The Sayaka is 40 percent smaller than previous endoscope cameras

Pop this pill, and eight hours later, doctors can examine a high-resolution video of your intestines for tumors and other problems, thanks to a new spinning camera that captures images in 360 degrees. Developed by the Japanese RF System Lab, the Sayaka endoscope capsule enters clinical trials in the U.S. this month.

How the Pill Films Your Innards

Down the Hatch
The patient gulps down the capsule, and the digestive process begins. Over the next eight hours, the pill travels passively down the esophagus and through roughly 20 to 25 feet of intestines, where it will capture up to 870,000 images. The patient feels nothing.

Power Up
The Sayaka doesn’t need a motor to move through your gut, but it does require 50 milliwatts to run its camera, lights and computer. Batteries would be too bulky, so the cam draws its power through induction charging. A vest worn by the patient contains a coil that continuously transmits power.

Start Snapping
When it reaches the intestines, the Sayaka cam begins capturing 30 two-megapixel images per second (twice the resolution of other pill cams). Fluorescent and white LEDs in the pill illuminate the tissue walls.

Spin For Close-Ups
Previous pill cameras place the camera at one end, facing forward, so the tissue walls are visible only in the periphery of their photos. Sayaka is the first that gets a clearer picture by mounting the camera facing the side and spinning 360 degrees so that it shoots directly at the tissue walls. As the outer capsule travels through the gut, an electromagnet inside the pill reverses its polarity. This causes a permanent magnet to turn the inner capsule and the image sensor 60 degrees every two seconds. It completes a full swing every 12 seconds—plenty of time for repeated close-ups, since the capsule takes about two minutes to travel one inch.

Offload Data
Instead of storing each two-megapixel image internally, Sayaka continually transmits shots wirelessly to an antenna in the vest, where they are saved to a standard SD memory card.

Deliver Video
Doctors pop the SD card into a PC, and software compiles thousands of overlapping images into a flat map of the intestines that can be as large as 1,175 megapixels. Doctors can replay the ride as video and magnify a problem area up to 75-fold to study details.

Leave the Body
At around $100, the cam is disposable, so patients can simply flush it away.



The tiniest endoscope yet takes 30 two-megapixel images per second and offloads them wirelessly. See how it works inside the body in an animation:
http://www.popsci.com/how-it-works/a...pe-camera-pill
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The Cassini spacecraft has uncovered evidence of a ring of space dust orbiting the second largest of Saturn’s moons, Rhea. No other moons have ever been found to have rings, so this could be a first, but it may also provide some interesting clues to Rhea’s past. When it captured the data in November 2005, Cassini was actually looking for evidence of an atmosphere around the moon.

The debris most likely consists of particles ranging in size from pebbles to boulders, and the ring extends several thousand miles. Scientists say that the space dust may be left over from a massive collision. If a large asteroid or comet hit the moon at some point in its distant past, this could have kicked up the debris. Cassini is due to pass by Rhea again in 2010. Scientists hope to gather more information then, but they say the probe will be on a safe course, and won't be in danger of running into any of those orbiting rocks.



The highest-endurance aircraft currently flying is Northrop Grumman’s Global Hawk UAV, which can stay aloft for up to 40 hours. Now Darpa—which, to its credit, is never short on outlandish ideas—wants to beat that endurance record more than 1,000 times. The goal of Darpa's recently launched Vulture Program is to build a kind of atmospheric satellite that can stay aloft for five years at a time with little or no maintenance.

It must be able to haul a 1,0000-pound payload all the while, and operate at an altitude of 60,000 to 90,000 feet. How does one power a plane that’s going go fly for five years? Solar seems to be the most logical option, though fuel cells could work, too. It’s not clear what shape the craft could take, though the NASA ultra-endurance concept aircraft pictured here could give some hints. Darpa says it’s close to awarding contracts; then phase one of the three-part program, which will focus on figuring out what this kind of plane might actually look like, can begin. Once someone has built a full-scale demonstrator that can stay in the air for 12 months, a Vulture program aircraft will enter production.



