Use an interceptor which separates into two parts.
The first part is 10 meter ahead and makes a crater.
The nuclear bomb part follows but is 20 times more effective by blowing up in the crater.
The fragmentation would reduce the impact to about 0.1% of non-fragmented asteroid.
Earth would pass through the fragment cloud.
The assembled interceptor rocket(s) needs to be fully assembled and waiting to launch.
Nextbigfuture – Skybox was founded out of the CubeSat community and they are ardent believers in the power of commodity, commercial electronics to change the cost of doing business in space. Traditional satellites capable of taking imagery at better than 1 meter resolution weigh thousands of kilograms, which makes it prohibitively expensive to launch enough of them to capture timely imagery. They have produced similar performance in a box 20x smaller by breaking open the many black boxes that define traditional systems and creating an optimized design using automotive grade electronics.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
Known for identifying cutting edge technologies, he is currently a Co-Founder of a startup and fundraiser for high potential early-stage companies. He is the Head of Research for Allocations for deep technology investments and an Angel Investor at Space Angels.
A frequent speaker at corporations, he has been a TEDx speaker, a Singularity University speaker and guest at numerous interviews for radio and podcasts. He is open to public speaking and advising engagements.