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Genetically engineered mosquitoes pass lethal gene to offspring

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  • Scientists carry out ‘positive’ trial on Cayman Islands
  • New breed of insect could be used to tackle malaria and dengue fever
  • But critics say it could lead to public health problems

Breakthrough or danger? A UK-based research team has found a way of genetically modifying the Aedes aegypti mosquito so they pass on a deadly gene to their offspring

Breakthrough or danger? A UK-based research team has found a way of genetically modifying the Aedes aegypti mosquito so they pass on a deadly gene to their offspring

Serious concerns have been raised over the release of a new breed of disease-fighting mosquito which has been genetically engineered to kill their own offspring.

There are hopes the project could be used to control agricultural pests and tackle deadly insect-borne illnesses such as dengue fever and malaria.

But the research has raised concerns about the possible side-effects on public health and the environment because, once released, the mosquitos cannot be recalled.

A UK-based scientific team revealed there had been positive signs from the first release into the environment of the mosquitoes, which are engineered to pass a lethal gene onto their offspring, killing them before adulthood.

The study team – which includes experts from Imperial College London and the Liverpool School of Tropical Medicine – released batches of modified mosquitoes in an area of the Cayman Islands where the dengue virus-carrying Aedes aegypti mosquito is common.

The study, published in Nature Biotechnology journal, looked at how successfully the lab-reared, genetically modified insects could mate.

About 19,000 mosquitoes engineered in a lab were released over four weeks in 2009 in a 25-acre area on Grand Cayman island.

Based on data from traps, the genetically engineered males accounted for 16per cent of the overall male population in the test zone, and the lethal gene was found in almost 10 percent of larvae.

Those figures suggest the genetically engineered males were about half as successful in mating as wild ones, a rate sufficient to suppress the population.

Disease fighter? The new breed of mosquitoes could be used to tackle killer illnesses like dengue fever and malaria which affect the world's poorest populations

Disease fighter?  The new breed of mosquitoes could be used to tackle killer illnesses like dengue fever and malaria which affect the world’s poorest populations

Luke Alphey, chief scientific officer at Oxitec, the firm which devised the technique, told the BBC: ‘We were really surprised how well they did.

‘For this method, you just need to get a reasonable proportion of the females to mate with GM males – you’ll never get the males as competitive as the wild ones, but they don’t have to be, they just have to be reasonably good.’

HOW MOSQUITOES KILL THEIR OWN CHILDREN

  • The genetic approach used to create the mosquitoes is a system known as tetracycline-controlled transcriptional activation (tTA).
  • The technique is an extension of one successfully used for decades to control or eradicate pests which involves sterilising millions of insects with radiation.
  • But the process has not worked with mosquitoes, partly because the radiation also injures them, making it difficult for them to compete with healthy counterparts for mates.
  • So Oxitec has now created the Aedes aegypti mosquitoes with a gene that will kill them unless they are given the common antibiotic tetracycline.
  • With tetracycline provided in the lab, the mosquitoes can be bred for generations and multiplied.
  • Males are then released into the wild, where tetracycline is not available.
  • They live long enough to mate but their progeny will die before adulthood.

 

Authorities in the Florida Keys hope to carry out an open-air test on the modified insects as early as December after experiencing the region’s first cases of dengue fever in decades.

Dr Alphey said the technique was safe because only males were released as it was only the females that bite people and spread the disease.

But critics say the process is by no means foolproof.

Alfred Handler, a geneticist at the Agriculture Department in Gainesville, Florida, said the mosquitoes can evolve resistance to the lethal gene while being bred for generations in a lab.

Todd Shelly, an entomologist for the Agriculture Department in Hawaii, also said in a commentary published on Sunday by Nature Biotechnology that 3.5per cent of the insects in a lab test survived to adulthood despite presumably carrying the lethal gene.

Also, the sorting of male and female mosquitoes, which is done by hand, can result in up to 0.5per cent of the released insects being female, the commentary said.

If millions of mosquitoes were released, even that small percentage of females could lead to a temporary increase in disease spread, it was reported by the New York Times.

Oxitec and a molecular biologist, Anthony A. James of the University of California, Irvine, say they have developed a solution — a genetic modification that makes female mosquitoes, but not males, unable to fly.

The grounded females cannot mate or bite people, and separating males from females before release would be easier.

