New bird flu poses 'serious threat' - scientists

By Kate Kelland

LONDON (Reuters) - A new strain of bird flu that is causing a deadly outbreak among people in China is a threat to world health and should be taken seriously, scientists said on Wednesday.

The H7N9 strain has killed 24 people and infected more than 125, according to the Geneva-based World Health Organization (WHO), which has described it as "one of the most lethal" flu viruses.

The high mortality rate, together with relatively large numbers of cases in a short period and the possibility it might acquire the ability to transmit between people, make H7N9 a pandemic risk, experts said.

"The WHO considers this a serious threat," said John McCauley, director of the WHO Collaborating Centre for Influenza at Britain's National Institute for Medical Research.

Speaking at a briefing in London, experts in virology said initial studies suggest the virus has several worrisome characteristics, including two genetic mutations that make it more likely to eventually spread from person to person.

"The longer the virus is unchecked in circulation, the higher the probability that this virus will start transmitting from person to person," Colin Butte, an expert in avian viruses at Britain's Pirbright Institute, said.

Of the some 125 people infected with H7N9 so far, around 20 percent have died, approximately 20 percent have recovered and the remainder are still sick. The infection can lead to severe pneumonia, blood poisoning and organ failure.

"This is a very, very serious disease in those who have been infected. So if this were to become more widespread it would be an extraordinarily devastating outbreak," Peter Openshaw, director of the centre for respiratory infection at Imperial College London, told the briefing.

Scientists who have analysed genetic sequence data from samples from three H7N9 victims say the strain is a so-called "triple reassortant" virus with a mixture of genes from three other flu strains found in birds in Asia.

Recent pandemic viruses, including the H1N1 "swine flu" of 2009/2010, have been mixtures of mammal and bird flu - hybrids that are likely to be milder because mammalian flu tends to make people less severely ill than bird flu.

Pure bird-flu strains, such as the new H7N9 strain and the H5N1 flu, which has killed about 371 of 622 the people it has infected since 2003, are generally more deadly for people.

Human cases of the H7N9 flu have been found in several new parts of China in recent days and have now been recorded in all of its provinces.

Last week a man in Taiwan became the first case of the flu outside mainland China, though he was infected while travelling there.

The H7N9 strain was unknown in humans until it was identified in sick people in China in March.

Scientists say it is jumping from birds - most probably chickens - to people, and there is no evidence yet of the virus passing from person to person.

Jeremy Farrar, a leading expert on infectious diseases and director of Oxford University's research unit in Vietnam, said the age range of those infected so far stretched from toddlers to people in their late 80s - a range that appeared to confirm the virus is completely new to the human population.

"That suggests there truly is no immunity across all ages, and that as humans we have not seen this virus before," he said.

"The response has to be calm and measured, but it cannot be taken lightly," he said.

(Reporting by Kate Kelland; Editing by Michael Roddy)

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Falling German Satellite Poses 1-in-2,000 Risk of Striking Someone This Month (SPACE.com)

A big German satellite near the end of life is expected to plunge back to Earth this month, just weeks after a NASA satellite fell from orbit, and where this latest piece of space junk will hit is a mystery.

The 2.4-ton spacecraft, Germany's Roentgen Satellite (ROSAT), is expected to fall Oct.  22 or 23.

The satellite will break up into fragments, some of which will disintegrate due to intense re-entry heat. But studies predict that about 1.6 tons of satellite leftovers could reach the Earth’s surface. That's nearly half ROSAT's entire mass.

There is a 1-in-2,000 chance that debris from the satellite could hit someone on Earth, though the likelihood of an injury is extremely remote, German space officials say. For German citizens, the risk of being struck is much lower, about 1 in 700,000.

All areas under the orbit of ROSAT, which extends to 53 degrees northern and southern latitude, could be in the strike zone of the satellite's re-entry.

The bulk of the debris is likely to hit near the ground/ocean track of the satellite. However, isolated fragments could descend to Earth in a 50-mile (80-kilometer) swath along that track. [Photos: Germany's ROSAT Satellite Falling to Earth] 

The satellite will be the second large spacecraft to make a pre-announced fall from space in as many months. On Sept. 24, NASA's 20-year-old Upper Atmosphere Research Satellite (UARS) crashed into the Pacific Ocean in a widely publicized death plunge.

The ROSAT project was a collaborative venture among Germany, the United States, and the United Kingdom. It was developed, built and launched on behalf of and under the leadership of the Deutsches Zentrum für Luft- und Raumfahrt (DLR), Germany's space agency.

