Asteroid retrieval is costly and uninspiring, Lamar Smith Op-ed, The Hill
"The proposed asteroid retrieval mission would contribute very little to planetary defense efforts. The size of the target asteroid for this mission is only 7-10 meters in diameter, too small to cause any damage to Earth. Any insight gained by such a mission would have little relevance to protecting against larger "city-killer" asteroids. Congress directed NASA in 2005 to identify and track 90 percent of asteroids larger than 140 meters by 2020. Asteroids of this size are ones that could cause significant damage, and NASA still has work to do to accomplish this goal. Asteroids that are 7-10 meters simply disintegrate in our atmosphere."
Russian Meteor's Origin and Size Pinned Down, Space.com
"The asteroid was about 17 meters in diameter and weighed approximately 10,000 metric tons," Peter Brown, a physics professor at the University of Western Ontario in Canada, said in a statement. "It struck Earth's atmosphere at 40,000 mph and broke apart about 12 to 15 miles above Earth's surface. The energy of the resulting explosion exceeded 470 kilotons of TNT." That's 30 to 40 times more powerful than the atomic bomb the United States dropped on the Japanese city of Hiroshima during World War II. The Russian fireball likely produced the most powerful such space rock blast since a 130-foot (40 m) object exploded over Siberia in 1908, flattening 825 square miles (2,137 square km) of forest.