News / Science & Technology

Plummeting US Satellite to Hit Earth Friday

This conceptual image shows the Upper Atmosphere Research Satellite, launched on September 15, 1991, by the space shuttle Discovery.
This conceptual image shows the Upper Atmosphere Research Satellite, launched on September 15, 1991, by the space shuttle Discovery.

Multimedia

Audio

NASA launched the Upper Atmosphere Research Satellite (UARS) 20 years ago this month.  And now that bus-sized satellite is plunging toward Earth.

Mark Matney, an orbital debris scientist at NASA's Johnson Space Center in Texas, says UARS will likely reenter the atmosphere on September 23, 2011.  He says scientists will be able to narrow the time frame as it gets closer.

As far as where it will crash, Matney says UARS passes over the Earth between 57 degrees north latitude and 57 degrees south latitude.  

"Everything from Canada down to the tip of South America, and from Siberia down to the tip of Africa and Australia [could be where the satellite lands]," says Matney.  "So, it's quite a bit of land."

It is also quite a bit of ocean.  Given that more than two-thirds of the planet is covered by water, space debris usually lands with a splash.  

Still, there is the chance that UARS could land with a thud, although NASA's Matney says this week's satellite reentry is not cause for great concern.

Take Cover?

"If you talk about the probability of you getting hit, it's something like one in trillions, so actually the odds of you getting hit is quite small," Matney says.  "So, I don't think anybody needs to be unduly concerned about it."  

NASA says it has no reports of a person being injured or property being significantly damaged by reentering debris.  But there was an incident in 1997.

"There actually was a lady in Oklahoma who was hit by a piece of very light debris from a reentering satellite, but it didn't hurt her.  It was a piece of insulation.  She was out jogging, and it hit her," recalls Matney.  "That same reentry dropped two tanks over Texas."

Matney says debris reentry is a common occurrence, averaging about one piece per day, but that the pieces usually are small.  But he says this will be the first time in 30 years that a U.S. space agency satellite of this size will have crashed back to Earth.  

Most of UARS is expected to burn up in the atmosphere.

Computer Modeling

Even though officials at NASA and the Department of Defense cannot yet provide a precise landing footprint, Matney says the science of figuring out what will land is exacting.  
"We actually take time to get the original specifications, to get the different parts of the spacecraft, the material types, their shape, their mass," explains Matney.  "And we actually have computer programs that model the dynamics as it begins to heat up and break up and look at the temperatures those pieces reach and whether they reach the melting point of the metal."  

For instance, he says that because of aluminum's relatively low melting temperature, aluminum objects usually disintegrate before they reach the surface of the Earth.

NASA expects 26 "potentially hazardous" pieces of UARS to reach the ground, most of them made of titanium, stainless steel or beryllium, which have high melting points.  These pieces of debris include batteries, wheel rims and empty fuel tanks.  UARS debris is expected to range in mass from 0.6 to 158 kilograms.     

Orbital Debris Management

NASA's Orbital Debris Program works to reduce the number of large debris pieces in orbit.  One aim is to prevent pieces of space junk from colliding and breaking into smaller pieces as well as to keep active satellites and spacecraft safe.

NASA's Mark Matney says the space agency took steps in 2005 to decommission the Upper Atmosphere Research Satellite.

"With what fuel was left on board UARS, we lowered the orbit to a point that we actually shaved 20 years off its lifetime, off its orbit lifetime, to try to remove it from orbit a bit sooner," the scientist explains.

Finders Keepers?

NASA officials say people should call their local law enforcement agencies if they find parts of the satellite.  Matney cautions that although the pieces are not toxic, they might have sharp edges.  Even though it is commonly referred to as "space junk," the debris still belongs to the country that owns the craft, in this case, the United States.

