[In 1963] the United States launched half a billion whisker-thin copper wires into orbit in an attempt to install a ring around the Earth. It was called Project West Ford, and it’s a perfect, if odd, example of the Cold War paranoia and military mentality at work in America’s early space program.
The Air Force and Department of Defense envisioned the West Ford ring as the largest radio antenna in human history. Its goal was to protect the nation’s long-range communications in the event of an attack from the increasingly belligerent Soviet Union.
During the late 1950’s, long-range communications relied on undersea cables or over-the-horizon radio. These were robust, but not invulnerable. Should the Soviets have attacked an undersea telephone or telegraph cable, America would only have been able to rely on radio broadcasts to communicate overseas. But the fidelity of the ionosphere, the layer of the atmosphere that makes most long-range radio broadcasts possible, is at the mercy of the sun: It is routinely disrupted by solar storms. The U.S. military had identified a problem.
A potential solution was born in 1958 at MIT’s Lincoln Labs, a research station on Hanscom Air Force Base northwest of Boston. Project Needles, as it was originally known, was Walter E. Morrow’s idea. He suggested that if Earth possessed a permanent radio reflector in the form of an orbiting ring of copper threads, America’s long-range communications would be immune from solar disturbances and out of reach of nefarious Soviet plots.
On June 3, 3.9 billion light-years away, two incredibly dense neutron stars— bodies that are each about 1.5 times the mass of the sun but just the size of mere cities—collided. Scientists studying the event say it solves an enduring mystery about the formation of elements in our universe….
[A]nalysis reveals that neutron star collisions are responsible for the formation of virtually all the heavy elements in the universe—a list that includes gold, mercury, lead, platinum and more.
“This question of where elements like gold come from has been around for a long time,” Berger says. Though many scientists had long argued that supernova explosions were the source, he says his team … have evidence that supernovas aren’t necessary. These neutron star collisions produce all elements heavier than iron, he says, “and they do it efficiently enough that they can account for all the gold that’s been produced in the universe.”
Such collisions occur when both the stars in a binary system separately explode as supernovas, and then collapse into themselves, leaving behind a pair of tightly bound neutron stars. As they circle each other, the stars are gradually pulled together by gravitational forces, until they collide.
“They’re extremely dense—essentially bullets flying at each other at about ten percent the speed of light,” Berger says. The resulting collision brings together so much mass in one location that it collapses on itself, triggering the formation of a black hole. A small amount of matter, though, gets thrown outward, and is eventually incorporated into the next generation of stars and planets elsewhere in the surrounding galaxy. Close observation of this latest neutron star collision has revealed the contents of this ejected matter….
“I’ve spent the last decade of my life trying to address the question of gamma-ray bursts, painstakingly collecting evidence and waiting for that one big event,” Berger says. “It’s so satisfying to finally get that evidence that can tell us what’s going on in a more definitive way.”
The Navy has awarded BAE Systems a contract to develop a next-generation launcher with higher rates of fire for its now-in-development Electromagnetic Railgun, service and industry officials explained.The Office of Navy Research is currently developing an EM Railgun which uses massive “pulses” of electricity to propel a projectile or an explosive at distances greater than 100 nautical miles.
The U.S. Navy’s Science and Technology community is deploying prototypes of electromagnetic rail guns, solid-state laser weapons and underwater unmanned vehicles in operational units with sailors and Marines….
A ship-mounted electromagnetic rail gun is one such prototype being tested on Navy vessels, Klunder said.
The rail gun, which can hit ranges of 100 miles or more, uses electricity stored on the ship to generate a high-speed electromagnetic pulse sufficient to propel a kinetic energy warhead. The result, is an inexpensive, high-impact and long-range offensive weapon, Klunder said.
“Electromagnetics have been around for a long time. How do you harness them and build the rails? We’re big fans of learning how to prototype these technologies for military applications,” he added. “We’ve fired this numerous times through testing. This is showing incredible results, so much so that we are very committed to this for the future.”
The United States has begun producing plutonium-238 again for the first time in a quarter century, marking a key step toward averting a feared shortage of this important spacecraft fuel, NASA officials say.
The U.S. Department of Energy’s plutonium reboot has not yet advanced beyond the test phase, but NASA is confident that production will eventually ramp up enough to power space probes for several decades to come.
"That’s going to revive our supply and allow us to be able to complete a number of potential plutonium-necessary missions over this decade, and position us well into the decade after that," Jim Green, head of NASA’s planetary science division, said Monday….
Plutonium-238 is not a bombmaking material, unlike its isotopic cousin plutonium-239. But Pu-238 is radioactive, emitting heat that can be converted to electricity using a device called a radioisotope thermoelectric generator (RTG).
For decades, RTGs have been the power system of choice for NASA missions to destinations in deep space, where weak sunlight tends to make solar arrays impractical. For example, the agency’s twin Voyager spacecraft, which are knocking on the door of interstellar space, both use RTGs, as does the car-size Mars rover, Curiosity.
