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

    Egypt Orders Trial for Journalists Charged With Harboring Reporters

    Order targets journalists' union chief Yehia Qalash, Khaled al-Balshy and Gamal Abdel Rahim for allegedly spreading false news, harboring fugitive colleagues

    Nigerian Oil Production Falls as Militant Attacks Take Toll

    Country no longer Africa's petroleum king due to renewed militancy in its oil-producing region

    Video Tunisia’s Ennahda Party Begins a New Political Chapter

    Party now moves to separate its political and religious activities; change described by party members as pragmatic response to political and economic challenges facing Tunisia today

    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.
    New Chapter for Tunisia's Ennahdai
    X
    Lisa Schlein
    May 31, 2016 1:56 PM
    Tunisia’s moderate Islamist Ennahda party says it is separating its religious and political activities in a broader bid to mark its so-called Muslim Democratic identity. The move appears to open a new chapter for a party that bounced back from the political wilderness of Tunisia’s pre-revolution days to become a key player in the North African country, and a member of the current coalition government. From Tunis, Lisa Bryant takes a look at how Tunisians are viewing its latest step.
    Video

    Video New Chapter for Tunisia's Ennahda

    Tunisia’s moderate Islamist Ennahda party says it is separating its religious and political activities in a broader bid to mark its so-called Muslim Democratic identity. The move appears to open a new chapter for a party that bounced back from the political wilderness of Tunisia’s pre-revolution days to become a key player in the North African country, and a member of the current coalition government. From Tunis, Lisa Bryant takes a look at how Tunisians are viewing its latest step.
    Video

    Video New Mobile App Allows Dutch Muslims to Rate their Imams

    If a young Dutch-Moroccan app developer has his way, Muslims in the Netherlands will soon be able to rate their imams online. Mohamed Mouman says imams rarely get feedback from their followers. He believes his app can give prayer leaders a better picture of what's happening in their communities — and can also keep young people from being radicalized. Serginho Roosblad reports from Amsterdam.
    Video

    Video Moscow Condemns NATO Plans to Beef Up Defense in Eastern Europe, Baltics

    NATO Secretary General Jens Stoltenberg said Monday an upcoming "landmark summit" will enhance the alliance's defensive and deterrent presence in eastern Europe and the Baltics. He is visiting Poland ahead of the NATO Summit in Warsaw. Zlatica Hoke reports
    Video

    Video Tech Startups Showcase Wares at Amsterdam Conference

    More than 20,000 tech enthusiasts, entrepreneurs and lovers of digital technology came together in Amsterdam recently at the Next Web Conference to discuss the latest developments in digital technology, look to the future and, of course, to connect. In recent years, there has been an explosion of so-called startup businesses that have created devices and applications that have changed the way we live; but, as Serginho Roosblad reports for VOA, there are pitfalls for such startups as well.
    Video

    Video US Military's Fallen Honored With Flags

    Memorial Day is a long weekend for most Americans. For some, it is the unofficial start of summer -- local swimming pools open and outdoor grilling season begins. But Memorial Day remains true to its origins -- a day to remember the U.S. military's fallen.
    Video

    Video Rolling Thunder Rolls Into Washington

    The Rolling Thunder caravan of motorcycles rolled into Washington Sunday, to support the U.S. military on the country's Memorial Day weekend
    Video

    Video A New Reading Program Pairs Kids with Dogs

    Dogs, it is said, are man's best friend. What some researchers have discovered is that they can also be a friend to a struggling reader. A group called Intermountain Therapy Animals trains dogs to help all kinds of kids with reading problems — from those with special needs to those for whom English is a second language. Faiza Elmasry has more on the New York chapter of R.E.A.D., or Reading Education Assistance Dogs, in this piece narrated by Faith Lapidus.
    Video

    Video Fan Base Grows for Fictional Wyoming Sheriff Longmire

    Around the world, the most enduring symbol of the U.S. is that of the cowboy. A very small percentage of Americans live in Western rural areas, and fewer still are cowboys. But the fascination with the American West is kept alive by such cultural offerings as “Longmire,” a series of books and TV episodes about a fictional Wyoming sheriff. VOA’s Greg Flakus recently spoke with Longmire’s creator, Craig Johnson, and filed this report from Houston.
    Video

    Video Chinese-Americans Heart Trump, Bucking National Trend

    A new study conducted by three Asian-American organizations shows there are three times as many Democrats as there are Republicans among Asian-American voters, and they favor Hillary Clinton over Donald Trump. But one group, called Chinese-Americans For Trump, is going against the tide and strongly supports the business tycoon. VOA’s Elizabeth Lee caught up with them at a Trump rally and reports from Anaheim, California.
    Video

    Video Reactions to Trump's Success Polarized Abroad

    What seemed impossible less than a year ago is now almost a certainty. New York real estate mogul Donald Trump has won the number of delegates needed to secure the Republican presidential nomination. The prospect has sparked as much controversy abroad as it has in the United States. Zlatica Hoke has more.
    Video

    Video F-35 Fighter Jet Draws Criticisms as Costs Mount

    America’s latest fighter plane, the F-35, has been mired in controversy. Critics cite cost, faulty design, and the attempt to use it to fill multiple roles. Even the pilot’s helmet is controversial. VOA’s Bernard Shusman reports from New York.
    Video

    Video Concerns Over Civilian Suffering as Iraqi Forces Surround Fallujah

    Thousands of residents are trapped inside the IS-held city ahead of a full scale Iraqi offensive aimed at retaking it.

    Special Report

    Adrift The Invisible African Diaspora