Asteroid Near-Misses (AKA: Holy Shit! We're All Going to Die)

[rynner2]

Giant asteroid to 'narrowly miss' Earth
A newly discovered asteroid the size of an office block will narrowly miss the Earth on Monday - coming 23 times closer than the moon.
By Josie Ensor
6:00AM BST 24 Jun 2011

The space rock will reach within 11,000 miles of the planet's surface and give off a light bright enough to be seen through a small telescope, experts said today.

It was only spotted on Wednesday by a robotic telescope in New Mexico that scans the skies for such hazards. An alert was then put out yesterday by the International Astronomical Union's Minor Planet Center in Massachusetts.

The find was confirmed by Peter Birtwhistle, who has discovered dozens of asteroids from his own UK observatory, with a photo taken from Great Shefford in Berkshire.

It will be daylight in the UK when the asteroid, which has been named 2011 MD, makes its close encounter over the southern hemisphere.
But astronomers in other parts of the world, such as South America, will be able to watch it brighten and fade rapidly as it speeds through the starry background.

Asteroid 2011 MD is estimated to be between 10 and 50 yards wide.
UK asteroid expert Dr Emily Baldwin said: "We are certain that it will miss us, but if it did enter the atmosphere, an asteroid this size would mostly burn up in a brilliant fireball, possibly scattering a few meteorites."

On November 8, a 400-meter wide asteroid weighing 50 million tons, called 2005 YU55, is expected to fly inside the orbit of the moon.
Passing by at a distance of just 201,000 miles, the asteroid is expected to be the largest object ever to approach the earth so close.

http://www.telegraph.co.uk/news/8595514 ... Earth.html

 

[rynner2]

Britain in list of countries 'most at risk' if an asteroid strikes
Britain has been identified among a host of countries scientists believe would be worst affected in the event of an asteroid strike.
6:55AM BST 30 Jun 2011

Experts at Southampton University have drawn up a league table of countries most likely to suffer severe loss of life or catastrophic damage should a large asteroid hit Earth.

The list is largely made up of developed nations including China, Japan, the United States and Italy, on the basis that the size of their populations would mean millions of deaths.
The US, China, Indonesia, India and Japan are most in danger on this basis. Canada, the US, China, Japan and Sweden are rated most at risk in terms of potential damage to their infrastructure.
The report comes after a rock the size of a house came within 7,500 miles of Earth earlier this week.

The list has been compiled using software called NEOimpactor, using data from NASA's Near Earth Object programme.
“The threat of Earth being hit by an asteroid is increasingly being accepted as the single greatest natural disaster hazard faced by humanity,” said Nick Bailey, of the University of Southampton, who developed the NEOimpactor software.
“The consequences for human populations and infrastructure as a result of an impact are enormous.”

He added that the devastation wreaked by an asteroid which landed in a remote spot near the Tunguska River in Russia in 1908 demonstrated the impact such an event could have on a populated place.
“While it only flattened unpopulated forest, had it exploded over London it could have devastated everything within the M25,” he said.
“Our results highlight those countries that face the greatest risk from this most global of natural hazards and thus indicate which nations need to be involved in mitigating the threat.”

An asteroid is thought to have been responsible for the extinction of the dinosaurs 65 million years ago – a rock up to 10 miles in diameter hit Earth at 25,000 an hour with a force of 100 megatons, the equivalent of one Hiroshima bomb for everyone on the planet.
Earth has avoided such an event since in part because of Jupiter’s gravitational field which limits our exposure to space rocks.

The countries most at risk:

China

Indonesia

India

Japan

The U.S

The Philippines

Italy

Britain

Brazil

Nigeria

http://www.telegraph.co.uk/science/spac ... rikes.html

 

[Pietro_Mercurios]

Any densely populated area, then?

 

[Trevp666]

...“While it only flattened unpopulated forest, had it exploded over London it could have devastated everything within the M25,”

And I expect quite a lot outside the M25 too. Or maybe not. Maybe someone could work out if, here in Hatfield, I would be okay and probably a lot nearer the coast?

