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

    California Republicans Mull Choices in Presidential Race

    Ted Cruz tells state's Republican Convention delegates campaign will be 'battle on the ground, district by district by district,' ahead of June 7 primary

    Video Kurdish Football Team Helps War-Torn City Cope

    With conflict still raging across much of Turkey’s predominantly Kurdish southeast, many Kurds are trying to escape turmoil by focusing on success of football team Amedspor

    South African Company Designs Unique Solar Cooker

    Two-man team of solar power technologists introduces Sol4, hot plate that heats up so fast it’s like cooking with gas or electricity

    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.
    Turkish Kurd Islamist Rally Stokes Tensionsi
    X
    April 29, 2016 12:28 AM
    In a sign of the rising power of Islamists in Turkey, more than 100,000 people recently gathered in Diyarbakir, the main city in Turkey’s predominantly Kurdish southeast, to mark the birthday of the Prophet Muhammad. The gathering highlighted tensions with the pro-secular Kurdish nationalist movement. Dorian Jones reports from Diyarbakir.
    Video

    Video Turkish Kurd Islamist Rally Stokes Tensions

    In a sign of the rising power of Islamists in Turkey, more than 100,000 people recently gathered in Diyarbakir, the main city in Turkey’s predominantly Kurdish southeast, to mark the birthday of the Prophet Muhammad. The gathering highlighted tensions with the pro-secular Kurdish nationalist movement. Dorian Jones reports from Diyarbakir.
    Video

    Video Pakistani School Helps Slum Kids

    Master Mohammad Ayub runs a makeshift school in a public park in Islamabad. Thousands of poor children have benefited from his services over the years, but, as VOA's Ayesha Tanzeem reports, roughly 25 million school-age youths don't get an education in Pakistan.
    Video

    Video Florida’s Weeki Wachee ‘Mermaids’ Make a Splash

    Since 1947, ‘mermaids’ have fascinated tourists at central Florida’s Weeki Wachee Springs State Park with their fluid movements and synchronized ballet. Performing underwater has its challenges, including cold temperatures and a steady current, as VOA’s Lin Yang and Joseph Mok report.
    Video

    Video Somali, African Union Forces Face Resurgent Al-Shabab

    The Islamic State terror group claimed its first attack in Somalia earlier this week, though the claim has not been verified by forces on the ground. Meanwhile, al-Shabab militants have stepped up their attacks as Somalia prepares for elections later this year. Henry Ridgwell reports there are growing frustrations among Somalia’s Western backers over the country’s slow progress in forming its own armed forces to establish security after 25 years of chaos.
    Video

    Video Bangladesh Targeted Killings Spark Wave of Fear

    People in Bangladesh’s capital are expressing deep concern over the brutal attacks that have killed secular blogger, and most recently a gay rights activist and an employee of the U.S. embassy. Xulhaz Mannan, an embassy protocol officer and the editor of the country’s only gay and transgender magazine Roopban; and his friend Mehboob Rabbi Tanoy, a gay rights activist, were hacked to death by five attackers in Mannan’s Dhaka home earlier this month.
    Video

    Video Documentary Tells Tale of Chernobyl Returnees

    Ukraine this week is marking the 30th anniversary of the world's worst nuclear accident, at the Chernobyl nuclear power plant. Soviet officials at first said little about the accident, but later evacuated a 2,600-square-kilometer "exclusion zone." Some people, though, came back. American directors Holly Morris and Anne Bogart created a documentary about this faithful and brave community. VOA's Tetiana Kharchenko reports from New York on "The Babushkas of Chernobyl." Carol Pearson narrates.
    Video

    Video Nigerians Feel Bite of Buhari Economic Policy

    Despite the global drop in the price of oil, Nigerian President Muhammadu Buhari has refused to allow the country's currency to devalue, leading to a shortage of foreign exchange. Chris Stein reports from Lagos businessmen and consumers are feeling the impact as the country deals with a severe fuel shortage.
    Video

    Video  Return to the Wild

    There’s a growing trend in the United States to let old or underused golf courses revert back to nature. But as Erika Celeste reports from one parcel in Grafton, Ohio, converting 39 hectares of land back to green space is a lot more complicated than just not mowing the fairway.
    Video

    Video West Urges Unity in Libya as Migrant Numbers Soar

    The Italian government says a NATO-led mission aimed at stemming the flow of migrants from Libya to Europe could be up and running by July. There are concerns that the number of migrants could soar as the route through Greece and the Balkans remains blocked. Western powers say the political chaos in Libya is being exploited by people smugglers — and they are pressuring rival groups to come together under the new unity government. VOA's Henry Ridgwell reports.
    Video

    Video Russia’s TV Rain Swims Against Tide in Sea of Kremlin Propaganda

    Russia’s media freedoms have been gradually eroded under President Vladimir Putin as his government has increased state ownership, influence, and restrictions on critical reporting. Television, where most Russians get their news, has been the main target and is now almost completely state controlled. But in the Russian capital, TV Rain stands out as an island in a sea of Kremlin propaganda.

    Special Report

    Adrift The Invisible African Diaspora