Europe against GMO crops! Please, sign the Avaaz petition! I already did.
It's us who decide, not Monsanto!!!

Thursday, 31 July 2008

The future of nukes

Something I have never discussed until now, because there was no need to. But these week I found few very interesting articles on the future of nuclear reactors and nuclear weapons.
I have to say I'm very pro- nuclear plants, because I think this is one of the cleanest possible sources of energy. Still, i want to emphasize that the safety of those reactors still is my greatest preoccupation. And after I read an article in NY Times about some leakages in nuclear plants in USA , I have some doubts on the regulations there. Anyway, here are the articles, enjoy them and my comments will be below. As usual :) I recommend you the second article which is dealing with a new type of enriched Uranium that may cause major troubles to plants around the world.

Next generation of nukes may not happen

The US House of Representatives last week voted to deny any further funding for a programme to design the next-generation nuclear warhead. Money will instead go towards "sustaining and modernising" the nation's existing stockpile of more than 4000 warheads.

The US National Nuclear Security Administration (NNSA) had argued that the Reliable Replacement Warhead was needed because it would be safer to stockpile and harder for terrorists to acquire and use. Electronic security features would render it useless in the wrong hands, and it would feature a new breed of explosives for triggering fission, making accidental detonation less of a risk. It would also need less fissile material, making it safer to stockpile.

Nevertheless, when the House Armed Services Committee revealed its 2009 Defense Authorization Bill on 15 May, it did not include the $33 million the NNSA had requested for next year.
source

My comment: I don't know whether I should be happy or sad. I mean, from one side, everyone would be happier to see warheads that cannot be used by terrorists, from another-how many warheads got in the hands of terrorists. Fortunately. But from the other side-I'd rather see the world decreasing the numbers of the warheads, instead of increasing it.

Nuclear super-fuel gets too hot to handle

from New Scientist, 09 April 2008

BluereactorcoreIf you make uranium burn stronger, hotter and longer in nuclear reactors, and you'll need less fuel, and there'll be less waste to deal with when it has been exhausted.

For decades, nuclear operators have done just that, but emerging safety and waste-disposal issues are raising questions about this approach. The latest high-efficiency fuel may prove to be unstable in an emergency, and so poses a greater risk of leakage of radioactive material into the environment. What's more, the waste fuel is more radioactive, meaning it could prove even more difficult than existing waste to store in underground repositories.

To boost the efficiency of their reactors, operators have progressively enriched the uranium they use as fuel to increase its "burn-up" rate. This is a measure of the amount of electricity extracted from a given amount of fuel, and is expressed in gigawatt-days per tonne of uranium (GWd/tU). The higher the burn-up, the longer the fuel rods can remain in the reactor. This has proved particularly successful in the pressurised water and boiling water reactors commonly used in the US and elsewhere. Since 1970, the average burn-up of these reactors worldwide has almost doubled, to more than 40 GWd/tU.

The next generation of nuclear plants will bring a further step-change. Applications for the construction of 30 reactors in the US and 10 in the UK are expected over the next few years, and plans for the two designs most likely to be built - Westinghouse's AP1000 and Areva's European Pressurised Reactor - envisage burn-up rates of 60 GWd/tU or more. At these rates, uranium fuel rods should burn for around a year longer than today's best burn-up fuel.

Such gains may come at a price. Last month, at conferences in Washington DC and Rockville, Maryland, organised by the US Nuclear Regulatory Commission (NRC), a team led by Michael Billone at Argonne National Laboratory in Illinois presented findings (1.8MB pdf) on the behaviour of high burn-up fuel. They say that fuels with a burn-up above 45 GWd/tU cause previously unforeseen safety problems, and would break existing NRC safety rules (120kb pdf) unless changes are made to the way fuel elements are packaged.

The danger would come if there were a sudden loss of cooling water - as in the accident that led to the partial meltdown of a reactor core at Three Mile Island, Pennsylvania, in 1979. To contain the radioactivity in such an event, it is crucial that the fuel rods and their zirconium alloy cladding maintain their integrity as they are doused with cold water from the emergency cooling system. If the cladding has become brittle, the rods may split open and leak plutonium and other radioactive material into the reactor building.

Even during normal operation, cooling water corrodes the surface of the cladding by reacting with zirconium to form zirconium oxide. The NRC's rules require that the corroded layer must not amount to more than 17 per cent of the thickness of the cladding.

Billone and colleagues say that where high burn-up fuels are used, this rule is not stringent enough. When they put different types of cladding used for fuel with a burn-up above 45 GWd/tU through a series of tests designed to simulate a loss-of-coolant incident, they found they all became brittle before oxidation had reached the 17 per cent limit.

They attribute this enhanced brittleness to the increased amounts of hydrogen released by high burn-up fuels during normal reactor operation. The gas is gradually absorbed into the cladding, where it increases the solubility of oxygen. Between 650 °C and 1200 °C, this can trigger "breakaway oxidation" of zirconium, making it rapidly more brittle in an emergency. Fuels operating at 60 GWd/tU would produce around 40 per cent more hydrogen than existing high burn-up fuels.

Edwin Lyman of the Union of Concerned Scientists (UCS) in Washington DC warns that the problems need to be solved long before the new reactors are switched on.

The Electric Power Research Institute, which represents US electricity producers, insists there is no imminent safety issue, and that modern reactors are operated in a way that ensures there will never be a catastrophic loss of coolant. Reactor materials expert Arthur Motta at Pennsylvania State University in University Park says it should be possible to solve the problems raised by Billone with new alloy types. "We should be able to safely increase burn-up."

Despite these reassurances, the NRC, which commissioned the Argonne research, has launched a three-year consultation with a view to tightening up the rules.

Questions also surround how the waste created by high burn-up fuel will be disposed of. Irradiating uranium for longer in a reactor makes it much more radioactive, and decay of this extra radioactivity generates correspondingly more heat when waste fuel is stored after being removed from the reactor. According to Nirex, which until 2006 was responsible for dealing with the UK's nuclear waste, fuel with a burn-up of 55 GWd/tU irradiated in a pressurised water reactor would be around 50 per cent more radioactive than low burn-up fuel of 33 GWd/tU throughout the time it needs to be stored.

To ensure that the build-up of heat is kept within safe limits, spent elements of the higher burn-up fuel will have to be stored further apart. Failure to allow for this would lead to a build-up of heat that could cause fractures in the containers in an underground storage site or in the surrounding rock, and so increase the risk of a leak. Though the increased efficiency of high burn-up fuel means there would be less of it, more storage space will still be required overall.

In the UK, this may mean that the government will need to find two underground repositories, instead of the one now envisaged, says Hugh Richards of the Nuclear Consultation Working Group, a group of activists and academics opposed to nuclear power. source

My comment: Notice how EPRI claims there aren't safety issues with the new reactors and then it says they are sure they can handle any problems. For me this means "we agree there are problems, we hoped no one would notice and we hope we can solve them". I think that isn't serious for something as dangerous as nuclear reactors. We shouldn't get paranoid, but when something is serious, it is serious and we have to deal with it as such! I hope this research will lead to more work and more results. And hopefully to cleaner and safer new reactors.

