Gecko-like gripper could clean up space junk

Right now, about 500,000 pieces of human-made debris are whizzing around space, orbiting our planet at speeds up to 17,500 miles per hour. The debris poses a threat to satellites, space vehicles, and astronauts.

What makes tidying up especially challenging is that the debris exists in space. Suction cups don’t work in a vacuum. Traditional sticky substances, like tape, are largely useless because the chemicals they rely on can’t withstand the extreme temperature swings. Magnets only work on objects that are magnetic.

Most proposed solutions, including debris harpoons, either require or cause forceful interaction with the debris, which could push those objects in unintended, unpredictable directions.

“There are many missions that would benefit from this, like rendezvous and docking and orbital debris mitigation.”

To tackle the mess, researchers designed a new kind of robotic gripper to grab and dispose of the debris. The device is described in Science Robotics.

“What we’ve developed is a gripper that uses gecko-inspired adhesives,” says senior author Mark Cutkosky, professor of mechanical engineering at Stanford University. “It’s an outgrowth of work we started about 10 years ago on climbing robots that used adhesives inspired by how geckos stick to walls.”

The group tested their gripper, and smaller versions, in their lab and in multiple zero gravity experimental spaces, including the International Space Station. Promising results from those early tests have led the researchers to wonder how their grippers would fare outside the station, a likely next step.

“There are many missions that would benefit from this, like rendezvous and docking and orbital debris mitigation,” says Aaron Parness, group leader of the Extreme Environment Robotics Group at NASA’s Jet Propulsion Laboratory. “We could also eventually develop a climbing robot assistant that could crawl around on the spacecraft, doing repairs, filming, and checking for defects.”

How to control the forces that let geckos cling

The adhesives have previously been used in climbing robots and even a system that allowed humans to climb up certain surfaces. They were inspired by geckos, which can climb walls because their feet have microscopic flaps that, when in full contact with a surface, create a Van der Waals force between the feet and the surface. These are weak intermolecular forces that result from subtle differences in the positions of electrons on the outsides of molecules.

The gripper is not as intricate as a gecko’s foot—the flaps of the adhesive are about 40 micrometers across while a gecko’s are about 200 nanometers—but gecko-inspired adhesive works in much the same way.

Like a gecko’s foot, it is only sticky if the flaps are pushed in a specific direction but making it stick only requires a light push in the right direction. This is a helpful feature for the kinds of tasks a space gripper would perform.

Robot hug

“If I came in and tried to push a pressure-sensitive adhesive onto a floating object, it would drift away,” says coauthor Elliot Hawkes, a visiting assistant professor from the University of California, Santa Barbara. “Instead, I can touch the adhesive pads very gently to a floating object, squeeze the pads toward each other so that they’re locked and then I’m able to move the object around.”

The pads unlock with the same gentle movement, creating very little force against the object.

The gripper the researchers created has a grid of adhesive squares on the front and arms with thin adhesive strips that can fold out and move toward the middle of the robot from either side, as though it’s offering a hug. The grid can stick to flat objects, like a solar panel, and the arms can grab curved objects, like a rocket body.

One of the biggest challenges of the work was to make sure the load on the adhesives was evenly distributed, which the researchers achieved by connecting the small squares through a pulley system that also serves to lock and unlock the pads. Without this system, uneven stress would cause the squares to unstick one by one, until the entire gripper let go. This load-sharing system also allows the gripper to work on surfaces with defects that prevent some of the squares from sticking.

The group also designed the gripper to switch between a relaxed and rigid state.

“Imagining that you are trying to grasp a floating object, you want to conform to that object while being as flexible as possible, so that you don’t push that object away,” says Hao Jiang, a graduate student in the Cutkosky lab and the paper’ lead author. “After grasping, you want your manipulation to be very stiff, very precise, so that you don’t feel delays or slack between your arm and your object.”

50,000 bits of space debris pose a risk

The group first tested the gripper in the Cutkosky lab. They closely measured how much load the gripper could handle, what happened when different forces and torques were applied and how many times it could be stuck and unstuck. Through their partnership with JPL, the researchers also tested the gripper in zero gravity environments.

In JPL’s Robodome, they attached small rectangular arms with the adhesive to a large robot, then placed that modified robot on a floor that resembled a giant air-hockey table to simulate a 2D zero gravity environment.

They then tried to get their robot to scoot around the frictionless floor and capture and move a similar robot.

