NASA Launches Satellite Command Game for Kids (SPACE.com)

NASA has launched an interactive, educational video game called NetworKing that gives kids an insider's perspective into how astronauts, mission controllers and scientists communicate during space missions.

NetworKing can be played online by installing a small browser plugin or can be downloaded to a computer for offline play. Developed by staff at NASA's Ames Research Center at Moffett Field, Calif., the game depicts how the Space Communication and Navigation (SCaN) network operates.

Players start small with one a single command base on Earth and can take on several clients who are operating Near Earth Network satellites. As they gain scientific and technological expertise, manage their network’s capacity and respond to calls for repair, they can construct a larger and more efficient network.

With enough resources, players can acquire more complex clients, such as the International Space Station, Hubble Space Telescope and the Kepler mission, and move into deep space.

Brief interactive tutorials are provided at the beginning of play and additional prompts will appear as play progresses if the system detects an action is needed on the part of the player.

In conjunction with NetworKing, the 3D Resources website also links visitors to the Station Spacewalk Interactive Game and the SCaN Interactive Demo that demonstrate the interaction between SCaN's ground-and-space facilities and NASA spacecraft.

To play the NetworKing game, go here.

This story was provided by TechNewsDaily, sister site to SPACE.com. Follow TechNewsDaily on Twitter @TechNewsDaily or on Facebook.

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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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Defunct 6-ton satellite crashing back to Earth (Reuters)

CAPE CANAVERAL, Florida (Reuters) – A defunct NASA science satellite dispatched by a space shuttle crew in 1991 will come crashing back to Earth this month, with debris most likely landing in an ocean or unpopulated region, officials said Friday.

The Upper Atmosphere Research Satellite, or UARS, was turned off in 2005, becoming another piece of space junk loitering in Earth orbit. The 6.5-ton spacecraft is expected to re-enter Earth's atmosphere later this month, although exactly when and where is unknown.

"The atmosphere changes on a daily basis. It's impossible to say how that's going to impact this re-entry," Michael Duncan, deputy chief of space situational awareness at the U.S. Strategic Command, told reporters during a conference call.

Satellites and rocket bodies falling back to Earth are nothing new. Last year, about 400 small pieces of trackable debris returned to the atmosphere.

Spent rocket bodies re-enter at a rate of about one per week. Large spacecraft, like the 35-foot long, 15-foot diameter (10-6-metres long, 4.5-metres diameter) UARS, fall back to Earth about once a year.

Most of UARS will burn up in the atmosphere, but up to 26 individual pieces, with a combined mass of about 1,100 pounds (500 kg), will survive the fall, said Nicholas Johnson, chief scientist of NASA's Orbital Debris Program office at the Johnson Space Center in Houston.

The largest chunk, part of the spacecraft's structure, is expected to be about 331 pounds (150 kg), he added.

The debris most likely will land in an ocean or in an uninhabited region of Earth.

The satellite's orbit takes it over most of the planet, from as far north as northern Canada to the southern part of South America.

"It's highly unlikely it's going to strike a populated area, just from a statistical standpoint," Johnson said.

"Throughout the entire 54 years of the space age, there's been no report of anybody in the world being injured or severely impacted by any re-entering debris," he said.

The chance that even one person will be struck by a piece of UARS debris is one in 3,200, NASA says.

The satellite is so big, its plunge through the atmosphere will be visible -- if anyone is around to see it.

"This should be quite a nice show," Johnson said. "Odds are though, it's going to happen over an ocean, unlikely to be seen unless it's by an airliner. We've had reports like that before.

"We just will not know precisely where it's going to come down until it comes down."

(Editing by Jane Sutton and Doina Chiacu)

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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.

Read more:

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China's Great Wall of Steel in the Blue Sky

Virgin Galactic CEO: What NASA Should be Doing

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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Defunct 6-ton satellite crashing back to Earth

By Irene Klotz

CAPE CANAVERAL, Florida | Fri Sep 9, 2011 3:44pm EDT

CAPE CANAVERAL, Florida (Reuters) - A defunct NASA science satellite dispatched by a space shuttle crew in 1991 will come crashing back to Earth this month, with debris most likely landing in an ocean or unpopulated region, officials said Friday.

