Tuesday, July 14, 2009

Latest Isreal warfare: Israel develops a glide bomb

Israel is developing a new "smart" glide bomb, a weapon that had its origins as far as back as World War I. It is likely to wind up in the Israel armory for operations against Palestinian militants and Lebanon's Hezbollah guerrillas.

The weapon, designated the Medium Laser-Guided Bomb, is still in the early stages of development by the state-run Israel Aerospace Industries, flagship of Israel's defense industry.

The bomb, on display for the first time at the recent Paris Air Show, was described as a "precision weapon for precision attacks or close air support against various types of targets such as buildings, small bunkers, time-critical targets and moving targets," offering "pinpoint accuracy for all-weather conditions" as well as trajectory control."

Glide bombs are aerodynamically configured to flatten and extend their normal flight trajectory and can be controlled from the launch aircraft for pinpoint attacks.

The Israeli air force frequently targets militants while they are moving around in vehicles. The weapons employed in such cases range from air-to-ground missiles fired from F-16 strike aircraft or helicopter gunships.

Other targets that might be suitable for the glide bomb are makeshift factories manufacturing homemade Qassam rockets used by Hamas to fire into Israel.

The militants are extending the range and firepower of these projectiles launched from Gaza to the point where they may soon target urban areas around Tel Aviv in central Israel.

The glide bomb is said to carry a 36-pound warhead and appears to be about the same size as the U.S. GBU-39/B Small Diameter Bomb.

The German Luftwaffe held flight trials with a German precision-guided Hope standoff penetrator glide bomb.

The results remain closely guarded, but Aviation Week reported on Sept. 25, 2008, that the weapon, using a GPS guidance system aided by an inertial navigation system, hit its targets precisely.

The bomb was launched from a Luftwaffe Tornado IDS strike aircraft at the flight test center at Vidsel in Sweden.

During World War I, Wilhelm von Siemens proposed a "torpedo glider" -- a wire-guided missile that was basically a naval torpedo with an airframe attached -- but the conflict ended before it could be developed.

But during World War II, the Germans introduced the first operational glider bombs, primarily as anti-shipping weapons as von Siemens had envisaged. These were radio-controlled weapons designated Ruhrstahl SD 1400 and generally known as Fritz-X.

On Nov. 26, 1943, the British troopship Rohna was sunk by one of these weapons as it carried U.S. troops from Oran, Morocco, to Port Said, Egypt, in an allied convoy traversing the Mediterranean.

The bomb ripped a huge hole in the ship's port side and set the vessel on fire. It sank and 1,235 soldiers and crewmen perished. The attack with this mysterious weapon was hushed up for many years, but it inflicted the highest U.S. death toll of any ship sunk in World War II.

After the war, the Americans developed the glide bomb, adding sophisticated electronics. These evolved in the 1960s into the U.S. Air Force's AGM-62 Walleye and later the AGM-65 Maverick.

SELEX Galileo Awarded Contract For ENFORCER Weapon Stations

SELEX Galileo is pleased to announce the award of over 40 ENFORCER Remote Controlled Weapon Stations (RCWS) for installation on the Ridgeback fleet.

The contract will equip a substantial proportion of the latest generation of protected mobility vehicles with highly capable and operationally proven equipment giving enhanced survivability, observation and firepower to its users.

Building on SELEX Galileo's expertise as the principle provider of RCWS to the UK army with over 400 systems already delivered, the provision of ENFORCER on Ridgeback builds further on its competitive selection under the UK MoD's PANTHER programme and under the Challenger II and Bulldog UoR.

ENFORCER will be integrated into the SELEX Galileo Indirect Vision System already fitted to the Mastiff and Ridgeback Fleet offering enhanced situational awareness to the vehicle crew.