It could slow carbon dioxide emissions, power cars and jets, and replace petroleum altogether. Pond scum or green slime–whatever you want to call it–algae is the next great hope in the world of environmental startups.

In the natural world, algae is fairly effective at creating large quantities of oil, but turning the byproducts into biodiesel remains a difficult task. Nevertheless, the promise and business potential of an ultra-green fuel has spurned dozens of startups around the world. While their tactics for growth and extraction differ, all are focused on solving the problems associated with turning algae’s oily output into relatively inexpensive, useable fuel. And they share the same ultimate goal, some going so far as to predict commercial-scale production within three years.




Yahoo surprised analysts yesterday, announcing that it is on track to meet its expected earnings for 2008. This changes the fight between the Sunnyvale-based company and Microsoft, which recently offered to pay $42 billion to swallow it up. Now Yahoo has a bit more leverage, and may be able to convince investors that it’s not in such bad shape after all. The company says it expects to double its cash flow and increase its revenue by 50 percent, mostly from banner and video advertising. But it’s not clear at this point whether the good news is going to force Microsoft to up its bid.

Google CEO Eric Schmidt recently blasted the proposed deal, saying that it could stall the free flow of information on the Internet. But you have to wonder if maybe he doesn’t just have the interests of the people in mind. A Microsoft-Yahoo merger would give the search king some serious competition.




Dakota is the name given to the remains of an Edmontosaurus discovered on a ranch in the Badlands in 1999. What sets Dakota apart from all but four other dinosaurs so far unearthed is its completeness. And not just its complete skeleton—nearly all of Dakota’s skin and soft tissues have been fossilized, which is an exceedingly rare discovery in paleontology. The perfect conditions had to exist at the time of the animal’s demise—being rapidly buried in substrate at just the right moisture level to bring about fossilization instead of decay.

Having recently been excavated from the ground, the five ton fossil was last month moved to the North Dakota state museum where scientists will spend at least a year working painstakingly to remove the sandstone in which the remains are trapped.

Researchers in the field are ecstatic with the prospect of getting the most complete look yet at the anatomy of these ancient animals. The quality and extent of the skin are proving to be unparalleled, even in comparison to the other three mummified specimens.



When I went from footloose freelancer to sessile nine-to-fiver in a huge building, I made a rule: unless an open elevator was waiting, always take the stairs. This is because I knew it was the healthy thing to do.

Go figure—I’m right, says a new JAMA study. But not only does the research show that taking fewer steps is unhealthy, it can actually cause disease.
The team asked active men who average 10,000 steps a day to use vehicles and elevators at every chance for two weeks. Then the scientists measured the levels of glucose and fat in their blood. They found that the less active volunteers cleared out these substances from their bloodstream less quickly, a risk factor for diabetes and other chronic diseases.

Says one of the authors, University of Missouri researcher Frank Booth: “Previously, we thought that not exercising just wasn’t healthy, but we didn’t think that a lack of activity could cause disease. That assumption was wrong.”


http://www.popsci.com/

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How to Deliver Pristine Sound

A circuit called a crossover divides the audio signal into different frequency ranges and routes each batch to one of four speakers in the earphone.

2. Activate the Speaker
The signal from the crossover enters a speaker and flows into a tiny copper coil, which responds with faint electromagnetic vibrations. Nearby, a small strip of metal, or armature, balances between the fields created by two magnets. The vibrations disrupt this magnetic field, causing the magnetized armature to pivot.

3. Move the Air
When the armature moves, it pushes a small rod connected to a diaphragm, which in turn pushes the surrounding air and generates sound waves.

4. Deliver the Sound
One sound tube carries the high frequencies while another handles the mids and the lows. Mixing treble and bass in your ear instead of in the headphones, as other earbuds do, makes music sound less like you’re hearing it inside a phone booth and more as it would in the hall where it was recorded. Acoustic filters prevent interference between the high and low frequencies inside the sound tubes.

