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Direct Push

Direct push solves


Schweickart ‘4 (Russell, Chair of the B612 Foundation, former astronaut, Executive Vice President of CTA Commercial Systems, Inc. and Director of Low Earth Orbit (LEO) Systems and research, and scientist at the Experimental Astronomy Laboratory of the Massachusetts Institute of Technology (MIT), “Asteroid Deflection; Hopes and Fears,” Aug., Presented at the World Federation of Scientists Workshop on Planetary Emergencies, Erice, Sicily, August 2004 http://www.b612foundation.org/papers/Asteroid_Deflection.doc)

Finally there is the concept of the direct push, most fully championed by the B612 Foundation, for which I serve as Chairman of the Board. The idea for the Foundation emerged from an October 2001 meeting of NEA-fluent astronomers, engineers and astronauts who decided to explore the possibility of seriously initiating work on NEA deflection. Our choice to develop the direct soft push concept was driven primarily by two considerations; our sense that a demonstration of capability should be demonstrated within the next 20 years (given the anticipated public policy demand), and the fact that there were several cost-effective key technologies that were developing rapidly. The concept, simply stated, is to land on an asteroid, and using the power and propulsion systems used to get there, control the spin axis of the asteroid and directly push on the surface of the asteroid to accelerate it in the desired direction. While the challenge of performing such an operation on a 1 km asteroid would be out of reach for decades we realized that with advanced nuclear electric power systems and plasma propulsion systems operating in the laboratory today, that a demonstration mission to a 200 meter diameter asteroid could be accomplished in a bit over a decade. With a space qualified nuclear electric reactor of about 1 megawatt and a plasma propulsion system which could generate 2.5 newtons with an exhaust velocity of 100,000 meters/sec a representative demonstration of asteroid deflection could be made by 2015. We therefore established the B612 goal to significantly alter the orbit of an asteroid, in a controlled manner, by 2015. After working through several mission designs, primarily addressing the challenge of thrusting continuously in the desired direction (given a rotating asteroid), we settled on an elegant mission design that first torques the spin axis of the rotating asteroid to a desired angle with respect to the orbit plane and then pushes directly parallel to the instantaneous velocity vector until the desired change in velocity is achieved. This demonstration mission design was presented in a recent Scientific American article. This rather ambitious agenda is surprisingly straight forward, but for one significant challenge, and that is the great unknown of how to attach the spacecraft (or anything) to the surface of an asteroid. In particular, while the spacecraft axis would be oriented vertically with the engine pointing radially outward, the engine would have to continuously thrust off the vertical axis to enable the necessary control of the asteroid spin axis. To achieve this capability the spacecraft would have to have lateral support in order to maintain its vertical position while thrusting at as much as 90 degrees off the vertical. While several concepts for providing such stabilization exist, none will become viable until we can visit one or more asteroids to understand better the near-surface structural characteristics of these bodies. Within several months after identifying the performance needed to accomplish the B612 demonstration mission NASA announced the formation of its Prometheus program targeted to develop and demonstrate the very same power and propulsion technologies that we had integrated into our design. In another few months NASA defined its first Prometheus mission utilizing these powerful new capabilities, a mission to orbit the icy moons of Jupiter (JIMO). At this point it became clear to us that we could quite easily adapt our preliminary mission design to utilize the specific power and propulsion systems which would be developed by NASA for the JIMO mission. Our task had then shifted quite dramatically to “convincing” NASA that one of its immediate follow-on Prometheus missions should be the B612 mission to a near Earth asteroid. Our efforts to convince NASA to adopt this goal have included both popular and technical papers defining the mission and designing specific techniques for various mission operations, the production of several commercial TV films supporting the mission rationale, participation in various international meetings on the subject of threat assessment and asteroid deflection, and testimony before the US Senate, the National Academy of Sciences, and others. To date NASA has shown polite interest but nothing more.

Solvency – Screw Rockets / Mass Driver




Screw rockets solve


Merali ‘7 (Zeeya, phd in physics, New Scientist, “"Screw rockets" could save Earth from asteroid catastrophe;” 8-11, lexis)

WE'VE been told to nuke 'em, tug 'em and even paint 'em. But burrowing into killer asteroids on a collision course with Earth might be the best way to deflect them. In 2029, the asteroid Apophis will pass near Earth, and our planet's gravity may then put it on collision course for when it comes back round in 2036. Although the chance of an impact is only 1 in 45,000, developing methods to save us from such near-Earth asteroids (NEAs) is vital, and current proposals simply aren't up to the job, says Daniele Fargion of the University of Rome La Sapienza, Italy. Proposals for deflecting NEAs have included blasting them with nuclear explosives, tugging them with nuclear-powered spacecraft or painting them white on one side so that reflected solar energy will nudge the asteroid off course. Blowing up the asteroid could leave vast fragments still Earthbound, however, and tugging and painting can only push the asteroid a few kilometres off course, says Fargion. He proposes an alternative, inspired by the way rockets are propelled forward as they eject mass when burning fuel. He suggests dropping nuclear-powered rockets, each tipped with a screw-shaped drill, onto the asteroid from a mother ship. After latching onto the asteroid's surface - not easy in almost zero gravity - each "screw rocket" will drill deep into the asteroid, projecting the rocky spoil behind it into space at high speed and pushing the asteroid off course. Fargion's calculations show that over 10 years, screw rockets could deflect a 1-cubic-kilometre asteroid by 30,000 kilometres. "Instead of carrying huge amounts of fuel from Earth to propel the asteroid this large distance, we simply exploit the asteroid's own material," he says.


Drilling techniques solve


Telegraph, 07

Rather than Hollywood's preferred option, engineers are trying to develop unmanned rockets that can land on space rocks and use the asteroids' own material to propel them into a safer orbit. The plan will be detailed at a conference, sponsored by Nasa next month, at which its scientists will reveal their -estimate that 100,000 asteroids orbiting near Earth are large enough to destroy a city. So far the agency has only been able to identify and track 4,000 of them. Just one football pitch-sized asteroid smashing into the planet would create destruction on a terrifying scale, wiping out any area it hit, sending flaming debris into the atmosphere and causing tidal waves. Scientists claim that it is only a matter of time before one is found on a collision course. Research to be unveiled at the three-day Planetary Defence Conference in Washington DC will reveal that defending the Earth may not be as simple as suggested by films such as Armageddon in which Bruce Willis's character destroys a giant asteroid using a nuclear bomb. Gianmarco Radice of Glasgow University will be one of more than 200 scientists at the conference. He said: "A nuclear blast may cause it to fragment. So instead of having one large object on an impact course, you have five largish objects. "Also, we do not know a huge amount about the composition of these asteroids. Some are made of rock, others are ice while others are just piles of rubble. If you smash something into a pile of rubble, it will just break up and then reform by gravity." Nasa has already tested the approach by smashing a spacecraft into an asteroid in its Deep Impact mission last year. The European Space Agency is planning a similar test, sending a craft to smash into a 500-yard wide asteroid while another spacecraft -monitors the results. Now an engineering firm in Atlanta, Georgia, has been commissioned by Nasa to develop a new kind of mission to land on an asteroid, drill through the surface and pump the debris into space. Anchoring several unmanned spacecraft, nicknamed Madmen, to an asteroid and ejecting material, would produce enough force in the opposite direction to push an asteroid slowly off its dangerous course. "It is like throwing rocks out of a rowing boat on a lake. The rocks go in one direction and the boat is slowly pushed in the other under the laws of physics," said John Olds, the chief executive of SpaceWorks, the firm behind the scheme. "Over several months we think we can make the difference between a hit and a miss."



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