English: Minuteman missile combat crew on alert. Typically, a two-person missile combat crew is on alert in an underground launch control center for 24 hours at a time monitoring their ICBMs, ready to launch them if directed. Under a test being conducted by 20th Air Force officials, three-person crews are going to pull 72-hour alerts at select facilities to weigh the advantages of going to such a schedule. Officials from 20th Air Force will evaluate the test after three months to determine whether to implement the initiative across the entire missile force.