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Archive for the ‘asteroid/comet impacts’ category: Page 12

Oct 9, 2007

Inflatable Mirrors on spacecraft would move asteroids fastest

Posted by in categories: asteroid/comet impacts, defense, existential risks, lifeboat, space

New Scientist reports on a new study by researchers led by Massimiliano Vasile of the University of Glasgow in Scotland have compared nine of the many methods proposed to ward off such objects, including blasting them with nuclear explosions.

The team assessed the methods according to three performance criteria: the amount of change each method would make to the asteroid’s orbit, the amount of warning time needed and the mass of the spacecraft needed for the mission.

The method that came out on top was a swarm of mirror-carrying spacecraft. The spacecraft would be launched from Earth to hover near the asteroid and concentrate sunlight onto a point on the asteroid’s surface.

In this way, they would heat the asteroid’s surface to more than 2100° C, enough to start vaporising it. As the gases spewed from the asteroid, they would create a small thrust in the opposite direction, altering the asteroid’s orbit.

Continue reading “Inflatable Mirrors on spacecraft would move asteroids fastest” »

Aug 6, 2007

NASA designs nuclear asteroid deflector

Posted by in categories: asteroid/comet impacts, existential risks, lifeboat, space

NASA’s Marshall Space Flight Center has designed a nuclear-warhead-carrying spacecraft, that would be boosted by the US agency’s proposed Ares V cargo launch vehicle, to deflect asteroids.

The Ares V launch vehicle is scheduled to first fly in 2018. It would launch 130 tons to LEO.

I welcome this study for providing a clearer analysis of the deflection options and the analyzing costs of searching for threatening asteroids.

The 8.9m (29ft)-long “Cradle” spacecraft would carry six 1,500kg (3,300lb) missile-like interceptor vehicles that would carry one 1.2MT B83 nuclear warhead each, with a total mass of 11,035kg.

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Mar 27, 2007

China, Indonesia, India, Japan and the US most vulnerable to asteroids

Posted by in categories: asteroid/comet impacts, defense, existential risks, lifeboat, space

Using maps of population density, the researchers charted the places likely to suffer the most casualties from asteroids. As might be expected, countries with large coastal populations turned out to be most vulnerable, with China, Indonesia, India, Japan and the US in the top five spots.

The team focused on smaller asteroids because they hit the Earth more frequently. An asteroid a few hundred metres across hits the planet about once every 10,000 years, on average, while those larger than 1 kilometre hit only every 100,000 years or so. Small asteroids are also harder to spot. They considered a range of impact energies corresponding to asteroids between 100 and 500 metres across, striking with typical solar system speeds of about 20,000 kilometres per second.


Simulations show the asteroid impact locations that would produce the most casualties in red. The Pacific coast of Asia is a particularly deadly place for an asteroid to strike because of tsunamis, while a direct strike on some densely populated inland areas could also cause a heavy toll (Illustration: Nick Bailey et al/University of Southampton)

The US faced the worst potential economic losses, since it has a lot of infrastructure on coastlines facing two different oceans. China was second, followed by Sweden, Canada, and Japan.

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Mar 5, 2007

United States unwilling to spend $300 million for asteroid location

Posted by in categories: asteroid/comet impacts, defense, existential risks, lifeboat, space

NASA estimates the cost to find at least 90 percent of the 20,000 potentially hazardous asteroids and comets by 2020 would be about $1 billion, according to a report NASA will release later this week. It would cost $300 million if a asteroid locating telescope was piggybacked on another vehicle. The report was previewed Monday at a Planetary Defense Conference in Washington.

The agency is already tracking bigger objects, at least 3,300 feet in diameter, that could wipe out most life on Earth, much like what is theorized to have happened to dinosaurs 65 million years ago. But even that search, which has spotted 769 asteroids and comets — none of which is on course to hit Earth — is behind schedule. It’s supposed to be complete by the end of next year.

A cheaper option would be to simply piggyback on other agencies’ telescopes, a cost of about $300 million, also rejected, Johnson said.

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Feb 28, 2007

Lasers to detect and deflect asteroids

Posted by in categories: asteroid/comet impacts, defense, existential risks, lifeboat, space

Graduate student (University of Alabama Huntsville) Blake Anderton wrote his master’s thesis on “Application of Mode-locked lasers to asteroid characterization and mitigation.” Undergraduate Gordon Aiken won a prize at a recent student conference for his poster and presentation “Space positioned LIDAR system for characterization and mitigation of Near Earth Objects.” And members of the group are building a laser system “that is the grandfather of the laser that will push the asteroids,” Fork said.

Anderton’s mode locked lasers could characterize asteroids up to 1 AU away (1.5 x 10 to the 11 meters). Arecibo and other radar observatories can only detect objects up to 0.1 AU away, so in theory a laser would represent a vast improvement over radar.

A one page powerpoint describes their asteroid detection and deflection approach About 12 of the 1AU detection volumes (around the sun in the asteroid belt) would be needed to cover the main areas for near earth asteroids.

40KW femtosecond lasers could deflect an asteroid the size of Apophis (320meters, would hit with 880 megaton force) given one year of illumination and an early start in the trajectory.

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Feb 18, 2007

Asteroid shield related: deflection mission and other proposals

Posted by in categories: asteroid/comet impacts, existential risks, lifeboat, space

A giant asteroid named Apophis has a one in 45,000 chance of hitting the Earth in 2036. If it did hit the earth it could destroy a city or a region. A slate of new proposals for addressing the asteroid menace was presented today at a recent meeting of the American Association for the Advancement of Science in San Francisco.

One of the Lifeboat Foundation projects is an Asteroid Shield and the issues and points discussed are in direct alignment with Lifeboat. The specific detection and deflection projects are in the Lifeboat Asteroid Shield project.

Edward Lu of NASA has proposed “gravitational tractor” is a spacecraft—up to 20 tons (18 metric tons)—that it could divert an asteroid’s path just by thrusting its engines in a specific direction while in the asteroid’s vicinity.

Scientists also described two massive new survey-telescope projects to detect would-be killer asteroids.

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Jan 23, 2007

AsteroidShield related news

Posted by in categories: asteroid/comet impacts, lifeboat, space

The New Scientist also has an article about how exploding robots could be sent to determine the composition of Near Earth Asteroids. This would be relevant in developing a proper Asteroid shield. A current project is the Lifeboat AsteroidShield

An illustration from Ball Aerospace and New Scientist.

The Ball Aerospace proposal of many small probes seems cost efficient and worthy of being advocated by the Lifeboat Foundation.

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