Apophis/2004 MN4/99942

An Asteroid known as 2004 MN4 or 99942 Apophis (from Egyptian God 'Apep/isfet' - an evil demon, the bringer of darkness and chaos) is scheduled to make several close orbits of the earth before either missing the earth or colliding with it. With each pass you will be able to see it fly around the earth from the naked eye, as will fly through the earth's atmosphere at 35,000 km above the surface (the moon is 360-405,000 km above the surface).

Governments and Corporations are working hard on defending the earth and have proposed several methods to resolve this asteroid threat. US researchers suggest either using a specially designed system called a gravitational tractor, which they will attach cables to the asteroid and pull it away. The next system uses six or more nuclear devices to blast the rock out of the way, though this is known to have some very serious problems with it. There is also a planned mission to land upon the asteroid and 'explore' it. The Europeans have come up with a system they like to call the 'Cheap Option'- In this method they propose impacting the asteroid and deploying a booster system to propel the asteroid out of harm's way. Each government uses different models on the size and mass of the Apophis.There are many unknowns such as the spin and composition, which is extremely important in any of these systems are to actually work. To make matters worse a German child was able to show that NASA really has not put any effort into figuring this out, by predicting that our own artificial satellites will likely cause the asteroid to be deflected into the earth.

"if the asteroid does collide with the planet, it will create a ball of iron and iridium 320m wide and weighing 200-billion tonnes, which will crash into the Atlantic Ocean. The shock waves from that would cause huge tsunami waves, destroying both coastlines and inland areas, while creating a thick cloud of dust that would darken the skies indefinitely."- NASA

The question comes down to how much you value your own survivability.
Do you trust others to care for you, or do you take responsibility for your own life?



Gravitational keyhole
A gravitational keyhole, or resonance keyhole, is a small region of space that if an asteroid were to pass through it, its course would be altered due to Earth's gravity in a way that could cause such an asteroid to collide with the Earth on its next orbital pass. See Also: 99942 Apophis

Orion Asteroid Mission
Land on the surface and look around
Wiki Orion

Nuclear Bombs
Based on its estimated mass of 2.11010 kg, its estimated radius of 125 m, and an assumption that it is spherical, the gravitational binding energy ( 3GmA2 /(5RA) ) of Apophis is 1.4108 J, and its escape velocity (v2GmA/RA ) is 0.15 m/s.

solution: six or more nuclear bombs(sat: payload) or gravitational tractor

Gravitational tractor
From Wikipedia, the free encyclopedia
"In asteroid deflection, a gravitational tractor is a way to use the gravitational attraction between a spaceship and an asteroid to modify its trajectory to prevent it from colliding with the Earth. In the plan, the spaceship hovers above the asteroid's surface using thrusters, and gravitational attraction deflects the asteroid. The thrusters must not point directly at the asteroid, else the effect would be voided by momentum transfer between exhaust gas and the asteroid's suface.

Writing in Nature, physicists Edward T. Lu and Stanley G. Love of NASA's Johnson Space Center show that a gravitational tractor is a reasonable proposition: it is robust to the asteroid's structure and rotation rate, and a technologically feasible plan (such as a 100 W nuclear electric propulsion system) could impart a delta v of a few millimeters per second to an asteroid with a diameter of 200 meters over the course of several years, sufficient to prevent an Earth impact.

Say we have an asteroid of 200m of diameter, assuming a density of 2.6 Kg/m^3, its mass will roughly be 1e10 Kg. The orbit of the asteroid is assumed to have a .7 eccentricity and a 3.7 AU semi-major axis. We start assessing the concept of attaching some engines to the asteroid."

The asteroid Apophis can be deflected by a lightweight Kinetic Impactor, before its 2029 passage. See Izzo D. et al., "Optimal Trajectories for the Impulsive Deflection of NEOs", Acta Astronautica, Vol. 59, No. 1-5, pp. 294-300, April 2006.

The Kinetic Impactor deflection concept is dynamically convenient with respect to long thrust duration strategies (land and push, gravity tractor). See Izzo D. et al., "Strategies for Near Earth Object Impact Hazard Mitigation", Paper AAS 05-147, Advances in the Astronautical Sciences, Volume 120 Part I., pp. 699-708, 2005.

"Cheap Option" Design Scenario
In the "Cheap Option", Vega, the future smallest European launcher, is used to place the spacecraft into a 300 km Low Earth Orbit (LEO) and then a Star 48 upper stage is then used to place Sancho onto a direct injection transfer to its target.

A simple chemical propulsion system is selected for the spacecraft in order to perform both the trajectory correction manoeuvres and to rendezvous with the asteroid upon arrival. Finally, a spacecraft design philosophy based on simplicity has also been adopted, leading to reduced complexity and cost.

The target selected for the "Cheap Option" mission scenario is the Amor Asteroid 2003 SM84 as it represents a good compromise in terms of size and distance from the Earth.

School boy corrects NASA
"A 13-year-old German schoolboy corrected Nasa's estimates on the chances of an asteroid colliding with the Earth, a German newspaper reported on Tuesday, after spotting the boffins had miscalculated.
If the asteroid strikes a satellite in 2029, that will change its trajectory and make it hit the Earth on its next orbit in 2036...
...Both Nasa and Marquardt agree that if the asteroid does collide with the planet, it will create a ball of iron and iridium 320m wide and weighing 200-billion tonnes, which will crash into the Atlantic Ocean. The shockwaves from that would cause huge tsunami waves, destroying both coastlines and inland areas, while creating a thick cloud of dust that would darken the skies indefinitely."

The actual Earth-Moon distance ranges from about 360,000 to 405, 000 kilometers, depending on the position in the Moon's orbit.

Papers and Media

American Institue of Aeronautics and Astronautics
Scenarios for Dealing with Apophis

Impact Risk

Radar Refinement (.pdf)
2004 Radar Echo
Radar Observations (.pdf)
Rotation Prediction (.mov)
Observations to be made
Impact Detection
Predicting the Earth encounters
Tidal disruptions

We predict that when Asteroid 2004 MN4 passes 5.61.4 Earth radii from Earth's center on April 13, 2029, terrestrial torques during the flyby will alter its spin state in a dramatic manner that will be observable using groundbased telescopes. Although the asteroid will most likely not undergo catastrophic disruption, it may be subject to localized failure across its surface and interior, providing a unique opportunity to measure otherwise inaccessible mechanical properties of an asteroid."
Abrupt alteration of Asteroid 2004 MN4's spin state during its 2029 Earth flyby

Other Papers
Head on Impact of NEAs (german)
Astroid Deflection (Chinese)
Current Problems of the asteroid hazard prevention (Russian)

If optical astrometry is obtained during 20082010, the best ground-based measurements (~0.2 arcsec standard errors) cannot provide enough new information to significantly change the trajectory estimate until 20112012..

Predicting Encounter

The current data-set does not permit reliable trajectory propagation to encounters later than 2029; this may not be possible until data from 2012-2013 are available.
Recent Radar Astrometry of Asteroid 2004 MN4