Invention: Diamond-cooled nuclear reactor

Nuclear plants can fail when the heat from the reactor is not removed quickly enough from the core. This can happen in pressurised water nuclear reactors if the water in the cooling system boils, because steam is a much poorer conductor of heat than liquid water.

These reactors have a primary water cooling system that directly takes heat away from the reactor. It is sealed under huge pressure to prevent it boiling and conducts heat to a secondary water cooling system that is not sealed.

But this secondary system is also at risk of boiling. If that happens, heat builds up in the primary cooling system, which can lead to meltdown.

Ronald Baney and colleagues at the University of Florida in Gainesville, think they can tackle this problem by turning to diamond – one of the best heat conductors known to science.

Their idea is to add diamond nanoparticles to the water of the secondary cooling system to dramatically improve its ability to transfer heat.

Baney and colleagues say such nanoparticles are chemically inert and radiation resistant, so are unlikely to clump together in a way that could block the cooling system. However, they don't say how much a diamond-based heat transfer fluid might cost.

Read the full diamond-cooled nuclear reactor patent application. source

My comment: Lol, that's cool. I just want to see the bill :) But it goes well with the previous article :)

Tuesday, 29 July 2008

Space-news

Time for news on space, dudes and dudettes! They are 3 and they are quite interesting. The first news is about a discovery of 45 planets in the MILKY WAY with size comparable to that of Earth. If we suppose that only a fraction of all such planets is discovered and that just 1 of those 45 is Earth-like, then again, we'll have a great chance to see an inhabited world. Read the article to find out some cool details, as that they can see the composition of the atmosphere of those planets. Which means that if the world has a space-bound civilization, we could even hope to see glimpses of their activity. Isn't that ultra cool, space fans? Yes, it would be hard, probably we would need a better space-telescope and so on, but still, there is a possibility. And that's not little.
The second article is about GLAST, a new gamma-ray-burst seeker and the third-about the eventual discovery of forming planet. My comments will be below them as usual.

How like Earth are alien planets?

AT LAST we are seeing big rewards in the hunt for “super-Earths” - rocky alien worlds a few times more massive than our own. That was the verdict from a landmark meeting of astronomers last week which saw the unveiling of a huge haul of new exoplanets in our galaxy.

The new discovery of a large number of small planets suggests that they are abundant in our galaxy, and outnumber Jupiter-sized giants by 3 to 1.

This contrasts with the nearly 300 alien planets previously discovered, of which the vast majority are Jupiter-like gas giants. Only a dozen or so are low-mass planets: either Neptune-like ice-worlds or rocky planets like Earth. Now researchers on the High Accuracy Radial Velocity Planet Searcher (HARPS) survey based at the European Southern Observatory in La Silla, Chile, have announced the discovery of 45 more planets in the Milky Way - all of them less than one-tenth of Jupiter’s mass.

They spotted them by recording how each planet’s gravitational tug makes its parent star wobble. According to Cristophe Lovis of the University of Geneva, Switzerland, a member of the HARPS team, these observations suggest that while many of the new worlds are likely to be “hot Neptunes” - planets composed mainly of water with a layer of hydrogen and helium on top - it is probable that some will turn out to be more like rocky super-Earths.

The announcement of this potential haul of super-Earths opens up the exciting prospect that we will be able to glean some detailed information about what these planets are like. For years, astronomers have been waiting for a super-Earth to be found with an orbit that “transits” its parent star: in other words, it passes directly in front of the star as viewed from Earth. This would allow them to deduce many of its characteristics, from its internal structure to the make-up of its atmosphere.

The likelihood of observing such transits is increased when exoplanets have a short orbit around their star. The HARPS planets fit the bill: all orbit in less than 50 days, and some in as little as 10 days. This means that during a relatively short period of observation, the HARPS planets will be much more likely than planets with longer orbits to pass in front of their star.

Now they are hoping the observation of transits (passage of the planet in front of the star as viewed from Earth) will provide us with a robust measure of the planet’s radius, for example, and by combining this with the mass estimate derived from the planet’s gravitational pull on its star it is possible to estimate its density. This in turn can be used to reveal something about the planet’s composition and internal structure.

Most exciting of all, says David Charbonneau of the Harvard Smithsonian Center for Astrophysics, transits allow us to study the atmosphere of a planet. The difference in the intensity of infrared radiation when the planet passes behind its star can be used to determine the temperature of the planet’s atmosphere.

It is also possible to glean information about the composition of the planet’s atmosphere by watching for changes in a star’s spectrum as it filters a fraction of the star’s light during a transit. Such observations of the star HD 189733 have recently revealed the presence of methane and water vapour in the gaseous atmosphere of a transiting Jupiter-size planet.

The dimming in the star’s light will be slight, so such shallow transits are best detected from space rather than with telescopes on the ground, where fluctuations in the Earth’s atmosphere can interfere with the observations.

A few satellites are capable of watching for a transit, among them the Canadian MOST satellite. This is particularly well suited to the task, as its instruments can stare at target stars for long periods of time. source article

Gamma-ray mission may detect dark matter


A computer animation illustrates GLAST's launch and deployment (Courtesy of NASA)
A simulation shows what the ever-changing gamma-ray sky might look like to NASA's GLAST observatory (Courtesy of NASA)
GLAST will scrutinise the sky in poorly-explored regions of the gamma-ray spectrum (Illustration: NASA)
GLAST will scrutinise the sky in poorly-explored regions of the gamma-ray spectrum (Illustration: NASA)

A new NASA satellite with powerful gamma-ray vision is set to launch on 3 June. It will observe the deaths of massive stars, probe the gamma-ray sky for unknown objects, and might even pin down the nature of the mysterious dark matter that pervades the universe.

The $700 million Gamma-ray Large Area Space Telescope (GLAST) is set to launch into low-Earth orbit at 1145 EDT (1645 GMT) from Cape Canaveral, Florida, US. It carries a gamma-ray telescope of unprecedented sensitivity and a monitor that can detect radiation from violent cosmic events called gamma-ray bursts.

The mission will provide the first detailed survey of the sky in a largely unexplored part of the energy spectrum of gamma rays, the highest-energy form of radiation.

The observatory's Large Area Telescope (LAT) is sensitive to gamma rays with energies between 20 mega-electronvolts (MeV) and 300 giga-electrovolts (GeV). The 10 to 100 GeV range is mostly invisible to ground-based telescopes and was poorly sampled by GLAST's predecessor, the Compton Gamma Ray Observatory.

Annihilating WIMPs

The spectrum around 100 GeV offers the possibility of an especially big breakthrough – the chance to identify the nature of dark matter. Dark matter is an invisible substance that outweighs ordinary matter in the universe and has so far only been detected by its gravitational influence on ordinary matter.

