Friday, September 30, 2011

Another Dead Satellite to Crash Land in November

A defunct NASA satellite that fell to Earth last week sparked some worldwide buzz, but it's not the only spacecraft falling out of space.

The decommissioned German X-ray space observatory, called the Roentgen Satellite or ROSAT, will tumble to Earth sometime in early November, but it's still too early to pinpoint exactly when and where debris from the satellite will land, according to officials at the German Aerospace Center.

The 2.4-ton spacecraft's orbit extends from the latitudes of 53 degrees north and south, which means the satellite could fall anywhere over a huge swath of the planet — stretching from Canada to South America, German Aerospace officials said. [6 Biggest Uncontrolled Spacecraft Falls From Space]

The latest estimates suggest that up to 30 large pieces of the satellite could survive the intense and scorching journey through Earth's atmosphere. In all, about 1.6 tons of the satellite components could reach the surface of the Earth, according to German Aerospace officials.

The re-entry will be similar to NASA's 6-ton Upper Atmosphere Research Satellite (UARS), which plunged into the southern Pacific Ocean on Saturday (Sept. 24).

ROSAT coming home

In 1998, ROSAT's star tracker failed, which caused its onboard camera to be pointed directly at the sun. The event permanently damaged the spacecraft and ROSAT was officially decommissioned in February 1999.

Scientists are actively tracking the dead satellite, but many of the details will remain uncertain until roughly two hours before it hits Earth.

"It is not possible to accurately predict ROSAT's re-entry," Heiner Klinkrad, head of the Space Debris Office at the European Space Agency, said in a webcast posted on the German Aerospace Center's website. "The uncertainty will decrease as the moment of re-entry approaches. It will not be possible to make any kind of reliable forecast about where the satellite will actually come down until about one or two hours before the fact."

It will, however, be possible to rule out certain geographical regions from the potential drop zone about a day in advance, Klinkrad said. The largest piece of debris is expected to be the telescope's heat resistant mirror.

"Generally speaking, whenever a satellite re-enters the atmosphere, about 20 to 40 percent of its mass actually reaches the Earth’s surface," Klinkrad said. "In the case of ROSAT, this figure could be slightly higher because one of its characteristic features is that it carries heat-resistant mirror structures on board." [Related: Falling Satellites & Space Junk: Q&A with Orbital Debris Expert]

Diamond stud

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Thursday, September 29, 2011

NASA's Chandra Finds Nearest Pair of Supermassive Black Holes

Astronomers using NASA's Chandra X-ray Observatory discovered the first pair of supermassive black holes in a spiral galaxy similar to the Milky Way. Approximately 160 million light years from Earth, the pair is the nearest known such phenomenon.

The black holes are located near the center of the spiral galaxy NGC 3393. Separated by only 490 light years, the black holes are likely the remnant of a merger of two galaxies of unequal mass a billion or more years ago.

"If this galaxy wasn't so close, we'd have no chance of separating the two black holes the way we have," said Pepi Fabbiano of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., who led the study that appears in this week's online issue of the journal Nature. "Since this galaxy was right under our noses by cosmic standards, it makes us wonder how many of these black hole pairs we've been missing."
Justify Full
Previous observations in X-rays and at other wavelengths indicated that a single supermassive black hole existed in the center of NGC 3393. However, a long look by Chandra allowed the researchers to detect and separate the dual black holes. Both black holes are actively growing and emitting X-rays as gas falls towards them and becomes hotter.

When two equal-sized spiral galaxies merge, astronomers think it should result in the formation of a black hole pair and a galaxy with a disrupted appearance and intense star formation. A well-known example is the pair of supermassive black holes in NGC 6240, which is located about 330 million light years from Earth.

However, NGC 3393 is a well-organized spiral galaxy, and its central bulge is dominated by old stars. These are unusual properties for a galaxy containing a pair of black holes. Instead, NGC 3393 may be the first known instance where the merger of a large galaxy and a much smaller one, dubbed a "minor merger" by scientists, has resulted in the formation of a pair of supermassive black holes. In fact, some theories say that minor mergers should be the most common way for black hole pairs to form, but good candidates have been difficult to find because the merged galaxy is expected to look so typical.

"The two galaxies have merged without a trace of the earlier collision, apart from the two black holes," said co-author Junfeng Wang, also from CfA. "If there was a mismatch in size between the two galaxies it wouldn't be a surprise for the bigger one to survive unscathed."

