Hmmm! This seems like a bad idea. Have they not seen Superman 2? hehe --- On Thu, 5/29/08, Ron Baalke <[EMAIL PROTECTED]> wrote:
> From: Ron Baalke <[EMAIL PROTECTED]> > Subject: [meteorite-list] Asteroid Deflection Research Center Established at > Iowa State > To: "Meteorite Mailing List" <meteorite-list@meteoritecentral.com> > Date: Thursday, May 29, 2008, 10:52 PM > http://www.scienceblog.com/cms/seeking-answers-asteroid-deflection-16559.html > > > Seeking answers to asteroid deflection > Science Blog > May 28, 2008 > > An Asteroid Deflection Research Center (ADRC) has been > established on > the Iowa State campus to bring researchers from around the > world to > develop asteroid deflection technologies. The center was > signed into > effect in April by the Office of the Executive Vice > President and Provost. > > "In the early 1990s, scientists around the world > initiated studies to > assess and devise methods to prevent near-Earth objects > from striking > Earth," said Bong Wie, the Vance D. Coffman Chair > Professor in Aerospace > Engineering and director of the center. "However, it > is now 2008, and > there is no consensus on how to reliably deflect them in a > timely > manner," he noted. > > Wie, whose research expertise includes space vehicle > dynamics and > control, modeling and control of large space structures, > and solar sail > flight control system development and mission design, > joined the Iowa > State faculty last August. "I am very happy that > Professor Bong Wie has > joined the faculty at ISU," said Elizabeth Hoffman, > executive vice > president and provost. "His work on asteroid > deflection is exciting and > of great importance." > > The ADRC will host an International Symposium on Asteroid > Deflection > Technology in fall 2008. Scientists and engineers from > NASA, the > European Space Agency, academia, and the aerospace industry > will be > invited to the Iowa State campus to formulate a roadmap for > developing > asteroid deflection technologies. > > Despite the lack of an immediate threat from an asteroid > strike, > scientific evidence suggests the importance of researching > preventive > measures. Sixty-five million years ago, a six-mile-wide > asteroid struck > near the Yucatan Peninsula in Mexico and created the > 106-mile-diameter > Chicxulub Crater. Most scientists now believe that a global > climate > change caused by this asteroid impact may have led to the > dinosaur > extinction. Seventy-four million years ago, a smaller > one-mile-wide > asteroid struck in central Iowa, creating the Manson > Crater. Now covered > with soil, it is the largest crater in North America at > more than 23 > miles across. > > Just 100 years ago, June 30, 1908, an asteroid or comet > estimated at > 100-200 feet in diameter exploded in the skies above > Tunguska, Siberia. > Known as the Tunguska Event, the explosion flattened trees > and killed > other vegetation over a 500,000-acre area. But if the > explosion had > occurred four hours later, it would have destroyed St. > Petersburg or > Moscow with an equivalent energy level of about 500 > Hiroshima nuclear bombs. > > The potential for such devastation has astronomers scanning > the skies to > find and track asteroids that pose a danger, and it has Wie > initiating > this concerted research effort now before any asteroids are > discovered > heading toward Earth. > > Last November, NASA reported 900 known potentially > hazardous objects > (PHOs), most of which are asteroids. PHOs are defined as > objects larger > than 492 feet in diameter whose trajectories bring them to > within about > 4.6 million miles of the Earth's orbit. NASA scientists > estimate the > total population of PHOs to be around 20,000. > "However," Wie said, "the > asteroid we have to worry about is the asteroid that we > don't know." > > "Developing technologies that can be used to prevent > or mitigate threats > from asteroids while also advancing space exploration is a > challenge we > accept as we work to assure a high quality of life for > future > generations," said Mark J. Kushner, dean of Iowa > State's College of > Engineering. "This research center serves as an > excellent opportunity to > provide leadership on an issue that has worldwide > implications." > > According to Tom Shih, professor and chair of aerospace > engineering, > "the potential for a major catastrophe created by an > asteroid impacting > Earth is very real. It is a matter of when, and humankind > must be > prepared for it. Our aerospace engineering department > strongly supports > Professor Bong Wie's effort in establishing this center > to address the > engineering and science issues of asteroid > deflection." > > Both high-energy nuclear explosions and low-energy > non-nuclear > alternatives will be studied as deflection techniques. The > nuclear > approach, which is often assessed to be 10-100 times more > effective than > non-nuclear approaches as stated in NASA's 2007 report > to Congress, will > be researched to verify its effectiveness and determine its > practical > viability, according to Wie. > > "A 20-meter (66 feet) standoff distance is often > mentioned in the > literature for a maximum velocity change of a 1-kilometer > (0.6 mile) > asteroid. However, we have to determine how close the > nuclear explosion > must be to effectively change the orbital trajectories of > asteroids of > different types, sizes, and shapes," Wie explained. > "We will develop > high-fidelity physical models to reliably predict the > velocity change > and fragmentation caused by a nuclear standoff > explosion." > > The non-nuclear alternatives include kinetic impactors and > slow-pull > gravity tractors. Wie, who has previously worked on solar > sail > technology as applied to asteroid deflection, will present > his recent > study, "Multiple gravity tractors in halo orbits for > towing a target > asteroid," at the American Institute of Aeronautics > and Astronautics > Astrodynamics Specialists Conference in August. His paper > has been > accepted for publication in the AIAA Journal of Guidance, > Control, and > Dynamics. > > The chances of having to use deflection technologies on an > asteroid in > the near future are admittedly remote. Scientists estimate > the frequency > of an extinction-class (6 miles in diameter or larger) > object striking > Earth as once every 50-100 million years, and for a > 200-foot or larger > object as once every 100-500 years. > > The technologies that will be developed, including > precision orbital > guidance and navigation and control, however, have other > applications as > well. These may include future advanced space vehicles that > will carry > astronauts to an asteroid or Mars and homeland security > applications. > ______________________________________________ > http://www.meteoritecentral.com > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ http://www.meteoritecentral.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