 

[rynner2]

While we wait for the next asteroid impact, here's something to think about in the meantime:

Don't worry, it's only a falling five-tonne space satellite
Nasa says chances of its dead 20-year-old satellite, due to fall to Earth later this month, hitting anyone are 3,200-1
Associated Press
guardian.co.uk, Thursday 8 September 2011 19.06 BST

Nasa says one of its dead satellites will soon fall to Earth but there is very little chance that it will hit anyone.

The space agency does not know when or where its 20-year-old satellite will drop. It will probably be in late September but could fall in October. And it could land anywhere south of Juneau, Alaska, and north of the tip of South America. Nasa says there is only a one in 3,200 chance of satellite parts hitting someone.

Experts say not to worry. In the more than 50 years of the space age, no one has ever been hurt by falling space debris. The 5.4-tonne satellite was used to monitor the atmosphere. Most of it will burn up during re-entry. Only about 550kg of metal should survive.

http://www.guardian.co.uk/science/2011/ ... pace-earth

 

[rynner2]

Reminder - a week to go?

Nasa satellite UARS nearing Earth 'could land anywhere'

A five tonne, 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.

Hurtling at 5m (8km) per second, 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.

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 was fined a $400 clean-up fee by the Australian government. 8)

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.

http://www.bbc.co.uk/news/world-us-canada-14952001

 

[rynner2]

Nasa satellite to fall to earth on Friday, showering debris
A defunct NASA science satellite is expected to fall back to Earth on Friday, showering debris somewhere on the planet although scientists cannot predict exactly where, officials said.
12:13AM BST 20 Sep 2011

...

As of Sunday, UARS was in a 133-mile by 149-mile (215-km by 240-km) high orbit around Earth. Re-entry is expected some time on Friday, although it could happen as early as Thursday or as late as Saturday.

The agency is posting updates on its website, http://www.nasa.gov/uars

http://www.telegraph.co.uk/science/spac ... ebris.html

 

[rynner2]

Six-tonne satellite on collision course with Earth
By Marcia Dunn
Thursday, 22 September 2011

A six-tonne satellite is expected to splash down on Earth on Friday.
Experts say Friday remains the most likely day that the NASA research satellite will come crashing down through the atmosphere.
An estimated 26 pieces, weighing 544kg, are expected to survive.

NASA is anticipating a splashdown rather than a landing, as some three-quarters of the world is covered by water. The Aerospace Corporation in California, in fact, predicts that re-entry will occur over the Pacific late Friday afternoon, give or take 14 hours.

http://www.independent.co.uk/news/scien ... 58883.html

But since a low-orbit satellite orbits in about 90 minutes, they're not really telling us very much!
Be safe, wear a crash helmet! :shock:

 

[rynner2]

UARS satellite return expected later
By Jonathan Amos, Science correspondent, BBC News

US officials now say the fall to Earth of Nasa's six-tonne UARS satellite could occur early on Saturday (GMT).
Estimates of where debris might fall will be narrowed hours before impact.
And a UK team studying the trajectory says the most likely time for re-entry could be after 23:00 GMT Friday, and as late as 03:00 GMT on Saturday.

Most of the decommissioned and now unpowered spacecraft should simply burn up, but modelling work suggests perhaps 500kg could survive to the surface.
UARS is the largest American space agency satellite to return uncontrolled into the atmosphere in about 30 years.

As of 15:30 GMT on Friday, the satellite was orbiting at an altitude between 160km and 170km (100 miles by 105 miles).
If the estimates for its re-entry are correct, it means the spacecraft will not come in over North America.
"The spacecraft orbits the Earth in 90 minutes, so even if we're off by a few minutes in the prediction - that's thousands of kilometres down range," said Mark Matney, an orbital debris scientist from Nasa's Johnson Space Center.
"We'll be able to know generally a few hours before, but we'll only get a final report after it re-enters. Even then, we won't know where the pieces fall because they'll be scattered over a 500-mile path," he told BBC News.

etc...

http://www.bbc.co.uk/news/science-environment-15034073

 

[GNC]

Have NASA said where this has landed yet? Or even that it's landed at all? A lot of people are wondering where it's gone (maybe NASA are too).

 

[Timble2]

There was a pretty high chance of it falling in the ocean. If it didn't NASA will be able to find where it came down by the location of the people who are selling bits on eBay.