If this was a minor merger, the black hole in the smaller galaxy should have had a smaller mass than the other black hole before their host galaxies started to collide. Good estimates of the masses of both black holes are not yet available to test this idea, although the observations do show that both black holes are more massive than about a million suns. Assuming a minor merger occurred, the black holes should eventually merge after about a billion years.

Both of the supermassive black holes are heavily obscured by dust and gas, which makes them difficult to observe in optical light. Because X-rays are more energetic, they can penetrate this obscuring material. Chandra's X-ray spectra show clear signatures of a pair of supermassive black holes.

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Wednesday, September 28, 2011

NASA Plans High-Speed Space Communications System

NASA is working on a laser-based optical communications system that will drastically reduce the time it takes to transmit multimedia from space, with data moving at rates up to 100 times faster than current systems.

The space agency aims to show off a high-speed communications system through a Laser Communications Relay Demonstration (LCRD) in 2016. LCRD is one of three next-generation space technologies NASA is working on as part of its plans to create more sophisticated solutions to meet goals for the future of its space program.

Now that NASA has retired its space shuttle program, the agency aims to send manned spacecraft beyond low-Earth orbit and push the boundaries of current space communications, among other aims.

To the latter point, while it currently takes 90 minutes to transmit high-resolution images from Mars, LCRD will allow for actual streaming of high-definition video from distances beyond the moon, according to the space agency.

NASA's Goddard Space Flight Center came up the idea for the LCRD, which is now being developed by a cross-organizational team that also includes NASA's Jet Propulsion Laboratory and the Lincoln Laboratory at the Massachusetts Institute of Technology. NASA will fly the system into space on a commercial communications satellite developed by Space Systems/Loral.

Dave Israel, who is leading the team developing the network, compared current NASA space communications capability to dial-up Internet speeds. Just as the home Internet user "hit the wall" with that technology, he said in a statement that NASA "is approaching the limit of what its existing communications network can handle."

LCRD, on the other hand, will be more comparable to a land-based optical network such as FIOS from Verizon, Israel added.

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Monday, September 26, 2011

Star Blasts Planet With X-rays

A nearby star is pummeling a companion planet with a barrage of X-rays 100,000 times more intense than the Earth receives from the sun.

New data from NASA's Chandra X-ray Observatory and the European Southern Observatory's Very Large Telescope suggest that high-energy radiation is evaporating about 5 million tons of matter from the planet every second. This result gives insight into the difficult survival path for some planets.

The planet, known as CoRoT-2b, has a mass about three times that of Jupiter -- 1,000 times that of Earth -- and orbits its parent star, CoRoT-2a at a distance roughly 10 times the distance between Earth and the moon.

The CoRoT-2 star and planet -- so named because the French Space Agency’s Convection, Rotation and planetary Transits, or CoRoT, satellite discovered them in 2008 -- is a relatively nearby neighbor of the solar system at a distance of 880 light years.

"This planet is being absolutely fried by its star," said Sebastian Schroeter of the University of Hamburg in Germany. "What may be even stranger is that this planet may be affecting the behavior of the star that is blasting it."

According to optical and X-ray data, the CoRoT-2 system is estimated to be between about 100 million and 300 million years old, meaning that the star is fully formed. The Chandra observations show that CoRoT-2a is a very active star, with bright X-ray emission produced by powerful, turbulent magnetic fields. Such strong activity is usually found in much younger stars.

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Sunday, September 25, 2011

Huge UARS Satellite's Fall From Space Captivates Skywatchers, Sparks Hoaxes

Skywatchers around the world were hoping for some unique views overnight Friday (Sept. 23), as a NASA satellite plunged to Earth on its final scorching journey through the atmosphere.

The 6.5-ton Upper Atmosphere Research Satellite, or UARS, most likely pierced through Earth's atmospheric shield within 20 minutes of 12:16 a.m. EDT Saturday (0416 GMT), according to NASA officials. The agency is unable to confirm the precise time and location of the satellite's re-entry, but orbital debris scientists said that the satellite would have been flying over the vast Pacific Ocean at the time, well away from the North American coastline.

Throughout the night, rumors circulated that the defunct satellite crashed over Alberta, Canada, raining debris on the small town of Okotoks, which lies south of Calgary. Local authorities who were called to investigate later called the claims a hoax. [6 Biggest Spacecraft to Fall Uncontrolled From Space]

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Thursday, September 22, 2011

Landing of Dead NASA Satellite 'Too Early to Predict': NASA

A dead 6.5 ton NASA UARS satellite would make its re-entry into Earth's atmosphere on Friday, Sept. 23, bringing along a chance to watch a spectacular sky show. But NASA is still not sure where on Earth the satellite would land.

