From The Daily Beast:

Thirty years after Vietnam, the Pentagon again found itself fighting elusive insurgents in Afghanistan, Iraq and other war zones. It again turned to the OV-10 for help. In 2011, Central Command and Special Operations Command borrowed two former Marine Corps Broncos—from NASA or the State Department, apparently—and fitted them with new radios and weapons.

The OV-10s’ deployment is one of the latest examples of a remarkable phenomenon. The United States—and, to a lesser extent, Russia—has seized the opportunity afforded it by the aerial free-for-all over Iraq and Syria and other war zones to conduct live combat trials with new and upgraded warplanes, testing out the aircraft in potentially deadly conditions before committing to expensive manufacturing programs.