The World Health Organisation expects to release guidance on how GM insects should be deployed in developing countries by the end of the year.

 

Via DailyMail

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Declassified US Spy Satellites Reveal Rare Look at Secret Cold War Space Program

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Twenty-five years after their top-secret, Cold War-era missions ended, two clandestine American satellite programs were declassified Saturday (Sept. 17) with the unveiling of three of the United States’ most closely guarded assets: the KH-7 GAMBIT, the KH-8 GAMBIT 3 and the KH-9 HEXAGON spy satellites.

The vintage National Reconnaissance Office satellites were displayed to the public Saturday in a one-day-only exhibit at the Smithsonian National Air and Space Museum’s Udvar-Hazy Center at Dulles Airport, Va. The three spacecraft were the centerpiece of the NRO’s invitation-only, 50th Anniversary Gala celebration held at the center last evening.

Saturday’s spysat unveiling was attended by a number of jubilant NRO veterans who developed and refined the classified spacecraft and its components for decades in secret, finally able to show their wives and families what they actually did ‘at the office’ for so many years. Both of the newly declassified satellite systems, GAMBIT and HEXAGON, followed the U.S. military’s frontrunner spy satellite system CORONA, which was declassified in 1995.

This National Reconnaissance Office released graphic depicts the huge HEXAGON spy satellite, a Cold War era surveillance craft that flew reconnaissance missions from 1971 to 1986.

This National Reconnaissance Office released graphic depicts the huge HEXAGON spy satellite, a Cold War era surveillance craft that flew reconnaissance missions from 1971 to 1986. The bus-size satellites weighed 30,000 pounds and were 60 feet long.

Big spy satellites revealed

The KH-9 HEXAGON, often referred to by its popular nickname “Big Bird,” lived up to its legendary expectations. As large as a school bus, the KH-9 HEXAGON carried 60 miles of high resolution photographic film for space surveillance missions.

Military space historian Dwayne A. Day was exuberant after his first look at the KH-9 HEXAGON.

“This was some bad-ass technology,” Day told SPACE.com. “The Russians didn’t have anything like it.”

Day, co-editor of “Eye in the Sky: The Story of the CoronaSpy Satellites,” noted that “it took the Soviets on average five to 10 years to catch up during the Cold War, and in many cases they never really matched American capabilities.”

Phil Pressel, designer of the HEXAGON’s panoramic ‘optical bar’ imaging cameras, agreed with Day’s assessment.

“This is still the most complicated system we’ve ever put into orbit …Period.”

The HEXAGON’s twin optical bar panoramic mirror cameras rotated as the swept back and forth as the satellite flew over Earth, a process that intelligence officials referred to as “mowing the lawn.”

Phil Pressel, one of the developers of the KH-9 Hexagon's panoramic camera system, proudly points out some of the spacecraft's once highly-classified features, which he had been unable to discuss publicly until the NRO's Sept. 17, 2011 declassification.of

Phil Pressel, one of the developers of the KH-9 Hexagon’s panoramic camera system, proudly points out some of the spacecraft’s once highly-classified features, a life’s work that he had been unable to discuss publicly until the NRO’s Sept. 17, 2011 declassification of the massive spy satellite.

Each 6-inch wide frame of HEXAGON film capturing a wide swath of terrain covering 370 nautical miles — the distance from Cincinnati to Washington — on each pass over the former Soviet Union and China. The satellites had a resolution of about 2 to 3 feet (0.6 to nearly 1 meter), according to the NRO. [10 Ways the Government Watches You]

According to documents released by the NRO, each HEXAGON satellite mission lasted about 124 days, with the satellite launching four film return capsules that could send its photos back to Earth. An aircraft would catch the return capsule in mid-air by snagging its parachute following the canister’s re-entry.

In a fascinating footnote, the film bucket from the first KH-9 HEXAGON sank to the bottom of the Pacific Ocean in spring 1972 after Air Force recovery aircraft failed to snag the bucket’s parachute.

The film inside the protective bucket reported contained high resolution photographs of the Soviet Union’s submarine bases and missile silos. In a daredevil feat of clandestine ingenuity, the U.S. Navy’s Deep Submergence Vehicle Trieste II succeeded in grasping the bucket from a depth of 3 miles below the ocean.