The Upper Atmosphere Research Satellite, or UARS, was turned off in 2005, becoming another piece of space junk loitering in Earth orbit. The 6.5-ton spacecraft is expected to re-enter Earth's atmosphere later this month, although exactly when and where is unknown.

"The atmosphere changes on a daily basis. It's impossible to say how that's going to impact this re-entry," Michael Duncan, deputy chief of space situational awareness at the U.S. Strategic Command, told reporters during a conference call.

Satellites and rocket bodies falling back to Earth are nothing new. Last year, about 400 small pieces of trackable debris returned to the atmosphere.

Spent rocket bodies re-enter at a rate of about one per week. Large spacecraft, like the 35-foot long, 15-foot diameter (10-6-metres long, 4.5-metres diameter) UARS, fall back to Earth about once a year.

Most of UARS will burn up in the atmosphere, but up to 26 individual pieces, with a combined mass of about 1,100 pounds (500 kg), will survive the fall, said Nicholas Johnson, chief scientist of NASA's Orbital Debris Program office at the Johnson Space Center in Houston.

The largest chunk, part of the spacecraft's structure, is expected to be about 331 pounds (150 kg), he added.

The debris most likely will land in an ocean or in an uninhabited region of Earth.

The satellite's orbit takes it over most of the planet, from as far north as northern Canada to the southern part of South America.

"It's highly unlikely it's going to strike a populated area, just from a statistical standpoint," Johnson said.

"Throughout the entire 54 years of the space age, there's been no report of anybody in the world being injured or severely impacted by any re-entering debris," he said.

The chance that even one person will be struck by a piece of UARS debris is one in 3,200, NASA says.

The satellite is so big, its plunge through the atmosphere will be visible -- if anyone is around to see it.

"This should be quite a nice show," Johnson said. "Odds are though, it's going to happen over an ocean, unlikely to be seen unless it's by an airliner. We've had reports like that before.

"We just will not know precisely where it's going to come down until it comes down."

(Editing by Jane Sutton and Doina Chiacu)

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Dead NASA Satellite Falling From Space, But When & Where? (SPACE.com)

This story was updated at 2:05 p.m. EDT.

An out-of-control NASA satellite that is dead in space will plunge back to Earth in the next few weeks, but exactly when and where the spacecraft will fall are still a mystery, space agency and military officials said today.

The spacecraft, called the Upper Atmosphere Research Satellite, is about the size of a school bus and is expected to re-enter Earth's atmosphere sometime between late September and early October, NASA officials said. The nearly 12,500-pound (5,668-kilogram) satellite will fall over a stretch of land more than 500 miles (804 kilometers) long somewhere between northern Canada and southern South America.

But NASA and U.S. military officials tracking the defunct UARS satellite won't have a better idea of where the spacecraft will fall until around two hours before it happens. [Photos: Space Debris & Cleanup Concepts]

"We continue to say late September is the best estimate that we can give right now," Air Force Maj. Michael  Duncan, deputy chief of the U.S. Strategic Command's space situational awareness division, told reporters today (Sept. 9).  " There are so many factors that will affect it between now and that point in time — the atmosphere changes on a daily basis —  that it's impossible to say how that's going to impact this re-entry."

Even two hours before re-entry, the military will only be able to pinpoint the area of impact to within about 6,000 miles (10,000 kilometers), Duncan said.

There is a 1-in-3,200 chance that a person somewhere on Earth could be hit by falling satellite debris, but the odds of the UARS spacecraft re-entering over a populated area are extremely remote, NASA officials said.

"So those are actually very, very low odds that anyone is going to be struck by a piece of debris," said Nick Johnson, the chief scientist of NASA's Orbital Debris Program at the agency's Johnson Space Center in Houston.

Johnson said 26 large pieces of the UARS satellite are expected to survive the re-entry and reach the Earth's surface. Altogether, about 1,170 pounds (532 kg) of material from the UARS satellite are expected to reach Earth. The largest piece of debris could weigh nearly 300 pounds (150 kg).

"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.

Dead satellite in space

The $750 million UARS satellite has been dead in orbit since 2005, when it was decommissioned after a 14-year Earth-observation mission.

