Nasa says its six-tonne UARS satellite plunged to Earth over the Pacific Ocean

NASA--Nasa says its six-tonne UARS satellite plunged to Earth over the Pacific Ocean, off the US west coast.

It appears likely the decommissioned craft came down between 03:23 and 05:09 GMT - with a best estimate of 04:16.

If correct, this means any debris that survived to the surface probably went into water and not on land.

The Upper Atmosphere Research Satellite (UARS) is the largest American space agency satellite to return uncontrolled into the atmosphere in about 30 years.

The fall to Earth was monitored by the Joint Space Operations Center (JSPOC) at Vandenberg Air Force Base in California. Its best estimate for the timing of the re-entry would have seen UARS come in at a point located at 31 degrees North latitude and 219 degrees East longitude - well out into the North Pacific.

However, if UARS re-entered many minutes after 04:16, it is possible debris could have reached the American landmass.

There were some unconfirmed reports of glowing wreckage moving across the sky in western Canada, but Nasa said it had yet to receive credible evidence that this was so, less still that any debris items had been found.

"I've got no reports that I've seen that talk about people who think they might have recovered debris," Nick Johnson, Nasa's chief scientist for orbital debris at the Johnson Space Center in Houston, told reporters during a media teleconference.

"Obviously, we're going to continue to keep our eyes and ears open, and if we receive any reports like that we'll try to go verify."

Most of the 20-year-old satellite should simply have burnt up on re-entry into the Earth's atmosphere, but modelling work indicated perhaps 500kg could have survived to the surface.

Calculations estimated this material would have been scattered over an 800km path. Nonetheless, with more than 70% of the Earth's surface covered by water, many experts had offered the view in recent weeks that an ocean grave was going to be the most probable outcome for UARS.

"Because we don't know where the re-entry point actually was, we don't know where the debris field might be. If the re-entry point was at the time that JSPOC has its best guess of 04:16 GMT then all that debris wound up in the Pacific Ocean," Nick Johnson reiterated.

UARS was deployed in 1991 from the space shuttle Discovery on a mission to study the Earth's upper atmosphere.

It contributed important new understanding on subjects such as the chemistry of the protective ozone layer and the cooling effect volcanoes can exert on the global climate.      Source: bbc.co.uk

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U.S. astronomers announced the discovery of planets with two suns

Washington--Still remember the picture of the planet Tatooine, Luke Skywalker's house in Star Wars that have two suns? Planets like it was really there in the universe.
U.S. astronomers announced the discovery of a planet with two suns in the latest scientific journal Science on Thursday (09/15/2011). The planet, named Kepler-16b was roughly the same size as the planet Saturn in our Solar System, and is located about 200 light years from Earth. The planet is located at a distance of about 105 million kilometers from the two parent star, and has an orbital period of 229 days.
The planet was found using the Kepler space telescope, which monitor 155,000 stars no less. "This discovery is very surprising. Once again, something that used to exist only in science-fiction story, has now become a reality," says Alan Boss of the Carnegie Institution for Science Department of Terrestrial Magnetism, one of the astronomers who wrote a scientific article.
The study found the Kepler-16b is led by astronomer Laurance Doyle of institutions Search for Extraterrestrial Intelligence (SETI) Institute, based in California, USA.
Previously, astronomers from around the world have seen some of the planet that they believe to be orbiting two stars at once. However, they have never seen these planets pass directly in front of the sun, so this discovery became the first evidence of a planet with two suns.
"Kepler-16b is the first example and no doubt from a planet sirkumbinari, ie planets orbiting two stars at once. Once again this proves that our Solar System is just one variation of the planetary system that can be realized by nature." Josh Carter said of the Harvard-Smithsonian Center for Astrophysics, which is also involved in this invention.
If there are creatures that inhabit the planet, they can enjoy moments of twilight, and two of the setting sun, as experienced by Luke Skywalker in Star Wars. However, the possibility of human-like creatures living on this planet is very small, given the very low surface temperatures, which ranged between minus 73 to minus 101 degrees Celsius.
Low temperature is possible because despite having two suns, both the size of the parent star is much smaller than our sun and emits less energy. The mass of the star is only one fifth of the mass of the Sun, and the second star only has 69 percent of the mass of the Sun.
Besides surrounded by Kepler planet-16b, two stars orbiting each other with each other in a "sky dance" with the orbital period of 41 days.

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A satellite on the verge of falling back to Earth appears

Miami (CNN) -- A satellite on the verge of falling back to Earth appears to have begun slowing down but will not re-enter the atmosphere until late Friday or early Saturday U.S. time, according to NASA.

