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

Conflicts Engulf Christians in Mideast

Research finds an increase in faith-based hostilities, and Christians are facing persecution in a growing number of countries in the region More

Chinese Americans: Don’t Call Us 'Model Minority'

Label points to collective achievement, but some say it triggers resentment, unrealistic expectations More

Iran Bolsters Phone, Internet Surveillance

Does increased monitoring suggest the government is nervous? 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.
West Africa Ebola Vaccine Trials Possible by Early 2015i
X
Carol Pearson
August 30, 2014 7:14 PM
A U.S. health agency is speeding up clinical trials of a possible vaccine against the deadly Ebola virus that so far has killed more than 1,500 people in West Africa. If successful, the next step would be a larger trial in countries where the outbreak is occurring. VOA's Carol Pearson has more.
Video

Video West Africa Ebola Vaccine Trials Possible by Early 2015

A U.S. health agency is speeding up clinical trials of a possible vaccine against the deadly Ebola virus that so far has killed more than 1,500 people in West Africa. If successful, the next step would be a larger trial in countries where the outbreak is occurring. VOA's Carol Pearson has more.
Video

Video Survivors Commemorate 70th Anniversary of Nazi Liquidation of Polish Ghetto

When the Nazi army moved into the Polish city of Lodz in 1939, it marked the beginning of a long nightmare for the Jewish community that once made up one third of the population. Roughly 200,000 people were forced into the Lodz Ghetto. Less than 7,000 survived. As VOA’s Kane Farabaugh reports, some survivors gathered in Chicago on the 70th anniversary of the liquidation of the Lodz Ghetto to remember those who suffered at the hands of the Nazi regime.
Video

Video Cost to Raise Child in US Continues to Rise

The cost of raising a child in the United States continues to rise. In its latest annual report, the U.S. Department of Agriculture says middle income families with a child born in 2013 can expect to spend more than $240,000 before that child turns 18. And sending that child to college more than doubles that amount. VOA’s Deborah Block visited with a couple with one child in Alexandria, Virginia, to learn if the report reflects their lifestyle.
Video

Video Chaotic Afghan Vote Recount Threatens Nation’s Future

Afghanistan’s troubled presidential election continues to be rocked by turmoil as an audit of the ballots drags on. The U.N. says the recount will not be completed before September 10. Observers say repeated disputes and delays are threatening the orderly transfer of power and could have dangerous consequences. VOA correspondent Meredith Buel reports.
Video

Video Ukraine Battles Pro-Russia Rebel Assault

After NATO concluded an emergency meeting to discuss the crisis in eastern Ukraine, the country is struggling to contain heavy fighting near the strategic port of Mariupol, on the Azov Sea. Separatist rebels are trying to capture the city, allegedly with Russian military help, and Ukraine's defense forces are digging in. VOA's Daniel Schearf spoke with analysts about what lies ahead for Ukraine.
Video

Video Growing Business Offers Paint with a Twist of Wine

Two New Orleans area women started a small business seven years ago with one thing in mind: to help their neighbors relieve the stress of coping with a hurricane's aftermath. Today their business, which pairs painting and a little bit of wine, has become one of the fastest growing franchises across the U.S. VOA’s June Soh met the entrepreneurs at their newest franchise location in the Washington suburbs.
Video

Video Ebola Vaccine Trials To Begin Next Week

The National Institutes of Health says it is launching early stage trials of a vaccine to prevent the Ebola virus, which has infected or killed thousands of people across West Africa. The World Health Organization says Ebola could infect more than 20,000 people across the region by the time the outbreak is over. The epidemic has health experts and governments scrambling to prevent more people from becoming infected. Zlatica Hoke has more.
Video

Video Asian Bacteria Threatens Florida Orange Trees

Florida's citrus fruit industry is facing a serious threat from a bacteria carried by the Asian insect called psyllid. The widespread infestation again highlights the danger of transferring non-native species to American soil. VOA’s George Putic reports.
Video

Video Aging Will Reduce Economic Growth Worldwide in Coming Decades

The world is getting older, fast. And as more people retire each year, fewer working-age people will be there to replace them. Bond rating agency Moody’s says that will lead to a decline in household savings; reducing global investments - which in turn, will lead to slower economic growth around the world. But experts say it’s not too late to mitigate the economic impact of the world’s aging populations. Mil Arcega has more.
Video

Video Is West Doing Enough to Tackle Islamic State?

U.S. President Barack Obama has ruled out sending ground troops to Iraq to fight militants of the so-called Islamic State, or ISIS, despite officials in Washington describing the extremist group as the biggest threat the United States has faced in years. Henry Ridgwell reports from London on the growing uncertainty over whether the West’s response to ISIS will be enough to defeat the terrorist threat.
Video

Video Coalition to Fight Islamic State Could Reward Assad

The United States along with European and Mideast allies are considering a broader assault against Islamic State fighters who have spread from Syria into Iraq and risk further destabilizing an already troubled region. But as VOA State Department Correspondent Scott Stearns reports, confronting those militants could end up helping the embattled Syrian President Bashar al-Assad.
Video

Video Made in America Socks Get Toehold in Online Fashion Market

Three young entrepreneurs are hoping to revolutionize the high-end sock industry by introducing all-American creations of their own. And they’re doing most of it the old-fashioned way. VOA’s Julie Taboh recently caught up with them to learn what goes into making their one-of-a-kind socks.
Video

Video Americans, Ex-Pats Send Relief Supplies to West Africa

Health organizations from around the world are sending supplies and specialists to the West African countries that are dealing with the worst Ebola outbreak in history. On a smaller scale, ordinary Americans and African expatriates living in the United States are doing the same. VOA's Carol Pearson reports.

AppleAndroid