The spacecraft is the largest NASA satellite to make an uncontrolled fall back to Earth in years, agency officials said. It is about 35 feet (10.7 meters) long and 15 feet (4.5 m) wide.

Johnson said that, on average, a spacecraft as large as UARS falls back to Earth about once a year. In 2010, a total of 400 pieces of satellites or spent rockets fell back to Earth, though most pieces either burned up during re-entry, fell into the ocean or fell over unpopulated areas, he added.

"Satellites re-entering is actually very commonplace," Johnson said.

NASA is encouraging any member of the public who finds a piece of the UARS satellite to not touch the object and notify local law enforcement authorities. The satellite's remains are still owned by the United States government and cannot be sold to space memorabilia hunters NASA officials said.

NASA launched the UARS satellite in 1991 aboard the space shuttle Discovery on a mission to study Earth's upper atmosphere. In particular, the spacecraft examined Earth's ozone layer to help scientists better understand ozone layer depletion. The satellite was also able to track atmospheric effects from the Mt. Pinatubo volcano eruption in the Philippines at the time, said Paul Hertz, chief scientist for NASA's science missions.

Hertz said that the UARS satellite was shut down because the observations it was collecting were being performed by newer, better satellites.

In 2005, NASA commanded the spacecraft to use all of its remaining propellant to move into a lower orbit, one that would send it on a funeral dive back through Earth's atmosphere in about five or six years, Johnson said.

"The current orbit is about 245 kilometers by 275 kilometers," he added. "And obviously decreasing every day."

Eyes on the sky

NASA and the military's space tracking division are keeping a close watch on the UARS satellite for any changes in its descent over the next few weeks.

The space agency is posting weekly updates on the falling spacecraft on a special UARS mission website. The updates are coming from the Joint Space Operations Center at the U.S. Strategic Command at Vandenberg Air Force Base, Calif., which is tracking the satellite.

"The reason for the updates on NASA's part is to keep you and the public informed," said NASA spokeswoman Beth Dickey. "We know we will get a lot of questions about it, so we want to be up front about it."

Space debris is one of the most challenging hurdles facing space agencies and satellite operators today. According to NASA, there are about 22,000 pieces of space junk larger than 4 inches (10 cm) currently being tracked by the U.S. Space Surveillance Network. Only 1,000 of those objects are actually working spacecraft, the agency states.

Last week, a report by the National Research Council found that the amount of space junk around Earth has reached a tipping point in which, even if no new debris were added, objects would continue to create more debris through collisions. That report states that the need to limit or clean up space debris is more important than ever.

Skywatchers on alert

Keeping a skywatching eye on the comings and goings of UARS as it nears re-entry is a global network of satellite surveillance amateurs.

According to satellite sleuth Harro Zimmer of Berlin, Germany, his current analysis — based on couple of different methods — shows a possible decay window between Sept. 29 and Oct. 5.

"The last word will be coming from the solar activity over the next two weeks," Zimmer told SPACE.com.

Zimmer also advised that Belgian observer, Bram Dorreman, has reported that UARS looks to be slowly rotating with a period of 17 seconds. Its magnitude changes from 1.2 to 3.5 on the scale astronomers use to measure the brightness of objects in space. On that scale, the brighter an object is, the lower the number of its magnitude.

Johnson said that if the UARS satellite does re-enter over a populated region, it should be a magnificent sight to skywatchers on the ground. But even that is a long shot.

"This would be quite a nice show. It is a relatively large vehicle, it would be visible in daylight, Johnson said. "Odds are it's going to happen over an ocean, unlikely to be seen unless it's, you know, an airliner. We've had reports like that before. "

SPACE.com's Space Insider Columnist Leonard David contributed to this report from Colorado.You can follow SPACE.com Managing Editor Tariq Malik on Twitter @tariqjmalik. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

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NASA Sun-Watching Satellite Spots Comet Elenin in Deep Space (SPACE.com)

A NASA spacecraft  aimed at the sun shifted its unblinking gaze to an approaching comet last week to snap a new photo of the icy object as it flew by.

