News / Science & Technology

Vague Predictions as Satellite Falls to Earth

In this image provided by NASA this is the STS-48 onboard photo of the Upper Atmosphere Research Satellite (UARS) in the grasp of the RMS (Remote Manipulator System) during deployment, from the shuttle in September 1991. The satellite is 35 feet long, 15
In this image provided by NASA this is the STS-48 onboard photo of the Upper Atmosphere Research Satellite (UARS) in the grasp of the RMS (Remote Manipulator System) during deployment, from the shuttle in September 1991. The satellite is 35 feet long, 15

At this very moment, the U.S. Department of Defense's Joint Space Operations Center is tracking thousands of pieces of space junk orbiting our Earth.  But, even as the Upper Atmosphere Research Satellite known as UARS comes hurtling back toward our planet, experts say it is hard to determine just when or where it will reenter the atmosphere.

Both the Department of Defense and NASA say it is nearly impossible to precisely predict where and when free-falling space debris will reenter the atmosphere, let alone strike or splash down on the planet.

Major Michael Duncan is the deputy chief of space situational awareness at the Defense Department's Joint Space Operations Center, known as JSpOC.  He says radars, telescopes and even assets in space provide positional data for orbital debris.  A team strings those data points together to create orbits.

"And with the right software you can take an orbit and from where it is right now you can predict where it will be, you know, one, two, three hours from now," Duncan said.

He said a five-member team at JSpOC works 24 hours a day, seven days a week, collecting updates from around the world.  

"We take in about 450,000 observations per day, and that helps us track the 22,000 space objects that we track currentl," he said.

Major Duncan said UARS is easy to track because it is about the size of a school bus.  But even with all the data points, high-tech software, and the team's accurate predictions, there are multiple variables that can have an effect on when and where debris will reenter.  

For instance, Duncan said, it is impossible to determine the way the debris will react once it reaches the atmosphere.

Like a stone skipping across a lake, space junk can bounce across the upper atmosphere.  And, Duncan said, even JSpOC's reentry predictions come with a window of plus or minus 15 minutes.

"But even that plus-or-minus 15 minutes can be a track of 5,000 miles difference," he said.

Most of UARS is expected to disintegrate as it reenters Earth's atmosphere.  

Mark Matney, an orbital debris scientist at NASA's Johnson Space Center in Texas, says a craft's orientation can even have an effect on how fast it decays.   

"It's basically an inert object, and so it can be tumbling.  Let's just say it's tumbling in such a way that it presents a large area or small area, it could speed up the rate at which it decays or slows it down," he said.

Matney says solar activity is another variable.

"Sometimes the energy from the sun goes up a little bit and causes the atmosphere to heat up and actually expand, and when that happens, it can accelerate the decay rate of the satellite.  If the solar activity were to go down, it would actually cause the atmosphere to cool and contract, and so the spacecraft would not encounter quite as much atmosphere and would slow down its decay," he said.

Major Duncan at JSpOC notes there was a solar storm last week that immediately changed the satellite's anticipated reentry by three days.

UARS was launched 20 years ago and decommissioned in 2005.  Matney says times and technologies have changed since 1991.

"Unfortunately, because UARS is an older satellite, it was not designed with the capability to do a targeted reentry, and we've done that before.  The Compton Gamma Ray Observatory is a good example where we actually were able to target its reentry over the Pacific Ocean, out in the middle of the ocean where it wouldn't hurt anybody," Matney said.

Still, NASA says the likelihood of UARS hurting anyone is slim.  The U.S. space agency says it has no confirmed reports of a person ever being injured or property being significantly damaged by falling debris.

And, given that more than two-thirds of the planet is covered by water, it is likely that UARS will land with a splash and not a thud.

You May Like

Yemen Brings US, Iran Closer to Naval Face-off

US sending two more ships to waters off coast of Yemen to take part in 'maritime security operations' More

Minorities Become Majority Across US

From 2000 to 2013, minorities became the majority in 78 counties in the United States. Here's where those demographic shifts are happening More

Japan's Maglev Train Breaks Own Speed Record

Seven-car 'magnetic levitation' train traveled at more than 600 kilometers per hour during test run Tuesday More

This forum has been closed.
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.
New Brain Mapping Techniques Could Ease Chronic Paini
Shelley Schlender
April 20, 2015 7:03 PM
Pain has a purpose - it can stop you from touching a flame or from walking on a broken leg. As an injury heals, the pain goes away. Usually. But worldwide, one out of every five people suffers from pain that lasts for months and years, leading to lost jobs, depression, and rising despair when medical interventions fail or health experts hint that a pain sufferer is making it up. From Boulder, Colorado, Shelley Schlender reports that new methods for mapping pain in the brain are providing validation for chronic pain and might someday guide better treatment.

Video New Brain Mapping Techniques Could Ease Chronic Pain

From Boulder, Colorado, Shelley Schlender reports that new methods for mapping pain in the brain are providing validation for chronic pain and might someday guide better treatment.

