Boeing and Northrop Grumman discussed proposed ideas with the Air Force last month as the service faces a 2019 deadline to specify requirements for the GBSD ground-based strategic deterrent.

WASHINGTON — Boeing and Northrop Grumman have presented design options to the U.S. Air Force for a new intercontinental ballistic missile. The companies are pitted in a head-to-head competition to build hundreds of ICBMs that will replace decades-old Minuteman 3 missiles.

Both firms recently discussed their proposed ideas with Air Force leaders as the service faces a 2019 deadline to specify requirements and map out a procurement strategy for the ground-based strategic deterrent, or GBSD.

The companies submitted what is known as “trade studies” to help the Air Force draft program requirements before it releases a final “request for proposals” possibly a year from now.

“We offered the Air Force cost and performance trades for a deterrent that will address emerging and future threats,” Frank McCall, vice president of Boeing Strategic Deterrence Systems, said on Friday in a news release.

Carol Erikson, Northrop Grumman vice president for the GBSD program, confirmed in an email to SpaceNews that the company also submitted trade studies.

“Last month, the Northrop Grumman team presented the Air Force with recommendations for defining the GBSD requirements,” Erikson said. “This key program milestone was the culmination of years of analysis aimed at helping the Air Force finalize its GBSD design.”

McCall said the Air Force as this stage of the program is looking for “opportunities for cost savings” and the studies submitted by the industry will help to set priorities.

Later this year the Air Force is scheduled to begin a “system functional review” that is required in major weapon acquisitions to ensure that goals set for the program can be met within the projected budget and schedule

An estimated $80 billion program, the GBSD is considered a “must win.” Either Boeing or Northrop Grumman, if selected, will own the U.S. strategic missile franchise for decades to come. The stakes also are high for engine suppliers. Each missile is powered by three solid-propellant rocket motors, and only two companies in the United States are able to produce these large rocket motors: Aerojet Rocketdyne and Northrop Grumman Innovation Systems (formerly Orbital ATK). Aerojet has warned the Air Force and Congress that it needs at least one third of GBSD solid rocket motors production work to remain a viable supplier.

GBSD is seen as a major test for the Defense Department, which has not designed a new ICBM since the early days of the Cold War. The Minuteman was conceived in the late 1950s and first deployed in the early 1960s. The Minuteman 3 was introduced in 1970. It has been modernized over time, and the Air Force concluded it needs to start replacing aging missiles in the 2020s for safety reasons and to ensure it has a modern system to counter Russia’s nuclear threat.

The current ICBM force consists of 450 Minuteman 3 missiles located at bases in Wyoming, Montana and North Dakota. The Air Force said it plans to acquire more than 650 missiles under the GBSD program.

After a three-way competition, the Air Force in August 2017 awarded a $349 million contract to Boeing and a $328 million contract to Northrop Grumman to mature the designs. If all goes as planned, competitors will present preliminary design reviews to the Air Force in 2020.