“We had one robot chase the other, catch it, and then pull it back toward where we wanted it to go,” says Hawkes. “I think that was definitely an eye-opener, to see how a relatively small patch of our adhesive could pull around a 300 kilogram robot.”

Next, Jiang and Parness went on a parabolic airplane flight to test the gripper in zero gravity. Over two days, they flew a series of 80 ascents and dives, which created an alternating experience of about 20 seconds of 2G and 20 seconds of zero-G conditions in the cabin. The gripper successfully grasped and let go of a cube and a large beach ball with a gentle enough touch that the objects barely moved when released.

Lastly, Parness’s lab developed a small gripper that went up in the International Space Station (ISS), where they tested how well the grippers worked inside the station.

Next steps for the gripper involve readying it for testing outside the space station, including creating a version made of longer lasting materials able to hold up to high levels of radiation and extreme temperatures. The current prototype is made of laser-cut plywood and includes rubber bands, which would become brittle in space. The researchers will have to make something sturdier for testing outside the ISS, likely designed to attach to the end of a robot arm.

Back on Earth, Cutkosky also hopes that they can manufacture larger quantities of the adhesive at a lower cost. He imagines that someday gecko-inspired adhesive could be as common as Velcro.

NASA, the National Science Foundation, and a Samsung Scholarship funded the work.

Source: Stanford University

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No one has ever seen 2 black holes this close together

Approximately 750 million light years from Earth lies a gigantic, bulging galaxy with two supermassive black holes at its center. These are among the largest black holes ever found, with a combined mass 15 billion times that of the sun.

Long-term observations suggest one of the black holes appears to orbit the other—the first duo ever shown to be moving in relation to each other. It is also, potentially, the smallest ever recorded movement of an object across the sky—known as angular motion.

“If you imagine a snail on the recently discovered Earth-like planet orbiting Proxima Centauri—a bit over four light years away—moving at one centimeter a second, that’s the angular motion we’re resolving here,” says Roger W. Romani, professor of physics at Stanford University and coauthor of the paper published in Astrophysical Journal.

The technical achievements of this measurement alone are reason for celebration. But the researchers also hope they’ll gain insight into how black holes merge, how the mergers affect the evolution of the galaxies around them, and ways to find other binary black-hole systems.

Over the past 12 years, scientists, led by Greg Taylor, a professor of physics and astronomy at the University of New Mexico, have taken snapshots of the galaxy containing the black holes—called radio galaxy 0402+379—with a system of 10 radio telescopes that stretch from the US Virgin Islands to Hawaii and New Mexico to Alaska.

Black holes kill more stars than astronomers expected

The galaxy was officially discovered back in 1995 and in 2006, scientists confirmed it as a supermassive black-hole binary system with an unusual configuration.

One of the black holes moved at an angle about 1 billion times smaller than the smallest thing visible with the naked eye.

“The black holes are at a separation of about seven parsecs, which is the closest together that two supermassive black holes have ever been seen before,” says graduate student and lead author Karishma Bansal.

The paper reports that one of the black holes moved at a rate of just over one micro-arcsecond per year, an angle about 1 billion times smaller than the smallest thing visible with the naked eye. Based on this movement, the researchers hypothesize that one black hole may be orbiting around the other over a period of 30,000 years.

Although directly measuring the black hole’s orbital motion may be a first, this is not the only supermassive black-hole binary ever found. Still, researchers believe that 0402+379 likely has a special history.

“We’ve argued it’s a fossil cluster,” Romani says. “It’s as though several galaxies coalesced to become one giant elliptical galaxy with an enormous halo of X-rays around it.”

Deepest X-ray image ever is chock-full of black holes

Researchers believe that large galaxies often have large black holes at their centers and, if large galaxies combine, their black holes eventually follow suit. It’s possible that the apparent orbit of the black hole in 0402+379 is an intermediary stage in this process.

“For a long time, we’ve been looking into space to try and find a pair of these supermassive black holes orbiting as a result of two galaxies merging,” Taylor says. “Even though we’ve theorized that this should be happening, nobody had ever seen it, until now.”

A combination of the two black holes in 0402+379 would create a burst of gravitational radiation, like the famous bursts recently discovered by the Laser Interferometer Gravitational-Wave Observatory, but scaled up by a factor of a billion. It would be the most powerful gravitational burst in the universe, Romani says.