• Size: Custom-fit
• Frequency Range: 10 Hz–16,500 Hz
• Price: $1,150

http://www.popsci.com/gear-gadgets/a...lest-subwoofer

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Vision: An infrared transceiver in the nostrils constantly bounces beams off surfaces to tell Pleo what’s ahead (and to keep him from walking off a table). The full-color camera above his nostrils provides more detail on an object’s shape. Pleo sees up to 15 feet away and notices light changes (he sometimes cries in the dark).


Hearing: Pleo has microphones on both sides of his head. He can identify the direction of a noise by determining in which ear the sound is loudest or, as we do, by sensing in which ear a sound arrives first.


Motion: Pleo’s main processor sends data to four less-powerful processors, each of which runs up to four motors simultaneously and controls movements in Pleo’s 15 joints.


Feeling: Eight capacitive sensors, which look like pieces of foil, detect the electrical charge from your fingers. (The iPhone works the same way.) Pleo distinguishes among touches by measuring the duration and location rather than the force. That data goes to the main processor (below), which can receive messages from several sensors at the same time, so Pleo can respond to multiple touches.


Learning: Pleo’s main processor (the white plastic box inside the trunk) triggers actions based on physical input—put his plastic leaf in his mouth, for instance, and if he’s hungry, he’ll chew on it—as well as information stored on internal flash memory. The episodic, or short-term, memory stores a limited number of events that the processor determines to be significant, like the time Pleo sensed being held up by his tail. But he can also record cumulative memories, like how many times you touch each sensor, and act accordingly. If he knows that you typically scratch him under the chin, he’ll crane his neck out and coo for it.



Snoozing: To prevent Pleo from overheating inside of his lifelike soft rubber skin, an internal thermostat tells the processor to make him less active as his temperature rises.


Stomping: Sensor pads in Pleo's paws can detect the texture of the surface being walked on and relay the information to the central processor.


Skeleton: The Pleo's bone structure is modeled after the fossilized bones of a real Camarasaurus. A pivot in the middle of its two-part spine allows Pleo to wiggle his torso.


http://www.popsci.com/node/19959

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The Financial Times reported yesterday that Apple is considering a plan to give people free access to its library of tunes if they pay more for their iPods or iPhones. Some analysts doubted theveracity of the report, though, suggesting that Apple would be creating an accounting headache, and risk alienating the artists in its iTunes universe. Rumors–which seem to follow Apple more than any other company–about the notion of an open iTunes have been around for years.

The FT cites anonymous sources in the music industry who claim that Apple is currently negotiating with record labels. One possibility would be a subscription, the other free access. It’s not clear, though, how much the prices of the devices would increase.

According to the FT, insiders say that the negotiations currently hinge on how much Apple would have to pay for access to the record labels’ songs. Nokia, which offers music on its handsets, is believed to pay almost $80 per device, but Apple is, at this point, offering one-fourth of that. So, how much more would you pay for an iPod or iPhone if it came with a library of music?


Everyone seems to be double-extra-cautiously optimistic about this finding, so don’t go running out to your telescope tonight looking for greetings from friendly space creatures.

But in work reported today in Nature, astronomers say they used the Hubble Space Telescope’s infrared imager to pick up signs of methane in the atmosphere of a Jupiter-sized planet orbiting a star some 63 million light years from Earth. And methane, an organic molecule, is an indicator of the possible presence of life.

The bad news, for ET fans, is that the planet is probably too close to its host star to support the kind of life we’re all really looking for. The good news is that the very presence of methane, and water, in the planet’s atmosphere could be evidence that some form of life may be out there, either on this planet or others. Methane is key to the formation of amino acids, the basic building blocks of organisms.

Another key takeaway from this work, scientists say, is that astronomers have now moved from simply finding these planets—a not-so-simple job in and of itself—to exploring them chemically.


Kids aren’t the only ones who think fake diamonds are hot. Engineers at Ohio State University are using zirconium dioxide (the ceramic from which we get synthetic diamonds) to protect jet engines from high-temperature corrosion.

