Government

The U.S. Government has instituted a program at NASA called Near-Earth Objects Program or NEO. NASA has installed the Sentry automatic impact monitoring system. The Sentry system took 2 years to create and is a highly automated system for continuos updates of the orbits, future close approaches and impact probabilities for all NEOs. NEOs are usually meteors or pieces of comets. The Sentry system was built to be complementary to the NEODyS CLOMON impact monitoring system operated in Pisa, Italy. Personnel from both systems are constantly communicating with each other and cross checking each other's results. They provide constructive feedback to continuously improve the efficiency and accuracy of both systems. The Deep Impact space mission will crash a space vehicle into a comet in 2005 to provide information for engineers on destroying NEOs. The energy of the crash will generate the equivalent of 4.5 tons of TNT. The most important part of this mission is to see if we can hit a 3.5 mile wide area from millions of miles away.

British scientists are calling for something to be done to protect the earth from hits by objects from space. The Task Force on Near Earth Objects, appointed by science minister Lord Sainsbury, has produced a report which says the threat of an asteroid hit is real and the government should take action to prevent it. The report, wants an international effort to develop an asteroid early warning system involving British telescopes.

Scientists agree the elements needed for a successful plan to protect the earth from NEOs are:
1. The ability to conduct space flight activities
2. Super-explosives
3. Ways to transport enough energy into space to fend off a menacing object
4. NEO-spotting telescopes rigged with digital gear, coupled to speedy computers and specialized software

At the present time 200 meter or less NEOs are not detectable and bigger telescopes are needed.

So how can we protect ourselves if we spot an asteroid heading for us? We, as far as I know, have no official program to deflect or destroy an object heading for us. We do have some very accurate rockets however that can be fitted with nuclear warheads. This presents us with another problem however. If we did have a warhead powerful enough to shatter an object heading for earth, we would have to hit it just right to make sure the pieces didn't hit us with a shot gun effect. which might be worse than the initial hit. We would have to hit the object relatively far out if it was large to try and change its trajectory. At the right distance a couple of degrees could make all the difference. The US and Russia have proposed launching a mirrored aluminum sail that would track the asteroid's orbit. Sunlight would be focused to 2000 degrees centigrade and would be reflected onto the asteroid at a certain point. This would vaporize rock and ice causing a vapor jet which would deflect the asteroid from hitting the earth.

The US military has been experimenting with lasers for several years now and although the results are secret, we might have a laser powerful enough to move or shatter an object, but this is only speculation. Laser beams defocus when aimed thorough the atmosphere which makes using them from earth almost impossible.

Suggestions have been put forth that we develop a fleet of space vehicles all built around the same body to save on cost and if a NEO would threaten the earth we could launch many of them at the same time, thus giving us a better chance of either blowing up or nudging the NEO.

We suffered a near miss in on October 30, 2000 when a 600 meter NEA named Toutatis came within less than 1/2 degree from earth. NASA remained silent.