Several high-profile weapon systems will be decided by the next Pentagon chief but one to modernize Cold War-era firepower may already be in trouble.
Retired Marine Corps Gen. James Mattis, President-elect Donald Trump's choice to become Defense secretary, expressed concern last year about the Air Force's ground-based Minuteman III, one leg of the nation's nuclear triad. Several of the major defense contractors are contenders to replace the aging Minuteman III with a next-generation missile technology.
"Is it time to reduce the triad to a diad, removing the land‐based missiles," the retired four-star general told the Senate Armed Services Committee last year. "This would reduce the false alarm danger."
In July, the Air Force requested proposals to replace the silo-based Minuteman III intercontinental ballistic missiles. The new ICBM program is formally known as the ground-based strategic deterrent and expected to cost up to $60 billion over 30 years.
Observers suggest Mattis could force the Pentagon to rethink the nuclear triad and other land-based missile systems. The three-leg nuclear deterrent has been a centerpiece of the nation's strategic defense since the 1960s.
"The wildcard here is that General Mattis has come in and said we could easily save a lot of money by getting rid of that ground-based element," said John Kenkel, a defense industry expert at PA Consulting Group. "So there could be some debate over the next five years on whether or not we want to move forward with that."
John Venable, an Air Force veteran and senior research fellow at the Heritage Foundation, said the nuclear triad to deliver nuclear weapons from land, sea and air remains critical to national security. "The people who came up with it wanted to make sure that we could survive a nuclear assault and still be able to bring a responding fire into the country that launched its attack."
The nation's biggest defense contractors, Boeing, Lockheed Martin and Northrop Grumman, are all competing for the ground-based missile program. The Air Force is expected to award up to two contracts for the program but the earlier comments by Mattis may add uncertainty.
Meantime, other Air Force programs that may find more support in the Trump administration include a replacement for the attack radar aircraft system known as JSTARS and the T-X trainer program, which is designed to provide advanced training to pilots.
JSTARS, which stands for joint surveillance target attack radar system, is a flying surveillance aircraft. The current JSTARS, a Northrop E-8C platform, was used in the 1991 Operation Desert Storm in Iraq and Kuwait.
Northrop, Boeing and Lockheed are in the running for the JSTARS replacement aircraft contract, and the Air Force is looking to procure 17 planes. Northrop's team includes Canada's Bombardier and Raytheon. There have been problems reported with some of the older planes, including loose bolts and other safety issues.
The final request for proposals on the replacement JSTARS are expected by early 2017.
At least four teams are competing for the roughly $10 billion contract for the T-X trainer jet program. Two bidding groups have international partners.
Trump has emphasized the importance of keeping jobs the U.S. but the T-X acquisition winner could end up doing some work overseas.
Under U.S. law, more than 50 percent of the cost of all the components in the military aircraft would need to be sourced from manufacturers in the U.S. to avoid going afoul of the Buy American Act. A person familiar with the T-X acquisition process said it is compliant with the Act.
Boeing and Sweden's Saab are paired together in the T-X competition, and Lockheed and Korean Aerospace Industries form another team. Raytheon and Italy's Alenia Aermacchi are also vying for the deal, while Northrop is linked with BAE Systems and L-3.
The trainer jet would replace the older T-38 that came online in the 1960s.
The Defense Department has an annual budget of around $600 billion. The Heritage Foundation think tank estimates the Pentagon would need $50 billion more to begin rebuilding. One major roadblock is that the Budget Control Act remains in place.
"The military needs to be able to unshackle itself and Congress is going to have to pass a law that kills the Budget Control Act," said Venable.
Given the tensions in the Republican caucus between defense hawks and fiscal hawks, there may not be much appetite in Congress to make bigger increases in defense spending.
"There may not be as much of an open wallet for every defense program as I think some people had anticipated," said Katherine Blakeley, a research fellow at the nonpartisan Center for Strategic and Budgetary Assessments.
Lockheed's F-35 fifth-generation fighter and Boeing's KC-46 Pegasus aerial tanker are also priorities as is Northrop's B-21 stealth bomber.
"The Air Force has the largest ramp-up in acquisition spending of the services in the 2020s," said Blakeley. "That's partly a function of all these programs happening at the same time."
The F-35 program alone is expected to cost up to $1.5 trillion by the end of the 55-year life of the program. The controversial program has gone through delays and tough development times, although industry experts believe it is safe, even with recent criticism from the president-elect about the program having "out of control" costs.
"We've got to apply the lessons learned from the F-35 acquisition program into the next program," said Venable. "It was a tough system to acquire because of the way Congress and the DoD levied the restrictions on how the services had to buy that jet."