Why half of them to Huntsville?
Huntsville is home to the Redstone Arsenal, the center for U.S. Army missile development. It also houses the Tactical UAV Project Office, and NASA's Marshall Space Flight Center. There is also a large FBI presence already located there, including the Operations and Analytical Support Headquarters, the Terrorist Explosive Device Analytical Center (TEDAC), the Hazardous Device School, and the Tennessee Valley Regional Computer Forensics Lab (TVRCFL). According to Wikipedia, anyway.