You May Like

Lebanese Media Unite to Support Palestinians in Gaza

Joint newscast billed as Arab world’s first unified news bulletin in support of Hamas-controlled Gaza Strip More

Photogallery Australian PM Alleges ‘Coverup’ at MH17 Crash Site

Meanwhile, Russia's ambassador to Malaysia denies plane's black boxes were opened before they were handed over to Malaysian officials More

Despite Advances in AIDS Treatment, Stigma Lingers

Leading immunologist tells VOA that stigma is often what prevents those infected with disease from seeking treatment More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
IAEA: Iran Turns its Enriched Uranium Into Less Harmful Formi
X
July 22, 2014 10:26 AM
Iran has converted its stockpiles of enriched uranium into a less dangerous form that is more difficult to use for nuclear weapons, according to the United Nations’ Atomic Energy Agency. The move complies with an interim deal reached with Western powers on Iran's nuclear program last year, in exchange for easing of sanctions. Henry Ridgwell reports for VOA from London.
Video

Video IAEA: Iran Turns its Enriched Uranium Into Less Harmful Form

Iran has converted its stockpiles of enriched uranium into a less dangerous form that is more difficult to use for nuclear weapons, according to the United Nations’ Atomic Energy Agency. The move complies with an interim deal reached with Western powers on Iran's nuclear program last year, in exchange for easing of sanctions. Henry Ridgwell reports for VOA from London.
Video

Video Relic of Saint Draws Catholics Worried About Immigration Issue

A Roman Catholic saint who is a figure of devotion for those crossing the border into the United States is attracting believers concerned about the plight of undocumented immigrants. Mike O'Sullivan reports from Los Angeles, where a relic of Saint Toribio has drawn thousands to local churches.
Video

Video Ukraine Rebels Surrender MH17 Black Boxes

After days of negotiations, a senior separatist leader handed over two black boxes from an airliner downed over eastern Ukraine to Malaysian experts early Tuesday. While on Monday, the U.N. Security Council unanimously demanded that armed groups controlling the crash site allow safe and unrestricted access to the wreckage.
Video

Video In Cambodia, HIV Diagnosis Brings Deadly Shame

Although HIV/AIDS is now a treatable condition, a positive diagnosis is still a life altering experience. In Cambodia, people living with HIV are often disowned by friends, family and the community. This humiliation can be unbearable. We bring you one Cambodian woman’s struggle to overcome a life tragedy and her own HIV positive diagnosis.
Video

Video Nature of Space Exploration Enters New Age

Forty-five years ago this month, the first humans walked on the moon. It was during an era of the space race between the United States and the Soviet Union. World politics have changed since then and -- as Elizabeth Lee reports -- so has the nature of space exploration.
Video

Video Chicago’s Argonne Lab Developing Battery of the Future

In 2012, the U.S. Department of Energy’s Office of Science awarded a $120 million grant to a new technology center focused on battery development - headquartered at Argonne National Laboratory in suburban Chicago, Illinois. As VOA’s Kane Farabaugh reports, there scientists are making the next technological breakthroughs in energy storage.
Video

Video In NW Pakistan, Army Offensive Causes Massive Number of Displaced

Pakistan’s army offensive in North Waziristan has resulted in the large-scale displacement of the local population. VOA's Ayaz Gul reports from northwest Pakistan where authorities say around 80 percent of the estimated 1 million internally displaced persons [IDPs] have settled in Bannu district, while much of the remaining 20 percent are scattered in nearby cities.
Video

Video Kurdish Peshmerga Force Secures Kirkuk, Its Oil

The Kurdistan regional government has sent its Peshmerga troops into the adjacent province of Kirkuk to drive out insurgents, and to secure the area's rich oil fields. By doing this, the regional government has added a fourth province to the three it officially controls. The oil also provides revenue that could make an independent Kurdistan economically strong. VOA’s Jeffrey Young went out with the Peshmerga and filed this report.
Video

Video Malaysia Reeling: Second Air Disaster in Four Months

Malaysia is reeling from the second air disaster in four months involving the country’s flag carrier. Flight 340 vanished in March and despite an extensive search, no debris has been found. And on Thursday, Flight 17, likely hit by a surface-to-air missile, came apart over eastern Ukraine. The two incidents together have left more than 500 people dead. VOA Correspondent Steve Herman reports from Kuala Lumpur.

AppleAndroid