The image shows the comet Elenin as it passed within 4.3 million miles (7 million kilometers) of one of NASA's twin Stereo sun-watching spacecraft during a series of deep space photo sessions that began on Aug. 1. NASA rolled the Stereo-B satellite to give its instruments a view of the comet flyby, officials said.

From Stereo's observations, the fuzzy comet Elenin can be seen streaking across a small portion of the sky. The comet was seen by Stereo's HI-2 telescope between Aug. 1 to 5, and by the higher resolution HI-1 telescope between Aug. 6 to 12, NASA officials said. Stereo mission scientists planned to take photos for one-hour every day through Aug. 12. [See the Stereo probe's new comet Elenin photo]

"From August 15 onward, the comet enters the HI-1 telescope's nominal field of view, at which time we should enjoy continuous viewing of the comet," NASA researchers explained in an update posted to the Stereo mission website.

Comet Elenin is expected to become brighter over the next few days, and could be detectable using Stereo's coronagraph instrument between Aug. 20 and Sept. 1, NASA officials said. Mission managers are then expecting the comet to become visible to another sun-watching spacecraft – NASA's Solar and Heliospheric Observatory (SOHO) – for six days, beginning on Sept. 23.

Comet Elenin was discovered in December by Russian astronomer Leonid Elenin, who spotted the icy wanderer using the International Scientific Optical Network's robotic observatory near Mayhill, New Mexico. 

Viewed from Earth, comet Elenin presently appears as a faint smudge of light in deep sky exposures. By late August the comet could be visible to the naked eye as a dim "fuzzy star" with a tail. [Best Close Encounters with Comets]

Comet Elenin will fly through the inner solar system in October 2011 and be 22 million miles (35 million kilometers) away at its closest approach to our planet, NASA scientists have said. The comet is not expected to be particularly dazzling, but the flyby may be a good chance to study a relatively young comet from the outer solar system.

Some doomsday theorists have pinned the Nibiru rogue planet hypothesis on the small comet.

Conspiracy theorists say a planet, known as Nibiru, will swing in from the outskirts of our solar system and collide with Earth and wipe out humanity in 2012. Since no rogue planet has been found in the outer solar system, some people have argued that comet Elenin will be the true culprit in the Nibiru-Earth collision.

NASA has dismissed the notion that comet Elenin is anything other than a dim, wimpy comet. It poses no threat to Earth, making its closest pass at a distance roughly 100 times farther than the distance from Earth to the moon.

NASA's identical twin Stereo spacecraft were launched in October 2006. They are offset from one another, one flying ahead of the Earth and the other behind. The name "Stereo" is short for Solar Terrestrial Relations Observatory.

Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

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'Stealth' Solar Eclipse Spotted in Satellite Photos (SPACE.com)

The moon blocked part of the sun in a partial solar eclipse today (July 1) in an event caught on camera by a European satellite, even though it was largely invisible to everyone on planet Earth.

The solar eclipse peaked at about 4:40 a.m. EDT (0840 GMT), but it was only visible from an extremely remote — and uninhabited — patch of the southern Atlantic Ocean just off the coast of Antarctica, south of Africa.  NASA classified the stealthy eclipse as the "eclipse that nobody sees," but the European Space Agency's Proba-2 satellite orbiting Earth managed to observe the event using a telescope called Swap.

The Proba-2 photos show the sun with a small, dark bite missing at the point where the moon blocked the star's light. The solar eclipse lasted about 90 minutes, with the moon blocking only about 9.7 percent of the sun's surface at the event's peak. [Proba-2 satellite's July 1 solar eclipse photos]

Proba-2's Swap telescope snapped views of the eclipse in the extreme-ultraviolet range of the light spectrum and managed to perform multiple observation passes as it orbited the Earth, mission scientists said.

"SWAP observes the solar eclipse in two subsequent orbits of Proba-2," scientists wrote on the satellite mission's website.

ESA's Proba-2 satellite has a dual mission to study the sun and test new spacecraft technologies. It carries two sun-watching instruments, two space weather monitors and 17 technology demonstration experiments.

Solar eclipses occur when the moon is in its new phase and at a point in its orbit that is between the Earth and the sun. When the moon aligns perfectly with the sun, as viewed from Earth, a total solar eclipse occurs, while at other times the sun is only partly obscured.