Colin Horner Vice President for Land Sales and Marketing said "We are extremely pleased that the MoD has chosen to enhance the capability of its latest generation of protected patrol vehicles with the selection of ENFORCER to meet this requirement. The intuitive nature of the system has already had real battle winning impact on current operations in both theatres of operation and the integration with the SELEX Galileo Indirect Vision System will provide all soldiers operating with Ridgeback a greater level of tactical situational awareness than previously available".

Germany axes planned bomb range

Opponents of a planned military bombing range northwest of Berlin won a nearly 17-year-long political battle Thursday when the government said it would axe the project.

The defence ministry had aimed to use a vast former Soviet training ground near the town of Wittstock for low-flying military aircraft, which would also have involved bombing runs.

But Defence Minister Franz Josef Jung said the plans for the so-called Bombodrom site had been cancelled "after extremely careful consideration".

"We no longer plan to use Wittstock as an air-to-surface bombing exercise site," Jung said.

Opponents who objected that the training activities would create massive noise pollution for residents of the area and drive away tourists won a key court battle in March against the government's plans.

Thousands of protesters had rallied most recently against the project in April during traditional Easter pacifist marches.

"This is a joyful day for the people of this region," the premier of Brandenburg state surrounding Berlin, Matthias Platzeck, said.

The German military already performs 75 percent of its training flights abroad in NATO partner countries including the United States, Italy and Canada.

Jung said the Bombodrom flights would now also be conducted outside Germany, a move he said would incur higher costs that he declined to estimate.

US Army Awards Javelin Joint Venture Support Contract

The U.S. Army selected the Raytheon-Lockheed Martin Javelin Joint Venture to provide life-cycle contract support for the Javelin anti-tank missile and command launch unit.

The five-year $298.6 million contract has a fiscal year 2009 funded value of $34.9 million. It requires the Javelin Joint Venture to provide the U.S. Army with depot spares, repair support, training and data.

"The Javelin Joint Venture is focused on our customer needs throughout the product life cycle," said Duane Gooden, Raytheon's Javelin program director and president of the Javelin Joint Venture. "We are extending the lifetime of our products through upgrades, while supporting the warfighter with training services and technical support."

Javelin is the world's first man-portable, fire-and-forget, medium-range missile system. The compact, lightweight missile is designed for one-soldier operations in all environments.

"The Javelin life-cycle contract support team continues to provide exceptional support to our warfighters with amazing turnaround time for hardware returned for repair or upgrade," said Barry James, vice president of the Javelin Joint Venture.

"The team has been able to coordinate shipments in and out of theater to the repair facility and back to the front line in a matter of days. We are committed to providing world-class focused support to ensure combat readiness."

LM DAGR Rockets Fired From Airborne AH-6 Little Bird

Lockheed Martin has launched DAGR rockets from an airborne AH-6 Little Bird helicopter and successfully hit the target in two separate trials. This is the second platform DAGR has fired from in the past few months-Lockheed Martin also fired DAGR rockets from the AH-64D Apache helicopter in March.

In preparation for the tests, conducted at the Yuma Army Proving Ground in Arizona, Lockheed Martin engineers mounted the DAGR four-pack launch canister on the outboard rail of a modified XM299 launcher carried by the AH-6 Mission Enhanced Little Bird test platform.

The Little Bird firings were performed as a running fire, using a ground designator, and then self designation using the Little Bird's onboard MX-15D1 targeting system. The DAGR rocket was extremely accurate in hitting the laser aimpoint in both tests.

"Not long ago we fired DAGR from an airborne Apache, and we are pleased to add the Little Bird to the roster of platforms that have demonstrated integration with the DAGR system," said Jerry Brode, DAGR program manager at Lockheed Martin Missiles and Fire Control.

"Pilots in theater have expressed a desire for a guided rocket that hits the target and minimizes collateral damage," he added. "With multiple platform firings under its belt, along with the live warhead test we conducted at Eglin Air Force Base last year, DAGR is being qualified to deliver that capability."

