Dark Lightning: Terrestrial Gamma Ray Flashes irradiate passengers

"What are the radiation doses to airplane passengers from the intense bursts of gamma-rays that originate from thunderclouds?" Florida Institute of Technology Department of Physics and Space Science faculty members addressed the issue and presented their terrestrial gamma ray flashes (TGFs) research modeling work at a press conference meeting of the European Geosciences Union in Vienna, Austria, April 10, 2013.

Joseph Dwyer

Joseph Dwyer, Ningyu Liu and Hamid Rassoul discussed a new physics-based model of radiation dose calculations and compared the calculations to previous work.

Scientists have known for almost a decade that thunderstorms are capable of generating brief but powerful bursts of gamma-rays called terrestrial gamma-ray flashes (TGFs).

These flashes of gamma-rays are so bright they can blind instruments many hundreds of kilometers away in outer space.

Because they can originate near the same altitudes at which commercial aircraft routinely fly, scientists have been trying to determine whether or not terrestrial gamma ray flashes present a radiation hazard to individuals in aircraft.

Until recently, the work to answer that question was hampered by a poor understanding of exactly how these gamma-rays are generated by thunderstorms, with initial dose estimates ranging from not-so-safe to downright scary.

Ningyu Liu

Now, scientists at Florida Tech have developed a promising physics-based model of exactly how thunderstorms manage to produce high-energy radiation.

According to their model, instead of creating normal lightning, thunderstorms can sometimes produce an exotic kind of electrical breakdown that involves high-energy electrons and their anti-matter equivalent called positrons.

The interplay between the electrons and positrons causes an explosive growth in the number of these high-energy particles, emitting the observed terrestrial gamma ray flashes while rapidly discharging the thundercloud, sometimes even faster than normal lightning.

Even though copious gamma-rays are emitted by this process, very little visible light is produced, creating a kind of electrical breakdown within the storms called "dark lightning."

Recent modeling work of dark lightning shows that it can explain many of the observed properties of terrestrial gamma ray flashes.

The model also calculates the radiation doses received by individuals inside aircraft that happen to be in exactly the wrong place at the wrong time.

Hamid Rassoul

Near the tops of the storms, for the types of terrestrial gamma-ray flashes that can be seen from space, the radiation doses are equivalent to about 10 chest x-rays, or about the same radiation people would receive from natural background sources over the course of a year.

"However, near the middle of the storms, the radiation dose could be about 10 times larger, comparable to some of the largest doses received during medical procedures and roughly equal to a full-body CT scan," said Dwyer.

"Although airline pilots already do their best to avoid thunderstorms, occasionally aircraft do end up inside electrified storms, exposing passengers to terrestrial gamma ray flashes."

"On rare occasions, according to the model calculation, it may be possible that hundreds of people, without knowing it, may be simultaneously receiving a sizable dose of radiation from dark lightning."

It is not known yet how often, if ever, this actually occurs, but ongoing research is working to address this issue.

Japanese company to construct space elevator by 2050

Finally, a Japanese invention that doesn’t boggle the mind. Tokyo-based engineers at Obayashi Corp have announced plans to build a space elevator by the middle of the century.

A genuine Stairway to Heaven, or as close as they can get it. Apparently the elevator will go 22,000 miles into orbit and carry 30 passengers at a time, taking up to a week to reach the Moon.

An artist's illustration of a space elevator hub station in space as a transport car rides up the line toward the orbital platform. Solar panels nearby provide power.

CREDIT: Obayashi Corp.

The device would carry passengers skyward at about 124 mph (200 kph), delivering them to a station 22,000 miles (36,000 kilometers) above Earth in a little more than a week.

In Obayashi's vision, a cable would be stretched from a spaceport on Earth's surface up to an altitude of 60,000 miles (96,000 km), or about one-quarter of the distance between our planet and the moon. A counterweight at its end would help "anchor" the cable in space.

A 30-passenger car would travel along the cable, possibly using magnetic linear motors as a means of propulsion, Yomiuri Shimbun reported.

Startram the Maglev train: Destination low earth orbit (LEO)

Getting into space is one of the harder tasks to be taken on by humanity.

The present cost of inserting a kilogram (2.2 lb) of cargo by rocket into Low Earth Orbit (LEO) is about US$10,000.

A manned launch to LEO costs about $100,000 per kilogram of passenger (except in China) but who says we have to reach orbit by means of rocket propulsion alone?

Instead, imagine sitting back in a comfortable magnetic levitation (maglev) train and taking a train ride into orbit.

Dr George Maise invented the Startram orbital launch system along with Dr James Powell, who is one of the inventors of superconducting maglev - for which he won the 2002 Franklin Medal in engineering. Startram is in essence a superconducting maglev launch system.

The system would see a spacecraft magnetically levitated to avoid friction, while the same magnetic system is used to accelerate the spacecraft to orbital velocities, just under 9 km/sec (5.6 miles/s).

Maglev passenger trains have carried passengers at nearly 600 kilometers per hour (373 mph) - spacecraft have to be some 50 times faster, but the physics and much of the engineering is the same.

The scope of the project is challenging.

