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Space Exploration Scenario
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Space Exploration ScenarioSpace debris threatens robotic and human space missions National Geographic News, 10 (“Space Junk Cleanup Needed, NASA Experts Warn,” p.1, October 28, NS) Scientists say the orbital debris, better known as space junk, poses an increasing threat to space activities, including robotic missions and human space flight. "This is a growing environmental problem," said Nicholas Johnson, the chief scientist and program manager for orbital debris at NASA in Houston, Texas. Johnson and his team have devised a computer model capable of simulating past and future amounts of space junk. The model predicts that even without future rocket or satellite launches, the amount of debris in low orbit around Earth will remain steady through 2055, after which it will increase. While current efforts have focused on limiting future space junk, the scientists say removing large pieces of old space junk will soon be necessary. Researchers present an overview of the space junk problem in tomorrow's issue of the journal Science. Fast-moving chunks of space debris zipped uncomfortably close to the International Space Station twice in the past week — cosmic close calls that will likely become more common over the next several years, experts predict. For one thing, after 50 years of spaceflight there is just more junk up there than there used to be, sharing space with vehicles and their human crews. And this debris can snowball — as when satellites collide, spawning thousands of new pieces of orbiting junk.
(Jeff, , editor and publisher of The Space Review, Ph.D in planetary science, The Space Review, “New Strategies for Exploration and Settlement,” http://www.thespacereview.com/article/1860/1) Spudis took issue with those who he believes have conflated exploration with science. “I think we’ve come in the last century to misunderstand the original meaning of exploration,” he said. Exploration enables science, he said, by making discoveries scientists then attempt to explain, but exploration is more than just science. “Fundamentally exploration is more important than science because it is broader and richer than science,” he said. “It includes both asset protection and wealth generation.”
(“Space Junk Threat Will Grow for Astronauts and Satellites,” April 6, NS) Recent space junk scares The recent debris flybys at the space station are just the latest encounters between crewed spacecraft and space junk. Tuesday (April 5), a piece of debris spawned by a 2007 Chinese anti-satellite test threatened the station and its three-person crew. It takes about three days' notice to move the station out of the way in a so-called "debris avoidance maneuver," NASA officials said. This piece wasn't detected in time. So astronauts prepared to take shelter in their attached Soyuz spacecraft, which can serve as a sort of lifeboat. Spaceflyers have resorted to this strategy four or five times in the station's history, Stansbery said. In the end, tracking data indicated that the debris would miss the station, so the astronauts did not have to hunker down in the Soyuz. That debris encounter came four days after another close shave. On Friday (April 1), flight controllers moved the space station clear of a piece of space junk left over from a 2009 collision between two satellites. The orbiting lab has made a dozen such debris avoidance maneuvers since 1999, five of them in the last 2 1/2 years, Stansbery said. A growing problem Pieces of space trash — which may be defunct spacecraft, abandoned launch vehicles, or fragments from satellite collisions — zip around Earth at speeds up to 17,500 mph (28,163 kph). That's so fast that even orbiting paint flecks can damage a spacecraft. And there's a lot of this stuff — much of it larger and far more dangerous than paint flecks. There are more than 20,000 pieces bigger than a softball, for example, and more than 500,000 bigger than a marble, according to NASA officials. Researchers are tracking more than 22,000 chunks of space debris in Earth orbit, but they can't watch it all. The 2007 Chinese anti-satellite test added about 3,000 pieces of space junk to the orbiting population, NASA officials said. The 2009 collision — between a defunct Russian satellite and a U.S. Iridium communications satellite — contributed another 2,000 or so. Sun is waking up These 5,000 new fragments initially started out higher up in Earth orbit than the space station, which flies around the Earth about 220 miles (354 km) up. But they're starting to come closer to the station now, because solar activity is ramping up. The sun is emerging from an extended quiescent period, and increased solar activity is causing Earth's atmosphere to expand, Stansbery said. As a result, the drag on high-altitude space junk is increasing, causing the stuff to spiral lower and lower. "When the solar cycle is ramped up, that's typically when we get a lot of this rain-down from higher altitudes," Stansbery said. Since the peak of solar activity is not expected until 2012 or 2013, astronauts aboard the station could be in for some more close calls in the near future, he added. [Video: The Sun Woke Up on Valentine's Day] Directory: 2011 2011 -> Enterprise Network Management iPost: Implementing Continuous Risk Monitoring at the Department of State 2011 -> Voices of the Old Sea Norman Lewis 2011 -> Malevil Robert Merle 2011 -> The Elephant Keeper’s Children Peter Hoeg 2011 -> January 1: Ecstasy zZz January 2: King of Anything Sara Bareillis 2011 -> Tracks, Mixes, Masters, and More!: Analyzing Preservation Priorities for Multitrack Recordings 2011 -> Department of Electrical Engineering 2011 Annual Report 2011 -> Jv packet •Mars Colonization Affirmative •Mars Colonization Negative 2011 -> Asian Pacific Mathematical Olympiad(apmo) 2011 -> Registration Form (Rev. 8-86) omb no. 1024-0018 Download 410.36 Kb. Share with your friends:
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