Because the DAGR system is designed to be compatible with the M299 family of launchers, it offers potential integration on all rotary-wing HELLFIRE platforms, including the Apache, Little Bird, Kiowa, Blackhawk, Cobra, and Tiger helicopters. A mixed loadout of HELLFIRE IIs and DAGRs can be mounted on the same launcher, providing operational flexibility that enables cost-effective multi-mission capability from a single platform.

In 12 successful guided flight tests, the DAGR system has repeatedly demonstrated its precision strike and maneuver capabilities, hitting short- and long-range off-axis targets within minimal distance of the laser-designated aimpoint. This provides Warfighters with increased capability and an expanded engagement envelope.

Lockheed Martin has developed the DAGR system with internal funding, and is now making the system available for integration and fielding. Qualification of DAGR products and configurations is ongoing.

Latest Powerful Ideas: Military Develops 'Cybug' Spies

Miniature robots could be good spies, but researchers now are experimenting with insect cyborgs or "cybugs" that could work even better.

Scientists can already control the flight of real moths using implanted devices.

The military and spy world no doubt would love tiny, live camera-wielding versions of Predator drones that could fly undetected into places where no human could ever go to snoop on the enemy. Developing such robots has proven a challenge so far, with one major hurdle being inventing an energy source for the droids that is both low weight and high power. Still, evidence that such machines are possible is ample in nature in the form of insects, which convert biological energy into flight.

It makes sense to pattern robots after insects - after all, they must be doing something right, seeing as they are the most successful animals on the planet, comprising roughly 75 percent of all animal species known to humanity. Indeed, scientists have patterned robots after insects and other animals for decades - to mimic cockroach wall-crawling, for instance, or the grasshopper's leap.

Mechanical metamorphosis

Instead of attempting to create sophisticated robots that imitate the complexity in the insect form that required millions of years of evolution to achieve, scientists now essentially want to hijack bugs for use as robots.

Originally researchers sought to control insects by gluing machinery onto their backs, but such links were not always reliable. To overcome this hurdle, the Hybrid Insect Micro-Electro-Mechanical Systems (HI-MEMS) program is sponsoring research into surgically implanting microchips straight into insects as they grow, intertwining their nerves and muscles with circuitry that can then steer the critters. As expensive as these devices might be to manufacture and embed in the bugs, they could still prove cheaper than building miniature robots from scratch.

As these cyborgs heal from their surgery while they naturally metamorphose from one developmental stage to the next - for instance, from caterpillar to butterfly - the result would yield a more reliable connection between the devices and the insects, the thinking goes. The fact that insects are immobile during some of these stages - for instance, when they are metamorphosing in cocoons - means they can be manipulated far more easily than if they were actively wriggling, meaning that devices could be implanted with assembly-line routine, significantly lowering costs.

The HI-MEMS program at the U.S. Defense Advanced Research Projects Agency (DARPA) has to date invested $12 million into research since it began in 2006. It currently supports these cybug projects:

  • Roaches at Texas A&M.
  • Horned beetles at University of Michigan and the University of California at Berkeley.
  • Moths at an MIT-led team, and another moth project at the Boyce Thompson Institute for Plant Research.

Success with moths

So far researchers have successfully embedded MEMS into developing insects, and living adult insects have emerged with the embedded systems intact, a DARPA spokesperson told LiveScience. Researchers have also demonstrated that such devices can indeed control the flight of moths, albeit when they are tethered.

To power the devices, instead of relying on batteries, the hope is to convert the heat and mechanical energy the insect generates as it moves into electricity. The insects themselves could be optimized to generate electricity.

When the researchers can properly control the insects using the embedded devices, the cybugs might then enter the field, equipped with cameras, microphones and other sensors to help them spy on targets or sniff out explosives. Although insects do not always live very long in the wild, the cyborgs' lives could be prolonged by attaching devices that feed them.