The uncontrollable ROSAT

ROSAT was placed into Earth orbit on June 1, 1990. The highly successful astronomy mission ended after nearly nine years, with commands sent on Feb. 12, 1999, to shut the spacecraft down. 

The spacecraft does not have its own propulsion system, so it could not  be maneuvered into a controlled re-entry at the end of its mission.

Moreover, the satellite is zipping through space in deaf and silent mode. That is, ROSAT is no longer able to communicate with DLR’s control center in Oberpfaffenhofen, nor is it possible to establish contact with the spacecraft.

Still, the DLR says the probability of ROSAT coming down over an inhabited area is extremely low. [6 Biggest Uncontrolled Spacecraft Falls From Space]

Re-entry prediction practice

Even in its death throes, ROSAT is expected to be a useful servant, albeit in a way unintended at launch.

According to Heiner Klinkrad, head of the European Space Operations Center's Space Debris Office in Darmstadt, Germany, the ROSAT tumble from space will be useful in sharpening re-entry prediction tools.

"ROSAT will be an official re-entry test campaign," Klinkrad told SPACE.com.

Klinkrad serves as secretary of the Inter-Agency Space Debris Coordination Committee, an international governmental forum for the worldwide coordination of activities related to the issues of human-made and natural debris in space.

The IADC has performed re-entry prediction test campaigns since 1998. Data-sharing has led to more-accurate re-entry predictions.

Targets used for IADC re-entry initiatives have included the UARS spacecraft, several Russian Cosmos satellites, various upper stages, and even the fall of a huge ammonia coolant tank that was purposely tossed off the International Space Station by spacewalking astronauts in July 2007. The ammonia tank burned up over the South Pacific in November 2008.

Heavy metal (really)

ROSAT's nose-dive may result in as many as 30 individual pieces striking the surface of the Earth. About 1.6 tons of the satellite could survive re-entry, according to DLR description.

The heaviest component to reach Earth could be the satellite’s X-ray optical system — with its mirrors and a mechanical support structure made of carbon-fiber reinforced composite  —  or at least a part of it, DLR officials said.

Fragments striking the surface of Earth could be traveling at speeds of up to roughly 280 mph (450 kph).

As ROSAT's demise approaches, German scientists will be evaluating data provided by the U.S. Space Surveillance Network. In addition, the Tracking and Imaging Radar, the large radar facility at the Fraunhofer Institute for High-Frequency Physics and Radar Techniques in Wachtberg near Bonn, will be monitoring the descent to further improve calculations of its trajectory.

Experts will be analyzing data to predict the moment of re-entry. All of this information will be collected and evaluated in the European Satellite Operations Center in Darmstadt, then forwarded to the DLR.

Leonard David has been reporting on the space industry for more than five decades. He is a winner of this year's National Space Club Press Award and a past editor-in-chief of the National Space Society's Ad Astra and Space World magazines. He has written for SPACE.com since 1999.

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Falling Satellite Poses Little Risk to Public, NASA Says (SPACE.com)

An outdated NASA satellite, which has been adrift in orbit for six years, is falling back to Earth, and some of its debris is expected to reach the ground in the next few weeks. But despite the chance that bits of debris could land in North or South America, the space agency is assuring the public that there is no reason to be alarmed.

"Satellites re-entering is actually very commonplace," Nick Johnson, chief scientist of the Orbital Debris Program at NASA's Johnson Space Center in Houston, said at a news briefing today (Sept. 9). "Last year, for example, we averaged over one object per day falling back uncontrolled into the atmosphere." [Photos: Space Debris & Cleanup Concepts]

NASA's Upper Atmosphere Research Satellite (UARS), a school bus-size spacecraft, will re-enter Earth's atmosphere sometime in late September or early October, agency officials said. Debris from the satellite could fall over a swath of land stretching more than 500 miles (804 kilometers) anywhere between northern Canada and southern South America.

Narrowing down the area of impact will not be possible until much closer to when the pieces will hit, said Air Force Maj. Michael  Duncan, deputy chief of the U.S. Strategic Command's space situational awareness division.

Johnson stressed that these incidents are not so rare. In 2010 alone, some 400 pieces of space debris were cataloged by the U.S. Space Surveillance Network, he said.