The most popular explanation says that dark matter is made of exotic elementary particles that rarely interact with ordinary matter. A zoo of such weakly interacting massive particles (WIMPs) have been proposed, such as neutralinos and axions, but Earth-based experiments have so far failed to confirm their existence.

WIMPs are expected to annihilate and release gamma rays when they hit one another. When GLAST opens its eyes to the sky, it might see bright spots due to clumps of dark matter sprinkled throughout the galaxy. Such clumps are predicted by theory, but whether GLAST will be able to detect them is highly uncertain.

Black hole evaporation

GLAST is bound to provide a wealth of information on some of the universe's most violent events. These gamma-ray bursts can put out more energy in a matter of seconds than the Sun will over its entire lifetime. Most of the bursts are thought to result from the collapse of massive stars and from collisions between neutron stars, while the origins of others are still mysterious.

The GLAST Burst Monitor (GBM) is sensitive enough to detect around 200 gamma-ray bursts each year, about twice the rate seen by NASA's Swift satellite, a gamma-ray burst observatory that launched in 2004. GLAST can see gamma rays across a much wider spectrum of energies than Swift, which will give scientists a more complete view of these events.

There is also an outside chance that GLAST could observe gamma rays from the explosion of microscopic black holes. According to some theories, these tiny primordial black holes would have formed in the violence of the big bang itself. Depending on what mass they were born with, they could be evaporating today in bursts of gamma rays through a process called Hawking radiation. source

My comment: Now, because I work exactly in these field, I can't say I'm not excited about that satellite. It's gonna bring GRB physics to another level, for sure. And maybe it will help us solve the puzzle of GRBs- like the process trough which they emit their massive energy output and the ir origin and so on. God Speed, GLAST!

Has the youngest known planet been spotted?

A team of astronomers says it may have spotted the youngest planet ever found, boasting an age of less than 100,000 years old, and perhaps as young as 1600 years old.

They say it bolsters a controversial theory that planets form very quickly, like stars – but other astronomers say the massive object may not be a planet at all but a 'failed' star, which explains its speedy birth.

Astronomers led by Jane Greaves at the University of St Andrews in Scotland used the Very Large Array of radio telescopes in New Mexico, US, and the MERLIN array at Jodrell Bank in the UK to image the dusty disc around a star called HL Tau. With an estimated age of less than 100,000 years, HL Tau lies about 460 light years away in the constellation Taurus.

Inside the disc, the team found a dense clump of matter at a distance of 65 astronomical units (where 1 AU is the distance between the Sun and Earth) from the star. The clump is about 14 times the mass of Jupiter.

The team reckons that the clump is a planet in its very early years of formation – at no more than 100,000 years old, it is much younger than the previous record holder for the youngest planet, which was less than 10 million years old.

They say the clump probably did not form by the 'core accretion' model favoured by most astronomers, in which planets form slowly, gradually building up mass like dust bunnies.

Instead, it probably formed quickly through a process called gravitational instability, whereby knots of matter in the dusty disc around the star collapse rapidly to form planets. The team says another star called XZ Tau may have kick-started the collapse when it passed near HL Tau as recently as 1600 years ago.

Such a process, which is similar to how stars form, reproduced the observations when team member Ken Rice of the University of Edinburgh in Scotland carried out a computer simulation of the system (watch a video of the simulation).

But the 14-Jupiter-mass object may not be a planet at all. Instead, it may be a brown dwarf – a type of object that is too massive to be a planet but not massive enough to trigger the type of nuclear fusion found in ordinary stars.

If the object grows to be a good-sized brown dwarf, it and its larger stellar neighbour will be more like a binary star system than a planetary system. "I think most astronomers would agree that it is a brown dwarf forming by a 'stellar' process," says Gibor Basri of the University of California, Berkeley, US.

Alternatively, the clump could simply go away. "When astronomers detect blobs of this kind in radio maps of discs, it is difficult determine for certain whether the blob is a forming object, or a transient clump that will dissipate over time," Luhman told New Scientist. source

My comment: That is interesting, but I'm rather skeptical to it, because it's hard to discern whether this is a planet or a brown dwarf or whatever. Not to mention that the gravitational instability is rather cloudy idea and there is still to require from it. But it is interesting to see this developing.

Sunday, 27 July 2008

I, Robot-from safer cars, trough creepy shop-windows to baby robots

You think Robots are in the Future? Well, they appear to be in the present. Check out those absolutely awesome articles.

  • Monkeys Think, Moving Artificial Arm as Own
  • Crash-predicting car can brace itself for impact
  • Shopper-watching windows
  • The rise of the emotional robot
All of them cover absolutely cool new technologies that can drastically improve our life not in the far future but quite soon. For my comment you can check the below each article.

Monkeys Think, Moving Artificial Arm as Own

By BENEDICT CAREY
Published: May 29, 2008

Two monkeys with tiny sensors in their brains have learned to control a mechanical arm with just their thoughts, using it to reach for and grab food and even to adjust for the size and stickiness of morsels when necessary, scientists reported on Wednesday.

The report, released online by the journal Nature, is the most striking demonstration to date of brain-machine interface technology. Scientists expect that technology will eventually allow people with spinal cord injuries and other paralyzing conditions to gain more control over their lives.

The findings suggest that brain-controlled prosthetics, while not practical, are at least technically within reach.

In previous studies, researchers showed that humans who had been paralyzed for years could learn to control a cursor on a computer screen with their brain waves and that nonhuman primates could use their thoughts to move a mechanical arm, a robotic hand or a robot on a treadmill.

The new experiment goes a step further. In it, the monkeys’ brains seem to have adopted the mechanical appendage as their own, refining its movement as it interacted with real objects in real time. The monkeys had their own arms gently restrained while they learned to use the added one.

Experts not involved with the study said the findings were likely to accelerate interest in human testing, especially given the need to treat head and spinal injuries in veterans returning from Iraq and Afghanistan.

The researchers, from the University of Pittsburgh and Carnegie Mellon University, used monkeys partly because of their anatomical similarities to humans and partly because they are quick learners.

In the experiment, two macaques first used a joystick to gain a feel for the arm, which had shoulder joints, an elbow and a grasping claw with two mechanical fingers.

Then, just beneath the monkeys’ skulls, the scientists implanted a grid about the size of a large freckle. It sat on the motor cortex, over a patch of cells known to signal arm and hand movements. The grid held 100 tiny electrodes, each connecting to a single neuron, its wires running out of the brain and to a computer.

The computer was programmed to analyze the collective firing of these 100 motor neurons, translate that sum into an electronic command and send it instantaneously to the arm, which was mounted flush with the left shoulder.

The scientists used the computer to help the monkeys move the arm at first, essentially teaching them with biofeedback.

After several days, the monkeys needed no help. They sat stationary in a chair, repeatedly manipulating the arm with their brain to reach out and grab grapes, marshmallows and other nuggets dangled in front of them. The snacks reached the mouths about two-thirds of the time — an impressive rate, compared with earlier work.

The monkeys learned to hold the grip open on approaching the food, close it just enough to hold the food and gradually loosen the grip when feeding.

