In 2016, the US Congress authorized the USAF to co-finance the development of new launch vehicles. The revised contracting structure fits with the USAF’s broader goal of getting out of the business of ‘buying rockets’ and moving to instead acquire launch services from companies. Initial cost-sharing partnerships were signed with United Launch Alliance (ULA), SpaceX, Orbital ATK, and Aerojet Rocketdyne. The USAF would initially like to move to having two domestic launch service providers, instead of being reliant on ULA. As of March 2018[update], the Air Force intended to select three companies by mid-year 2018 so that the Space and Missile Systems Center could contract for launch system prototypes.