Video Hope, Prayer Enter Fight Against S. Africa Xenophobia

South Africa has been swept by disturbing attacks on foreign nationals. Some blame the attacks on a legacy of colonialism, while others say the economy is to blame. Whatever the cause, ordinary South Africans - and South African residents from around the world - say they're praying for the siege of violence to end. Anita Powell reports from Johannesburg.

Video Italy Rescues Migrants After Separate Deadly Capsize Incident

Italy continued its massive search and rescue operation in the Mediterranean Monday for the capsized boat off the coast of Libya that was carrying hundreds of migrants, while at the same time rescuing Syrian migrants from another vessel off the coast of Sicily. Thirteen children were among the 98 Syrian migrants whose boat originated from Turkey on the perilous journey to Europe.

Video New Test Set to Be Game Changer in Eradicating Malaria

The World Health Organization estimates 3.4 billion people are at risk of malaria, with children under the age of five and pregnant women being the most vulnerable. As World Malaria Day approaches (April 25), mortality rates are falling, and a new test -- well into the last stage of trials -- is having positive results in Kenya. Lenny Ruvaga reports for VOA from Nairobi.

Video Are Energy Needs Putting Thailand's Natural Beauty at Risk?

Thailand's appetite for more electricity has led to the construction of new dams along the Mekong River to the north and new coal plants near the country's famous beaches in the south. A proposed coal plant in a so-called "green zone" has touched off a debate. VOA's Steve Sandford reports.

Video Overwhelmed by Migrants, Italy Mulls Military Action to Stabilize Libya

Thousands more migrants have arrived on the southern shores of Italy from North Africa in the past two days. Authorities say they expect the total number of arrivals this year to far exceed previous levels, and the government has said military action in Libya might be necessary to stem the flow. VOA's Henry Ridgwell reports.

Video Putin Accuses Kyiv of ‘Cutting Off’ Eastern Ukraine

Russian President Vladimir Putin, in his annual televised call-in program, again denied there were any Russian troops fighting in Ukraine. He also said the West was trying to ‘contain’ Russia with sanctions. Henry Ridgwell reports on reactions to the president’s four-hour TV appearance.

Video Eye Contact Secures Dog's Place in Human Heart

Dogs serve in the military, work with police and assist the disabled, and have been by our side for thousands of years serving as companions and loyal friends. We love them. They love us in return. VOA’s Rosanne Skirble reports on a new study that looks at the bio-chemical bond that cements that human-canine connection.

Video Ukrainian Volunteers Search for Bodies of Missing Soldiers

As the cease-fire becomes more fragile in eastern Ukraine, a team of volunteer body collectors travels to the small village of Savur Mohyla in the what pro-Russian separatists call the Donetsk Peoples Republic - to retrieve bodies of fallen Ukrainian servicemen from rebel-held territories. Adam Bailes traveled with the team and has this report.

Video Xenophobic Violence Sweeps South Africa

South Africa, long a haven for African immigrants, has been experiencing the worst xenophobic violence in years, with at least five people killed and hundreds displaced in recent weeks. From Johannesburg, VOA’s Anita Powell brings us this report.

Video Apollo 13, NASA's 'Successful Failure,' Remembered

The Apollo 13 mission in 1970 was supposed to be NASA's third manned trip to the moon, but it became much more. On the flight's 45th anniversary, astronauts and flight directors gathered at Chicago's Adler Planetarium to talk about how the aborted mission changed manned spaceflight and continues to influence space exploration today. VOA’s Kane Farabaugh reports.

Video Badly Burned Ukrainian Boy Bravely Fights Back

A 9-year-old Ukrainian boy has returned to his native country after intensive treatment in the United States for life-threatening burns. Volodia Bubela, burned in a house fire almost a year ago, battled back at a Boston hospital, impressing doctors with his bravery. Faith Lapidus narrates this report from VOA's Tetiana Kharchenko.

Video US Maternity Leave Benefits Much Less Than Many Countries

It was almost 20 years ago that representatives of 189 countries met at a UN conference in Beijing and adopted a plan of action to achieve gender equality around the world. Now, two decades later, the University of California Los Angeles World Policy Analysis Center has issued a report examining what the Beijing Platform for Action has achieved. From Los Angeles, Elizabeth Lee has more.

Video Endangered Hawaiian Birds Get Second Chance

Of the world's nearly 9,900 bird species, 13 percent are threatened with extinction, according to BirdLife International. Among them are two Hawaiian honeycreepers - tiny birds that live in the forest canopy, and, as the name implies, survive on nectar from tropical flowers. Scientists at the San Diego Zoo report they have managed to hatch half a dozen of their chicks in captivity, raising hopes that the birds will flutter back from the brink of extinction. VOA’s George Putic reports.

Video Exhibit Brings Renaissance Master Out of the Shadows

The National Gallery of Art in Washington has raised the curtain on one of the most intriguing painters of the High Renaissance. Mostly ignored after his death in the early 1500s, Italian master Piero di Cosimo is now claiming his place alongside the best-known artists of the period. VOA’s Ardita Dunellari reports.

VOA Blogs