On several occasions, a monkey kept its claw open on the way back, with the food stuck to one finger. At other times, a monkey moved the arm to lick the fingers clean or to push a bit of food into its mouth while ignoring a newly presented morsel.

The animals were apparently freelancing, discovering new uses for the arm, showing “displays of embodiment that would never be seen in a virtual environment,” the researchers wrote.

Scientists have to clear several hurdles before this technology becomes practical, experts said. Implantable electrode grids do not generally last more than a period of months, for reasons that remain unclear.

The equipment to read and transmit the signal can be cumbersome and in need of continual monitoring and recalibrating. And no one has yet demonstrated a workable wireless system that would eliminate the need for connections through the scalp.

Yet Dr. Schwartz’s team, Dr. Donoghue’s group and others are working on all of the problems, and the two macaques’ rapid learning curve in taking ownership of a foreign limb gives scientists confidence that the main obstacles are technical and, thus, negotiable.

In an editorial accompanying the Nature study, Dr. John F. Kalaska, a neuroscientist at the University of Montreal, argued that after such bugs had been worked out, scientists might even discover areas of the cortex that allow more intimate, subtle control of prosthetic devices.
source

Robo-monkeys use brain power to grab a bite

Most people who become paralysed or lose limbs retain the mental dexterity to perform physical actions. And by tapping into a region of the brain responsible for movement – the motor cortex – researchers can decode a person's intentions and translate them into action with a prosthetic.

This had been done mostly with monkeys and in virtual worlds or with simple movements, such as reaching out a hand. But two years ago, an American team hacked into the brain of a patient with no control over his arms to direct a computer cursor and a simple robotic arm.

Schwartz's team extracted even more complicated information from the brains of two rhesus macaques by reading the electrical pulses of about 100 brain cells. Normally, millions of neurons fire when we lift an arm or grab a snack, but the signals from a handful of cells are enough to capture the basics, Schwartz says.

His macaques controlled a robotic arm that moved at the shoulder and elbow and could clench and open its hand.

To train the monkeys, the researchers first recorded their brain activity as they controlled the robotic arm with a joystick. Once the monkeys had learned to feed themselves in this way, Schwartz's team secured their arms and made them rely on controlling the robot with their brain.

To avoid frustrating the animals during their first attempts, the researchers partially guided the robot themselves. Gradually, these training aids were dispensed with, and after three weeks the monkeys had mastered the robotic arm.

In tests where a monkey had to grab marshmallows or grapes and feed himself, one monkey succeeded 61% of the time, often reaching for another treat while still chewing on the last one. The animals manoeuvred the arm around obstacles and readjusted its path when researchers moved the food.

"It's impressive how naturally the animal interacts with the robot," says John Kalaska, a neuroscientist at the University of Montreal. "It's a natural extension of their own body because they control it so easily just by thinking."

He says Schwartz's gradual and assisted approach to training the monkeys is likely to work with neural prosthetics in human patients.

Journal reference: Nature, DOI: 10.1038/nature06996 source

My comment:I'm always particularly interested in any synergies between the brain and a computer for many reasons. This article only shows how well the things are going for these kind of technologies. People seem to not understand why interacting with the brain is important- well, that's why. How would you feel if they have to cut your arm? Probably very sucky. What about if that arm can be replaced. It won't be the same (at least not yet), but you will be able to use it as your own. It makes a difference, right?

Crash-predicting car can brace itself for impact


A car that protects those inside by strengthening its frame just before a side-on collision has been crash-tested by European engineers.

The system is the latest demonstration of car safety devices that take action before a crash, not just afterwards. Even established safety features like airbags and seatbelts could be much more effective if they took pre-emptive action just milliseconds before an impact.

The prediction systems that are needed to prepare for an impact are becoming possible due to improvements in sensors and computing, and side impacts may be where they offer the greatest benefit.

Evidence from both real and simulated crashes shows that drivers rarely manage to react to a typical 30 to 40 kilometres per hour side impact, and there is very little distance between passengers and the object that strikes the car.

The system recently crash-tested uses radar and cameras to anticipate an impact just a fraction of a second before it occurs.

When activated, a metal bar slides into place to create a temporary brace that makes the car's frame significantly stronger. The bar bridges a gap between the front door and another bar running across the car and anchored on the chassis.

"The energy of the impact is transferred to the 'unstruck' side of the vehicle," says Joachim Tandler, an engineer at car maker Continental, which is leading EU-funded project APROSYS. "Normally that connection could not be complete," Tandler adds.

Design constraints, like the need to lower the door window, mean car frames cannot be built with the beam already in place. Like airbags, once activated, the brace would need a trip to the workshop to be reset, but the team are working on making the brace retractable.

For the reinforcing bar to be deployed before a crash, the safety system must predict a collision about 230 milliseconds before it happens.

Crash-prediction software uses two radars and stereo cameras positioned in the back window, looking out of the car's side with a range of about 20 metres.

Once the software decides to deploy the moving bar, it snaps into place in 70 milliseconds, driven by a powerful spring. The spring is held back by a coil of shape-memory alloy wire, but an electric current rapidly heats the coil, causing it to "remember" a previous shape and release the spring to drive the bar into place.

The car was subjected to a safety test used by European car safety watchdog NCAP, which involves hitting it with a barrier travelling at 50 km/h. The tests took place at the Research and Development Center in Transport & Energy in Valladolid, Spain.

The brace-for-impact system reduced the amount that the barrier penetrated the car by between 5 and 8 centimetres – enough to make a difference to the safety of the passengers in the car. "The intrusion velocity was considerably reduced," says Tandler.

Although the brace was a success, the sensors and software used to predict a collision are the parts most likely to be adopted first by car manufacturers. "We can give conventional in-crash devices like airbags more time to react," he adds.

But, in the end, it is economics that decide whether new safety technologies make it onto the road, he says: "It comes down to the manufacturers deciding if the extra weight and cost of installing the system on new cars is worth it." source

My comment: This is even cooler. I live in a country where people die on the streets in numbers you can't even grasp. I don't support reckless driving, but that for sure will help eventual victims of such driving. I doubt it would help for a head-on collision, but it would be great to have it for side colisions.

Shopper-watching windows

Gaze-tracking shop windows

Eye tracking software has become a mature technology that works effectively in many real situations. So the consumer electronics company Philips hopes to apply it to displays in shop windows.

The company's idea is to track the gaze of window shoppers to determine which items in the window they are staring at, then to display enlarged pictures, a slide show or other information about those items on nearby computer screens.

Philips says that the system could also be used in museums and art galleries to provide visitors with extra information as they need it

Read the full gaze-tracking display patent application. source

My comment:Now that's a rather creepy one. Why I find it useful is the eventual use for pupil-controlling of a computer. That could be great. No need to use that annoying touchpad anymore. You just gaze somewhere and you click. Cool, huh?