On average, one moderate-size object, which could be an old, intact spacecraft or rocket body, falls to Earth every week. The majority of the debris disintegrates upon re-entry into Earth's atmosphere, but some of the vehicle components do reach the surface, Johnson said. These pieces of space junk typically fall over broad ocean areas or desolate regions like the Australian outback or the Canadian tundra.

Regarding larger objects such as the nearly 12,500-pound (5,668 kilograms) UARS, the U.S. Space Surveillance Network typically sees one of these re-entering the atmosphere per year.

The spacecraft is about 35 feet (10.7 meters) long and 15 feet (4.5 m) wide. And while agency officials said UARS is the largest NASA satellite to make an uncontrolled fall back to Earth in years, Johnson clarified that re-entry events of this size are "certainly not unknown or unprecedented." [Related: Space Junk FAQ: Falling Space Debris Explained]

"Last year there were 75 metric tons of spacecraft and rocket bodies falling back to Earth in an uncontrolled manner," Johnson explained. "In perspective, UARS is less than 6 metric tons, so it's a very small percentage of the annual re-entry of satellites into Earth's atmosphere."

Even when pieces of defunct satellites and rocket bodies do reach the ground, the chances of them posing a risk to people and their property is very remote, NASA said.

NASA officials estimate that there is a 1-in-3,200 chance that a person somewhere on Earth will be hit by UARS debris, and the odds of the dead satellite re-entering over a densely populated area is very small. [Video: The Expanding Danger of Space Debris]

NASA and the U.S. Space Surveillance Network has closely studied the satellite to determine the potential risks during its re-entry. Current projections show that 26 large pieces, totaling approximately 1,170 pounds (532 kg), will survive the trip through Earth's atmosphere.

Still, the chances of the UARS satellite causing any real harm is very small, officials said.

"Throughout the entire 54 years of the Space Age there has been no report of anyone being injured or impacted by any re-entering debris," Johnson said.

You can follow SPACE.com staff writer Denise Chow on Twitter @denisechow. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

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NASA: UARS Satellite Debris Poses 1 in 3,200 Chance of Hitting Someone (ContributorNetwork)

NASA's Upper Atmosphere Research Satellite (UARS) will fall to Earth sometime during late September or early October, NASA told reporters today in a teleconference. Atmospheric changes that take place on a daily basis making it impossible to predict exactly where or when it will come down with any real accuracy even as close as two hours prior to the re-entry.

Satellites the size of UARS, on average fall to Earth about once every year and are the subject of detailed break-up analyses by NASA scientists. In this case, NASA expects that UARS will break up in such a way that 26 pieces will strike the ground at speeds ranging from tens of miles per hour to hundreds of miles per hour, according to Nick Johnson of NASA's Orbital Debris Program. In fact, said Johnson, NASA has calculated the odds of any piece of the debris striking a person as 1 in 3200. A number which he says is very, very low and is simply based on the area of possible landfall and global population density.

The re-entry of UARS should be very visible even if it occurs in daylight said Johnson. However, it will b impossible to give enough advance information about where it will re-enter to advise people where and when to look for it. Based on the amount of water versus the amount of land in possible impact field, it is most likely that it will take place out over an ocean and may only be incidentally visible to passing aircraft or ocean vessels.

UARS made a number of important scientific observations over its 14 year effective lifespan including detailed measurement of Earth's atmosphere and of solar radiation. Since 2005, other satellites have replaced its full suite of observational capabilities.

Factbox:

* UARS was built in the 1980's and launched in 1991 at a total cost of $750 million.

* Intact, UARS masses 5.7 metric tons and completely fills the cargo bay of a space shuttle.

* Without NASA intervention, UARS would have remained in orbit until 2025, but its orbital decay was intentionally accelerated by using up all remaining onboard maneuvering propellants in 2005 when it had exhausted its scientific usefulness.

* UARS was the first satellite to record solar flux data over and entire 11 year solar cycle.

* The largest piece of UARS expected to reach the ground masses a little over 300 pounds.

* Other than being struck by fallen debris, NASA says, the biggest risk from the debris is a person getting cut by sharp edges if they try to handle the debris after is has landed. There are absolutely no toxic materials on board, according to Paul Hertz of NASA's Science Mission Directorate.

* All pieces of UARS remain the property of the U.S. government and their location should be made known to local law enforcement officials. Possession or sale of any of the debris by private individuals in the United States is illegal and subject to prosecution.

* In a typical year, 400 pieces of tracked man-made debris re-enters Earth's atmosphere.