The fan blades in modern aircraft engines are coated with a protective ceramic to keep them from overheating. When the metal heats up, it expands, and the ceramic coating expands with it. But when grains of sand are inevitably sucked in and contact the many thousand-degree blades, they melt and make glass. The glass not only breaks down the coating when hot, but when it cools, it forms an inelastic layer on top of the protective coating. When the blades heat up again, the glass doesn’t expand and breaks off the ceramic, shortening the life of the engine.

The promise of the zirconia lies in its ability to force the glass to bond with other elements in the coating, changing it into a stable crystal. It in effect turns the glass into an additional layer of protective ceramic every time new sand contacts the blades and melts.


Unlike the ring for your middle school girlfriend, this zirconium application doesn’t come cheap. It’s a cost-intensive process to manufacture and has yet to be tested on complex shapes. But even in its early stages, it promises to be a boon for efficiency not just in aircraft engines, but ultimately for automobiles as well.


Researchers from the University of Wisconsin-Madison and Florida International University have developed a technique that enables them to identify the weak spots in a structure from afar.

The program they developed, Scan and Solve, uses 3D data of an object to predict where it is most likely to fracture, and how its faulty spots will be affected by outside forces such as gravity or other forms of strain.

The team tested the software on one of the most famous sculptures in the world, Michelangelo’s David, and the results of the program matched previous analyses of the statue. David has already incurred damage from cracks, and Scan and Solve “predicted” those weak spots. The idea, though, is that the program could be used to identify trouble areas in artifacts or statues or structures that have not yet begun to break down, giving engineers a chance to address those potential problems before serious damage sets in.

In the future, the researchers say the technique could be combined with medical imaging technology to help doctors pinpoint weakness in a patient’s bone structure.


http://www.popsci.com/

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As cameras continue to shrink in size and weight, an often overlooked side effect is their lack of image stability. Naturally, the heavier the camera, the less your shaky hands move its lens. Via optical image stabilization, the Panasonic HDC-SD5 keeps footage rock solid while maintaining a pocket-size form factor.

How to Create Color-Rich, Steady-Handed Video

1. Collect the Light
Light enters the front of the camcorder and passes through a series of aspherical lenses and so-called low-dispersion lenses, which are made of ultra-pure glass. Together, these bend the light to magnify the images but don’t spread out colors the way a prism or cheap lens would. (That can lead to green or red smears in the footage.) A motor-driven zoom lens slides back and forth to change the view from slightly wider than the naked eye’s to an 8.5-fold magnification. With a large aperture (f/1.8), the camera captures enough light to record clear action in a candlelit room.

2. Stabilize It
Light then passes to an optical image stabilizer that smoothes out jitters from shaky handheld shooting. Gyrosensors below the lens barrel measure the camcorder’s minute movements up and down and left and right. A processor analyzes the data and sends signals to the stabilizer, where a lens floats in a magnetic field. Adjusting the electromagnets nudges the lens in the opposite direction of the camera jitter, as frequently as 4,000 times per second, to compensate for the movement and deliver a steady beam of light to the image sensors.

3. Split It
Before the image can be recorded, the light beam has to be divided into the red, green and blue components that your TV will later use to reassemble the video. Most camcorders split the light with alternating color filters over the individual pixels on a single imaging chip. But those filters absorb much of the light and dull the colors. Panasonic instead uses a series of prisms to separate the beam into three color streams. Each stream strikes a separate image sensor that measures its intensity on 560,000 pixels to produce more-vivid video than single-sensor cameras can.




http://www.popsci.com/node/19964

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The Stanford camera goes a few steps deeper by taking the many lenses off the main lens assembly (the Adobe model), and miniaturizing and attaching them directly to the image sensor. This technique means the traditional main lens doesn’t need to be of high quality, as it’s now only a gateway for the lenses on the sensor. The 12,616 lenses together on the chip produce a powerful tool for three-dimensional imaging and modeling. The researchers see robotics as the ideal application for the system, potentially giving machines better depth perception than humans so they can perform delicate tasks. Other uses include facial recognition in security applications and three-dimensional biological imaging.