Hubble vs. HEXAGON

Former International Space Station flight controller Rob Landis, now technical manager in the advanced projects office at NASA’s Wallops Flight Facility in Virginia, drove more than three hours to see the veil lifted from these legendary spacecraft.

Landis, who also worked on NASA’s Hubble Space Telescope program, noticed some distinct similarities between Hubble and the huge KH-9 HEXAGON reconnaissance satellite.

“I see a lot of Hubble heritage in this spacecraft, most notably in terms of spacecraft size,” Landis said. “Once the space shuttle design was settled upon, the design of Hubble — at the time it was called the Large Space Telescope — was set upon. I can imagine that there may have been a convergence or confluence of the designs. The Hubble’s primary mirror is 2.4 meters [7.9 feet] in diameter and the spacecraft is 14 feet in diameter. Both vehicles (KH-9 and Hubble) would fit into the shuttle’s cargo bay lengthwise, the KH-9 being longer than Hubble [60 feet]; both would also fit on a Titan-class launch vehicle.”

The ‘convergence or confluence’ theory was confirmed later in the day by a former spacecraft designer, who declined to be named but is familiar with both programs, who confided unequivocally: “The space shuttle’s payload bay was sized to accommodate the KH-9.”

The NRO launched 20 KH-9 HEXAGON satellites from California’s Vandenberg AFB from June 1971 to April 1986.

The HEXAGON’s final launch in April 1986 — just months after the space shuttle Challenger explosion — also met with disaster as the spy satellite’s Titan 34D booster erupted into a massive fireball just seconds after liftoff, crippling the NRO’s orbital reconnaissance capabilities for many months.

A side view of a KH-7 GAMBIT spy satellite on display at the Smithsonian National Air and Space Museum's Udvar-Hazy Center at Dulles Airport, Va., on Sept. 17, 2011.

A side view of a KH-7 GAMBIT spy satellite on display at the Smithsonian National Air and Space Museum’s Udvar-Hazy Center at Dulles Airport, Va., on Sept. 17, 2011.

The spy satellite GAMBIT

Before the first HEXAGON spy satellite systems ever launched, the NRO’s GAMBIT series of reconnaissance craft flew several space missions aimed at providing surveillance over specific targets around the world.

The  satellite program’s initial system, GAMBIT 1, first launched in 1963 carrying a KH-7 camera system that included a “77-inch focal length camera for providing specific information on scientific and technical capabilities that threatened the nation,” according to an NRO description. A second GAMBIT satellite system, which first launched aboard GAMBIT 3 in 1966, included a175-inch focal length camera.

The GAMBIT 1 series satellite has a resolution similar to the HEXAGON series, about 2 to 3 feet, but the follow-up GAMBIT 3 system had an improved resolution of better than 2 feet, NRO documents reveal.

The GAMBIT satellite program was active from July 1963 to April 1984. Both satellites were huge and launched out of Vandenberg Air Force Base.

The satellite series’ initial version was 15 feet (4.5 m) long and 5 feet (1.5 m) wide, and weighed about 1,154 pounds (523 kilograms). The GAMBIT 3 satellite was the same width but longer, stretching nearly 29 feet (9 m) long, not counting its Agena D rocket upper stage. It weighed about 4,130 pounds (1,873 kg).

Unlike the follow-up HEXAGON satellites, the GAMBIT series were designed for extremely short missions.

The GAMBIT 1 craft had an average mission life of about 6 1/2 days. A total of 38 missions were launched, though 10 of them were deemed failures, according to NRO documents.

The GAMBIT 3 series satellites had missions that averaged about 31 days. In all, 54 of the satellites were launched, with four failures recorded.

Like the CORONA and HEXAGON programs, the GAMBIT series of satellites returned their film to Earth in re-entry capsules that were then snatched up by recovery aircraft. GAMBIT 1 carried about 3,000 feet (914 meters) of film, while GAMBIT 3 was packed with 12,241 feet (3,731 meters) of film, NRO records show.

The behemoth HEXAGON was launched with 60 miles (320,000 feet) of film!

A mission description of the NRO's GAMBIT 3 spy satellite flight profiles.

This image shows the flight profile for the NRO’s GAMBIT 3 spy satellite missions between 1966 and 1984. The program was declassified in Sept. 2011.

HEXAGON and GAMBIT 3 team up

During a media briefing, NRO officials confirmed to SPACE.com that the KH-8 GAMBIT 3 and KH-9 HEXAGON were later operated in tandem, teaming-up to photograph areas of military significance in both the former Soviet Union and China.