* One piece of man-made space debris survives to reach the ground, on average, each week.

* In 2010, approximately 75 metric tons of man-made space debris fell from orbit Earth.

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Follow @Space_Matters on Twitter or 'like' the Space Matters Fan Page on Facebook for more of this author's space-related writing.

Brad Sylvester writes about the space program for the Yahoo! Contributor Network. Watching the Apollo missions through the static on a small black and white television sparked a lifelong interest in the space sciences for him. Since then, he has spent 40 years watching improvements in the technologies of space travel and our understanding of the universe.

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Space Junk Cleanup Poses Grand Challenge for 21st Century (SPACE.com)

The buildup of space debris orbiting the Earth, which poses a threat to spacecraft and the environment, has reached a critical point, scientists say.

The space junk trend no longer can be reversed by full compliance with mitigation measures now in place; it will get worse without more-aggressive action such as active debris removal, or ADR. And that just might pose the biggest engineering challenge of the 21st century, according to J.-C. Liou of the Orbital Debris Program Office at NASA's Johnson Space Center.

"As the international community gradually reaches a consensus on the need for ADR, the focus will shift from environment modeling to completely different challenges: technology development, systems engineering, and operations," Liou explained in the July edition of NASA's Orbital Debris Quarterly News, issued by his office in Houston.

Liou told SPACE.com: "Orbital debris is an environment problem … and it's everybody's problem, not just the United States' or a NASA problem. All the spacefaring nations share the same environment." [Worst Space Debris Events of All Time]

Liou said that even if nations are in 100 percent compliance of all the measures now in effect to help curb space junk — guidelines more than a decade in the making — "it would not be enough. … We have reached that point. We need to take more aggressive measures."

In the meantime, smashups between objects in space lead to fragmentation, constantly creating more debris.

Four Cs of space junk cleanup

A long-term strategic plan for removing orbital clutter requires the four C's, Liou says — four critical steps needed at the international level:

Consensus on active debris removal.Cooperation: the removal targets may belong to a different country.Collaboration:  It is highly unlikely that any single organization or country can accomplish the goal by itself.Contributions: Cost-sharing will be the key for engaging in active debris removal.

"In the next five to 10 years, I think we'll be in a much better place than where we are today in terms of trying to remediate the environment," Liou predicted. [Video: The Expanding Danger of Space Debris ]

Space debris removal operations

Liou said that five key questions must be addressed at the beginning of any ADR planning. They are: Where is the most critical region for ADR? What are the mission objectives? Which debris should be removed first? What are the benefits to the environment? How should the operations be carried out?

To control the future increase in space debris or reduce the number of fragmentations, officials should focus removal operations on large rocket bodies or spacecraft — objects at least several meters long, Liou explained. And to reduce mission-ending threats to operational spacecraft, the focus should be on the 5-millimeter to 1-centimeter debris.

"Targeting anything outside these two size regimes will not be an effective means to remediate the environment, nor to mitigate mission-ending risks to operational spacecraft," Liou concluded.

First things first

Over the years, a number of space debris removal ideas have been proposed, from space tethers, giant foam balls and laser beams to garbage scows and even huge fishing nets.

But Liou said what’s needed is a first-things-first approach.

"We need to be more specific about the question we want to address. You don't want to spend hundreds of millions or billions of dollars to just go up there and remove debris when you cannot quantify the benefits to the environment," Liou pointed out. "We need to take a very focused, efficient approach to address the key problems."

Liou added that orbital debris-removal appraisals currently underscore two criteria: "It's not just based on size or mass, it's based on the collision probability and mass."

That being the case, if the goal is to stabilize the debris population environment in low-Earth orbit at today's levels, about five large, intact objects need to be removed per year.

Many — but not all — of the potential targets in the current environment are spent Russian upper stages.

Road map needed

As for next steps, Liou flagged the recent National Space Policy, a White House document released in June 2010.

That policy, for one, calls upon NASA and the U.S. Department of Defense to pursue research and development of technologies and techniques to mitigate and remove debris in orbit now, reduce hazards and increase understanding of the current and future debris environment.

What's needed now, Liou said, is an implementation plan or a road map. This long-term plan would engage international partners regarding orbital debris removal.

"International collaboration will be the key," Liou concluded. "We all need to work together to move forward."

Leonard David has been reporting on the space industry for more than five decades. He is a winner of this year's National Space Club Press Award and a past editor-in-chief of the National Space Society's Ad Astra and Space World.

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