Ultra-high-energy cosmic rays carry more energy than any known particles in the universe, so we should probably all take it as good news that scientists have confirmed that they don't originate in our cosmic neighborhood. In fact, the majority of these rays—which are mostly hydrogen and helium—lose most of their juice on their way towards Earth because they interact with the cosmic microwave background radiation, the energetic leftover of the Big Bang.

Back in 1966, a trio of physicists described a cutoff point for the rays—particles with more energy than what's now known as the GZK limit would rarely reach Earth, they said. Now, using the University of Utah's High-Resolution Fly's Eye cosmic ray observatory, plus the new Auger detector in Argentina, scientists have bolstered this idea. The ultra-high-energy rays do get through, but much less frequently than standard rays.

The source of the rays is still something of a mystery. Other recent research has suggested that they're produced in active galaxies harboring supermassive black holes.


A new low-cost, nanotech-based approach to power generation developed by researchers at Boston College and MIT could lead to cleaner-running semiconductors, air conditioners, car exhausts and more. The technique, published online yesterday in Science, uses the nanostructures to dramatically increase thermal efficiency.

The researchers didn't invent a new material so much as re-work an old one, a semiconductor alloy that's been used in various devices for five decades. "We have found a way to improve an old material by breaking it up and then rebuilding it in a composite of nanostructures in bulk form," says BC physicist Zhifeng Ren.

And this isn't some far-off application, either: The scientists say it could be applied to existing products, enabling them to consume less energy, and use energy that might other was be wasted.


Let's get to the limitations right away: Mac and even Firefox users will have to sit this one out, since it only runs on a PC, in Internet Explorer. And XP is probably your best bet, too, since Vista users have apparently reported some glitches when using the beta version of this very cool new interactive tool.

All that aside, though, the Visible Body, a new, and free, interactive experience from Argosy Publishing, is pretty mind-blowing. It's Gray's Anatomy in 3-D. (The book, people, not the show.)

At this point the app doesn't impart too much information; it helps the casual browser learn what's where, but not how things work. Navigating the 3-D model is fairly intuitive, and the program keeps things simple by starting with a basic skeleton, and letting the user add different systems or organs one at a time. Med students or undergrads cramming for exams are probably going to love it, but it's a neat experience for a run-of-the-mill nerd, too.


The mantis shrimp (which oddly is neither a mantis nor a shrimp, but a crustacean that resembles both) has arguably the most complicated visual system of any animal on Earth. Its compound eyes sit on independently moving stalks and can see colors ranging from ultra-violet to infra-red. Each eye is divided into three regions for tracking motion, forms, depth, and color. All of this, it is theorized, is done without the aid of its tiny brain. (It’s also got claws that can smash through glass, but that we’ll save for another article). Now add to this an entirely new kind of vision previously unknown: the mantis shrimp can see circular polarized light.

We humans can see the effects of linear polarized light when we put on polarized sunglasses and go out on a boat. Linear polarization is observed when transparent materials reflect light, so on a sunny day, the ocean’s surface will look glassy to us. Put on polarized sunglasses and the glare is eliminated. Circular polarization is a bit more complicated. It has to do with out-of-phase stereo imaging, which can best be explained by the effect you get when you put on 3-D glasses and watch a movie in 3-D. That’s circular polarization.