 

[rynner2]

Latest from NASA:

Update #16
Sat, 24 Sep 2011 04:37:25 PM UTC+0100

NASA’s decommissioned Upper Atmosphere Research Satellite fell back to Earth between 11:23 p.m. EDT Friday, Sept. 23 and 1:09 a.m. EDT Sept. 24. The Joint Space Operations Center at Vandenberg Air Force Base in California said the satellite entered the atmosphere over the North Pacific Ocean, off the west coast of the United States. The precise re-entry time and location of any debris impacts are still being determined. NASA is not aware of any reports of injury or property damage.

This is your source for official information on the re-entry of UARS. All information posted here has been verified with a government agency or law enforcement.

NASA will conduct a media telecon at 2 p.m. ET to discuss the re-entry. The telecon will be streamed live at www.nasa.gov/newsaudio

But that time has now passed...

I'd have thought they could have tracked it better.

Other reports have some debris in Western Canada.

 

[Cultjunky]

There was a pretty high chance of it falling in the ocean. If it didn't NASA will be able to find where it came down by the location of the people who are selling bits on eBay.

I caught a news report regarding this yesterday on the Beeb. The reporter emphasised the fact that as it was the property of the US government, no bits could be sold on Ebay. 8)

 

[rynner2]

There was a pretty high chance of it falling in the ocean. If it didn't NASA will be able to find where it came down by the location of the people who are selling bits on eBay.

I caught a news report regarding this yesterday on the Beeb. The reporter emphasised the fact that as it was the property of the US government, no bits could be sold on Ebay. 8)

I'd like to see that tested in court!

There are Maritime salvage laws, but does Space have something equivalent?

 

[rynner2]

Nasa's UARS satellite fell far from major landmass
By Jonathan Amos, Science correspondent, BBC News

Nasa's UARS spacecraft fell to Earth to the north-east of the Vanuatu archipelago.
Orbital tracking experts have now established that the defunct satellite entered the atmosphere over the Pacific Ocean at 14.1 degrees South latitude and 170.2 degrees West longitude.
Any debris that survived Saturday's fiery descent would have plunged into open water, the US space agency says.
The exact time the six-tonne craft engaged the atmosphere is now given as 0401 GMT.

The Upper Atmosphere Research Satellite (UARS) was the largest American space agency research platform to return uncontrolled from orbit in about 30 years.
Its fall from the sky generated huge interest worldwide at the weekend, with the possibility that its destruction would produce a spectacular fireball in the sky for anyone close enough to see it.

The return was monitored by the Joint Space Operations Center (JSPOC) at Vandenberg Air Force Base in California.
On Saturday, JSPOC's best estimate for the timing of the re-entry was 0416 GMT. Post-fall analysis has now brought that forward by 15 minutes, meaning the event occurred much further from the west coast of North America than was originally thought.

Modelling work had indicated perhaps 500kg of mangled metal could have survived to the surface, spread over a path some 800km long. If the latest analysis is correct, it seems certain all of that debris would have gone into the ocean.

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.

Tracking stations will typically witness the uncontrolled return of at least one piece of space debris every day; and on average, one intact defunct spacecraft or old rocket body will come back into the atmosphere every week.
Something the size of UARS is seen perhaps once a year. Much larger objects such as space station cargo ships return from orbit several times a year, but they are equipped with thrusters capable of guiding their dive into a remote part of the Southern Ocean.

http://www.bbc.co.uk/news/science-environment-15084746

I feel such a fool now, walking around all day wearing a crash helmet...

 

[Jerry_B]

An interesting image: Asteroids Near Earth...

 

[Mythopoeika]

:shock:

 

[rynner2]

Here comes another satellite...

Satellite expected to hit Earth
Friday, 21 October 2011

German scientists say they expect pieces of a defunct satellite hurtling toward the atmosphere to hit Earth this weekend.
Andreas Schuetz, a spokesman for the German Aerospace Center, said the best estimate is still that the ROSAT scientific research satellite will impact sometime Saturday or Sunday.

The center says parts of the minivan-sized satellite will burn up during re-entry but up to 30 fragments weighing a total of 1.87 tons (1.7 metric tons) could crash into the Earth with a speed of up to 280 mph (450 kph).