The scientists are now working toward controlled, untethered flight, with the final goal being delivering the insect within 15 feet (5 m) of a specific target located 300 feet (100 meters) away, using electronic remote control by radio or GPS or both, standing still on arrival.

Although flying insects such as moths and dragonflies are of great interest, hopping and swimming insects could also be useful, too, DARPA noted. It's conceivable that eventually a swarm of cybugs could converge on targets by land, sea and air.

Monday, July 6, 2009

US and Russia agree key nuclear deal

Russia and the US agreed today to cut their nuclear warhead arsenals to as few as 1,500 each, aiming toward the lowest levels of any US-Russia arms control deal.

The initial agreement signed by presidents Barack Obama and Dmitry Medvedev at a Moscow summit, is meant to guide negotiators as the nations work toward a replacement pact for the START strategic arms control reduction treaty, which expires in December.

The joint understanding, signed after about three hours of talks at the Kremlin, also commits the new treaty to lower each nation's longer-range missiles for delivering nuclear bombs to between 500 and 1,100.

Under current treaties, each country is allowed a maximum of 2,200 warheads and 1,600 launch vehicles.

A White House statement said the new treaty "will include effective verification measures."

"The new agreement will enhance the security of both the US and Russia, as well as provide predictability and stability in strategic offensive forces," the statement said.

The leaders also announced several other deals meant to show progress toward repairing badly damaged US-Russian relations including Moscow allowing the United States to transport arms across its land and airspace into Afghanistan for the war there.

They outlined other ways to work together to help stabilise Afghanistan, including increasing assistance to the Afghan army and police and training counter-narcotics personnel. A joint statement said the United States and Russia welcomed increased international support for upcoming Afghan elections and they were prepared to help Afghanistan and Pakistan work together against the "common threats of terrorism, extremism and drug trafficking."

Other side agreements include reviving a joint commission to try to account for missing service members of both countries dating back to the Second World War and new cooperation on public health issues.

The commission was first created by the first President Bush and President Boris Yeltsin in the early 1990s, but the Russians later downgraded their participation. The US hope Russia will open some of its more sensitive archives to US researchers seeking details about missing American servicemen.

Mr Obama needs Russia's help chiefly in pressuring Iran and North Korea to give up their nuclear weapons ambitions, but also in tackling terrorism, global warming and the economy. But with relations frayed with Moscow's war with Georgia last year and US missile defence plans in eastern Europe, Mr Obama's desire to reset relations is a huge test of his diplomatic skills.

"The United States and Russia have more in common than they have differences," Mr Obama said as he and Medvedev first sat down.

His host launched the high-stakes summit with similar good will.

"We'll have a full-fledged discussion of our relations between our two countries, closing some of the pages of the past and opening some of the pages of the future," Mr Medvedev said.

However the two sides remain at stalemate over the US pursuit of a missile-defence system in Europe, pushed hard by Mr Bush and under review by Mr Obama.

The US insists it is designed to protect US allies in Europe from a potential nuclear attack by Iran. But the Russians see it as a first step toward a system that could weaken their offensive nuclear strike potential.

The summit starts a week-long trip for Mr Obama that also features G8 meetings and a visit with the pope in Italy, and a speech in Ghana.

Thursday, July 2, 2009

North Korea test-fires 4 short-range missiles

SEOUL, South Korea – North Korea test-fired four short-range missiles Thursday, South Korea's Defense Ministry said, a move that aggravates already high tensions following Pyongyang's recent nuclear test and U.N. sanctions imposed as punishment.

Two ground-to-ship missiles were fired from the eastern coastal city of Wonsan on Thursday afternoon, a ministry official said on condition of anonymity citing department policy.

The North also fired a third missile later from the east coast, but the exact site and the type of a rocket was not immediately known, the official said. Another ministry official — also speaking on condition of anonymity citing department policy — said the North later fired a fourth missile, though she provided no details.