The KH-9 would image a wide swath of terrain, later scrutinized by imagery analysts on the ground for so-called ‘targets of opportunity.’ Once these potential targets were identified, a KH-8 would then be maneuvered to photograph the location in much higher resolution.

“During the era of these satellites — the GAMBIT and the HEXAGON — there was a Director of Central Intelligence committee known as the ‘Committee on Imagery Requirements and Exploitation’ that was responsible for that type of planning,” confirmed the NRO’s Robert McDonald, Director of the Center for the Study of National Reconnaissance.

NASA’s Rob Landis was both blunt and philosophical in his emotions over the declassification of the GAMBIT and HEXAGON programs.

“You have to give credit to leaders like President Eisenhower who had the vision to initiate reconnaissance spacecraft, beginning with the CORONA and Discoverer programs,” Landis said. “He was of the generation who wanted no more surprises, no more Pearl Harbors.”

“Frankly, I think that GAMBIT and HEXAGON helped prevent World War III.”

 

Via Space

‘Mind-reading device’ recreates what we see in our heads

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Mind reading could become a reality after scientists unveiled a device which translates what we are seeing in our heads onto a screen.

By monitoring the brain activity of people while they watched Hollywood movie trailers, researchers were able to recreate a moving picture similar to the real footage being played.

While the technology is not yet capable of reading our thoughts, it could eventually lead to ways of translating our dreams and memories onto screen.

If it is refined enough the method could even be used to explore the minds of stroke patients, experts said.

Researchers from the University of California, Berkeley, used MRI scanners to monitor the blood flow in people’s brains as they watched films including Madagascar 2, Pink Panther 2 and Star Trek unfold on a screen.

After analysing how the brain’s visual centre responded to on-screen movements, the scientists created a computer program which could accurately guess what the person was looking at.

When the researchers watched a second set of clips, this time Hollywood film trailers, the programme was able to produce an approximate version of what they were watching.

It did this by scanning a library of random YouTube videos, pulling out the most similar clips to what it guessed the person was watching, and blending them together.

Because the program’s video library contains just 18 million seconds of footage – a relatively small amount – it is highly unlikely that any clip will be very similar to the real footage.

To combat this problem, the program averages together the 100 shots from the video library that it thinks are the best match.

The result is a blurry but continuous video in which the movements of the shapes on screen reflect the action in the genuine Hollywood trailer.

Prof Jack Gallant, one of the study’s authors, said: “We’re trying to reconstruct the movie that was seen by searching through a large library of completely different, random movies.

“This is a major leap toward reconstructing internal imagery. We are opening a window into the movies in our minds.”

The averaging process makes the resulting video blurry, but the researchers said boosting the size of the programme’s video library could improve the quality of the reconstruction.

The study, published in the Current Biology journal, is believed to be the first experiment to successfully interpret brain signals as they respond to moving images.

The current technology can only process film clips that people have already viewed, but the breakthrough could lead to programmes which can reproduce dreams and memories because our natural visual experience is similar to watching a film.

We are still decades from a machine which can read people’s thoughts and intentions, but the technology could eventually be used to read the minds of stroke and coma patients, and to allow cerebral palsy or paralysis sufferers to guide computers with their minds, researchers said.

 

Watch video here

 

Via Telegraph

Written by Nokgiir

September 26, 2011 at 2:04 am

Incredible time-lapse video from the International Space Station

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It took Phileas Fogg 80 days to circumnavigate the world but, thanks to the wonders of technology, it is now possible to do it in just a minute.

This whirlwind video tour of the planet is a compilation of time-lapse images shot from the International Space Station (ISS).

James Drake spliced together the images from the ISS, which travels at about 220 miles above the surface, to create the one-minute footage which he posted online – and it has become an internet sensation.

Science teacher Mr Drake used some 600 free-to-access images on the website The Gateway to Astronaut Photography of Earth, and knitted them together so everyone can enjoy the amazing view of North and South America.

The Earth is shown at night - and the yellow flashes here show the ionosphere - a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere

The Earth is shown at night – and the yellow flashes here show the ionosphere – a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere.

The science teacher, James Drake, stitched together over 600 images to create the amazing video

The science teacher, James Drake, stitched together over 600 images to create the amazing video.