Friday's partial solar eclipse marked the third in a rare series of sun and moon eclipses within a one-month period and also kicked off a new cycle of eclipse events, which astronomers call Saros cycle 156.

The event followed a spectacular June 1 partial solar eclipse, which was visible over the northern polar regions of Europe and Asia, as well as the total lunar eclipse of June 15 that was observed by skywatchers across the Eastern Hemisphere.

The next eclipse of 2011 will also be a partial solar eclipse and will occur on Nov. 25. That event will be visible from southern South Africa, Antarctica, and New Zealand.

A Dec. 10 total lunar eclipse, which should be visible from eastern Asia, Australia, and northwestern North America, will round out the 2011 sun and moon eclipse events.

You can follow SPACE.com Managing Editor Tariq Malik on Twitter @tariqjmalik. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

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Iran puts satellite into orbit: state TV

TEHRAN | Wed Jun 15, 2011 4:02pm EDT

TEHRAN (Reuters) - Iran has successfully launched a second domestically built satellite into orbit, Iran's Arabic language al-Alam television reported on Wednesday.

The United States and its allies fear Iran is seeking to build nuclear bombs and are concerned that the long-range ballistic technology used to put satellites into orbit can also be used to launch warheads.

"Iran launched a domestically built rocket and the Rasad 1 (satellite) has been put into orbit," al-Alam reported.

In February 2009, Iran launched its first domestically-built satellite, the OMID (Hope) research and telecoms satellite, in what it described as a big step coinciding with the 30th anniversary of its 1979 Islamic revolution.

Iran, which regards its space program as a matter of national pride, says its nuclear program is solely to generate electricity.

The Rasad 1 (Observation) satellite will be used for transmitting images and weather forecasts, TV reported.

"The satellite was launched by a Safir rocket. It was put into orbit 260 km (163 miles) above the Earth," al-Alam reported.

Iran gave no further description of the satellite's orbit. Western experts say Iran rarely gives enough detail for them to determine the extent of its technological advances, while much Iranian technology consists of modifications of equipment supplied by China, North Korea and others.

(Writing by Parisa Hafezi; Editing by Peter Graff)

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Satellite study helps thirsty Sahel (AFP)

PARIS (AFP) – Embattled farmers in the Sahel countries of West Africa can take heart from a new study that should boost the accuracy of rainfall prediction in one of the world's most fragile regions.

Sharp differences in moisture in small patches of land can trigger precious rain, says the paper, published online on Sunday in the journal Nature Geoscience.

Researchers from Britain, France and Australia looked at satellite data that located nearly 4,000 rainstorms which occurred in the Sahel between 2006-2010.

Between 80 and 90 percent of rainfall in the Sahel comes from this kind of storm, which can brew suddenly when moisture-laden air lifts from heated earth.

The scientists then overlaid this data with satellite information on soil moisture.

They found that an area where there are large differences in soil moisture plays a big role in making rain.

A moist area just 10 to 40 kilometres (six to 25 miles) across can trigger rain provided it is next to a far drier patch.

This small-is-beautiful finding contrasts with conventional weather models.

These tend to calculate the probability of rainfall on the basis of huge swathes of moist land and on the presence of rain-making features like mountain ranges.

"Rainfall is difficult to predict, particularly in regions such as the Sahel where huge storms can grow from nothing in a matter of hours," said lead author Chris Taylor of Britain's Centre for Ecology and Hydrology.

"We found that areas with contrasting soil moisture can play an important role in the creation of new storms, a factor not accounted for in current climate models.

"(...) This effect is important for typically one in eight storms, in a region particularly prone to droughts and associated crop failures."

In areas where there are these sharp differences in soil moisture, rainstorms are twice as likely compared to regions where the moisture level is uniform.

The rain often falls around 10 kilometres (six miles) upwind of the moist patch, not downwind, Taylor explained to AFP.

This occurs when the moist air is driven against weak prevailing winds by a strong local breeze coming from the opposite direction.

The study could help fine-tune knowledge about how climate change could affect the Sahel, he said.

Semi-arid, tropical west Africa is one of the most demanding regions in the world for agriculture, given its fragile soils and a short growing season that is crucially dependent on when and where rain will land.

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