Yonhap news agency, citing an unnamed military official, reported all four missiles flew about 60 miles (100 kilometers) and identified them as KN-01 missiles with a range of up to 100 miles (160 kilometers).

North Korea had earlier called for a no-sail zone in waters off its east coast through July 10 for military drills. That designation was viewed as a prelude to such missile tests.

The launches came as North Korea's relations with the United States, South Korea and other countries were already severely strained after its May 25 underground nuclear test and a series of missile firings. The U.N. Security Council adopted a tough sanctions resolution last month to punish the communist regime.

"We had expected that they will fire short-range missiles at any time," South Korea's Foreign Minister Yu Myung-hwan told The Associated Press at a reception held at the U.S. ambassador's residence to mark Independence Day on July 4, which falls this weekend. "It's not a good sign because they are demonstrating their military power."

In Tokyo, Japanese Prime Minister Taro Aso called the missile launches "provocative acts" and urged the North to refrain.

Russian Foreign Ministry spokesman Andrei Nesterenko also expressed concern over the North's missile launches, saying, "We have always asked North Koreans to abstain from actions that may exacerbate the situation."

The first launch came just before the U.S. ambassador's reception started in the late afternoon, while the second and third came as it was under way, based on times provided by the Defense Ministry. The timing for the fourth launch was not immediately available.

While it was not clear if the firings were meant to coincide with the event, the North did launch a long-range missile in 2006 in the early morning hours of July 5, which coincided with the July 4 holiday in the United States.

The United States is seeking Chinese support to enforce U.N. sanctions imposed on the North to punish it over the nuclear test. Philip Goldberg, in charge of coordinating the implementation of sanctions against the North, told reporters in Beijing that he had "very good conversations" with Chinese officials Thursday, though not give details of the talks .

Separately, China's top nuclear envoy, Wu Dawei, left Thursday for Russia as part of diplomatic efforts to push North Korea back to the stalled nuclear disarmament talks, according to the Chinese Foreign Ministry.

The trip will also take Wu to the U.S., Japan, and South Korea, the ministry said. The five nations have engaged in the talks since 2003 in an effort to persuade the North abandon its nuclear programs in return for economic aid and other concessions.

"The purpose of Wu Dawei's visit is to exchange views with relevant parties on the nuclear issues on the Korean peninsula," Chinese Foreign Ministry spokesman Qin Gang said in a regular press briefing.

Earlier in the day, Seoul's JoongAng Ilbo newspaper reported that North Korea could fire a barrage of missiles in coming days, including ballistic Scud or Rodong rockets that the North is banned from testing under U.N. resolutions.

North Korea has also threatened to test-fire an intercontinental ballistic missile. Last month, a Japanese newspaper reported that the North could test-fire a long-range missile toward Hawaii as early as July 4. The U.S. has increased defenses around the island state.

But Seoul's YTN television news network said Thursday that there are no signs of an imminent long-range missile launch.

The reported missile moves came after a North Korean ship — suspected of possibly carrying illicit weapons — changed course and was heading back the way it came after remaining under U.S. surveillance for more than a week.

The North Korean ship is the first vessel monitored under the new U.N. sanctions that seek to clamp down on Pyongyang's trading of banned arms and weapons-related material by requiring U.N. member states to request inspections of ships suspected of carrying prohibited cargo.

The North has said it would consider the interception of its ships a declaration of war.

Afghan Updates: US Marines launch major offensive in Afghanistan

NAWA, Afghanistan – Thousands of U.S. Marines poured from helicopters and armored vehicles into Taliban-controlled villages in southern Afghanistan on Thursday in the first major operation under President Barack Obama's strategy to stabilize the country.

The offensive was launched shortly after 1 a.m. Thursday local time (4:30 p.m. EDT Wednesday, 2030 GMT Wednesday) in Helmand province, a Taliban stronghold and the world's largest opium poppy-producing area. The goal is to clear insurgents from the hotly contested region before the nation's Aug. 20 presidential election.