The film, which was uploaded on September 15 and has attracted almost 50,000 hits on YouTube, starts over the Pacific Ocean and then moves over North and South America before entering daylight near Antarctica.

Some cities and landmarks can be spied, and they include, in chronological order, Vancouver Island, Victoria, Vancouver, Seattle, Portland, San Fransisco, Los Angeles, Phoenix, various large conurbations in Texas, New Mexico, Mexico City, the Gulf of Mexico, and the Yucatan Peninsula.

Further around lightning can be seen in the Pacific Ocean, before other countries included in the video are Guatemala, Panama, Columbia, Ecuador, Peru, Chile, and the Amazon.

The sun is shown rising in the incredible pictures taken from the ISS, which takes 91 minutes to orbit the Earth

The sun is shown rising in the incredible pictures taken from the ISS, which takes 91 minutes to orbit the Earth.

Some 600 images were used to make the one-minute video

In addition, the Earth’s ionosphere (thin yellow line) and the stars of our galaxy can be made out in the fascinating footage.

The Gateway to Astronaut Photography of Earth, where Mr Drake downloaded the pictures from, has been storing over a million images from space, beginning with the Mercury missions in the early 1960s.

The website’s blurb reads: ‘Our database tracks the locations, supporting data, and digital images for these photographs.

‘We process images coming down from the International Space Station on a daily basis and add them to the 1,118,120 views of the Earth already made accessible on our website.’

The ISS has been manned for almost 11 years, and images of the Earth are regularly beamed back by their astronauts

The ISS has been manned for almost 11 years, and images of the Earth are regularly beamed back by their astronauts.

The ISS is currently on Expedition 29, and the astronauts will be on the space station until mid-November, when they will be replaced by another crew

The ISS is currently on Expedition 29, and the astronauts will be on the space station until mid-November, when they will be replaced by another crew.

The ISS, a habitable, artificial satellite in low Earth orbit, follows the Salyut, Almaz, Cosmos, Skylab, and MIR space stations, as the 11th space station launched into orbit by humanity.

It serves as a research laboratory that has microgravity environment in which crews conduct experiments in many fields including biology, human biology, physics, astronomy and meteorology.

The station has a unique environment for the testing of the spacecraft systems that will be required for missions to the Moon and Mars.

The station is expected to remain in operation until at least 2020, and potentially to 2028, when some Russian modules will be separated to form the OPSEK space station.

And the European Space Agency estimate that the cost of the station will be €100 billion over 30 years.

On November 2 last year the ISS marked its 10th anniversary of continuous human occupation, and it was launched almost 11 years ago, on October 31, 2000.

At the time of the anniversary, the station’s odometer read more than 1.5 billion statute miles (the equivalent of eight round trips to the Sun), over the course of 57,361 orbits around the Earth.

Flashes of lightening can be shown over the Pacific Ocean

Flashes of lightening can be shown over the Pacific Ocean.

The South American coast can be seen from the space station which travels at about 220 miles from the Earth's surface

The South American coast can be seen from the space station which travels at about 220 miles from the Earth’s surface.

The 29th expedition crew settled in to their new home for the next couple of months last week, with Mike Fossum commanding and being aided by Satoshi Furukawa and Sergei Volkov.

They will be up there, travelling about 17,000mph – meaning it takes about 91 minutes to orbit the Earth – until mid-November.

The Expedition 29 crew which will continue to support research into the effects of microgravity on the human body, biology, physics and materials.

The trio took over from Expedition 28 last week, and Commander Andrey Borisenko and Flight Engineers Alexander Samokutyaev and Ron Garan – who had spent 164 days in space – landed their Soyuz TMA-21 spacecraft in Kazakhstan a few seconds before midnight on Friday.

The space station and its large solar arrays is the size equivalent of an American football field – including the end zones – and weighs 861,804 pounds (390,908 kilograms), not including visiting vehicles.

The complex now has more liveable room than a conventional five-bedroom house, and has two bathrooms, a gymnasium and a 360-degree bay window.

The International Space year celebrated a decade of human occupation

The International Space year celebrated a decade of human occupation.