The theorized convergence between the black holes of 0402+379, however, may never occur. Given how slowly the pair is orbiting, the scientists think the black holes are too far apart to come together within the estimated remaining age of the universe, unless there is an added source of friction. By studying what makes this stalled pair unique, the scientists say they may better understand the conditions under which black holes normally merge.

Romani hopes the work is just the beginning of heightening interest in unusual black-hole systems.

“My personal hope is that this discovery inspires people to go out and find other systems that are even closer together and, hence, maybe do their motion on a more human timescale. I would sure be happy if we could find a system that completed orbit within a few decades so you could really see the details of the black holes’ trajectories.”

Other researchers from the University of New Mexico, the National Radio Observatory, and the United States Naval Observatory are coauthors. NASA and the National Radio Astronomical Observatory funded the work.

Source: Stanford University

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To stop cancer’s spread, break its ‘legs’

Cancer cells most often kill by crawling away from their original tumors to later re-root in vital parts of the body in a process called metastasis.

Bristly leg-like protrusions that cover cancer cells enable them to creep. When researchers gently heated minuscule gold rods with a laser in experiments on common laboratory cultures (in vitro) of cancerous human cells, they were able to mangle the protrusions and prevent cell migration, a key mechanism in metastasis.

In the future, the technique could potentially offer clinicians going after individual tumors a weapon to combat cancer’s spread at the same time.

“If cancer stays in a tumor in one place, you can get to it, and it’s not so likely to kill the patient, but when it spreads around the body, that’s what really makes it deadly,” says lead researcher Mostafa El-Sayed, professor of chemistry and biochemistry at Georgia Institute of Technology and lead researcher of the study in the Proceedings of the National Academy of Sciences.

Squished cancer cells break free from the crowd

The treatment can also easily kill cancer cells, but in this experiment, it was vital to specifically show that it greatly slowed cell migration.

The experimental treatment also spares healthy cells, in these and in prior experiments, making it potentially much less taxing on patients than commonly used chemotherapy. In past tests in animal models, there were no toxic side effects from the gold used in the treatment, and no observable damage to healthy tissue from the low-energy laser. And there was no recurrence of the treated cancer.

“The method appears to be very effective as a locally administered treatment that also protects the body from cancers spread away from the treated tumors, and it is also very mild, so it can be applied many times over if needed,” El-Sayed says.

How it works

A close-up look at a cell and what malignant cancer can do to it clarifies how the treatment works, researchers say.

Many people think of cells as watery balloons—fluid encased in a membrane sheath with organelles floating around inside. But that picture is incomplete. Cells have support grids called cytoskeletons that give them form and that have functions.

The cytoskeletons also form bristly protrusions called filopodia, which extend out from a weave of fibers called lamellipodia on the cells fringes. The protrusions normally help healthy cells shift their location in the tissue that they are part of.

But in malignant cancer, normally healthy cell functions often lunge into destructive overdrive. Lamellipodia and filopodia are wildly overproduced.

“All these lamellipodia and filopodia give the cancer cells legs,” says Yue Wu, a graduate student in bioanalytical chemistry. “The metastasis requires those protrusions, so the cells can travel.”

Bubble pushes 1 cancer cell from device at a time

The gold nanorods thwart the protrusions in two ways. The rods are comprised of a small collection of gold atoms—nano refers to something being just billionths of meters (or feet) in size.

First, El-Sayed’s nanorods are introduced locally, where they encumber the leggy protrusions on cancerous cells. The rods are coated with molecules (RGD-peptides) that make them stick specifically to a type of cell protein called integrin.

“The targeted nanorods tied up the integrin and blocked its functions, so it could not keep guiding the cytoskeleton to overproduce lamellipodia and filopodia,” says Yan Tang, a postdoctoral assistant in computational biology. The binding of the integrin alone slowed down the migration of malignant cells.

But healthy cells stayed safe. “There are certain, specific integrins that are overproduced in cancerous cells,” says Moustafa Ali, one of the study’s first authors. “And you don’t find them so much in healthy cells.”

Gentle laser

In the second phase, researchers hit the gold nanoparticles with a low-energy laser of near-infrared (NIR) light. It brought the migration of the cancer cells to an observable halt.

“The light was not absorbed by the cells, but the gold nanorods absorbed it, and as a result, they heated up and partially melted cancer cells they are connected with, mangling lamellipodia and filopodia,” Ali says. “It didn’t kill all the cells, not in this experiment. If we killed them, we would not have been able to observe whether we stopped them from migrating or not.” But if necessary, the treatment can be adjusted to kill the cells.