The rise of the emotional robot

Watch an exclusive video about emotional robots

Duke is careering noisily across a living room floor resplendent in the dark blue and white colours of Duke University in Durham, North Carolina. He's no student but a disc-shaped robotic vacuum cleaner called the Roomba. Not only have his owners dressed him up, they have also given him a name and gender.

Duke is not alone. Such behaviour is common, and takes myriad forms according to a survey of almost 400 Roomba owners, conducted late last year by Ja-Young Sung and Rebecca Grinter, who research human-computer interaction at the Georgia Institute of Technology in Atlanta.

Sung believes that the notion of humans relating to their robots almost as if they were family members or friends is more than just a curiosity. "People want their Roomba to look unique because it has evolved into something that's much more than a gadget," she says. Understanding these responses could be the key to figuring out the sort of relationships people are willing to have with robots.

Until now, robots have been designed for what the robotics industry dubs "dull, dirty and dangerous" jobs, like welding cars, defusing bombs or mowing lawns. Even the name robot comes from robota, the Czech word for drudgery. But Sung's observations suggest that we have moved on. "I have not seen a single family who treats Roomba like a machine if they clothe it," she says.

The Roomba, which is made by iRobot in Burlington, Massachusetts, isn't the only robot that people seem to bond with. US soldiers serving in Iraq and interviewed last year by The Washington Post developed strong emotional attachments to Packbots and Talon robots, which dispose of bombs and locate landmines, and admitted feeling deep sadness when their robots were destroyed in explosions. Some ensured the robots were reconstructed from spare parts when they were damaged and even took them fishing, using the robot arm's gripper to hold their rod.

Figuring out just how far humans are willing to go in shifting the boundaries towards accepting robots as partners rather than mere machines will help designers decide what tasks and functions are appropriate for robots. Meanwhile, working out whether it's the robot or the person who determines the boundary shift might mean designers can deliberately create robots that elicit more feeling from humans.

Not surprisingly, though there are similarities between the way people view robots and other human beings, there are also differences. Daniel Levin and colleagues at Vanderbilt University in Nashville, Tennessee, showed people videos of robots in action and then interviewed them. He says that people are unwilling to attribute intentions to robots, no matter how sophisticated they appear to be.

Further complicating the matter, researchers have also shown that the degree to which someone socialises with and trusts a robot depends on their gender and nationality (See "Enter the gender-specific robot").

But Hiroshi Ishiguro of Osaka University in Japan thinks that the sophistication of our interactions with robots will have few constraints. He has built a remote-controlled doppelgänger, which fidgets, blinks, breathes, talks, moves its eyes and looks eerily like him (New Scientist, 12 October 2006, p 42). Recently he has used it to hold classes at his university while he controls it remotely. He says that people's reactions to his doppelgänger suggest that they are engaging with the robot emotionally. "People treat my copy completely naturally and say hello to it as they walk past," he says. "Robots can be people's partners and they will be."source

My comment: This article is great for several reasons. I don't think it was a great surprise to see people impersonating robots, we do that to trees and rock, and the robot even seems to respond. What is interesting is that companies may design robots in a way that they will provoke a specific feelings for certain robot. Which brings us a step closer to the movie, The AI. A movie that I always found to sad, but anyway.

Friday, 25 July 2008

The history conspiracy

Heh, lots of conspiracies lately :) This is a tough one for writing since people easily disqualify you as crazy. But still, I can't just pass and forget about it. So, today- Stonehenge and American Indians. The first one says they discovered burial remnants in Stonehenge dating back to 3000BC. In the second, there are evidences that the migration on people in Americas happened trough the coasts, no trough the inland. I'm gonna put my comment this time in the beginning rather than in the end, so that we're clear what we're looking for. First of all, Stonehenge...Ok, they found bones. Which for them prove its purpose was to be a graveyard. Now, why did those people have to bring those huge rocks, just to cover someone's grave. How elite can someone be and even more, his offspring to be, because their hypotheses is this is the reason why the burials are more in the later periods. My idea is that this was a sacrificial ground. It makes much much more sense than theirs! And it completes the hypotheses that Stonehenge had spiritual, religious and probably astronomic meaning to its people. Of course, my next thought is that it was some kind of sign for the nephilims, because such large structures make sense only from the air. I won't speculate on that, it's not the point. The point is that once again, archaeologists try to manipulate history. I'm referring to Black Egypt-something that was published in National Geographic and that is an absolute nonsense. Egypt is on geographical crossroad-there are major evidences for the flow of knowledge between Egypt and Mesopotamia, which imply exchange of major groups of people. Not to mention the artefacts we have that has no traces of black race. And please, mind you, I don't say that from any racial point of view, I'm only interested in truth. And I see truth clouded from political correctness. The second article is on spread of people in Americas. The claim is that they claim trough passages of land on the north pole. But obviously those people were coastal people, because they know how to use the fruits of the ocean. Isn't then much easier to suppose they came with ships? The question is where did they come from? For the answer, check the pic in the right :) I'm not going to say it :) SG fans, enjoy :)
The third article speaks of the curious past of Greenland that obviously has a genetic connection with a weird group of islands near Kamchatka. Obviously even 5000 years ago people were quite travelers.

Stonehenge Used as Cemetery From the Beginning

Ken Geiger/National Geographic
Published: May 30, 2008

At least part of the mystery of Stonehenge may have now been solved: It was from the beginning a monument to the dead.

New research shows that Stonehenge was used for more than 500 years as a cemetery. The burials were initially uncovered in a pit around the edge and in the nearby ditch surrounding the monument.

New radiocarbon dates from human cremation burials among and around the brooding stones on Salisbury Plain in England indicate that the site was used as a cemetery from 3000 B.C. until after the monuments were erected around 2500 B.C., British archaeologists reported Thursday.

What appeared to be the head of a stone mace, a symbol of authority, was found in one grave, the archaeologists said, indicating that this was probably a cemetery for the ruling dynasty responsible for erecting Stonehenge.

“It’s now clear that burials were a major component of Stonehenge in all its main stages,” said Mike Parker Pearson, an archaeologist at the University of Sheffield in England.

In a teleconference with reporters, arranged by the National Geographic Society, Dr. Parker Pearson described three burials of burned bones and teeth that were dated in recent weeks. Researchers estimated that up to 240 people were buried there, all as cremation deposits. Other evidence from the British Isles shows that skeletal burials were rare at this time and that cremation was the custom for the elite.

Another Sheffield archaeologist, Andrew Chamberlain, noted one reason to think that the Stonehenge burials were for generations of a single elite family. The clue, he said, is the small number of burials in the earliest period and the larger numbers in later centuries, as offspring would have multiplied.

The earliest burial to be tested came from a pit at the edge of the stone monuments; it dates to more or less 3000 B.C. The second burial dates to around 2900 B.C. The most recent one is from around the time the first arrangements of stones appeared on the plain, about 2500 B.C. It was previously believed that the site was a burial ground for only a century after 2700 B.C., well before the distinctive large stones were put in place.