ISS IN NUMBERS

1.5bn: The number of statute miles the ISS managed in a decade (November 2, 2010)

57,361: Orbits around the Earth managed in the same time period

136: Number of launches to the ISS – up to September 2011 – since the launch of the first module, Zarya on November 1998

161: Total number of space walks performed from the ISS – over 1,015 hours

861,804: Pounds it weighs (390,908 kilograms)

2.3m: Number of lines of computer code used

17,239.2: Average speed – in miles per hour

91 minutes: Time it takes to orbit the Earth

€100bn: The estimated cost of the station over a 30-year period, by ESA

 

Via DailyMail

Written by Nokgiir

September 19, 2011 at 3:29 am

Gene that lights up under green light could help find cure for HIV

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Glowing kittens with resistance to disease have been created by scientists searching for a cure for Aids.

The domestic cats had their DNA modified with a gene that fights off an HIV-like virus and a second one – from a fluorescent jellyfish – that makes their bodies shine green under ultraviolet light.

The purpose of the study was to show how a natural protein that prevents macaque monkeys developing Aids can do the same in cats.

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Way to glow: The eerie looking feline that has been genetically modified with DNA from a fluorescent jellyfish protein

Way to glow: The eerie looking feline that has been genetically modified with DNA from a fluorescent jellyfish protein

Hard to hide: The kitten's fur, claws and whiskers emit an eerie green glow

Hard to hide: The kitten’s fur, claws and whiskers emit an eerie green glow

The two genes are linked and the jellyfish gene is used to track the other one for the protein.

Shining a UV light on the cats produced an eerie green glow, confirming that the protein was being made in their tissues and that the technique had worked.

The genetically modified cats’ creators say the research will speed up the search for vaccines and treatments against HIV, the Aids virus that has claimed more than 30million lives around the world.

With HIV-like viruses also wreaking havoc among felines, from domestic moggies to big cats, the research could improve animal health.

In future, people could buy pets that are resistant to numerous diseases, removing the need for frequent and expensive trips to the vet for vaccination.

Novelty glow-in-the-dark breeds are also a possibility.

Test subject: Under normal lighting the cat's ability to glow remains a secret

Test subject: Under normal lighting the cat’s ability to glow remains a secret

But critics say the technique takes a high toll on animal welfare and that scientists should be reducing the number of animals they experiment on.

The researchers, from the respected Mayo Clinic in the U.S., used harmless viruses to transfer genes into eggs removed from pet cats during routine spaying.

One gene makes a fluorescent protein, the other produces a protein that fights off feline immunodeficiency virus, or FIV, the cat version of HIV. The eggs were then fertilised through IVF and implanted in surrogate mothers.

Sharp thinking: The cat's paws glow too. Scientists say that cats are the best subjects for this kind of research

Sharp thinking: The cat’s paws glow too. Scientists say that cats are the best subjects for this kind of research

Twenty-two attempts led to the birth of five kittens – three of which survived, the journal Nature Methods reports.

Two were healthy but one suffered medical problems, although the researchers do not believe they were linked to the genetic manipulation.

The anti-viral gene was also present and cells taken from the kittens were able to resist infection with FIV better than those from normal cats.

Two of the cats went on to have kittens of their own, all of which carried the new genes.

Via DailyMail

Written by Nokgiir

September 19, 2011 at 3:12 am

Nasa satellite UARS nearing Earth ‘could land anywhere’

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Upper Atmosphere Research Satellite

A five ton, 20-year-old satellite has fallen out of orbit and is expected to crash somewhere on Earth on or around 24 September, according to Nasa.

Nasa says the risk to life from the UARS – Upper Atmosphere Research Satellite – is just 1 in 3,200.

It could land anywhere between 57 degrees north and 57 degrees south of the equator – most of the populated world.

However, most of the satellite will break or burn up before reaching Earth.

Scientists have identified 26 separate pieces that could survive the fall through the earth’s atmosphere, and debris could rain across an area 400-500km (250-310 miles) wide.

Nasa said scientists would only be able to make more accurate predictions about where the satellite might land two hours before it enters the Earth’s atmosphere.

Falling space debris

Rocket propellant tank (Nasa)
  • Hardware re-enters at shallow angles (<1 degree)
  • Some 50 items weighing >1 tonne re-enter a year
  • Major break-up occurs about 80km altitude
  • 10-40% of dry mass on orbit will survive
  • Debris spreads over long, thin “footprints”
  • It can be a hazard to people and property

Re-entry

The 1 in 3,200 risk to public safety is higher than the 1 in 10,000 limit that Nasa aims for.

