Gamera could save the world from an asteroid threat. Just ask Japanese monster movie fans.
Posted on 11/09/2005 4:09:21 PM PST by anymouse
An asteroid the size of two football fields could wipe out a large city or set off a series of tsunamis across the world. The threat of such an Earth-smashing asteroid has lead scientists to dream up several methods of defending the planet against such a catastrophe.
Solutions have ranged from pushing the asteroid with a spacecraft to mounting a thruster on its surface. But pushing it would require too much fuel and could break up the asteroid. Also, asteroids rotate, which could complicate the firing of a surface thruster.
Now, two NASA astronauts have presented a plan for an "asteroid tractor"--an unmanned, 20-ton spacecraft that uses the invisible bond of gravity to gently pull an asteroid into a new, non-threatening orbit.
"You can think of it like a big elastic band between the two pulling them together," said Edward Lu, who presents the concept for the spacecraft with fellow astronaut Stanley Love in the Nov. 10 issue of the journal Nature.
The tractor would hover above the surface of the asteroid, without touching it, and use gravity as a towline. If the spacecraft maintains a consistent distance between it and the asteroid, and always tows in the same direction, this method won't disturb the asteroid's rotation or composition.
Despite the urge to give the asteroid a hardy tug, the key to moving an asteroid with gravity is to be gentle. An asteroid is likely to be loosely packed material, so tugging on it too hard could break it into unmanageable pieces. Or, the force from the spacecraft's thrusters could break up the asteroid or stir up unwanted dust if fired too vigorously.
To make sure the thrusters couldn't break up the asteroid--or hinder the net towing force by pushing the asteroid away--Lu and Love angled the thrusters slightly away from the body of the spacecraft.
"The jets fire off to the side, not quite as efficient as firing straight down. It's like rowing forward by pushing off to the sides--it keeps you moving forward, but very slowly," Lu told SPACE.com. "It takes less than a pound of force--about what you need to hold up a cup of coffee."
In 2029, the 1,000-foot (320 meters) asteroid 99942 Apophis (2004 MN4) will whiz by Earth at a distance of about 18,600 miles (30,000 kilometers). That's about as close as many geosynchronous satellites. It will swing by the Earth again in either 2035 or 2036, and scientists predict it has a small chance of hitting the planet on this pass.
"The kind of spacecraft we've talked about could move an asteroid 650 feet (200 meters) across provided we have decades of advanced warning," Lu said. "That's not out of line with what you'd expect - we can predict the orbit of an asteroid decades in advance."
"You can think of it like a big elastic band between the two pulling them together," said Edward Lu, who presents the concept for the spacecraft with fellow astronaut Stanley Love in the Nov. 10 issue of the journal Nature.
You would think that astronauts would have a little firmer grasp of physics.
Unintended space humor ping. :)
Bob, is this you again?
"The kind of spacecraft we've talked about could move an asteroid 650 feet (200 meters) across provided we have decades of advanced warning,"
Who would want to spend decades on a tug?
Let's see. 20 tons versus 20 brazillion tons. Sure, that'll work.
Why don't we just teather Michael Moore to the asteroid with a rope?
Seems like it would take a whole lot more energy to keep the tractor in place than it would to simply move the asteroid itself.
Is it green? Does it have a John Deer sticker on it?
Gamera could save the world from an asteroid threat. Just ask Japanese monster movie fans.
Better yet, line up everyone's weird uncle and in unison pull their fingers.
or MST3K fans
To pull the asteroid toward the spacecraft and result in a net movement of the asteroid, it would have to be in the equivalent of a geosynchronous orbit. That is, it would have to hover above one spot, orbiting at the same rate that the asteroid rotates. If the spacecraft rotated faster, it would move around the asteroid, pull sometimes one way, sometimes another, and have no net effect on the asteroid's position.
Aren't these the same bozos who write speeches for Al Gore?
Most asteroids would be a lot like the comet they hit with Deep Impact. It would go a lot easier on earth to be hit with a fine dusting than with the whole thing coming down in a clump like Tunguska. Blow it up. That would take the biggest nuke bomb ever. The Russians would be pleased to get the contract.
."Look, it's the Asteroid !!"
Beats me.
Put the DemonKats in charge of it -- they want SOMETHING BIG to be chief mucky-mucks of ...
We (the citizens on earth) could all line up on one side or the other and cause the earths orbit to yee or haw or in an extreme case to yee-haw and possibly miss the asteroid.
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