Although most of the cremated remains were uncovered decades ago, Dr. Parker Pearson said, it is only in recent years that improved methods of radiocarbon dating have made it possible to analyze burned bones.

In other recent findings at Stonehenge and adjacent sites, archaeologists uncovered a piece of a red-deer antler that was apparently used as a pick for digging. It was found in what is known as the Stonehenge Greater Cursus, a cigar-shaped ditched enclosure nearly two miles long that is thought to have a sacred significance.

Julian Thomas, an archaeologist at the University of Manchester, who led this investigation, said the antler was dated at 3630 to 3375 B.C. That puts the cursus about 1,000 years before the large stones were erected, meaning, he said, that “this landscape maintains its significance over a long period of time.” source

Seaweed Suggests First Humans in America Took the Coastal Route

Published: May 13, 2008

It is now largely accepted that humans first entered the Americas over what was then a land bridge in the area of the Bering Strait. There is more of a debate about what they did next, whether they spread southward by inland routes or along the Pacific Coast.

The coastal route would seem more likely. The migrants would have had an obvious direction to travel, full of familiar resources. In fact, some researchers have argued that these ancient people would have spread along the coast rapidly. But there is little archaeological evidence. For one thing, rising sea levels since then would have submerged any sites.

New findings from a 14,000-year-old settlement in southern Chile support the coastal idea. But they also suggest that the migration may have been relatively slow.

The evidence is in the form of seaweed found at Monte Verde, a site that back then was on a small river about 50 miles east of the Pacific and 10 miles north of an inland bay. Tom D. Dillehay, a professor at Vanderbilt University, and colleagues discovered the seaweed, some of which had been chewed into a cud, as well as a stone tool with remains of seaweed on an edge. The findings were reported in Science.

Dr. Dillehay said the work showed that the seaweed was used for food and medicine and “indicates that these people had a very sophisticated knowledge of these marine ecological zones to the west and south.”

Gaining such knowledge takes time and many trips back and forth to the coast, he added. That suggests that rather than traveling steadily southward, early migrants may have occasionally settled upstream along some of the thousands of rivers on the coast. source


DNA Offers Clues to Greenland’s First Inhabitants

Published: May 30, 2008

A swatch of hair, so thick and tangled it could have belonged to man or bear, has provided answers about a mysterious culture and its origins half a world away.

The culture is that of the first people to have occupied Greenland some 4,500 years ago. Known to archaeologists as the first Paleo-Eskimo culture, it gave way to a second Paleo-Eskimo culture some 2,500 years ago and then 700 years ago to the Thule culture of the present-day Inuit peoples. Some archaeologists suggested that each culture might have descended from its predecessor, but proof required obtaining DNA from the earlier cultures and comparing it with that of the Inuit.

The human DNA differed from that of the Thule people and of American Indians. Its closest match was to people who live in the Commander Islands, the two westernmost islands of the Aleutian chain that arcs from southern Alaska to the Kamchatka Peninsula in Russia, Dr. Willerslev and colleagues reported in an article published online Thursday by the journal Science.

Because the Commander Islands are at the Siberian end of the Aleutian chain, the new finding indicates a heretofore unknown migration from Siberia to the New World, Dr. Willerslev said. Earlier migrations brought the ancestors of American Indians and of the Neo-Eskimos who developed the Thule culture. But Dr. Crawford noted that the hair had provided DNA just on the maternal side and from a single individual, making it hard to generalize about populations.

The Thule culture, which originated in Alaska, developed the technology for hunting bowhead whales. This enabled it to expand across the northern coast of Canada, eventually reaching Greenland. Dr. Crawford said the Aleutian people probably took the same route but depended on fish and seals.

Early peoples had no maps and were not traveling to known destinations; rather, as their population expanded, they followed the natural resources on which they depended. This strategy evidently led the Aleutians some 5,000 years ago to embark on a circumpolar journey that took them all the way to Greenland.

The three Eskimo cultures in Greenland now seem to have been generated by at least two separate arrivals. source


Wednesday, 23 July 2008

Fancy new toys

A funny video of small robot with big goals and the article that explains it:



Grasshopper' robot sets high-jump record

  • 17:00 21 May 2008

Taking its inspiration from the grasshopper, a tiny two-legged robot that stores elastic energy in springs has leaped 27 times its own height, smashing the record of 17 times set by a previous robot.

Its creators hope that swarms of such hopping robots could spread out to explore disaster areas, or even the surfaces of other planets.

The robot is only 5 centimetres tall, and weighs just 7 grams. A motor designed to power the vibration unit of a pager drives a system of gears that gradually wind two metal springs (see image, right).

When they are fully wound and then released, they straighten two metal legs that propel the robot upwards. The jumping robot was developed by researchers at the Swiss Federal Institute of Technology in Lausanne, Switzerland.

Hop on over

Hopping provides an effective way for tiny robots to get around on rough terrain, says Dario Floreano, who worked on the robot with colleague Mirko Kovac.

Just as for insects like crickets, or animals such as frogs, small robots whether legged or wheeled find even small obstacles insurmountable barriers. Hopping can be the only way to get over them.

The new robot's motor takes 3.5 seconds to fully recharge the springs, and its 10 mAh battery is enough to power 108 jumps.

Each of its legs has two segments that attach at an angle, making a knee-like bend in the legs. Adjusting the angle of the "knees" makes the robot hop either more vertically, or further forward.

The prototype doesn't have any way to direct itself, and as yet can't even land on its feet ready for the next hop. Floreano says they are working on a number of refinements.

Just add wings

First, they want to build a wire superstructure to make the robot automatically regain its feet when it lands and add wings to let it glide like a real grasshopper while airborne.

After that they hope to add solar panels, some simple sensors and a microprocessor. These would allow the robot to control its hopping and possibly communicate with other robots in the swarm, as well as recharge its battery.

Such robots might be simple, but they could also be cheap. A group could coordinate themselves to spread across an area to, for example, trace an environmental pollutant, Floreano says.

"They have done excellent work, making this very light robot that can cover very long distance," says Umberto Scarfogliero, at the Institute for Advanced Studies in Lucca, Italy. Scarfogliero and colleagues presented a similar jumping robot called Grillo last year at the IEEE robotics conference.

Floreano and Kovac's robot will be presented today at the IEEE International Conference on Robotics and Automation in Pasadena, California, US. source

My comment: Just imagine the look of 100 such robots(or more) hopping around on the surface of Mars. For example. Though I guess they'll jump pretty hight there. Too high to be usable. But what about over frozen mountain in search of survivors of some disaster. All of them, hopping around. Almost gaily. Honestly, I think that's pretty cool and usable!


Project Digitizes Works From the Golden Age of Timbuktu


Published: May 20, 2008

From Timbuktu to here, to reverse the expression, the written words of the legendary African oasis are being delivered by electronic caravan. A lode of books and manuscripts, some only recently rescued from decay, is being digitized for the Internet and distributed to scholars worldwide.

