Project Icarus by David S. F. Portree, Robot Explorers

Walter Baade used the 48-inch telescope at Palomar Observatory to capture humankind’s first image of asteroid 1566 Icarus 60 years ago (June 26, 1949). Icarus, it was soon found, is unusual because its elliptical orbit takes it from the inner edge of the Main Asteroid Belt beyond Mars’s orbit to well within Mercury’s orbit. Every 19 years Icarus and Earth pass within five million miles of each other at a relative velocity of about 18 miles per second. Baade detected Icarus during one of these close encounters.

MIT Professor Paul Sandorff taught the Interdepartmental Student Project in Systems Engineering in the Spring 1967 Term at Massachusetts Institute of Technology (MIT) in Boston. He noted that Icarus and Earth would pass each other at a distance of four million miles on June 19, 1968. He then asked his students to suppose that, instead of missing Earth on that date, Icarus would strike in the Atlantic Ocean east of Bermuda with the explosive force of 500,000 megatons of TNT. Debris flung into the atmosphere would cool the planet and a 100-foot wave would inundate MIT. Sandorff gave his class until May 27, 1967 to develop a plan for averting the catastrophe.

Full article here:

http://robotexplorers.blogspot.com/2009/07/project-icarus-1967.html