The terror attacks on New York and Washington on Sept. 11, 2001, changed the lives of all Americans — few more so than the millions who have participated in the two major wars that followed the attacks. For a few tens of thousands of Americans, the wars even created essentially brand-new careers by massively expanding demand for what were once obscure, niche fields. Drone pilot, ground-robot wrangler, bomb hunter and other military and civilian specialties ... these are the jobs that barely existed on Sept. 10, 2001.

In 2001, the U.S. military possessed just a few ground robots that it used...