NASA Issues RFP For Second Mobile Launch Platform Written 6 July 2018

Space News reports that NASA has called for proposals to construct a “second mobile launch platform that will be used by an upgraded version of the Space Launch System [SLS] rocket starting in the early 2020s.” The NASA solicitation was issued June 29 for Mobile Launcher 2 (ML2), which will go through a “two-step process, starting with a request for qualifications due at the end of July.” NASA plans to ask up to five companies from that phase to “submit full-fledged proposals, due in November.” NASA describes ML2 as “similar in nature to and concept of operations to the existing mobile launch platform.” The new launcher will be built for the SLS Block 1B rocket, and is also “intended to support future versions of the SLS.” NASA expects to award an ML2 contract in February 2019, with completion planned by late 2022. The first launch of the “Block 1B version of the SLS would thus not take place until after that, likely 2023.” 
More Info (Space News)