The Marines have not suffered any serious casualties and have seen only a sporadic resistance, said Lt. Abe Sipe, a spokesman for the unit.

"The enemy has chosen to withdraw rather than engage for the most part," Sipe said. "We had a couple of heat casualties, but not deemed serious in nature at this time."

The operation came as U.S. military announced that one of its soldiers was missing and believed captured by insurgents in eastern Afghanistan on Tuesday. The missing soldier was not involved in the Helmand operation.

Officials described the offensive — dubbed Khanjar or "Strike of the Sword" — as the largest and fastest-moving of the war's new phase and the biggest Marine offensive since the one in Fallujah, Iraq, in 2004. It involves nearly 4,000 newly arrived Marines plus 650 Afghan forces. British forces last week led similar, but smaller, missions to clear out insurgents in Helmand and neighboring Kandahar province.

"Where we go we will stay, and where we stay, we will hold, build and work toward transition of all security responsibilities to Afghan forces," Marine Corps Brig. Gen. Larry Nicholson said in a statement.

Pakistan's army said it had moved troops from elsewhere on its side of the Afghan border to the stretch opposite Helmand to try to stop any militants from fleeing the offensive. It gave no more details, but U.S. and Pakistani officials have expressed concern that stepped-up operations in southern Afghanistan could push the insurgents across the border.

Transport helicopters carried hundreds of Marines into the village of Nawa, some 20 miles (30 kilometers) south of the provincial capital of Lashkar Gah, in a region where no U.S. or other NATO troops have operated in large numbers.

The troops took many insurgents by surprise, dropping behind Taliban lines, said Capt. Drew Schoenmaker, from Greene, New York.

"We are kind of forging new ground here. We are going to a place nobody has been before," said Schoenmaker, 31, who commands Bravo Company of the 1st Battalion, 5th Marine Regiment.

Daybreak brought the sporadic crackle of gunfire. Medical helicopters circled overhead and landed, indicating possible early casualties among the Marines.

A Marine unit in Nawa traded gunfire with a group of some 20 insurgents, while Afghan troops exchanged small arms fire with militants after they were attacked with rocket propelled grenades fired from several houses. A Cobra helicopter circling overhead for most of the day fired rockets at a tree line nearby. Other troops walked through fields of corn and past mud-wall homes. Only a handful of villagers dared to venture outside.

A roadside bomb early in the mission wounded one Marine, but he was able to continue, spokesman Capt. Bill Pelletier said.

Southern Afghanistan is a Taliban stronghold but also a region where Afghan President Hamid Karzai is seeking votes from fellow Pashtun tribesmen.

The Pentagon is deploying 21,000 additional troops to Afghanistan in time for the elections and expects the total number of U.S. forces there to reach 68,000 by year's end. That is double the number of troops in Afghanistan in 2008 but still half as many as are now in Iraq.

The Taliban, who took control of Afghanistan in 1996 and were ousted from power following a U.S.-led invasion in 2001, have made a violent comeback, wreaking havoc in much of the country's south and east, forcing the United States to pour in the new troops.

Pelletier said troops in Thursday's operation were sent in by a mixture of aircraft and ground transport under the cover of darkness.

The operation aims to show "the Afghan people that when we come in, we are going to stay long enough to set up their own institutions," Pelletier said.

Once on the ground, the troops will meet with local leaders, hear their needs and act on them, Pelletier said.

"We do not want people of Helmand province to see us as an enemy. We want to protect them from the enemy," Pelletier said.

Thousands of British forces, fighting under NATO command, have been in Helmand since 2006 with broadly the same strategy, but security has deteriorated. They have met with stronger resistance than initially expected against Taliban fighters bankrolled by the vast opium and heroin trade.

Reversing the insurgency's momentum has been a key component of the new U.S. strategy, and thousands of additional troops allow commanders to push and stay into areas where international and Afghan troops had no permanent presence before.

