The service branch awarded in August 2017 approximately $678 million in combined contracts to Boeing and Northrop to perform technology maturation and risk reduction work on the GBSD program.
GBSD is designed to replace the Minuteman III ICBM system and is expected to cost approximately $100 billion over the next 10 years.
The companies expect the Air Force to assess GBSD design concepts in 2019 and make a concept selection by 2020.
The report noted that Orbital ATK supports both companies on the GBSD propulsion system work.
Carol Erikson, GBSD vice president at Northrop's aerospace systems business, said Aerojet Rocketdyne and Orbital ATK are both members of the firm's GBSD team.
Northrop agreed to acquire Orbital ATK for approximately $9.2 billion in September 2017 and expects to close the transaction in the first half of 2018.