The satellite orbits the Earth every 90 minutes and scientists can only say that it could hit Earth anywhere along its path, between 53-degrees north and 53-degrees south — a vast swath of territory that includes much of the planet outside the poles.

http://www.independent.co.uk/news/scien ... 74062.html

Better get the crash-hat out again...

 

[rynner2]

More on ROSAT here:
http://www.bbc.co.uk/news/science-environment-15402157

Just as for Nasa's UARS satellite, which plunged into the atmosphere in September, no-one can say precisely when and where Rosat will come in.

What makes the redundant German craft's return interesting is that much more debris this time is likely to survive all the way to the Earth's surface.
Experts calculate that perhaps as much as 1.6 tonnes of wreckage - more than half the spacecraft's launch mass - could ride out the destructive forces of re-entry and hit the planet.

In the case of UARS, the probable mass of surviving material was put at only half a tonne (out of a launch mass of more than six tonnes).
The difference is due to some more robust components on the German space agency (DLR) satellite.

Rosat was an X-ray telescope mission and had a mirror system made of a reinforced carbon composite material. This mirror complex and its support structure are expected to form the largest single fragment in what could be a shower of some 30 pieces of debris to make it through to the surface.

But again, as was the case with UARS, any Rosat wreckage is strongly tipped to hit the ocean, given that so much of the Earth's surface is covered by water.

...

Tracking stations will typically witness the uncontrolled return of at least one piece of space debris every day; and on average, one intact defunct spacecraft or old rocket body will come back into the atmosphere every week.

Something the size of Nasa's UARS satellite is seen to enter uncontrolled perhaps once a year.
Much larger objects such as space station cargo ships return from orbit several times a year, but they are equipped with thrusters capable of guiding their dive into a remote part of the Southern Ocean.

 

[rynner2]

German satellite crashed in southeast Asia
A defunct German research satellite crashed into the Earth somewhere in southeast Asia on Sunday, a US scientist said – but no one is still quite sure where.
11:23PM BST 23 Oct 2011

Most parts of the car-sized ROSAT research satellite were expected to burn up as they hit the atmosphere at speeds up to 280mph, but up to 30 fragments weighing a total of 1.87 tons, could have crashed, the German Aerospace Center said.

Jonathan McDowell of the Harvard-Smithsonian Centre for Astrophysics in Cambridge, Massachusetts, said the satellite appears to have gone down over southeast Asia. He said two Chinese cities with millions of inhabitants each, Chongqing and Chengdu, had been in the satellite's projected path during its re-entry time.
"But if it had come down over a populated area there probably would be reports by now," the astrophysicist, who tracks man-made space objects, said.

Calculations based on US military data indicate that satellite debris must have crashed somewhere east of Sri Lanka over the Indian Ocean, or over the Andaman Sea off the coast of Burma, or further inland in Burma or as far inland as China, he said.

The satellite entered the atmosphere between 0245 BST to 0315 BST and would have taken 15 minutes or less to hit the ground, the German Aerospace Centre said. Hours before the re-entry, the centre said the satellite was not expected to land in Europe, Africa or Australia.
There were no immediate reports from Asian governments or space agencies about the fallen satellite.

The satellite used to circle the planet in about 90 minutes, and it may have travelled several thousand miles during its re-entry, rendering exact predictions of where it crashed difficult.
German space agency spokesman Andreas Schuetz said a falling satellite also can change its flight pattern or even its direction once it sinks to within 90 miles above the Earth.

...

http://www.telegraph.co.uk/science/spac ... -Asia.html

 

[rynner2]

Asteroid Yu55 on course for close encounter with Earth
Astronomers hope to learn more about the asteroid's chemical composition when it passes inside the moon's orbit
Ian Sample, science correspondent guardian.co.uk, Sunday 6 November 2011 18.34 GMT

Astronomers around the world have readied their telescopes to catch a glimpse of a speeding ball of rock that will hurtle past the Earth on Tuesday night.
Scientists say the asteroid, which is about a quarter of a mile wide, will pass inside the moon's orbit and come within 198,000 miles (319,000km) of Earth at 23.28GMT. This is the closest a tracked object this size has come to the planet.