"It is still too early to predict the time and location of re-entry with any more certainty, but predictions will become more refined in the next 24 to 48 hours," National Aeronautics and Space Administration (NASA) said in a statement.

NASA added that the debris from the defunct satellite would not cause harm to humans.

NASA conducted a detailed re-entry risk assessment for UARS in 2002 and it showed that the debris from UARS is not harmful to human beings. Following are the excerpts of the study:

* Number of potentially hazardous objects expected to survive: 26

* Total mass of objects expected to survive: 532 kg

* Estimated human casualty risk (updated to 2011): About 1 in 3200

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Tuesday, September 20, 2011

Tonnes of satellite space junk to pelt earth on weekend

Look out for a six-tonne satellite plummeting from the sky this weekend.

NASA scientists are doing their best to predict exactly when and where it will fall.

For now, they believe the earliest it will hit is Friday (NZ time), while the latest is Sunday.

Scientists put the odds of it hitting someone at 1-in-3200.

Over the years, space debris has fallen into the ocean or empty spaces.

If you do come across what you think may be a satellite piece, NASA doesn't want you to pick it up.

Or sell it on eBay.

As US government-owned property, it should be returned to its rightful owner – by being reported to police.

The 20-year-old research satellite is expected to break into more than 100 pieces as it enters the atmosphere, most of it burning up, the New Zealand Herald reports.

Twenty-six of the heaviest metal parts are expected to reach Earth, the biggest chunk weighing about 136 kilograms. The debris could be scattered over an area about 800 kilometres long.

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Origin of Dinosaur-Killing Asteroid Remains a Mystery

PASADENA, Calif. -- Observations from NASA's Wide-field Infrared Survey Explorer (WISE) mission indicate the family of asteroids some believed was responsible for the demise of the dinosaurs is not likely the culprit, keeping open the case on one of Earth's greatest mysteries.

While scientists are confident a large asteroid crashed into Earth approximately 65 million years ago, leading to the extinction of dinosaurs and some other life forms on our planet, they do not know exactly where the asteroid came from or how it made its way to Earth. A 2007 study using visible-light data from ground-based telescopes first suggested the remnant of a huge asteroid, known as Baptistina, as a possible suspect.

According to that theory, Baptistina crashed into another asteroid in the main belt between Mars and Jupiter about 160 million years ago. The collision sent shattered pieces as big as mountains flying. One of those pieces was believed to have impacted Earth, causing the dinosaurs' extinction.

Since this scenario was first proposed, evidence developed that the so-called Baptistina family of asteroids was not the responsible party. With the new infrared observations from WISE, astronomers say Baptistina may finally be ruled out.

"As a result of the WISE science team's investigation, the demise of the dinosaurs remains in the cold case files," said Lindley Johnson, program executive for the Near Earth Object (NEO) Observation Program at NASA Headquarters in Washington. "The original calculations with visible light estimated the size and reflectivity of the Baptistina family members, leading to estimates of their age, but we now know those estimates were off. With infrared light, WISE was able to get a more accurate estimate, which throws the timing of the Baptistina theory into question."

WISE surveyed the entire celestial sky twice in infrared light from January 2010 to February 2011. The asteroid-hunting portion of the mission, called NEOWISE, used the data to catalogue more than 157,000 asteroids in the main belt and discovered more than 33,000 new ones.

Visible light reflects off an asteroid. Without knowing how reflective the surface of the asteroid is, it's hard to accurately establish size. Infrared observations allow a more accurate size estimate. They detect infrared light coming from the asteroid itself, which is related to the body's temperature and size. Once the size is known, the object's reflectivity can be re-calculated by combining infrared with visible-light data.

The NEOWISE team measured the reflectivity and the size of about 120,000 asteroids in the main belt, including 1,056 members of the Baptistina family. The scientists calculated the original parent Baptistina asteroid actually broke up closer to 80 million years ago, half as long as originally proposed.

This calculation was possible because the size and reflectivity of the asteroid family members indicate how much time would have been required to reach their current locations -- larger asteroids would not disperse in their orbits as fast as smaller ones. The results revealed a chunk of the original Baptistina asteroid needed to hit Earth in less time than previously believed, in just about 15 million years, to cause the extinction of the dinosaurs.