A launch system design for routine passenger flight into LEO should have rather low acceleration - perhaps about 3 g's maximum, which then requires 5 minutes of acceleration to reach LEO transfer velocities. In that period, the spacecraft will have traveled 1,000 miles (1,609 km).

The maglev track must be 1,000 miles in length - similar in size to maglev train tracks being considered for cross-country transportation.

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Space Elevator Plans Unveiled by Japanese

Getting to space may become be as simple as pressing the "door close" button of an elevator, as imagined by Japanese construction company Obayashi Corp.

The company unveiled plans Wednesday to build a space elevator with a hopeful completion date of 2050.

According to the proposal, 30 passengers at a time would depart from the equator and travel in an enclosure guided by a 60,000 mile (96,000 km) cable that stretches a quarter of the way to the moon.

The final destination would be a spaceport that contains laboratories and living quarters 22,000 miles (35,000 km) above the Earth's surface.

Engineers expect to anchor the cable by a counterweight attached to the space end to help keep the line taut. Solar panels would provide electricity to power the station.

Don't expect a quick ride though. Even travelling at 124 mph (200 km/h) the trip would expect to take a week.

One issue that has plagued space elevator designs is finding the right material to build such a long cable. Engineers from Obayashi Corp. believe carbon nanotubes, super-light and super-strong sheets of carbon rolled into tubes, might be the answer if they can be mass produced cheap enough.

"At this moment, we cannot estimate the cost for the project," an Obayashi official reported. "However, we'll try to make steady progress so that it won't end just up as simply a dream."

Safety would play a large role in the construction of the elevator. Passengers need to be protected from the expected radiation exposure during the trip. In addition, the elevator and spaceport would not orbit around the Earth, which puts it at risk of collision with orbiting satellites.

Space elevators are not a new concept. In 1895, Russian scientist Konstantin Tsiolkovsky was inspired by the Eiffel Tower and conceptually designed a space elevator 22,200 miles (35,800 km) high he called a "celestial castle", according to NASA.

Space Tourism: An Update

With the age of suborbital tourism beckoning, hundreds of wealthy people have signed up to take rides to the edge of space, a trip that will end almost as soon as it begins, but should confer serious bragging rights when the talk turns to summer vacations.

Of course, if just experiencing weightlessness is your goal, you can already do it for far less than Virgin Galactic’s $200,000 ticket price—but only in 30-second bursts.

Inside a modified Boeing 727 operated by Zero Gravity Corporation, adventure tourists can spend a few thousand dollars to get a taste of weightlessness and sample lunar and Martian gravity as the airplane flies repeated roller-coaster-like parabolas.

During their half-minutes of reduced gravity they can float, tumble, even get married. But there’s no view of Earth, and it’s more like an amusement park ride than a rocket launch.

The suborbital spaceships now on the drawing boards will carry tourists to the edge of space (traditionally set at 100 kilometers, or 62 miles altitude), but not so high or fast that they go into orbit.

Virgin Galactic’s SpaceShipTwo will provide up to six minutes of weightlessness, while Armadillo Aerospace, XCOR, and various other companies will make you feel weightless for about three minutes.

Since XCOR’s Lynx spacecraft holds just a pilot and one passenger in a tiny side-by-side cockpit, the company has decided that passengers will remain strapped in for the whole trip—just as Alan Shepard and Gus Grissom did during their 15-minute suborbital missions to test out NASA’s new Mercury spacecraft in 1961.

Other companies have released animations showing passengers unstrapping from their couches, floating around in weightlessness, then returning to their couches before atmospheric reentry.

XCOR thinks that’s a bad idea.

“Unstrapping and re-strapping in such a short time frame would be a risky endeavour,” says the company’s communications representative, Mike Masse. He believes that passengers will be so engrossed by the spectacular view that they won’t mind being confined to their couches.

Read More here: AirSpaceMag

US Boeing 738 Makes Emergency Landing with Large Hole in Fuselage

CHARLESTON, W.Va. -- Southwest Airlines Co. inspected about 200 planes overnight after a football-sized hole opened up in the passenger cabin of a jet in flight, forcing an emergency landing in West Virginia.

Travelers on the Boeing 737 aircraft could see through the 1-foot-by-1-foot hole that appeared during the flight Monday.

The cabin lost pressure, but no one was injured on the Nashville-to-Baltimore flight with 126 passengers and five crew members on board.

Passenger Brian Cunningham told NBC's "Today" show Tuesday that he had dozed off in his seat in mid-cabin when he was awakened by "the loudest roar I'd ever heard."He said the hole was above his seat. People stayed calm and put on the oxygen masks that dropped from the ceiling."

After we landed in Charleston, the pilot came out and looked up through the hole, and everybody applauded, shook his hand, a couple of people gave him hugs," Cunningham said.

It's not clear what caused the damage. The incident occurred just four months after Southwest agreed to pay $7.5 million to settle charges that it operated planes that had missed required safety inspections for cracks in the fuselage.

Southwest spokeswoman Marilee McInnis said the airline inspected 200 Boeing 737-300-series jets overnight at hangars around the country and discovered no other similar problems." It was a walk-around visual inspection just to check for structural integrity," McInnis said.