Nasa calculates the 400-metre (1,312ft) wide asteroid, known as 2005 YU55, has roughly a one in 10m chance of hitting Earth in the next century. Were it to strike, the collision would unleash the equivalent of several thousand megatonnes of TNT.

Even with clear skies the asteroid will not be visible to the naked eye, but professional and amateur astronomers will turn their telescopes on the rock to learn about its surface and chemical composition.

Because the asteroid is approaching from the sun's direction, there will be too much glare to observe the rock with optical or infra-red telescopes until the day of closest approach.

"Most of the asteroids we see are so far out that we only get a small amount of information from the light reflected off them," said Kevin Yates, at the Near Earth Objects Information Centre at the National Space Centre in Leicester. "Because this one is coming in so close we'll be able to get more radar observations, which will give us a detailed surface map, and be able to get more of a chemical signature on the minerals it's made up from."

The Arecibo telescope in Puerto Rico last year revealed the asteroid to be remarkably spherical while its surface is very dark, suggesting it is rich in carbon.

Observatories at Nasa's Goldstone Deep Space Communications Complex, in the Mojave desert of California, and at Green Bank, West Virginia, will join forces with Arecibo to watch the asteroid pass this week. Operators have called on scores of amateur astronomers to help with observations, using 10-12in telescopes with special filters.

A similar flyby will not happen until 2028 when asteroid 2001 WN5 swings past the Earth at a distance of 143,000 miles.

"We are finding a whole variety of unusual shapes out there and this asteroid is particularly spherical. If we can characterise them more and understand them more, then if we ever do have a threat from one, understanding the structure and the materials they're made from would better equip us to divert one. It may be that there are materials on board that could be used as a fuel to drive an engine that would push it into a different orbit over 20 years," Yates added.

The asteroid is among the most ancient objects in the solar system, having formed from the dust and gas disc that surrounded the sun 4.5bn years ago. Though born in the asteroid belt between Mars and Jupiter the rock was pulled by gravity or nudged by collisions on to its new orbital course.

"These are the building blocks left over from when the solar system formed and this particular carbonaceous asteroid is one of the most primitive types," Yates said. "Understanding its chemical composition is like looking into the ingredients book to see how it was put together."

The asteroid will pass close to Venus in 2029, which will disturb its orbit to mean its next passage past Earth, in 2041, could be between 198,000 miles and nearly 30m miles from the planet. The close encounter after that will be with Mars in 2072.

http://www.guardian.co.uk/science/2011/ ... lose-earth

 

[sirwiggum]

I was reading the follow-up on BBC News, and one sentence caught my eye

Giant asteroid passes near Earth

http://www.bbc.co.uk/news/science-environment-15572634

An asteroid that is 400m (1,300ft) wide has passed by Earth, much to the delight of astronomers.

Although invisible to the naked eye, scientists said they spotted strange structures on its surface as it spun past at 30,000mph (48 280.32 km/h).

Asteroid 2005 YU55's was the closest an asteroid has been to Earth in 200 years, according to Nasa.

It is also the largest space rock fly-by Earth has seen since 1976; the next visit by a large asteroid will be 2028.

The aircraft-carrier-sized asteroid was darkly coloured in visible wavelengths and nearly spherical, lazily spinning about once every 20 hours as it raced through our neighbourhood of the Solar System.

Ron Dantowitz, the director of the Clay Centre Observatory in Massachusetts, followed the asteroid through a telescope.

"We're tracking the asteroid itself, so the stars are moving by in the background and the asteroid is actually streaking by at about 30,000mph," he said.

"As we track it, it looks like the stars are moving in the background and the asteroid is locked on in the centre view.

"It's not so much that we can see it tumbling like a rock in space, we're examining it for the brightness and colour."
'Closest approach'

Nasa said it had been no closer than 201,700 miles (324,600km), as measured from the centre of the Earth. The rock reached its closest point to Earth at 23:28 GMT on Tuesday.
Continue reading the main story
“Start Quote

2005 YU55 cannot hit Earth, at least over the interval that we can compute the motion reliably - which extends for several hundred years”

Lance Benner Nasa

It will now trace a path across the whole sky through to Thursday.