These are works of law and history, science and medicine, poetry and theology, relics of Timbuktu’s golden age as a crossroads in Mali for trade in gold, salt and slaves along the southern edge of the Sahara. If the name is now a synonym for mysterious remoteness, the literature attests to Timbuktu’s earlier role as a vibrant intellectual center.

In recent years, thousands of these leather-bound books and fragile manuscripts have been recovered from family archives, private libraries and storerooms. The South African government is financing construction of a library in Timbuktu to house more than 30,000 of the books. Other gifts support renovations of family libraries and projects for preserving, translating and interpreting the documents.

Now, the first five of the rare manuscripts from private libraries have been digitized and made available online (www.aluka.org) to scholars and students. At least 300 are expected to be available online by the end of the year.

Many documents in the graceful Arabic calligraphy are a visual delight. Although the writing is mostly in Arabic, quite a few manuscripts are in vernaculars adapted to the Arabic script, which is sure to pose a challenge for scholars.

“The manuscripts of Timbuktu add great depth to our understanding of Africa’s diverse history and civilizations,” said Rahim S. Rajan, the collection development manager at Aluka.

Researchers have been struck by the range of subjects that attracted Timbuktu’s scholars over several centuries and into the 19th century. Most of the first digitized ones are from the 17th through 19th centuries. The topics include the sciences of astronomy, mathematics and botany; literary arts; Islamic religious practices and thought; proverbs; legal opinions; and historical accounts.

In a recent seminar conducted online, members of the Aluka-Northwestern team described some of the problems in starting the digitizing facility in Timbuktu: frequent interruptions of electric power and dust storms fouling delicate electronic components.

“It wasn’t as bad as other places that I’ve seen,” said Harlan Wallach, director of the Advanced Media Production Studio at Northwestern, who has set up similar installations in Asia. “We blew out a lot more transformers and equipment working on a project in China than in Timbuktu.”

While there may be no substitute for seeing the actual manuscripts, Mr. Wallach said, it is better to read them in the digitized form. Many of the pages are so fragile they should not be handled.

Even if Timbuktu today is a dusty, mud-brick shadow of its past renown, living mainly on the few tourists attracted by its name and legend, the pages of its history are emerging from obscurity and, in some cases, are being disseminated by the speed of light. source

My comment: This is utterly great. Just imagine what it is to read a 400 years old manuscript on you monitor. Yeah, of course, there is nothing like the original, but if we want to read only the letters, the monitor is fine for me. I applaud the efforts of that group. This is a true preservation of our history as a planet.

Shuttle to Take Big Science Lab to Space Station

Published: May 27, 2008

The space shuttle Discovery is set to deliver the International Space Station’s biggest room, in what its commander calls “a complicated, busy mission” that is scheduled to begin on Saturday.

The new science laboratory is the second of three parts of a Japanese assembly called Kibo, which means hope. Only a few feet shorter than a big Winnebago, and much larger around, the new module fit inside the shuttle’s payload bay only after astronauts removed an extension for the shuttle’s robotic arm during the last mission and stored it at the station.

The cylindrical laboratory is nearly 37 feet long and 14.4 feet in diameter. The module is so heavy that much of its equipment was shipped up on that previous mission as well, in a small room known a logistics module.

During the current mission, astronauts will also install the module’s robotic arm, which will eventually be used in experiments placed on an external platform — Kibo’s back porch — that will be carried to the station in a mission scheduled to take place next year. Kibo, pronounced ki-BO, will be managed by a control center in Tsukuba, Japan, along with the main mission control center in Houston.

The new mission includes three spacewalks to help install Kibo, perform station maintenance and test techniques for cleaning a troubled rotary joint that is a critical part of the station’s power supply.

That joint, 10 feet in diameter, rotates one of the station’s sets of solar arrays so that they face the Sun during each orbit. But the joint has been idle since last year, when it was found to be damaged by metal shavings that peppered its inner workings and were being ground in by the operation of the joint.

Several spacewalks in the past year have been devoted to examining the damage, but the cause of the problem and the precise part that was being ground away by the rotating joint are still unclear. Although the station has the power it needs now even with a stationary joint, it cannot reach its full functional size without the energy boost from the joint’s rotation. During this mission, astronauts will test techniques that might be used to clean off the shavings.

The astronauts will use a putty knife to smooth the surface of the “race ring,” the part that has been most damaged by the errant particles, and grease and cloths to see what works best at the task.

Later crews will try to correct the problem that caused the shavings by either replacing the source of the grinding or, if it cannot be tracked down, to switch to the use of a second, backup race ring that is already part of the joint assembly.

The crew will also perform science experiments during the mission in fields that include space medicine, biology and Earth observation.

While no technical issues stand in the way of launching, there was some question as to whether the mission should begin before a mystery is resolved: a recurring malfunction in the Russian Soyuz return modules, whose propulsion module failed to separate from the crew module until well into the descent. The malfunction sent the capsule into a backup mode of return that is called a ballistic entry with G-forces that were much higher than usual and a steep trajectory that put it hundreds of miles off course.

The cause of the problem — the second in a row for the Soyuz, and the third in five years — is still under investigation by the Russian space agency.

William Gerstenmaier, associate administrator for space operations at NASA, said managers decided to go forward because the chances of an emergency that would require the station to be evacuated are low and added that the landings, even with the discomfort of ballistic entry, have been safe.source

My comment: I love the International Space Station and thus I'm quite happy that it grows little by little and gets more functional. Because admit it, it's not so much fun (or scientific interest) to put a person or two in orbit for few months. Scientific modules are the key to the monastery and we get them every once in a while. So, Gos Speed Shuttle and Kibo. And Suyuz!

Monday, 21 July 2008

The danger in Nanotechnologies

Recently I read in NY Times and New Scientist 2 similar articles on a research showing nanotubes can have same effect as asbestos on lungs-that is to cause lesions and ultimately very deadly cancer.
Because I often read about the worries of European Commission over the unknown dangers in nanotechnologies, I'm going to put an article here, just to have it in mind. To me, that study is not very definitive, it still has to tell what are the odds of inhaling such materials or of other kind of penetration in our body and as well, what is the quantity that is toxic. And maybe the measures that can keep us safe from those troubles, because obviously for the moment, the lab workers are in greatest danger.
But definitive or not the alarm is set off, so a further investigation ought to be done. Because obviously it's needed. And now, EC has a really good reason to fund that study and make a decent risk-assessment of those technologies.

Nanotubes' toxic effects 'similar to asbestos'

  • 18:00 20 May 2008

Injecting carbon nanotubes into mice shows they can trigger similar toxic responses to asbestos fibres, causing a strong immune response and possibly cancer in the abdominal cavity, researchers say.

But another recent study suggests the tiny tubes, which are increasingly appearing in commercial and industrial products, are not dangerous when inhaled, probably because they do not persist in the body as asbestos fibres do.

Carbon nanotubes (CNTs) first came to the attention of researchers in the early 1990s. Incredibly strong for their size and able to function as both conductors and semiconductors, the tiny structures are thought to be ideal for applications that range from drug delivery to space elevators.

