the issues which have to be resolved before the space elevator becomes a reality.

Why is it Worth the Effort?

The current cost of transporting cargo into space using spacecraft is around $20,000 per kilogram. Using a space elevator, Obayashi claims that this cost will be drastically reduced to just of only a few hundred dollars per kilogram of cargo. Apart from the obvious benefits of transporting material into space in a more cost effective manner, a space elevator also has huge applications for space launches.

Overcoming the Earth’s gravitational field and atmosphere is one of the major costs and difficulties associated with a space shuttle launch. However, if a space elevator could transport a spacecraft into space ready to be launched, then the effects of gravity and atmosphere would no longer pose a challenge to space travel in the future.

The development of a space elevator represents an important first step towards travel and exploration into deep space, as well as opening up the possibility of a civilisation that spans our solar system.

References and Further Reading

• Smallest Possible Diamonds Form Ultra-thin Nanothreads – Pennsylvania State University
• How Space Elevators Will Work – HowStuffWorks
• ​Japanese Company Plans Space Elevator by 2050 – CNET
• Carbon Nanotubes – SpaceElevatorWiki.com

NASA Chooses Microfluidic Electrochemical Reactor for Potential “Mission to Mars” Technology

NASA has selected UT Arlington as one of four U.S. institutions to develop improved methods for oxygen recovery and reuse aboard human spacecraft, a technology the agency says is crucial to “enable our human journey to Mars and beyond.”

NASA’s Game Changing Development Program awarded $513,356 recently to the UT Arlington team. UT Arlington and three other teams are charged with the goal of increasing oxygen recovery to 75 percent or more.

Principal investigators on the UT Arlington project are Brian Dennis, associate professor of mechanical and aerospace engineering in the College of Engineering; Krishnan Rajeshwar, distinguished professor of chemistry and biochemistry in the College of Science; and Norma Tacconi, a research associate professor of chemistry and biochemistry.

Principal investigators on the UT Arlington project are from left: Krishnan Rajeshwar, distinguished professor of chemistry and biochemistry in the College of Science; Brian Dennis, associate professor of mechanical and aerospace engineering in the College of Engineering; and Norma Tacconi, a research associate professor of chemistry and biochemistry.

They will design, build and demonstrate a “microfluidic electrochemical reactor” to recover oxygen from carbon dioxide that is extracted from cabin air. The prototype will be built over the next year at the Center for Renewable Energy Science and Technology, CREST, at UT Arlington.

“At the end of this 15 month Phase I project, we will demonstrate the prototype to NASA officials. If we are selected to move to Phase II, we plan to build a full-scale unit. We hope the technology will be flight tested on the International Space Station sometime in the future,” Dennis said. “That’s what we’re really excited about and what we’ll be aiming for.”

Dennis said the design uses water and carbon dioxide as reactants and produces oxygen and hydrocarbon gases, such as methane. The gases can be vented into space and the oxygen is used for breathing.

“We have developed a nanocomposite electrode that speeds oxygen evolution at lower potential. That basically means it can produce more oxygen in a shorter time with less power and less reactor volume,” said Dennis. “This is important since power on a spacecraft is limited because it comes from solar panels and spacecraft capacity also is limited. Things should be as compact and lightweight as possible.”

Current methods of oxygen recovery used on the International Space Station, or ISS, achieve only about a 50 percent recovery rate. A better recovery rate means less oxygen needs to be stored and would free up precious cargo space on prolonged missions. With current technology, a trip to Mars would take about eight months, though scientists are working to shorten that time.

In a statement from NASA, Associate Administrator for Space Technology Michael Gazarak said improving oxygen recovery and designing a system with high reliability is crucial to long-duration human spaceflight.

“These ambitious projects will enable the critical life support systems needed for us to venture further into space and explore the high frontier and are another example of how technology drives exploration,” Gazarak said. NASA’s full announcement is available here.

Dennis said the proposed UT Arlington device has an advantage over the ISS method because not as much water is needed to achieve 75 percent recovery. The team estimates its system would require less water than what can be recovered in one day from a person’s sweat and urine. A water recovery system that converts bodily fluids to water is already at work on the ISS.

For years, Dennis, Rajeshwar and Tacconi have developed novel nanocomposites to be used in targeted electrochemical reactions for fuel cells and other purposes. The new project builds on that work and is another demonstration of the key role electrochemistry can play in technological advances, Tacconi and Rajeshwar said.

James Grover, interim dean of the UT Arlington College of Science, said the new NASA-funded project is a great chance for the College of Science and College of Engineering to make an impact in a field that captures human imagination and inspires innovation.

“Discoveries are cultivated through interdisciplinary collaboration and UT Arlington scientists and engineers have embraced that spirit to achieve advances,” Grover said.

Khosrow Behbehani, dean of the College of Engineering, said the interdisciplinary project speaks to practical aspects of space research.

“This project has great implication for space explorations,” Behbehani said. “Through collaboration of scientists and engineers at UT Arlington such innovations have become possible which can put us closer to exploring farther destinations in space.”

Source: University of Texas at Arlington

Read more: Microfluidic electrochemical reactor chosen by NASA as potential Mars mission technology

Nanotechnology: It Isn’t Science Fantasy: NASA Nanotechnology Project

ORLANDO, FLA. — Nanotechnology is fast moving from the world of science fiction to science fact, with developments and applications that will ultimately create new, lighter and stronger materials that it is hoped will benefit business and public alike. So said Michael Meador, manager of NASA’s Game Changing Development Program’s Nanotechnology Project, at an Antec session at NPE 2015 in Orlando March 23.Meador, who also is chief of NASA’s Glenn Polymers Branch and is currently on loan to the White House Office of Science and Technology as director of the National Nanotechnology Coordination Office, said he and his colleagues at the National Nanotechnology Institute were pursuing a vision set out by President Clinton in a speech 15 years  ago to produce lighter,  stronger and more durable materials.

The NNI has been funded to the tune of $22 billion since its creation, but nanotechnology research is not just an expensive pipe dream for white-coated scientists. It has already found its way into a number of products: silica aerogels were in use on insulation materials for batteries on the Mars Rover, while a carbon nanotube-based sensor was used on the International Space Station.

An element of Clinton’s vision was the ability of nanotechnology to increase the capacity to store huge amounts of data in smaller and smaller devices, and detect cancer tumors within a small number of cells.

But it appears that aerospace will be where much of the potential lies. Ultra-lightweight structural nanomaterials can reduce the density of state-of-the-art structural composites by 50 percent and yet have  the same or better properties.

Using such technology, the weight of a space vehicle could potentially be reduced by up to 30 percent, which Meador described as a “game changer.” Meanwhile, the use of carbon nanotubes for cables can reduce the amount of material used in commercial aircraft, as well as spacecraft, leading to yet more weight reduction.

Crucially, Meador said the future direction of nanotechnology lies in its intersection with other industries — advanced manufacturing, precision medicine, brain research and anti-microbial resistant bacteria — and opportunities for collaboration and new applications.

There are enormous possibilities surrounding developments in changing the properties of a range of structures, some of which currently remained undiscovered, he added.