The asteroid often travels in the vicinity of Earth, Mars and Venus, but Nasa said this fly-by had been the closest the asteroid had come to Earth in at least 200 years.

"This is the closest approach by an asteroid that large that we've ever known about in advance," said Lance Benner of Nasa's Jet Propulsion Laboratory.

But he stressed that there had been no chance that the pass would be anything other than a close encounter.

"2005 YU55 cannot hit Earth, at least over the interval that we can compute the motion reliably - which extends for several hundred years," he said.

Instead, the pass gave astronomers a rare opportunity to study the asteroid in detail.

In particular, two radio telescopes - the Goldstone Observatory in California, US and the Arecibo Observatory in Puerto Rico, US - tracked radio echoes off it in a bid to understand better what it is made of and how it is shaped.

The precise details of the asteroid's path will also help scientists to predict where it will go much further into the future.

Earth has several regular visitors like 2005 YU55 - most famously the Apophis asteroid. Apophis has in the past been claimed as a possible future impactor when it returns to our neighbourhood in 2029 and again in 2036.

There is, according to the latest calculations, no danger from Apophis either. However, it will pass much closer to Earth on 13 April 2029 - at a distance of 18,300 miles (29,500km).

I could not find an elaboration on the 'strange structures' quote.

My mind immediately went into imagination overdrive, recalling stories I'd read before about supposed Lunar / Mars artificial structures.

Rationally, they're probably artifacts from impacts in space / 'natural' formations from it's source (Imagine if a telescope/space probe saw the likes of the Giants Causeway on a foreign object/planet).

 

[amester]

Is it a Monolith?

 

[sirwiggum]

Thats along the lines I was thinking of!

Something like Rama!

Though the logical explanation is probably craters similar to the large crater anomaly on Phobos.

 

[Mythopoeika]

Thats along the lines I was thinking of!

Something like Rama!

Though the logical explanation is probably craters similar to the large crater anomaly on Phobos.

I'm surprised we didn't take the opportunity to 'rendezvous' with it.

 

[rynner2]

Crash helmets on again:

Catastrophe looms as toxic 13-tonne Mars probe falls to Earth
Steve Connor Saturday 17 December 2011

The heaviest interplanetary spacecraft ever launched is about to become one of the most dangerous man-made objects to fall from space when it crashes to the ground early in the new year.

The Russian Phobos-Ground probe was destined to land on a moon of Mars but problems soon after launch in November meant that it was stuck in an unstable, low-Earth orbit.

Russia's space agency, Roscosmos, said yesterday that the lorry-sized probe weighing 13.2 tonnes and laden with 11 tonnes of toxic rocket fuel and 10kg of radioactive cobalt-57 will fall to Earth between 6 and 19 January.
The agency told the Associated Press that it will not be possible to calculate the precise crash site until a few days before the £120m probe re-enters the Earth's atmosphere.

However, it insisted that much of the dangerous material will be incinerated during re-entry and any remaining fragments will pose little danger to people on the ground.

Phobos-Ground, which was designed to bring back rock samples from Phobos, one of two Martian moons, was launched from the Baikonur cosmodrome in Kazakhstan.
It separated from its booster rocket 11 minutes after launch but its engines subsequently failed to fire it out of Earth's orbit.

Roscosmos said that between 20 and 30 fragments of the probe are expected to fall to Earth somewhere between 51.4 degrees north of the Equator and 51.4 degrees south, which covers much of the most densely populated areas on Earth.

Some experts said soon after the probe failed to leave the Earth's orbit that the on-board fuel of nitrogen tetroxide and hydrazine could freeze solid before re-entry, which may make it less liable to burning up during re-entry.

http://www.independent.co.uk/news/scien ... 78357.html

 

[Mythopoeika]

'Phobos-Ground'? Wasn't it originally called 'Phobos-Grunt'?

 

[rynner2]

'Phobos-Ground'? Wasn't it originally called 'Phobos-Grunt'?

Apparently Grunt is the Russian for Ground.

 

[rynner2]

It's still coming down...