But under a microscope, some CNTs look identical to asbestos fibres, leading to concerns that they could cause similar health problems. Occupational exposure to asbestos led to widespread lung disease, and cancers known as mesothelioma, in the 20th century.

Deadly lookalike

Asbestosis research revealed a checklist of features that makes the fibres dangerous, says Ken Donaldson at the University of Edinburgh, UK.

Ever since, it was presumed that any needle-like fibres around 20 micrometers long with an ability to persist in the body could have similarly dangerous effects. Donaldson and colleagues have now shown this holds true for carbon nanotubes.

When they injected multi-walled carbon nanotubes – composed of a hierarchy of tubes within tubes – into the abdominal cavity of mice, they saw a strong immune reaction within seven days to tubes longer than 20 micrometers. Lesions known as granulomas had developed in the tissue surrounding the abdominal organs.

The granulomas form when the macrophage immune cells that usually swallow and neutralise foreign particles take on the tubes. The cells get ruptured and die when they try to swallow fibres longer than 20 micrometers.

Highly charged

But Donaldson points out that his study does not reveal whether nanotubes are able to persist in the body long enough to reach the areas he directly injected them into. "We need to show this result in an inhalation study," he says.

James Bonner at the North Carolina State University, Raleigh, US, will shortly publish one of the first such studies.

In his experiments, mice breathed air containing 40-micrometer-long multi-walled nanotubes. "Very little inflammatory or fibrogenic effect was observed," he says.

Donaldson notes that determining the true risks of nanotubes will involve measuring the ways in which people will be exposed to them, something studies on toxicity cannot judge.

There is little evidence about exposure so far, says Donaldson. "But the good news is that nanotubes are probably not very 'dirty'," he says. "They are quite highly charged and stick together, so they don't seem to get airborne easily."

Journal reference: Nature Nanotechnology (DOI: 10.1038/nnano.2008.111) source

Link to NY Times article

Saturday, 19 July 2008

Flying with magnets

If you are a teki type, or randomly interested in LISA, the project intending to catch gravity waves from cosmic scandals like binary mergers (contrarily the fact on-ground projects didn't catch any glimpse from those from GRB's that are thought to origin from such events- a fact that is rather suspicious to me, but i won't dare to utter the words) check out this article. I find it rather cool from the least scientific point of view-it's new and it seems to be working. Though the military funding is rather uncool, but whatever, money are money, right. And LISA is so expensive already :)

Magnets help spacecraft fly in formation

(A computer animation illustrates how electromagnets can keep spacecraft in formation (Benjamin Schweighart/MIT-SSL)
Experiments at the MIT Space Systems Laboratory show that by varying the current running through superconducting coils, mock spacecraft can be made to attract, repel, and move sideways relative to each other (Courtesy of MIT-SSL)

Superconducting magnets could help a fleet of spacecraft fly in precise formation without using up limited fuel reserves, two groups of researchers say. But others foresee problems with the technology.

Many proposals for groundbreaking space missions require multiple spacecraft to fly in formation, including NASA's Terrestrial Planet Finder, which would hunt for Earth-like planets around other stars, and the Laser Interferometer Space Antenna (LISA), which would search for ripples in the fabric of space called gravitational waves.

One way to keep spacecraft in the right arrangement is to use thrusters, which fire jets of gas to push a craft in the opposite direction. Unfortunately, thrusters can limit the lifetime of a mission because they rely on limited supplies of fuel.

But two groups of researchers are developing a technology that replaces thrusters with electromagnets.

In this scenario, each spacecraft in the fleet would be outfitted with coils made of superconducting wire. Running electric currents through the coils turns each spacecraft into a magnet with a north and south pole.

By adjusting the current, the orientation of the poles can be changed to either attract multiple spacecraft towards each other or push them farther apart, keeping them at the desired distance.

Solar arrays

A group headed by David Miller of MIT's Space Systems Laboratory in Cambridge, US, has been testing out the concept in the laboratory using mock spacecraft.

The test vehicles squirt jets of air down from their bases in order to hover nearly frictionless on a glass table to simulate floating in space. Using superconducting coils, the vehicles attract and repel each other, and even move sideways relative to one another, (see video at right).

"The biggest advantage is that you have no fuel that can run out," Miller told New Scientist. "The magnetic coils work purely on electrical energy, which you can generate through solar arrays that point at the Sun."

Cooling system

The superconducting coils would need to be kept at low temperatures in order for them to work properly – a temperature of 77 K (-196 °C) is required for one commercially available superconducting material, for example. This temperature could be achieved with a combination of insulation and an electrically powered cooling system, Miller says.

But there are some potential drawbacks to the technology, which is called electromagnetic formation flight (EMFF).

One worry is that the electromagnetic fields generated by the coils could interfere with electronics on board the spacecraft, says Fred Hadaegh, who heads NASA's formation flying efforts at the agency's Jet Propulsion Laboratory in Pasadena, California, US.

Miller counters that the magnetic fields do not need to be very strong, and are weaker than Earth's naturally occurring magnetic field. Some sensitive equipment could be wrapped in a thin layer of nickel-iron alloy called mu-metal, which shields against magnetic fields, he says.

Earth interference

For some equipment, though, shielding is not an option. Wrapping a camera in mu-metal would block light from entering it, making it useless. And shielding a radio antenna would prevent it from sending or receiving signals. But Miller says such devices could be protected by putting small secondary electromagnet coils next to them, tuned in a way that locally cancels the field from the main coils.

Earth's naturally occurring magnetic field could also be a problem for the technique. It would pull on the magnets, which could set the spacecraft spinning.

But a team led by Shin-ichiro Sakai of the Japan Aerospace Exploration Agency (JAXA) believes it has a way to overcome this problem. They recently presented their work at a conference on formation flying in Noordwijk, The Netherlands.

To prevent Earth's magnetic field from disturbing the spacecraft, they propose switching the polarity of the magnets several times each minute. This would prevent the spacecraft from building up any unwanted spin, they say, without interfering with forces between the magnets needed to keep the spacecraft in formation.

Military funding

Hadaegh's team is responsible for developing formation flying technology for NASA's Terrestrial Planet Finder, a mission that the agency postponed indefinitely in 2006, in part because of concerns that formation flying techniques were unproven.

He says his team studied EMFF for possible use on TPF. "As a technologist, I get extremely excited about seeing new technology advances, so I welcome any type of breakthrough ideas," he told New Scientist. But he said the team decided that traditional thrusters were a better choice for the mission.

TPF would reside far from any gravitational disturbances, at a spot in space where Earth's gravity balances that of the Sun. In this quiet zone, very little fuel would actually be needed for the thrusters to maintain the spacecraft formation, he says. And he says he is not satisfied that problems with EMFF like the need for shielding have been solved.

Still, the concept is promising enough that the US Defense Advanced Research Projects Agency (DARPA) is funding the MIT group to develop it for possible use in a project called F6. That project aims to create clusters of little spacecraft that can collectively do everything a single, large satellite can. source