Officers with a finger on the trigger of the U.S. Air Force’s most powerful nuclear missiles are complaining of a wide array of morale-sapping pressures, according to internal emails obtained by the Associated Press.

The complaints shed fresh light on dissatisfactions roiling this critical arm of the Air Force, an undercurrent that has captured the attention of the service’s leaders.

Key themes among the complaints include working under “poor leadership” and being stuck in “dead-end careers” in nuclear weapons, one email said. The sentiments were expressed privately by members of the 91st Missile Wing at Minot Air Force Base, N.D, in an unpublished study for the Air Force. The complaints also said there was a need for more experienced missile officers, a less arduous work schedule and “leaders who will listen.”

Taken together, the complaints suggest sagging morale in arguably the most sensitive segment of the American military. The 91st at Minot operates 150 intercontinental ballistic missiles — one-third of the entire ICBM force. The missiles stand in underground silos on constant alert for launch within minutes of a presidential order.

In the nuclear missile business, morale is not a trivial matter. Mental state is treated as a vital sign — like physical health, criminal record and technical knowhow — that must be monitored to indicate whether an individual is fit to be trusted with weapons of such destructive power.

The question of morale at Minot coincides with trouble inside the ranks of the 91st. Last month, 17 launch crew members — representing about 10 percent of the launch crew force — were taken off duty for remedial training after a poor showing in a key portion of an inspection. That was based on an April 12 internal Air Force email that said the 91st suffered from “rot” within its ranks, including tolerance of weapons safety rules violations. Air Force leaders told Congress the problem was less about poor performance than about poor attitude.

Last week the Air Force said two additional launch officers at Minot had been sidelined, for a total of 19. An Air Force spokesman, Lt. Col. Ronald Watrous, said 10 of the 19 had completed the two-month process of regaining certification. Most of the rest are expected to do so by the end of this month.

The AP obtained a second internal Air Force email describing Minot morale issues at Minot that were hinted at broadly in the first email. Both notes were written by Lt. Col. Jay Folds, deputy commander of the unit in charge of the 91st’s three missile squadrons at Minot.

The second Folds email, dated March 21, said complaints were registered in a confidential study initiated by the Air Force’s most senior officer, Gen. Mark Welsh, who was considering “solutions to our problems.” The study was done between December 2012 and February 2013 by the Rand Corp., a federally funded think tank that Welsh enlisted to study workforce issues inside the three missile wings, including the one at Minot.

The email briefly summarized complaints at Minot; it did not refer to what people at the other two missile wings — at F.E. Warren Air Force Base, Wyo., and Malmstrom Air Force Base, Mont. — told the researchers.

The Air Force confirmed that Folds and his immediate superior, Col. Bryan Haderlie, are leaving their posts, but Watrous, spokesman for the Air Force Global Strike Command, said both are being moved in a “normal rotation.”