Why the mantis shrimp has the ability to, in effect, put on 3-D glasses is still a mystery. But Professor Justin Marshall (the researcher who discovered it), from the Queensland Brain Institute, surmises it has something to do with sex. Only the males are able to see this way, so his theory is it is some as of yet unknown communication for mating. "[We] humans only have three color channels," he said. "These little guys have 12, and can see both linear and circular polarized light—it is remarkable."



http://www.popsci.com/

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How Wheel Motors Drive the Car

Putting electric motors directly inside the wheels eliminates the transmission, which typically wastes 10 to 20 percent of the engine’s energy. An interior disc, mounted to the wheel bearings, contains a series of independently controlled electromagnets, which emit a magnetic field in response to an electrical current. Around that, an outer ring contains permanent magnets. Step on the accelerator, and a computer in the interior ring begins to rapidly switch the polarity of the electromagnets, repelling or attracting the permanent magnets. The faster the polarity changes, the faster the motor spins the wheels.

The challenge is controlling four independent motors—if one spins even slightly faster, the car could veer violently. The ReCharge team’s next big hurdle is refining the software that maintains precise control. As for performance, the car will have permanent all-wheel drive with no gearbox standing between your foot and the motors—in other words, it should go like a rocket.

Batteries power all four motors and the car’s electronics. Unlike most plug-in hybrids, the ReCharge uses a lithium-polymer (rather than lithium-ion) battery. This is not only safer—it uses sheets of plastic instead of a volatile electrolyte solution—but it also powers the car for 60 miles before the engine kicks in to recharge it. Small lithium-polymer batteries have started to show up in gadgets such as the iPhone, but Volvo gets its larger, experimental versions from an undisclosed manufacturer.

The engine charges the battery when the car isn’t plugged in. The concept design calls for either a 1.6-liter flex-fuel or turbodiesel engine, but since the engine doesn’t have to actually spin a drive shaft, a fuel cell or a second battery could do the job just as well. It would kick in to recharge the battery only after the battery was at 30 percent capacity, so the ReCharge could travel 160 miles on a single gallon of gas.

A charger feeds power to the battery when the car is plugged in at home. Eventually, the ReCharge will be equipped with an intelligent version that can automatically sense strain in your area’s electrical grid and either cut back its power consumption or feed electricity from its battery back into the system.

Tires must be as thin as possible since the motor makes each wheel bigger.The ReCharge uses specially designed Michelin tires with a soft, resilient surface that also reduces rolling resistance.



http://www.popsci.com/cars/article/2...morrows-hybrid

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In a new review article in Nature Geoscience, two scientists say that black carbon, the stuff that gets kicked up into the air from biomass burning and diesel engines, among other things, could account for as much as 60 percent of the warming effect of carbon dioxide. That's three to four times greater than most estimates, and more than that of any greenhouse gas save CO2.

Scripps atmospheric scientist V. Ramanathan and University of Iowa chemical engineer Greg Carmichael looked at data from satellites, aircraft and surface instruments to gauge the real effect of black carbon.

They also explored the sources. Roughly a third of carbon that gets into the atmosphere originates in China and India, most likely from the burning of wood and cow manure, or coal to heat homes. Countries that rely on diesel fuel for transportation are also big contributors.

The soot can be a killer, too, and the scientists argue that eliminating black carbon would have a significant effect both on the environment and the people who inhale it regularly.



One of the biggest issues facing conservation movements worldwide is how to balance the needs of local populations with the protection of animal habitats. Ecotourism is a popular solution. Through a program of education and careful land management, local economies can be adapted to benefit more from preservation and tourism than removing and selling natural resources. In some areas, however, the situation is too heated for the concept to take hold. The Democratic Republic of the Congo (DRC) is one of those regions, and at the heart of their trouble is the endangered mountain gorilla.

Nearly half the remaining 700 mountain gorillas on the planet live in the Virunga National Park on the eastern border of Congo. Ecotourism has been all but nonexistent due to the instability resulting from a decade-long civil war. While park management has recently achieved effective poaching controls, the illegal charcoal trade has been much more difficult to contain.



Now, not only is the gorilla’s habitat threatened by illegal logging, but the animals themselves have come into the line of fire. Last year, ten gorillas were executed in the park. Officials and conservationists widely believed the killings were meant as a diversion from the charcoal trade or a threatening gesture toward the park employees. If they had been the work of poachers, the animals would have been taken. Instead, their bodies were left untouched.