However, Nasa told reporters that nobody had ever been hurt by objects re-entering from space.

Members of the public are not allowed to keep pieces of the satellite that may fall to Earth, or sell them on eBay, as they remain the property of the US government.

The UARS was launched in 1991 by the Discovery space shuttle, and was decommissioned in 2005.

The latest satellite re-entry is much smaller than Skylab, a satellite that re-entered the earth’s atmosphere in 1979.

It was some 15 times heavier than the UARS, and when it crashed in Western Australia the US government had to pay clean-up costs to the Australian government.

Sputnik 2 crashed on Earth in 1958, travelling from over New York to the Amazon in 10 minutes. It was viewed by many people and left a trail of brightly coloured sparks behind it.

Via BBC

Written by Nokgiir

September 19, 2011 at 2:48 am

‘Super-Earth’ Found in Habitable Zone

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The Milky Way abounds with low-mass planets, including small, rocky ones such as Earth. That’s the main conclusion of a team of European astronomers, based on their latest haul of extrasolar planets. The new discoveries—55 new planets, including 19 “super-Earths”—were presented here today at the Extreme Solar Systems II conference by team leader Michel Mayor of the University of Geneva in Switzerland. “We find that 40% of all Sun-like stars are accompanied by at least one planet smaller than Saturn,” he says. The number of Earth-like planets is expected to be even higher.

The new planets were found with HARPS (High Accuracy Radial velocity Planet Searcher), an extremely sensitive instrument used to analyze starlight, mounted on the 3.6-meter telescope of the European Southern Observatory (ESO) at Cerro La Silla in northern Chile. HARPS detects the minute periodic wobbles of stars, caused by the gravity of orbiting planets. So far, HARPS has discovered 155 exoplanets, including two-thirds of all planets less massive than Neptune.

Of the 19 newly found super-Earths (exoplanets between a few and 10 times the mass of Earth), the most intriguing is HD 85512b, which weighs in at only 3.6 Earth masses. Its orbit lies in the habitable zone of its parent star, which means temperatures are just right for liquid water to exist on its surface, says Lisa Kaltenegger of the Max Planck Institute for Astronomy in Heidelberg, Germany. “We’re entering an incredibly exciting period in history.”

Meanwhile, scientists disagree about which technique offers the best chances of finding the first true “Earth analog”—an Earth-like planet orbiting in the habitable zone of its Sun-like star. (H85512b is too massive, and it’s star is too cool.) Mayor says HARPS might find this Holy Grail of exoplanet research within 5 years or so, after new upgrades to increase the instrument’s sensitivity. But planet hunter Geoffrey Marcy of the University of California, Berkeley, disagrees. NASA’s Kepler space telescope is “by far the best,” he says. “We will find them if they’re there, probably within the next 2 or 3 years.”

At the meeting, Kepler co-investigator Natalie Batalha of NASA’s Ames Research Center announced that the number of exoplanet candidates from the Kepler mission has increased by some 50% since last February, to 1781. Most are less than three times the size of the Earth. Kepler, launched in March 2009, finds planets by measuring the slight periodic dimming of their parent stars, when they happen to pass between the star and Earth.

No matter who finds the first Earth analog, the HARPS planets offer better prospects for detailed follow-up observations, Mayor says, because HARPS focuses on relatively nearby stars, while almost all Kepler stars are much farther away. For instance, ESO astronomer Markus Kissler-Patig predicts that the future 39.2-meter European Extremely Large Telescope (E-ELT) should be able to directly image HD 85512b. Analyzing the starlight it reflects will provide important information about the planet’s atmospheric composition. “The E-ELT will be able to probe for biomarkers,” Kissler-Patig says, referring to chemicals thought to indicate the presence of life.

While ESO is planning more-sensitive planet-hunting instruments for its existing Very Large Telescope and for the future E-ELT, Kepler is facing an uncertain future. “Kepler’s goal of finding true Earth analogs can only be reached by extending the mission duration” past its planned operational lifetime of 3.5 years, Batalha says. In February 2012, NASA will decide on a possible mission extension. Marcy is optimistic. Kepler is so incredibly successful, he says, that it seems unlikely NASA will terminate the mission next year. “I’m sure NASA is wiser than that.”

 

Via ScienceNow