Early experiments in animal models in vivo with hotter lasers didn’t work as well.  “That caused inflammation, which made it possible to heat one time only,” Ali says. “As a result, that high temperature would wipe out many cancer cells, but not all of them. Some hidden ones might have survived, and also still been able to migrate.”

“This gentle laser didn’t burn the skin or damage tissue, so it could be dosed multiple times and more thoroughly stop the cancer cells from being able to travel,” says researcher Ronghu Wu.

How some breast cancer cells return after chemo

Researchers envision treating head, neck, breast, and skin cancers with direct, local nanorod injections combined with the low-power near-infrared laser, which can hit the gold nanorods 2-3 centimeters (around an inch) deep inside tissue. “But it could go as deep as 4-5 centimeters,” Ali says.

Deeper tumors could conceivably be treated with deeper injections of nanorods. “Then you’d need to go in with a fiber optic or endoscopic laser,” El-Sayed says. Injecting the nanorods directly into the bloodstream as a broad treatment is not currently a viable option.

El-Sayeds group has previously published in vivo experiments in mice in the Proceedings of the National Academy of Sciences together with Emory University School of Medicine. That study showed no observable toxicity from the gold in mice 15 months after treatment.

“A lot of it ended up in the liver and spleen,” El-Sayed says. “But the functions of these organs appeared intact upon examination, and treated mice were alive and healthy over a year later.”

Other coauthors are from Georgia Tech and Georgia State University. The National Science Foundation Division of Chemistry and the National Institutes of Health funded the work.

Source: Georgia Tech

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Snoozle alarm clock won't be silenced until you get out of bed

The Snoozle alarm clock is actually made up of two parts

The hardest part of any morning (apart from maybe getting out of the warm shower) is extracting yourself from those cosy sheets and blankets. A snooze button within arm’s reach certainly doesn’t make things any easier, so the folks behind Snoozle aim to get slow risers up and at ‘em with an alarm clock that won’t be silenced until you carry it across the room.

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Category: Around The Home

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Prehistoric lizard wasn't what we thought

The fossilized Eusaurosphargis dalsassoi skeleton

Back in 2003, the fossilized remains of a prehistoric armored lizard known as Eusaurosphargis dalsassoi were discovered in Italy. The skeleton was disarticulated and incomplete, plus it was found with the remains of fish and marine reptiles, leading scientists to think that the lizard was aquatic. Now, however, thanks to a marvellously-complete skeleton found in the Alps of eastern Switzerland, that’s no longer thought to be the case.

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Category: Biology

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Tick spit could save hearts and lives

A cayenne tick, full of P991_AMBCA

Although ticks are generally thought of as being the spreaders of illness, they may actually be able to help save peoples’ lives. According to a new study from the University of Oxford, proteins found in tick saliva could be used to treat a potentially fatal heart disease.

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projects • Re: Induction (Wireless) Charging Earbuds

I finally had time to make mock-ups to see if the battery would pull the earbuds out.
The earbuds stayed on when it had a wingtip or an over the ear hook feature.
So from there I made 3 battery charger (A-C) concepts and 3 earbud (1-3) concepts.
Any opinions on a winning configuration?

For example configuration 1/A or 1/C wouldn’t work as the earbud would fall out, but 1/B could work.


design employment • Re: Mech Eng in New Product Development

I agree with moczys, contacting firms directly is probably a good way to go. I think a lot of design consultants do need a jack of all trades, and you might just fit the bill for the firms needs even if they haven’t advertised yet. That’s how I got my job (I’m your mirror image, an industrial designer who can pretend to be a mechanical engineer) – a small ME firm was considering a project that required some ID and I just happened to contact them at the right time. I’m not saying happenstance is necessarily a good job search strategy, but you might at least get a good conversation with some of the firms out of it.

I know less about corporate gigs, but even though you may lack some of the specific qualifications I wouldn’t shy away from jobs you might be interested in. If you can get past an HR gatekeeper there may be some who are interested in getting some variety of background on their team. You’d might fit best at the fuzzy front end of R&D at some places if you can find those departments.

Regarding your skills, I’d make sure to brush up on at least the basics of designing for injection molding and other plastic processes (even looking on injection molders’ websites for their guidelines is a start), and try to learn some CAD surfacing and learn a little about curvature continuity. As a designer I cringe at the thought of anyone creating final CAD of a form without the ability to realize the subtleties that can really make a design shine. Not all roles require this, but it seems like the roles you are looking for might.