While Marine troops were the bulk of the force, recently arrived U.S. Army helicopters were also taking part in the operation.

In March, Obama unveiled his strategy for Afghanistan, seeking to defeat al-Qaida terrorists there and in Pakistan with a bigger force and a new commander. Taliban and other extremists, including those allied with al-Qaida, routinely cross the two nations' border in Afghanistan's remote south.

Last year, NATO and Pakistani forces cooperated in a series of complementary operations on the border, but the overall commitment of Islamabad to Washington's aims in Afghanistan has long been questioned. Pakistan has frequently been accused in the past of failing to stop — and sometimes aiding — the movement of insurgents into Afghanistan from its side of the border.

The governor of Helmand province predicted Operation Khanjar would be "very effective."

"The security forces will build bases to provide security for the local people so that they can carry out every activity with this favorable background and take their lives forward in peace," Gov. Gulab Mangal said in a Pentagon news release.

Obama aims to boost the Afghan army from 80,000 to 134,000 troops by 2011 — and greatly increase training by U.S. troops accompanying them — so the Afghan military can take control of the war. The White House also is pushing forces to set clear goals for a war gone awry, provide more resources and make a better case for international support.

There is no timetable for withdrawal, and the White House has not estimated how many billions of dollars its plan will cost.

Elsewhere in Afghanistan, insurgents captured an American soldier on Tuesday, said Capt. Elizabeth Mathias, a U.S. military spokeswoman. The missing soldier was not part of the Helmand operation.

"We are using all of our resources to find him and provide for his safe return," Mathias said.

Mathias did not provide details on the soldier, the location where he was captured or the circumstances.

Afghan Police Gen. Nabi Mullakheil said the soldier went missing in the Mullakheil area of eastern Paktika province, where there is an American base.

Zabiullah Mujaheed, a spokesman for the Taliban, could not confirm that the soldier was with any of their militant forces. A myriad of insurgent groups operate in eastern Afghanistan, and the Taliban is only one of them.

The soldier was noticed missing during a routine check of the unit on Tuesday and was first listed as "duty status whereabouts unknown," a U.S. defense official said on condition of anonymity because details are still sketchy.

Two U.S. defense sources said the soldier "just walked off" post with three Afghan counterparts after he finished working. They said they had no explanation for why he left the base. He was assigned to a combat outpost, one of a number of smaller bases set up by foreign forces in Afghanistan, the officials said.

The most important insurgent group operating in that area is known as Haqqani network and is led by Siraj Haqqani, whom the U.S. has accused of masterminding beheadings and suicide bombings.

Wednesday, July 1, 2009

What is a Sonic Boom? How to see it?

There's something strange about the notion of seeing the sound barrier, as this Navy photograph suggests is the case. The sound barrier is just a certain velocity relative to the surrounding environment, not an actual membrane to be penetrated by a jet's nose.

The visual phenomenon in this picture is caused by a layer of water droplets trapped between two high-pressure surfaces of air. In humid conditions, condensation can gather in the trough between two crests of the sound waves produced by the jet. This effect does not necessarily coincide with the breaking of the sound barrier, although it can.

On October 14, 1947, U.S.A.F. Major Charles "Chuck" Yeager flew into aviation history by piloting a Bell XS-1 research plane to supersonic speeds. These days NASA is flying unmanned aircrafts at close to Mach 10 velocity.

The origins of the Mach number stretch back before humans ever took flight, to 1887, when Austrian physicist Ernst Mach established his principles of supersonics. His famous Mach number is the ratio of an object’s velocity to the velocity of sound, relative to the local environment. Sounds are waves of disturbance in the atmosphere and so their velocities depend on air temperature and pressure.

At sea-level pressure in 59-degree Fahrenheit air, sound travels 760 mph. Flying any faster is a noisy enterprise. When moving at subsonic speeds (Mach number <>