"This doesn't give the remnants from the collision very much time to move into a resonance spot, and get flung down to Earth 65 million years ago," said Amy Mainzer, a co-author of a new study appearing in the Astrophysical Journal and the principal investigator of NEOWISE at NASA's Jet Propulsion Laboratory (JPL) in Pasadena. Calif. "This process is thought to normally take many tens of millions of years." Resonances are areas in the main belt where gravity nudges from Jupiter and Saturn can act like a pinball machine to fling asteroids out of the main belt and into the region near Earth.

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Monday, September 19, 2011

NASA satellite expected to crash to Earth in days

The sky is not falling. A 12,500-pound NASA satellite the size of a school bus is, though.

It's the Upper Atmosphere Research Satellite, and it's tumbling in orbit and succumbing to Earth's gravity. It will crash to the surface Friday.

Or maybe Thursday. Or Saturday.

Out-of-control crashing satellites don't lend themselves to exact estimates even for the precision-minded folks at NASA. The uncertainty about the "when" makes the "where" all the trickier, because a small change in the timing of the re-entry translates into thousands of miles of difference in the crash site.

As of the moment, NASA says the 35-foot-long satellite will crash somewhere between 57 degrees north latitude and 57 degrees south latitude - a projected crash zone that covers most of the planet, and particularly the inhabited parts. In this hemisphere, that includes everyone living between northern Newfoundland and the frigid ocean beyond the last point of land in South America.

Polar bears and Antarctic scientists are safe.

It's the biggest piece of NASA space junk to fall to Earth in more than 30 years. It should create a light show. The satellite will partially burn up during re-entry, and, by NASA's calculation, break into about 100 pieces, creating fireballs that should be visible even in daytime.

An estimated 26 of those pieces will survive the re-entry burn and will spray themselves in a linear debris field 500 miles long. The largest chunk should weigh about 300 pounds.

As the Friday-ish crash gets closer, NASA will refine its estimate of timing and location, but the fudge factor will remain high.

"There are too many variations on solar activity which affect the atmosphere, the drag on the vehicle," said Nicholas Johnson, chief scientist for orbital debris at NASA.

The good news is that the satellite will probably splatter into the open ocean, because Earth is a water planet. And humans, for all their sprawl, occupy a very limited portion of its surface.

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Thursday, September 15, 2011

Satellite falls faster than forecast

NASA's Upper Atmosphere Research Satellite is now expected to fall to Earth sometime between Sept. 23 and 25, orbital experts reported today.

That's toward the early end of the original projections for UARS' fiery descent: Last week, when NASA announced that the long-defunct, six-ton satellite would crash, the time frame was given as late September to early October. That wide window of possibilities was due to the uncertainties over atmospheric conditions. Now the picture is becoming clearer, said Nicholas Johnson, head of NASA's Orbital Debris Program Office at Johnson Space Center in Texas.

"The sun has become very active since the beginning of this week, and it's accelerating the prediction," he told me.

Higher solar activity heats and expands the upper atmosphere, creating more drag for satellites in decaying orbits. The increased drag pulls down those satellites more quickly — and that's what's behind the earlier prediction.

NASA's UARS status page said the bus-sized satellite's orbit was 143 by 158 miles (230 by 255 kilometers) as of today, compared with 155 by 174 miles (250 by 280 kilometers) a week ago. Johnson said the status page would be updated again on Friday.

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Tuesday, September 13, 2011

Behind the Scenes of NASA’s Upcoming MMORPG

These days, nearly every game company is trying to get their fingers in the MMORPG (Massively Multiplayer Online Role Playing Game) pie. Given the past successes of games like Ultima Online and Everquest and the current success of games like EVE Online and World of Warcraft, it’s no surprise that companies want try to create the next “killer app” of the MMORPG market.

One such game company that will be launching a new game is the company partnered with NASA to develop a space-based MMORPG for the space agency. Having raised nearly $40,000 in pledged funding via kickstarter, the company aims to start beta testing their offering some time next year.

So what does this new MMORPG do differently that will attract and retain paying customers? What makes Astronaut: Moon, Mars and Beyond different from say, EVE Online, Star Trek Online, or Star Wars Galaxies?

When a game developer becomes associated with a “big-name” property, expectations from both fans and developers can be quite high. Despite securing a license to create a game based on the Stargate franchise, a game development company never released the game and eventually ended up in bankruptcy. Star Trek Online, despite being one of the most anticipated MMORPG franchises went through two developers and when finally released had less than stellar sales. Of course, many fans of MMORPG’s are all too familiar with the myriad issues that plagued Star Wars Galaxies.

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