Posted on 01/23/2007 8:52:26 PM PST by John W
HONOLULU - NASA astronaut and former University of Hawaii solar physicist Edward Lu is calling for a new spacecraft that would divert asteroids on a path to slam into Earth.
The small space tractor, costing between $200 million and $300 million, would hover near an asteroid to exert enough gravitational pull that the space rock's orbit would change and a collision with our planet would be averted, Lu said before a crowd packed into a 300-capacity auditorium at the University of Hawaii-Manoa Monday night.
"We're only trying to get a really tiny change in the velocity of the asteroid to prevent an impact," he said.
Lu was part of a panel including three Hawaii scientists who characterized the chances of an asteroid colliding with Earth as rare but deserving of the same level of attention as major earthquakes, tsunamis and hurricanes.
A report on the appearance appeared on the Honolulu Star-Bulletin Web site on Tuesday.
The asteroid Apophis will pass within about 20,000 miles of Earth on Friday, April 13, 2029.
"It's going to come so close to the Earth in 2029 that its orbit will change and it might change enough so that it comes back and hits us in 2036," said Hawaii planetary astronomer David Tholen, who discovered Apophis.
During the asteroid's next close pass to the sun in 2013 that risk will be assessed in radar surveys, he said.
Objects the size of a grain of sand frequently hit the Earth's atmosphere, appearing as shooting stars in the night sky. But a larger impact could be devastating. Asteroids are blamed for the death of the dinosaurs 65 million years ago and an explosion over Tunguska, Russia, in 1908 that wiped out 60 million trees over a 830-square-mile area.
According to a presentation by university astronomer Robert Jedicke, a Tunguska-size explosion would be able to blast or burn nearly all of Oahu.
Because the devastation would be great, the risk to a person of perishing in a major asteroid collision is about 1 in 10,000 or 20,000 over a 100-year lifetime - the same dying in a plane crash, Jedicke said.
The University of Hawaii's Pan-STARRS program would train four powerful digital cameras toward the heavens to watch for would-be intruders.
Officials from the project are hoping to garner public support of a plan to locate on Mauna Kea. The telescopes also could be built at two sites on Haleakala, where a prototype is being built, but scientists warn the project would take twice as long to complete there.
Environmentalists and Hawaiian activists have argued against additional development on Mauna Kea and some scientists have expressed concern about additional construction as the volcano already hosts 13 telescopes.
The program would be able to provide decades of warning of an impending impact, the scientists said.
That would be enough time to launch a tractor spacecraft to knock the asteroid into a safe orbit, said Lu, who spent six month aboard the International Space Station in 2003 and was a postdoctoral fellow at the University of Hawaii's astronomy institute from 1992 to 1995.
To do nothing would be to invite disaster, he said.
"If we are wiped out by an asteroid, that will be our own fault at this point," he said.
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On the Net:
University of Hawaii's Pan-STARRS program: http://pan-starrs.ifa.hawaii.edu/public/
I'd like to develop space factories which land on asteroids and process them into something useful. With a long enough lead time, why just move things around?
You would need space docking and refueling. What would the propulsion system be? It would need to catch asteroids early enough that small changes in their orbits would translate to clean misses of earth. You can't do that in low earth orbit!
But just think of what it would mean to have a craft that could flit around the inner solar system with enough power to nudge asteroids! Just that technology alone could open up space travel!
Gravitational pull is determined by mass and distance. Distanc eisn't much of a problem but you're going to have to have a lot of mass to get the asteroid moved in time unless we can get far away from Earth to alter it's pass before it gets close.
Seems unrealistic but a novel idea anyways.
A tractor of that magnitude would have to have a LOT of mass to make enough of a difference. Ping for later research
Comes with previous crash experience.
The gravity tractor method is feasible if the threatening asteroid is detected early enough and at a sufficient distance from Earth. Based on calculations, it’s theorized that a 20 ton spacecraft could sufficiently deflect a typical 200 meter in diameter asteroid if given a lead time of 20 years. Deflecting a larger asteroid would require a spacecraft of greater mass or more lead time.
Whatever methods are employed to divert the trajectory of asteroids, early detection and better understanding of the objects are critical. That’s why there is great interest in funding increased efforts to explore known Near-Earth Orbit objects and search for presently undetected NEO objects.
Space barge!
I'm catching on here.
Now I think I know where they get polaroids.
http://www.space.com/news/051103_asteroid_apophis.html
More info.....
Asteroid 99942 Apophis – first labeled as 2004 MN4 -- is estimated to be roughly 1,000 feet (320 meters) in diameter. Were it to strike Earth, it would not set off global havoc but would generate significant local or regional damage, experts say.
However
The ruin stemming from asteroid Apophis colliding with Earth would potentially be very great.
Indeed, the consequences, Schweickart suggested, would dwarf those seen as a result of the Indian Ocean tsunami in December 2004, hurricanes Katrina and Rita in September of this year, and the Pakistan earthquake last month.
The gravity tractor method is feasible if the threatening asteroid is detected early enough and at a sufficient distance from Earth. Based on calculations, it’s theorized that a 20 ton spacecraft could sufficiently deflect a typical 200 meter in diameter asteroid if given a lead time of 20 years. Deflecting a larger asteroid would require a spacecraft of greater mass or more lead time.
Whatever methods are employed to divert the trajectory of asteroids, early detection and better understanding of the objects are critical. That’s why there is great interest in funding increased efforts to explore known Near-Earth Orbit objects and search for presently undetected NEO objects.
That's kind of what I suspected.
We currently have nothing with the power to move large asteroids a sufficient distance anywhere near the earth, and no propulsion systems which could get way out (say, orbit of Mars) to take the long slow approach.
I think the price estimate of a few hundreds of millions of dollars are realistic for startup costs rather than hardware in orbit.
Moving a 200 meter diameter asteroid is a major effort unless its done millions of miles out. Even then you would need a craft that could accelerate to the asteroid, slow down and reverse course to match orbit, and then effect a change in the asteroid's orbit. And after that, hopefully slow down enough to return to earth at less than asteroid speeds.
I don't think we have the propulsion systems for this yet. And I don't think we are going to develop and launch it for a few hundred million dollars.
But we should be working on such a system whatever the cost. A craft that could do that could do a lot of other important things as well.
Hmmmm...I hadn't thought about up-time of the spacecraft. Twenty years is a long time to keep something running continuously with no maintenance in a very hostile environment.
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And we'll just tx the crap out of people to pay for these dumb idea's, right? Of course, we'll need Al- Gore to make a "documentry" a few years in advance to sell the idea, cause a panic, and get the sheeple to wllingly give you their money.
cant we just build a really cool laser? it would be more fun.
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