This week finally brings some good news. The Congolese Nature Conservation Institute – the park authority in DRC – has brought charges against one of its senior officials for having arranged the killings. Six other rangers are being questioned as well. While it is still too early to say whether this is a serious effort at rooting out corruption in the agency, it is at the very least a welcome start.



This past week we happened to cover both dolphin ecoholation and facialrecognition. Today comes a reporton a study that may bring the two concepts a little closer together. German researchers have devised a computer algorithm which is able to identify plant species using sonar echoes, in the same way bats are able to find fruit and insects. If the technology is one day sufficiently refined, it could ultimately be used for facial recognition.

Bats rely on echolocation to find their way around and to hunt prey and forage for fruit. In order better to understand how the bats identify which plants bear the fruit they prefer, the researchers at the University of Tübingen devised a software routine that could analyze the echo response time and frequency of sound waves reflected off isolated plants. Each presented a distinct signature, based on the size and number of branches and leaves. The team was able to achieve nearly 100 percent accuracy once the study was complete.

Not only will the findings be valuable for the science of bats and echolocation, but the applications for humans are potentially great as well. The distinct advantage of a sonar identification system over a visual-based system is that it would be able to operate in low light or total darkness.




What’s more, the software then uses both the map data and the eye feedback to present a static image when the surgeon is operating in an area of the body which is moving. The robot keeps its tools in sync with a beating heart, for example, but the surgeon sees only a still image, allowing for greater precision. It can even show tissue and vessels below and around the area to highlight healthy parts and reduce the potential for unnecessary cutting.



http://www.popsci.com/

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How to Capture Images From 425 Miles Up

The 4,400-pound GeoEye-1 will travel 425 miles into space on the back of a Delta 2 rocket from Vandenberg Air Force Base near Lompoc, California. Over the satellite’s planned seven-year life, it will be able to adjust its orbital altitude by 60 miles, which it will need to do to maintain a consistent view of Earth: Atmospheric drag and pressure from solar winds will gradually push the satellite down.

2. Receive Commands
GeoEye operators send instructions on what and when to photograph from one of four ground stations in Alaska, Virginia, Norway and Antarctica. Even though the satellite will be used commercially, all transmissions are encrypted under the licensing terms of the National Oceanic and Atmospheric Administration.

3. Get in Position
GeoEye-1 is the first non-military satellite to use military-grade GPS units, highly accurate devices that tell the satellite exactly where it is in the sky. Two star trackers calibrate the camera’s location and angle based on known star coordinates. Combined, these systems can pinpoint an object’s position on the ground within nine feet, 1.5 times as accurate as previous satellites.

4. Align the Camera
Once the satellite is over the target—a New York City block or a miles-wide patch of rainforest in Brazil—reaction wheels spin to orient it. As it nears the proper position, the wheels spin in reverse to halt the satellite’s rotation and train the camera on the target.

5. Check the Lighting
Ground control calculates the sun’s and the satellite’s angle to Earth to determine exposure time. Because the satellite’s 16-inch resolution depends critically on the precise shape and spacing of the optics, they are sealed in a tube and kept at around 72°F to prevent them from warping in the widely varying temperatures of space. The tube’s door opens only when the camera is ready to take an image.

6. Take the Shot
The camera scans the target in 20,000 37,500-by-1-pixel strips every two seconds, allowing it to easily create a 90-billion-pixel image (about 6,000 square miles) in two minutes. A data-processing unit compresses the image files and stores them on a one-terabyte solid-state drive.

7. Beam it Down
The sat can capture an area the size of Texas every day. It downloads encrypted images to the ground stations 40 times a day over radio waves. Once GeoEye combines the strips into full images, they are sent to buyers including Google Earth and countries with limited or no surveillance satellites, as well as the government’s National Geospatial- Intelligence Agency, which is GeoEye’s primary customer.

See an interactive animation of GeoEye-1 in action: http://www.popsci.com/military-aviat...ace-yet?page=1

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