Parts of stricken Mars probe Phobos-Grunt may strike Earth
Russian space agency Roscosmos says 200kg fragments may survive re-entry but expects toxic fuel to vaporise
Ian Sample, science correspondent
guardian.co.uk, Sunday 1 January 2012 18.22 GMT

A Russian spacecraft that became stranded in orbit on the way to Mars last year is expected to fall back to Earth next week.

The 13.5 tonne Phobos-Grunt has been circling Earth since November when rocket boosters failed to ignite and send the spaceship on its journey to the Martian moon of Phobos. The spacecraft suffered a computer malfunction after launch and when repeated attempts to contact the rocket failed, the Russian space agency, Roscosmos, had to abandon the mission.

Officials at Roscosmos admitted that 20 to 30 fragments of Phobos-Grunt, weighing a total of 200kg, might hit the Earth. Among the most likely parts to survive are the cone-shaped sample return capsule that is protected with a heat shield. The capsule was designed to survive a crash landing without a parachute.
Any components that are not vaporised during re-entry are likely to fall into the ocean or land in sparsely populated areas.

The spacecraft, the largest planetary rocket ever built by Russia, was designed to return rock samples from Phobos, the first time material would have been brought back from the moon of another planet. The rocket was to deliver a Chinese Mars orbiter and carried containers of bacteria to test their survival in space.

Space agencies tracking the rocket from radar stations around the world have stepped up their monitoring to once every day. As the spacecraft nears re-entry, officials will track its descent hour by hour to improve predictions of where any debris might land.

Heiner Klinkrad, head of the space debris office at the European Space Agency, said Phobos-Grunt was due to re-enter the Earth's atmosphere around 14 January, though the date could be several days earlier or later.

Tracking Phobos-Grunt will allow space agencies to work out when the rocket will begin re-entry, but does little to help predict where debris might land. The spacecraft is travelling so fast it completes an orbit of Earth every 90 minutes, so even a small uncertainty in its trajectory or how it breaks up can make a difference of hundreds of miles on the Earth's surface.
"In general, we would know fairly well on what continent the debris would land, but when it comes to identifying the country, there can be problems," said Klinkrad.

Risk assessments by the Russian, German and US space agencies have focused on whether the highly toxic fuel, known as unsymmetrical dimethylhydrazine (UDMH) and dinitrogen tetroxide (DTO), could contaminate the debris site.
"All came up with same conclusion that Phobos-Grunt will not be a very high risk re-entry object," Klinkrad said. "It's a very delicate structure and it will break up fairly quickly. Largely it consists of propellant to take it to Mars, which is still left in the tank, and none of that is expected to survive re-entry."
According to the agencies' reports, the spacecraft's aluminium fuel tanks are likely to rupture and leak at an altitude of about 100km and burn up, perhaps completely, on re-entry. The fuel will either ignite or be dispersed in the atmosphere.

One experiment on the spacecraft contains 10 micrograms of radioactive cobalt, but Klinkrad said the tiny amount of material was not a concern and was expected to burn up as Phobos-Grunt fell to Earth.

http://www.guardian.co.uk/science/2012/ ... ace-russia

 

[rynner2]

Video tracks stricken Mars probe

The failed Russian Mars probe Phobos-Grunt has been pictured moving across the sky by the Paris-based amateur astronomer Thierry Legault.
The spacecraft is seen moving left to right in the video. The bulbous shape of its fuel tanks and its outstretched solar panels are easily discernable.

...

Dr Krag and colleagues at Esoc, like a number of teams around the world, are now busy modelling the decay in Phobo-Grunt's orbit.

Esa is a member of the Inter-Agency Space Debris Coordination Committee (IADC), a forum for the worldwide coordination of activities related to the issues of man-made and natural debris in space.
The other teams working through the IADC will all be using slightly different assumptions in their models and, as a consequence, will all arrive at slightly different timings for the period of impact. A host of amateur groups will be engaged in a similar endeavour.
The hope is that by comparing the different pre-fall projections with the observed re-entry data after the event, future modelling efforts can be finessed.

At the moment, the projections are very uncertain. They are clustering around Sunday 15 January (GMT) and Monday 16.

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http://www.bbc.co.uk/news/science-environment-16444063