The United States is once again an unlikely but potential target for the 26 pieces of the Upper Atmosphere Research Satellite, expected to survive the descent. Those pieces, made of stainless steel, titanium and beryllium that won't burn, will range from about 10 pounds to hundreds of pounds, according to NASA.

NASA said Friday morning that it would be hours before it would be able to zero in on the time and place of the re-entry.

Mark Matney of NASA's Orbital Debris team in Houston said there's no way to know exactly where the pieces will come down.

"Keep in mind, they won't be traveling at those high orbital velocities. As they hit the air, they tend to slow down. ... They're still traveling fast, a few tens to hundreds of miles per hour, but no longer those tremendous orbital velocities," he explained.

Because the satellite travels thousands of miles in a matter of minutes as it orbits -- even just before it begins re-entry -- it will be impossible to pinpoint the exact location the pieces will come down. On top of that, Matney said, the satellite is not stable.

"Part of the problem is, the spacecraft is tumbling in unpredictable ways, and it is very difficult to very precisely pinpoint where it's coming down even right before the re-entry."

Where will satellite debris strike?

Because water covers 70% of the Earth's surface, NASA has said that most if not all of the surviving debris will land in water. Even if pieces strike dry land, there's very little risk any of it will hit people.

However, in an abundance of caution, the Federal Aviation Administration on Thursday released an advisory warning pilots about the falling satellite, calling it a potential hazard.

"It is critical that all pilots/flight crew members report any observed falling space debris to the appropriate (air traffic control) facility and include position, altitude, time and direction of debris observed," the FAA statement said.

The FAA said warnings of this sort typically are sent out to pilots concerning specific hazards they may encounter during flights such as air shows, rocket launches, kites and inoperable radio navigational aids.

NASA says space debris the size of the satellite's components re-enters the atmosphere about once year. Harvard University astrophysicist Jonathan McDowell noted that the satellite is far from being the biggest space junk to come back.

"This is nothing like the old Skylab scare of the '70s, when you had a 70-ton space station crashing out of the sky. So, I agree with the folks in Houston. It's nothing to be worried about," McDowell said.

Pieces of Skylab came down in western Australia in 1979.

The only wild card McDowell sees is if somehow a chunk hits a populated area.

"If the thing happens to come down in a city, that would be bad. The chances of it causing extensive damage or injuring someone are much higher."

NASA said that once the debris hits the atmosphere 50 miles up, it will take only a matter of minutes before the surviving pieces hit the Earth.

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NASA will posthumously honor Alan B. Shepard Jr., the first American astronaut in space who later walked on the moon

WASHINGTON - NASA will posthumously honor Alan B. Shepard Jr., the first American astronaut in space who later walked on the moon, with an Ambassador of Exploration Award for his contributions to the U.S. space program.

Shepard's family members will accept the award on his behalf during a ceremony at 5:30 p.m. EDT on Thursday, April 28, at the U.S. Naval Academy Museum, located at 74 Greenbury Point Road in Annapolis, Md. His family will present the award to the museum for permanent display. NASA's Chief Historian Bill Barry will represent the agency at the event, which will include a video message from NASA Administrator Charles Bolden.

Shepard, a 1945 graduate of the Naval Academy, was one of NASA's original seven Mercury astronauts selected in April 1959. On May 5, 1961, he was launched from Cape Canaveral, Fla., aboard the Freedom 7 spacecraft on a suborbital flight that carried him to an altitude of 116 miles.

Shepard made his second spaceflight as the commander of Apollo 14 from Jan. 31 to Feb. 9, 1971. He was accompanied on the third lunar landing by astronauts Stuart Roosa and Edgar Mitchell. Maneuvering the lunar module "Antares" to a landing in the hilly upland Fra Mauro region of the moon, Shepard and Mitchell deployed and activated a number of scientific instruments and collected almost 100 pounds of lunar samples for return to Earth.

Reporters interested in covering the award ceremony must contact the Naval Academy's public affairs office at 410-293-2292 or mediarelations@usna.edu by noon, Wednesday, April 27, for access information.

NASA is giving the Ambassador of Exploration Award to the first generation of explorers in the Mercury, Gemini and Apollo space programs for realizing America's goal of going to the moon. The award is a moon rock encased in Lucite, mounted for public display.

The rock is part of the 842 pounds of lunar samples collected during six Apollo missions from 1969 to 1972. The astronauts or family members receiving the award present it to a museum of their choice, where the moon rock is placed on public display.

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