Japan said Tuesday that it had extracted gas from offshore deposits of methane hydrate — sometimes called “flammable ice” — a breakthrough that officials and experts said could be a step toward tapping a promising but still little-understood energy source.
The gas, whose extraction from the undersea hydrate reservoir was thought to be a world first, could provide an alternative source of energy to known oil and gas reserves. That could be crucial especially for Japan, which is the world’s biggest importer of liquefied natural gas and is engaged in a public debate about whether to resume the country’s heavy reliance on nuclear power.
Experts estimate that the carbon found in gas hydrates worldwide totals at least twice the amount of carbon in all of the earth’s other fossil fuels, making it a potential game-changer for energy-poor countries like Japan. Researchers had already successfully extracted gas from onshore methane hydrate reservoirs, but not from beneath the seabed, where much of the world’s deposits are thought to lie.
The exact properties of undersea hydrates and how they might affect the environment are still poorly understood, given that methane is a greenhouse gas. Japan has invested hundreds of millions of dollars since the early 2000s to explore offshore methane hydrate reserves in both the Pacific and the Sea of Japan.
Two giant swaths of radiation, known as the Van Allen Belts, surrounding Earth were discovered in 1958. In 2012, observations from the Van Allen Probes showed that a third belt can sometimes appear. The radiation is shown here in yellow, with green representing the spaces between the belts. (NASA/Van Allen Probes/Goddard Space Flight Center; via Universe Today)
In principle, [lasers] are simple devices. They consist of a couple of mirrors, a source of energy, usually light, and a lasing cavity in which the light can bounce back and forth.
The trick is to fill the lasing cavity with a material known as a gain medium which amplifies at a specific frequency when stimulated by light of another frequency. When this amplified light is directed out of the cavity, using a half-mirror, it forms a narrow beam of coherent light of a single specific frequency–a laser beam.
For many applications, the shape of this beam– the way the light intensity varies across the beam–is important.
Physicists currently change the shape by placing various kinds of beam-shaping devices in front of the laser. These include lenses, mirrors and digital holograms generated using spatial light modulators.
But because these devices are essentially bolted on to the front of a laser, they all require expensive custom optics that have to be calibrated each time they are changed.
Today, however, Sandile Ngcobo at the University of KwaZulu–Natal in South Africa and few buddies, say they’ve worked out a way round this. And they’ve designed and built a device to test their idea.
The solution is simple. Instead of putting a spatial light modulator in front of the laser, they’ve built one in to the device, where it acts as the mirror at one end of the cavity. In this way, the spatial light modulator shapes the beam as it is being amplified.
The result is that the beam is already shaped in the required way when it emerges from the laser cavity…. The big advantage of all this is that the spatial light modulator generates patterns electronically. That allows these guys to change the beam shape at the touch of a button and without any of the time-consuming set up required with other methods.
Aerospace engineers have long known that ditching a conventional tubular fuselage in favor of a manta-ray-like “hybrid wing” shape could dramatically reduce fuel consumption. A team at NASA has now demonstrated a manufacturing method that promises to make the design practical.
Combined with an extremely efficient type of engine, called an ultra-high bypass ratio engine, the hybrid wing design could use half as much fuel as conventional aircraft. Although it may take 20 years for the technology to come to market, the manufacturing method developed at NASA could help improve conventional commercial aircraft within the next eight to 10 years, estimates Fay Collier, a NASA program manager.
The manufacturing technique lowers the weight of structural components of an aircraft by 25 percent, which could significantly reduce fuel consumption. The advances are the culmination of a three-year, $300 million effort by NASA and partners including Pratt & Whitney and Boeing.
DARPA plans to buy a second Hellads high-energy laser system from General Atomics Aeronautical Systems (GA-ASI), to provide to the Office of Naval Research (ONR) for the demonstration of a laser weapon system against targets relevant to surface ships.
Hellads is a liquid-cooled, solid-state laser that has been under development for DARPA for several years. GA-ASI is building a 150kW Hellads laser to be integrated with an existing US Air Force beam control system for a ground demonstration in 2014….
After focusing its directed-energy research for years on the free electron laser, ONR has launched a program to mature available solid-state electric laser technology with a goal of getting laser weapons on ships more quickly.
Hellads is designed to meet a weight goal of less that 5kg/kW, enabling a high-energy laser weapon to be integrated onto tactical aircraft. DARPA and the Air Force Research Laboratory are planning a follow-on flight demonstration under the Electric Lasers on Large Aircraft (ELLA) program.
The design is based on combining a series of unit cell modules together to produce a single 150kW laser. DARPA says GA-ASI demonstrated the required power output and optical performance with a single module, then showed that two unit cells could be integrated to produce more than 34kW.
Fabrication of the 150kW laser was planned to be completed the end of 2012. Plans for 2013 include its integration with the power, thermal management, beam control, and command-and-control subsystems to produce a laser weapon ready for low-power testing. Shoot-down tests against targets such as surface-to-air missiles and rockets will follow in 2014.